| 1. |
- Gronbaek, J. Kjaer, et al.
(författare)
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Postoperative speech impairment and cranial nerve deficits after secondary surgery of posterior fossa tumours in childhood : a prospective European multicentre study
- 2022
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Ingår i: Child's Nervous System. - : Springer Nature. - 0256-7040 .- 1433-0350. ; 38:4, s. 747-758
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Brain tumours constitute 25% of childhood neoplasms, and half of them are in the posterior fossa. Surgery is a fundamental component of therapy, because gross total resection is associated with a higher progression-free survival. Patients with residual tumour, progression of residual tumour or disease recurrence commonly require secondary surgery. We prospectively investigated the risk of postoperative speech impairment (POSI) and cranial nerve dysfunction (CND) following primary and secondary resection for posterior cranial fossa tumours. Methods In the Nordic-European study of the cerebellar mutism syndrome, we prospectively included children undergoing posterior fossa tumour resection or open biopsy in one of the 26 participating European centres. Neurological status was assessed preoperatively, and surgical details were noted post-operatively. Patients were followed up 2 weeks, 2 months and 1 year postoperatively. Here, we analyse the risk of postoperative speech impairment (POSI), defined as either mutism or reduced speech, and cranial nerve dysfunction (CND) following secondary, as compared to primary, surgery. Results We analysed 426 children undergoing primary and 78 undergoing secondary surgery between 2014 and 2020. The incidence of POSI was significantly lower after secondary (12%) compared with primary (28%, p = 0.0084) surgery. In a multivariate analysis adjusting for tumour histology, the odds ratio for developing POSI after secondary surgery was 0.23, compared with primary surgery (95% confidence interval: 0.08-0.65, p = 0.006). The frequency of postoperative CND did not differ significantly after primary vs. secondary surgery (p = 0.21). Conclusion Children have a lower risk of POSI after secondary than after primary surgery for posterior fossa tumours but remain at significant risk of both POSI and CND. The present findings should be taken in account when weighing risks and benefits of secondary surgery for posterior fossa tumours.
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| 2. |
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| 3. |
- Christiansen, H. H., et al.
(författare)
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The Thermal State of Permafrost in the Nordic Area during the International Polar Year 2007-2009
- 2010
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Ingår i: Permafrost and Periglacial Processes. - : Wiley. - 1099-1530 .- 1045-6740. ; 21:2, s. 156-181
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Tidskriftsartikel (refereegranskat)abstract
- This paper provides a snapshot of the permafrost thermal state in the Nordic area obtained during the International Polar Year (IPY) 2007-2009. Several intensive research campaigns were undertaken within a variety of projects in the Nordic countries to obtain this snapshot. We demonstrate for Scandinavia that both lowland permafrost in palsas and peat plateaus, and large areas of permafrost in the mountains are at temperatures close to 0 degrees C, which makes them sensitive to climatic changes. In Svalbard and northeast Greenland, and also in the highest parts of the mountains in the rest of the Nordic area, the permafrost is somewhat colder, but still only a few degrees below the freezing point. The observations presented from the network of boreholes, more than half of which were established during the IPY, provide an important baseline to assess how future predicted climatic changes may affect the permafrost thermal state in the Nordic area. Time series of active-layer thickness and permafrost temperature conditions in the Nordic area, which are generally only 10 years in length, show generally increasing active-layer depths and risings permafrost temperatures. Copyright (C) 2010 John Wiley & Sons, Ltd.
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| 4. |
- Das, Anirban, et al.
(författare)
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Combined immunotherapy improves outcome for replication repair deficient (RRD) high-grade glioma failing anti-PD1 monotherapy: A report from the International RRD Consortium.
- 2024
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Ingår i: Cancer discovery. - 2159-8290. ; 14:2, s. 258-273
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Tidskriftsartikel (refereegranskat)abstract
- Immune-checkpoint inhibition (ICI) is effective for replication-repair deficient, high-grade gliomas (RRD-HGG). Clinical/biologic impact of immune-directed approaches after failing ICI-monotherapy are unknown. We performed an international study on 75 patients treated with anti-PD1; 20 are progression-free (median follow-up: 3.7-years). After 2nd-progression/recurrence (n=55), continuing ICI-based salvage prolonged survival to 11.6-months (n=38; p<0.001), particularly for those with extreme mutation burden (p=0.03). Delayed, sustained responses were observed, associated with changes in mutational spectra and immune-microenvironment. Response to re-irradiation was explained by an absence of deleterious post-radiation indel signatures (ID8). Increased CTLA4-expression over time, and subsequent CTLA4-inhibition resulted in response/stable disease in 75%. RAS-MAPK-pathway inhibition led to reinvigoration of peripheral immune and radiological responses. Local (flare) and systemic immune adverse events were frequent (biallelic mismatch-repair deficiency > Lynch syndrome). We provide mechanistic rationale for the sustained benefit in RRD-HGG from immune-directed/ synergistic salvage therapies. Future approaches need to be tailored to patient and tumor biology.
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| 5. |
- Kilic Afsar, Özgun, et al.
(författare)
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OmniFiber : Integrated Fluidic Fiber Actuators for Weaving Movement based Interactions into the Fabric of Everyday Life'
- 2021
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Ingår i: UIST 2021 - Proceedings of the 34th Annual ACM Symposium on User Interface Software and Technology. - New York, NY, USA : Association for Computing Machinery (ACM). ; , s. 1010-1026
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Konferensbidrag (refereegranskat)abstract
- Fiber - a primitive yet ubiquitous form of material - intertwines with our bodies and surroundings, from constructing our fibrous muscles that enable our movement, to forming fabrics that intimately interface with our skin. In soft robotics and advanced materials science research, actuated fibers are gaining interest as thin, flexible materials that can morph in response to external stimuli. In this paper, we build on fluidic artificial muscles research to develop OmniFiber - a soft, line-based material system for designing movement-based interactions. We devised actuated thin (øouter < 1.8 mm) fluidic fibers with integrated soft sensors that exhibit perceivably strong forces, up to 19 N at 0.5 MPa, and a high speed of linear actuation peaking at 150mm/s. These allow to flexibly weave them into everyday tangible interactions; including on-body haptic devices for embodied learning, synchronized tangible interfaces for remote communication, and robotic crafting for expressivity. The design of such interactive capabilities is supported by OmniFiber's design space, accessible fabrication pipeline, and a fluidic I/O control system to bring omni-functional fluidic fibers to the HCI toolbox of interactive morphing materials.
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| 6. |
- Kropp, Heather, et al.
(författare)
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Shallow soils are warmer under trees and tall shrubs across Arctic and Boreal ecosystems
- 2021
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Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- Soils are warming as air temperatures rise across the Arctic and Boreal region concurrent with the expansion of tall-statured shrubs and trees in the tundra. Changes in vegetation structure and function are expected to alter soil thermal regimes, thereby modifying climate feedbacks related to permafrost thaw and carbon cycling. However, current understanding of vegetation impacts on soil temperature is limited to local or regional scales and lacks the generality necessary to predict soil warming and permafrost stability on a pan-Arctic scale. Here we synthesize shallow soil and air temperature observations with broad spatial and temporal coverage collected across 106 sites representing nine different vegetation types in the permafrost region. We showed ecosystems with tall-statured shrubs and trees (>40 cm) have warmer shallow soils than those with short-statured tundra vegetation when normalized to a constant air temperature. In tree and tall shrub vegetation types, cooler temperatures in the warm season do not lead to cooler mean annual soil temperature indicating that ground thermal regimes in the cold-season rather than the warm-season are most critical for predicting soil warming in ecosystems underlain by permafrost. Our results suggest that the expansion of tall shrubs and trees into tundra regions can amplify shallow soil warming, and could increase the potential for increased seasonal thaw depth and increase soil carbon cycling rates and lead to increased carbon dioxide loss and further permafrost thaw.
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| 7. |
- Lobo, D. N., et al.
(författare)
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Perioperative nutrition : Recommendations from the ESPEN expert group
- 2020
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Ingår i: Clinical Nutrition. - : Churchill Livingstone. - 0261-5614 .- 1532-1983. ; 39:11, s. 3211-3227
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Forskningsöversikt (refereegranskat)abstract
- Background & aims: Malnutrition has been recognized as a major risk factor for adverse postoperative outcomes. The ESPEN Symposium on perioperative nutrition was held in Nottingham, UK, on 14–15 October 2018 and the aims of this document were to highlight the scientific basis for the nutritional and metabolic management of surgical patients. Methods: This paper represents the opinion of experts in this multidisciplinary field and those of a patient and caregiver, based on current evidence. It highlights the current state of the art. Results: Surgical patients may present with varying degrees of malnutrition, sarcopenia, cachexia, obesity and myosteatosis. Preoperative optimization can help improve outcomes. Perioperative fluid therapy should aim at keeping the patient in as near zero fluid and electrolyte balance as possible. Similarly, glycemic control is especially important in those patients with poorly controlled diabetes, with a stepwise increase in the risk of infectious complications and mortality per increasing HbA1c. Immobilization can induce a decline in basal energy expenditure, reduced insulin sensitivity, anabolic resistance to protein nutrition and muscle strength, all of which impair clinical outcomes. There is a role for pharmaconutrition, pre-, pro- and syn-biotics, with the evidence being stronger in those undergoing surgery for gastrointestinal cancer.Conclusions: Nutritional assessment of the surgical patient together with the appropriate interventions to restore the energy deficit, avoid weight loss, preserve the gut microbiome and improve functional performance are all necessary components of the nutritional, metabolic and functional conditioning of the surgical patient.
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| 8. |
- Persson, K., et al.
(författare)
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Preoperative word-finding difficulties in children with posterior fossa tumours : a European cross-sectional study
- 2024
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Ingår i: Child's Nervous System. - 0256-7040 .- 1433-0350. ; 40:1, s. 87-97
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Posterior fossa tumour surgery in children entails a high risk for severe speech and language impairments, but few studies have investigated the effect of the tumour on language prior to surgery. The current crosslinguistic study addresses this gap. We investigated the prevalence of preoperative word-finding difficulties, examined associations with medical and demographic characteristics, and analysed lexical errors. Methods: We included 148 children aged 5–17 years with a posterior fossa tumour. Word-finding ability was assessed by means of a picture-naming test, Wordrace, and difficulties in accuracy and speed were identified by cut-off values. A norm-based subanalysis evaluated performance in a Swedish subsample. We compared the demographic and medical characteristics of children with slow, inaccurate, or combined slow and inaccurate word finding to the characteristics of children without word-finding difficulties and conducted a lexical error analysis. Results: Thirty-seven percent (n = 55) presented with slow word finding, 24% (n = 35) with inaccurate word finding, and 16% (n = 23) with both slow and inaccurate word finding. Children with posterior fossa tumours were twice as slow as children in the norming sample. Right-hemisphere and brainstem location posed a higher risk for preoperative word-finding difficulties, relative to left-hemisphere location, and difficulties were more prevalent in boys than in girls. The most frequent errors were lack of response and semantically related sideordinated words. Conclusion: Word-finding difficulties are frequent in children with posterior fossa tumours, especially in boys and in children with right-hemisphere and brainstem tumours. Errors resemble those observed in typical development and children with word-finding difficulties.
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| 9. |
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| 10. |
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| 11. |
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| 12. |
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| 13. |
- Bjerketorp, J., et al.
(författare)
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Rapid lab-on-a-chip profiling of human gut bacteria
- 2008
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Ingår i: Journal of Microbiological Methods. - : Elsevier BV. - 0167-7012 .- 1872-8359. ; 72:1, s. 82-90
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Tidskriftsartikel (refereegranskat)abstract
- The human gut microbiota has a substantial impact on human health. Different factors such as disease, diet and drug use can have significant impacts on the gut microbiota. Therefore, it is of interest to have simple, rapid methods for analysis of the composition of the gut microbiota for clinical diagnostic purposes. Since only a minor fraction of the gastrointestinal bacterial community is presently possible to cultivate, molecular approaches are currently the best suited to investigate its composition. However, most of these molecular approaches require technical expertise and expensive equipment to run and they are not routinely available. Ideally, the analyses should be point-of-care options that can be run on a chip. In this study, an existing lab-on-chip (LOC) system for sizing/quantifying DNA was combined with length heterogeneity PCR (LH-PCR), a PCR-based profiling method targeting bacterial 16S rRNA gene sequences, to develop a fast, straightforward, reproducible, and economical method for profiling bacterial communities. The LOC LH-PCR method was first evaluated using a standardized gut cocktail containing genomic DNA from eight different bacterial species representing different genera of relevance for human health. The method was also tested on DNA that was directly extracted from human faecal samples and it was consistently capable of detecting alterations in the bacterial samples before and after antibiotic treatment. Although the resolution of the method needs improvement, this study represents the first step towards development of a diagnostic LOC for profiling gut bacterial communities.
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| 14. |
- Bjorkman, H, et al.
(författare)
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Diamond microchips for fast chromatography of proteins
- 2001
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Ingår i: SENSORS AND ACTUATORS B-CHEMICAL. - 0925-4005. ; 79:1, s. 71-77
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Tidskriftsartikel (refereegranskat)abstract
- As a material for bioanalysis polycrystalline diamond surfaces have attractive characteristics, such as the highest thermal conductivity, optical transparency, chemical inertness, and by choice, electrical insulation or semiconduction. In addition, diamon
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| 15. |
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| 16. |
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| 17. |
- Davegårdh, Cajsa, et al.
(författare)
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VPS39-deficiency observed in type 2 diabetes impairs muscle stem cell differentiation via altered autophagy and epigenetics
- 2021
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Insulin resistance and lower muscle quality (strength divided by mass) are hallmarks of type 2 diabetes (T2D). Here, we explore whether alterations in muscle stem cells (myoblasts) from individuals with T2D contribute to these phenotypes. We identify VPS39 as an important regulator of myoblast differentiation and muscle glucose uptake, and VPS39 is downregulated in myoblasts and myotubes from individuals with T2D. We discover a pathway connecting VPS39-deficiency in human myoblasts to impaired autophagy, abnormal epigenetic reprogramming, dysregulation of myogenic regulators, and perturbed differentiation. VPS39 knockdown in human myoblasts has profound effects on autophagic flux, insulin signaling, epigenetic enzymes, DNA methylation and expression of myogenic regulators, and gene sets related to the cell cycle, muscle structure and apoptosis. These data mimic what is observed in myoblasts from individuals with T2D. Furthermore, the muscle of Vps39(+/-) mice display reduced glucose uptake and altered expression of genes regulating autophagy, epigenetic programming, and myogenesis. Overall, VPS39-deficiency contributes to impaired muscle differentiation and reduced glucose uptake. VPS39 thereby offers a therapeutic target for T2D. Insulin resistance and lower muscle strength in relation to mass are hallmarks of type 2 diabetes. Here, the authors report alterations in muscle stem cells from individuals with type 2 diabetes that may contribute to these phenotypes through VPS39 mediated effects on autophagy and epigenetics.
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| 18. |
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| 19. |
- Enfors, Sven-Olof, et al.
(författare)
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Physiological responses to mixing in large scale bioreactors
- 2001
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Ingår i: Journal of Biotechnology. - 0168-1656 .- 1873-4863. ; 85:2, s. 175-185
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Tidskriftsartikel (refereegranskat)abstract
- Escherichia coli fed-batch cultivations at 22 m(3) scale were compared to corresponding laboratory scale processes and cultivations using a scale-down reactor furnished with a high-glucose concentration zone to mimic the conditions in a feed zone of the large bioreactor. Formate accumulated in the large reactor, indicating the existence of oxygen limitation zones. It is suggested that the reduced biomass yield at large scale partly is due to repeated production/reassimilation of acetate from overflow metabolism and mixed acid fermentation products due to local moving zones with oxygen limitation. The conditions that generated mixed-acid fermentation in the scale-down reactor also induced a number of stress responses, monitored by analysis of mRNA of selected stress induced genes. The stress responses were relaxed when the cells returned to the substrate limited and oxygen sufficient compartment of the reactor. Corresponding analysis in the large reactor showed that the concentration of mRNA of four stress induced genes was lowest at the sampling port most distant from the feed zone. It is assumed that repeated induction/relaxation of stress responses in a large bioreactor may contribute to altered physiological properties of the cells grown in large-scale bioreactor. Flow cytometric analysis revealed reduced damage with respect to cytoplasmic membrane potential and integrity in cells grown in the dynamic environments of the large scale reactor and the scale-down reactor.
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| 20. |
- Ercan, Ayse Bahar, et al.
(författare)
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Clinical and biological landscape of constitutional mismatch-repair deficiency syndrome: an International Replication Repair Deficiency Consortium cohort study.
- 2024
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Ingår i: The Lancet Oncology. - : ELSEVIER SCIENCE INC. - 1470-2045 .- 1474-5488. ; 25:5, s. 668-682
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Tidskriftsartikel (refereegranskat)abstract
- Constitutional mismatch repair deficiency (CMMRD) syndrome is a rare and aggressive cancer predisposition syndrome. Because a scarcity of data on this condition contributes to management challenges and poor outcomes, we aimed to describe the clinical spectrum, cancer biology, and impact of genetics on patient survival in CMMRD.In this cohort study, we collected cross-sectional and longitudinal data on all patients with CMMRD, with no age limits, registered with the International Replication Repair Deficiency Consortium (IRRDC) across more than 50 countries. Clinical data were extracted from the IRRDC database, medical records, and physician-completed case record forms. The primary objective was to describe the clinical features, cancer spectrum, and biology of the condition. Secondary objectives included estimations of cancer incidence and of the impact of the specific mismatch-repair gene and genotype on cancer onset and survival, including after cancer surveillance and immunotherapy interventions.We analysed data from 201 patients (103 males, 98 females) enrolled between June 5, 2007 and Sept 9, 2022. Median age at diagnosis of CMMRD or a related cancer was 8·9 years (IQR 5·9-12·6), and median follow-up from diagnosis was 7·2 years (3·6-14·8). Endogamy among minorities and closed communities contributed to high homozygosity within countries with low consanguinity. Frequent dermatological manifestations (117 [93%] of 126 patients with complete data) led to a clinical overlap with neurofibromatosis type 1 (35 [28%] of 126). 339 cancers were reported in 194 (97%) of 201 patients. The cumulative cancer incidence by age 18 years was 90% (95% CI 80-99). Median time between cancer diagnoses for patients with more than one cancer was 1·9 years (IQR 0·8-3·9). Neoplasms developed in 15 organs and included early-onset adult cancers. CNS tumours were the most frequent (173 [51%] cancers), followed by gastrointestinal (75 [22%]), haematological (61 [18%]), and other cancer types (30 [9%]). Patients with CNS tumours had the poorest overall survival rates (39% [95% CI 30-52] at 10 years from diagnosis; log-rank p<0·0001 across four cancer types), followed by those with haematological cancers (67% [55-82]), gastrointestinal cancers (89% [81-97]), and other solid tumours (96% [88-100]). All cancers showed high mutation and microsatellite indel burdens, and pathognomonic mutational signatures. MLH1 or MSH2 variants caused earlier cancer onset than PMS2 or MSH6 variants, and inferior survival (overall survival at age 15 years 63% [95% CI 55-73] for PMS2, 49% [35-68] for MSH6, 19% [6-66] for MLH1, and 0% for MSH2; p<0·0001). Frameshift or truncating variants within the same gene caused earlier cancers and inferior outcomes compared with missense variants (p<0·0001). The greater deleterious effects of MLH1 and MSH2 variants as compared with PMS2 and MSH6 variants persisted despite overall improvements in survival after surveillance or immune checkpoint inhibitor interventions.The very high cancer burden and unique genomic landscape of CMMRD highlight the benefit of comprehensive assays in timely diagnosis and precision approaches toward surveillance and immunotherapy. These data will guide the clinical management of children and patients who survive into adulthood with CMMRD.The Canadian Institutes for Health Research, Stand Up to Cancer, Children's Oncology Group National Cancer Institute Community Oncology Research Program, Canadian Cancer Society, Brain Canada, The V Foundation for Cancer Research, BioCanRx, Harry and Agnieszka Hall, Meagan's Walk, BRAINchild Canada, The LivWise Foundation, St Baldrick Foundation, Hold'em for Life, and Garron Family Cancer Center.
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| 21. |
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| 22. |
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| 23. |
- Francis, Nader K., et al.
(författare)
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Consensus on Training and Implementation of Enhanced Recovery After Surgery : A Delphi Study
- 2018
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Ingår i: World Journal of Surgery. - : Springer. - 0364-2313 .- 1432-2323. ; 42:7, s. 1919-1928
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Enhanced Recovery After Surgery (ERAS) is widely accepted in current surgical practice due to its positive impact on patient outcomes. The successful implementation of ERAS is challenging and compliance with protocols varies widely. Continual staff education is essential for successful ERAS programmes. Teaching modalities exist, but there remains no agreement regarding the optimal training curriculum or how its effectiveness is assessed. We aimed to draw consensus from an expert panel regarding the successful training and implementation of ERAS.METHODS: A modified Delphi technique was used; three rounds of questionnaires were sent to 58 selected international experts from 11 countries across multiple ERAS specialities and multidisciplinary teams (MDT) between January 2016 and February 2017. We interrogated opinion regarding four topics: (1) the components of a training curriculum and the structure of training courses; (2) the optimal framework for successful implementation and audit of ERAS including a guide for data collection; (3) a framework to assess the effectiveness of training; (4) criteria to define ERAS training centres of excellence.RESULTS: An ERAS training course must cover the evidence-based principles of ERAS with team-oriented training. Successful implementation requires strong leadership, an ERAS facilitator and an effective MDT. Effectiveness of training can be measured by improved compliance. A training centre of excellence should show a willingness to teach and demonstrable team working.CONCLUSIONS: We propose an international expert consensus providing an ERAS training curriculum, a framework for successful implementation, methods for assessing effectiveness of training and a definition of ERAS training centres of excellence.
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| 24. |
- Gausemel, H., et al.
(författare)
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Decay of 127In and 129In.
- 2004
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Ingår i: Phys. Rev. C. ; 69:054307
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Tidskriftsartikel (refereegranskat)
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| 25. |
- Gisnås, Kjersti, et al.
(författare)
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Permafrost Map for Norway, Sweden and Finland
- 2017
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Ingår i: Permafrost and Periglacial Processes. - : Wiley. - 1045-6740 .- 1099-1530. ; 28:2, s. 359-378
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Tidskriftsartikel (refereegranskat)abstract
- A research-based understanding of permafrost distribution at a sufficient spatial resolution is important to meet the demands of science, education and society. We present a new permafrost map for Norway, Sweden and Finland that provides a more detailed and updated description of permafrost distribution in this area than previously available. We implemented the CryoGRID1 model at 1km(2) resolution, forced by a new operationally gridded data-set of daily air temperature and snow cover for Finland, Norway and Sweden. Hundred model realisations were run for each grid cell, based on statistical snow distributions, allowing for the representation of sub-grid variability of ground temperature. The new map indicates a total permafrost area (excluding palsas) of 23 400km(2) in equilibrium with the average 1981-2010 climate, corresponding to 2.2 per cent of the total land area. About 56 per cent of the area is in Norway, 35 per cent in Sweden and 9 per cent in Finland. The model results are thoroughly evaluated, both quantitatively and qualitatively, as a collaboration project including permafrost experts in the three countries. Observed ground temperatures from 25 boreholes are within +/- 2 degrees C of the average modelled grid cell ground temperature, and all are within the range of the modelled ground temperature for the corresponding grid cell. Qualitative model evaluation by field investigators within the three countries shows that the map reproduces the observed lower altitudinal limits of mountain permafrost and the distribution of lowland permafrost.
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| 26. |
- Greek, S, et al.
(författare)
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Mechanical considerations in the design of a micromechanical tuneable InP-based WDM filter
- 1999
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Ingår i: JOURNAL OF MICROELECTROMECHANICAL SYSTEMS. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 1057-7157. ; 8:3, s. 328-334
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- A FVDM photodetector for fiberoptic communication systems using a wavelengths around 1.55 mu m has earlier been proposed as a tuneable Fabry-Perot interferometer micromachined on InP and integrated with a photodiode, The interferometer consists of a mirro
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| 27. |
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| 28. |
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| 29. |
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| 30. |
- Hjort, K., et al.
(författare)
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Cell cycle regulation in the hyperthermophilic crenarchaeon Sulfolobus acidocaldarius
- 2001
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Ingår i: MOLECULAR MICROBIOLOGY. - : BLACKWELL SCIENCE LTD. - 0950-382X. ; 40:1, s. 225-234
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Tidskriftsartikel (refereegranskat)abstract
- The regulation and co-ordination of the cell cycle of the hyperthermophilic crenarchaeon Sulfolobus acidocaldarius was investigated with antibiotics. We provide evidence for a core regulation involving alternating rounds of chromosome replication and geno
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| 31. |
- Hjort, K, et al.
(författare)
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Cell cycle regulation in the hyperthermophilic crenarchaeon Sulfolobus acidocaldarius.
- 2001
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Ingår i: Molecular Microbiology. - 0950-382X .- 1365-2958. ; 40:1, s. 225-34
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Tidskriftsartikel (refereegranskat)abstract
- The regulation and co-ordination of the cell cycle of the hyperthermophilic crenarchaeon Sulfolobus acidocaldarius was investigated with antibiotics. We provide evidence for a core regulation involving alternating rounds of chromosome replication and genome segregation. In contrast, multiple rounds of replication of the chromosome could occur in the absence of an intervening cell division event. Inhibition of the elongation stage of chromosome replication resulted in cell division arrest, indicating that pathways similar to checkpoint mechanisms in eukaryotes, and the SOS system of bacteria, also exist in archaea. Several antibiotics induced cell cycle arrest in the G2 stage. Analysis of the run-out kinetics of chromosome replication during the treatments allowed estimation of the minimal rate of replication fork movement in vivo to 250 bp s-1. An efficient method for the production of synchronized Sulfolobus populations by transient daunomycin treatment is presented, providing opportunities for studies of cell cycle-specific events. Possible targets for the antibiotics are discussed, including topoisomerases and protein glycosylation.
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| 32. |
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| 33. |
- Hjort, K, et al.
(författare)
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Changes in cell size and DNA content in Sulfolobus cultures during dilution and temperature shift experiments.
- 1999
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Ingår i: Journal of Bacteriology. - : American Society for Microbiology. - 0021-9193 .- 1098-5530. ; 181:18, s. 5669-75
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Tidskriftsartikel (refereegranskat)abstract
- Stationary-phase cultures of different hyperthermophilic species of the archaeal genus Sulfolobus were diluted into fresh growth medium and analyzed by flow cytometry and phase-fluorescence microscopy. After dilution, cellular growth started rapidly but no nucleoid partition, cell division, or chromosome replication took place until the cells had been increasing in size for several hours. Initiation of chromosome replication required that the cells first go through partition and cell division, revealing a strong interdependence between these key cell cycle events. The time points at which nucleoid partition, division, and replication occurred after the dilution were used to estimate the relative lengths of the cell cycle periods. When exponentially growing cultures were diluted into fresh growth medium, there was an unexpected transient inhibition of growth and cell division, showing that the cultures did not maintain balanced growth. Furthermore, when cultures growing at 79 degrees C were shifted to room temperature or to ice-water baths, the cells were found to "freeze" in mid-growth. After a shift back to 79 degrees C, growth, replication, and division rapidly resumed and the mode and kinetics of the resumption differed depending upon the nature and length of the shifts. Dilution of stationary-phase cultures provides a simple protocol for the generation of partially synchronized populations that may be used to study cell cycle-specific events.
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| 34. |
- Hjort, Karin, et al.
(författare)
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Chitinase genes revealed and compared in bacterial isolates, DNA extracts and a metagenomic library from a phytopathogen-suppressive soil
- 2010
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Ingår i: FEMS Microbiology Ecology. - United Kingdom : Wiley-Blackwell Publishing Ltd.. - 0168-6496 .- 1574-6941. ; 71:2, s. 197-207
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Tidskriftsartikel (refereegranskat)abstract
- Soil that is suppressive to disease caused by fungal pathogens is an interesting source to target for novel chitinases that might be contributing towards disease suppression. In this study, we screened for chitinase genes, in a phytopathogen-suppressive soil in three ways: (1) from a metagenomic library constructed from microbial cells extracted from soil, (2) from directly extracted DNA and (3) from bacterial isolates with antifungal and chitinase activities. Terminal restriction fragment length polymorphism (T-RFLP) of chitinase genes revealed differences in amplified chitinase genes from the metagenomic library and the directly extracted DNA, but approximately 40% of the identified chitinase terminal restriction fragments (TRFs) were found in both sources. All of the chitinase TRFs from the isolates were matched to TRFs in the directly extracted DNA and the metagenomic library. The most abundant chitinase TRF in the soil DNA and the metagenomic library corresponded to the TRF103 of the isolate Streptomyces mutomycini and/or Streptomyces clavifer. There were good matches between T-RFLP profiles of chitinase gene fragments obtained from different sources of DNA. However, there were also differences in both the chitinase and the 16S rRNA gene T-RFLP patterns depending on the source of DNA, emphasizing the lack of complete coverage of the gene diversity by any of the approaches used.
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| 35. |
- Hjort, Karin, et al.
(författare)
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Community structure of actively growing bacterial populations in plant pathogen suppressive soil.
- 2007
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Ingår i: Microbial Ecology. - : Springer Science and Business Media LLC. - 0095-3628 .- 1432-184X. ; 53:3, s. 399-413
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Tidskriftsartikel (refereegranskat)abstract
- The bacterial community in soil was screened by using various molecular approaches for bacterial populations that were activated upon addition of different supplements. Plasmodiophora brassicae spores, chitin, sodium acetate, and cabbage plants were added to activate specific bacterial populations as an aid in screening for novel antagonists to plant pathogens. DNA from growing bacteria was specifically extracted from the soil by bromodeoxyuridine immunocapture. The captured DNA was fingerprinted by terminal restriction fragment length polymorphism (T-RFLP). The composition of the dominant bacterial community was also analyzed directly by T-RFLP and by denaturing gradient gel electrophoresis (DGGE). After chitin addition to the soil, some bacterial populations increased dramatically and became dominant both in the total and in the actively growing community. Some of the emerging bands on DGGE gels from chitin-amended soil were sequenced and found to be similar to known chitin-degrading genera such as Oerskovia, Kitasatospora, and Streptomyces species. Some of these sequences could be matched to specific terminal restriction fragments on the T-RFLP output. After addition of Plasmodiophora spores, an increase in specific Pseudomonads could be observed with Pseudomonas-specific primers for DGGE. These results demonstrate the utility of microbiomics, or a combination of molecular approaches, for investigating the composition of complex microbial communities in soil.
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| 36. |
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| 37. |
- Hjort, K, et al.
(författare)
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Quartz micromachining by lithographic control of ion track etching
- 1996
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Ingår i: APPLIED PHYSICS LETTERS. - : AMER INST PHYSICS. - 0003-6951. ; 69:22, s. 3435-3436
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- A micromachining process, using ion track etching in combination with lithographic patterning, is presented. The technique employs a substrate pre-irradiated with swift heavy ions and uses a conventional Lithographic technique to control the access of a t
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| 38. |
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| 39. |
- Hjort, Mattias, 1972-, et al.
(författare)
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Utredning av regler för vinterdäck till tunga fordon : Ett regeringsuppdrag
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- VTI har tillsammans med Transportstyrelsen fått i uppdrag av regeringen att analysera dagens krav på vinterdäck för tunga fordon och utreda behovet av förändrade krav på vinterdäck eller däckutrustning för att minska framkomlighets- och säkerhetsproblem i vägtrafiken när det råder vinterväglag. Om behov finns ska Transportstyrelsen föreslå regeländringar. 2018 togs beslut fram på skärpta krav på vinterdäck till tunga fordon. Kraven blev aktiva 1 juni 2019. I uppdraget från regeringen ingick att följa upp hur de skärpta kraven efterlevs och bedöma vilken effekt som regeländringarna har fått på framkomlighet och trafiksäkerhet. Vi har i denna utredning genomfört fokusgrupper och intervjuer, samlat in statistik och genomfört olycksriskanalyser, samt utfört ett par fältstudier av däckens kondition för lastbilar och bussar i trafik. Vi har gått igenom befintligt regelverk i detalj och jämfört dem med regelverken i Norge och Finland, där man har liknande vinterförhållanden som i Sverige. Baserat på dessa analyser ser vi inga skäl till förändringar av befintligt regelverk för vinterdäck till tunga fordon. Den statistiska analysen kunde inte påvisa någon förbättring av halkrelaterade problem efter skärpningen av vinterdäcksreglerna 2019, varken när det gäller framkomlighet eller trafiksäkerhet.
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| 40. |
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| 41. |
- Hultman, Jens, et al.
(författare)
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Handeln rustar för multi-kanal
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Handelsbranschen står inför omfattande utmaningar och möjligheter som kan – och kommer – att förändra verksamheten i grunden. En av dessa genomgripande förändringar är handelns digitalisering och dess konsekvenser för detaljhandelns styrning och utveckling av multikanalserbjudanden. Från en situation där kunder och handel primärt tänker fysisk butik, till en situation där handel via internet präglar det mesta som händer; från hur kunder handlar till hur företagen tänker strategiskt på sitt erbjudande. Det är en lång resa som långtifrån är färdig och som hänger samman med digitaliseringen av samhället i stort, big data och andra möjligheter (och utmaningar) som den tekniska utvecklingen innebär.Denna utveckling är mångfacetterad och det är viktigt att belysa den ur flera perspektiv. Centrum för handelsforsknings verksamhet är unik i den bemärkelse att vi i samtliga forskningsprogram arbetar tvärvetenskapligt där forskare från alla de discipliner som är representerade i Centrum finns med i varje forskningsprogram. Detta garanterar en mångsidig belysning av de forskningsproblem som vi tar oss an. Under 2014–2015 har vi drivit forskningsprogrammen E-handel och Kunniga kunder. Därefter startade vi programmen Retail destination och Retail innovation.I denna skrift sammanfattas forskningsresultaten från forskningsprogrammet E-handel. Programchef för E-handel har Jens Hultman varit. Deltagande forskare i programmet har varit Klas Hjort, Veronika Tarnovskaya, Ulf Johansson och Christian Fuentes. Under 2014 och 2015 (och även 2016) har resultat från programmet presenterats i olika sammanhang. De har presenterats vid forskningsseminarier och workshops som Centrum har arrangerat, de har presenterats vid vetenskapliga konferenser och vid praktikerkonferenser och de har tidigare också beskrivits i rapporter och vetenskapliga artiklar. Nu presenterar vi resultaten inom ramen för Handelsrådets rapportserie.
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| 42. |
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| 43. |
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| 44. |
- Jeong, S. H., et al.
(författare)
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Liquid alloy printing of microfluidic stretchable electronics
- 2012
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 12:22, s. 4657-4664
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Tidskriftsartikel (refereegranskat)abstract
- Recently, microfluidic stretchable electronics has attracted great interest from academia since conductive liquids allow for larger cross-sections when stretched and hence low resistance at longer lengths. However, as a serial process it has suffered from low throughput, and a parallel processing technology is needed for more complex systems and production at low costs. In this work, we demonstrate such a technology to implement microfluidic electronics by stencil printing of a liquid alloy onto a semi-cured polydimethylsiloxane (PDMS) substrate, assembly of rigid active components, encapsulation by pouring uncured PDMS on-top and subsequent curing. The printing showed resolution of 200 μm and linear resistance increase of the liquid conductors when elongated up to 60%. No significant change of resistance was shown for a circuit with one LED after 1000 times of cycling between a 0% and an elongation of 60% every 2 s. A radio frequency identity (RFID) tag was demonstrated using the developed technology, showing that good performance could be maintained well into the radio frequency (RF) range.
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| 45. |
- Kawasaki, Jason K., et al.
(författare)
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A simple electron counting model for half-Heusler surfaces
- 2018
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- Heusler compounds are a ripe platform for discovery and manipulation of emergent properties in topological and magnetic heterostructures. In these applications, the surfaces and interfaces are critical to performance; however, little is known about the atomic-scale structure of Heusler surfaces and interfaces or why they reconstruct. Using a combination of molecular beam epitaxy, core-level and angle-resolved photoemission, scanning tunneling microscopy, and density functional theory, we map the phase diagram and determine the atomic and electronic structures for several surface reconstructions of CoTiSb (001), a prototypical semiconducting half-Heusler. At low Sb coverage, the surface is characterized by Sb-Sb dimers and Ti vacancies, while, at high Sb coverage, an adlayer of Sb forms. The driving forces for reconstruction are charge neutrality and minimizing the number of Sb dangling bonds, which form metallic surface states within the bulk bandgap. We develop a simple electron counting model that explains the atomic and electronic structure, as benchmarked against experiments and first-principles calculations. We then apply the model to explain previous experimental observations at otherhalf-Heusler surfaces, including the topological semimetal PtLuSb and the half-metallic ferromagnet NiMnSb. The model provides a simple framework for understanding and predicting the surface structure and propertiesof these novel quantum materials.
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| 46. |
- Kawasaki, Jason K., et al.
(författare)
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Epitaxial growth and surface studies of the Half Heusler compound NiTiSn (001)
- 2013
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Ingår i: Journal of Vacuum Science and Technology B. - : American Vacuum Society. - 1520-8567. ; 31:4
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Tidskriftsartikel (refereegranskat)abstract
- The Half Heuslers are currently an attractive family of compounds for high temperature thermoelectrics research, and recently, there has been renewed interest since some of these compounds are proposed to be topological insulators. NiTiSn belongs to the family of 18 valence electron Half Heuslers that are predicted to be semiconducting, despite being composed entirely of metallic elements. The growth of the Half Heusler compound NiTiSn by molecular beam epitaxy is demonstrated. The NiTiSn films are epitaxial and single crystalline as observed by reflection high-energy electron diffraction and x-ray diffraction. Temperature dependent transport measurements suggest the films may be semiconducting, but with a high background carrier density indicative of a high density of electrically active defect states. Methods of protecting the sample surface for synchrotron-based photoemission measurements are explored. These methods may be applied to the study of surface electronic structure in unconventional materials. (C) 2013 American Vacuum Society.
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| 47. |
- Kolari, K., et al.
(författare)
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Flow restrictor silicon membrane microvalve actuated by optically controlled paraffin phase transition
- 2014
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Ingår i: Journal of Micromechanics and Microengineering. - : IOP Publishing. - 0960-1317 .- 1361-6439. ; 24:8, s. 084003-
-
Tidskriftsartikel (refereegranskat)abstract
- Restrictor valves allow proportional control of fluid flow but are rarely integrated in microfluidic systems. In this study, an optically actuated silicon membrane restrictor microvalve is demonstrated. Its actuation is based on the phase transition of paraffin, using a paraffin wax mixed with a suitable concentration of optically absorbing nanographite particles. Backing up the membrane with oil (the melted paraffin) allows for a compliant yet strong contact to the valve seat, which enables handling of high pressures. At flow rates up to 30 mu L min(-1) and at a pressure of 2 bars, the valve can successfully be closed and control the flow level by restriction. The use of this paraffin composite as an adhesive layer sandwiched between the silicon valve and glass eases fabrication. This type of restrictor valve is best suited for high pressure, low volume flow silicon-based nanofluidic systems.
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| 48. |
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