| 1. |
- Falkengren-Grerup, U., et al.
(författare)
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Does nitrogen deposition change the flora?
- 2000
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Ingår i: Effects of nitrogen deposition on forest ecosystems. - Stockholm : Naturvårdsverket.
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Bokkapitel (refereegranskat)
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| 2. |
- Falkengren-Grerup, Ursula, et al.
(författare)
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Förändras floran av kvävenedfallet?
- 2000
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Ingår i: Effekter av kvävenedfall på skogsekosystem. - 9162050664
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Abstract is not available
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| 3. |
- Falkengren-Grerup, U., et al.
(författare)
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Förändras floran av kvävenedfallet?
- 2000
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Ingår i: Effekter av kvävenedfall på skogsekosystem. - Stockholm : Naturvårdsverket.
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Bokkapitel (refereegranskat)
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| 4. |
- Hansson, EM, et al.
(författare)
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Control of Notch-ligand endocytosis by ligand-receptor interaction
- 2010
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Ingår i: Journal of cell science. - : The Company of Biologists. - 1477-9137 .- 0021-9533. ; 123:17Pt 17, s. 2931-2942
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Tidskriftsartikel (refereegranskat)abstract
- In Notch signaling, cell-bound ligands activate Notch receptors on juxtaposed cells, but the relationship between ligand endocytosis, ubiquitylation and ligand-receptor interaction remains poorly understood. To study the specific role of ligand-receptor interaction, we identified a missense mutant of the Notch ligand Jagged1 (Nodder, Ndr) that failed to interact with Notch receptors, but retained a cellular distribution that was similar to wild-type Jagged1 (Jagged1WT) in the absence of active Notch signaling. Both Jagged1WT and Jagged1Ndr interacted with the E3 ubiquitin ligase Mind bomb, but only Jagged1WT showed enhanced ubiquitylation after co-culture with cells expressing Notch receptor. Cells expressing Jagged1WT, but not Jagged1Ndr, trans-endocytosed the Notch extracellular domain (NECD) into the ligand-expressing cell, and NECD colocalized with Jagged1WT in early endosomes, multivesicular bodies and lysosomes, suggesting that NECD is routed through the endocytic degradation pathway. When coexpressed in the same cell, Jagged1Ndr did not exert a dominant-negative effect over Jagged1WT in terms of receptor activation. Finally, in Jag1Ndr/Ndr mice, the ligand was largely accumulated at the cell surface, indicating that engagement of the Notch receptor is important for ligand internalization in vivo. In conclusion, the interaction-dead Jagged1Ndr ligand provides new insights into the specific role of receptor-ligand interaction in the intracellular trafficking of Notch ligands.
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| 5. |
- Marklund, U, et al.
(författare)
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Domain-specific control of neurogenesis achieved through patterned regulation of Notch ligand expression
- 2010
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Ingår i: Development (Cambridge, England). - : The Company of Biologists. - 1477-9129 .- 0950-1991. ; 137:3, s. 437-445
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Tidskriftsartikel (refereegranskat)abstract
- Homeodomain (HD) transcription factors and components of the Notch pathway [Delta1 (Dll1), Jagged1 (Jag1) and the Fringe (Fng) proteins] are expressed in distinct progenitor domains along the dorsoventral (DV) axis of the developing spinal cord. However, the internal relationship between these two regulatory pathways has not been established. In this report we show that HD proteins act upstream of Notch signalling. Thus, HD proteins control the spatial distribution of Notch ligands and Fng proteins, whereas perturbation of the Notch pathway does not affect the regional expression of HD proteins. Loss of Dll1 or Jag1 leads to a domain-specific increase of neuronal differentiation but does not affect the establishment of progenitor domain boundaries. Moreover, gain-of-function experiments indicate that the ability of Dll1 and Jag1 to activate Notch is limited to progenitors endogenously expressing the respective ligand. Fng proteins enhance Dll1-activated Notch signalling and block Notch activation mediated by Jag1. This finding, combined with the overlapping expression of Fng with Dll1 but not with Jag1, is likely to explain the domain-specific activity of the Notch ligands. This outcome is opposite to the local regulation of Notch activity in most other systems, including the Drosophila wing, where Fng co-localizes with Jagged/Serrate rather than Dll/Delta, which facilitates Notch signalling at regional boundaries instead of within domains. The regulation of Notch activation in the spinal cord therefore appears to endow specific progenitor populations with a domain-wide autonomy in the control of neurogenesis and prevents any inadequate activation of Notch across progenitor domain boundaries.
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| 6. |
- Aberg, J, et al.
(författare)
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Electrical properties of the TiSi2-Si transition region in contacts : The influence of an interposed layer of Nb
- 2001
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 90:5, s. 2380-2388
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Tidskriftsartikel (refereegranskat)abstract
- The influence of an interposed ultrathin Nb layer between Ti and Si on the silicide formation and the electrical contact between the silicide formed and the Si substrate is investigated. The presence of the Nb interlayer results in the formation of ternary alloy (Nb,Ti)Si-2 in the C40 crystallographic structure adjacent to the Si substrate. Depending on the nature of the Si substrates and/or the amount of the initial Nb, the interfacial C40 (Nb,Ti)Si-2 leads, in turn, to either epitaxial growth of a highly faulted metastable C40 TiSi2 or formation of the desired C54 TiSi2 at a lower temperature than needed for it to form in reference samples with Ti deposited directly on Si. On p-type substrates doped to various concentrations, the Nb also leads to a considerably lower specific contact resistivity than that obtained in the reference samples: a twofold to fourfold reduction in the contact resistivity is found using cross-bridge Kelvin structures in combination with two-dimensional numerical simulation. As C40 (Nb,Ti)Si-2 forms at the interface when an interfacial Nb is present, the interface characterized is likely to represent the one between (Nb,Ti)Si-2 and Si. For the reference samples, the interface studied is between TiSi2 and Si.
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| 7. |
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| 8. |
- Adcox, K, et al.
(författare)
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PHENIX detector overview
- 2003
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 499:2-3, s. 469-479
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Tidskriftsartikel (refereegranskat)abstract
- The PHENIX detector is designed to perform a broad study of A-A, p-A, and p-p collisions to investigate nuclear matter under extreme conditions. A wide variety of probes, sensitive to all timescales, are used to study systematic variations with species and energy as well as to measure the spin structure of the nucleon. Designing for the needs of the heavy-ion and polarized-proton programs has produced a detector with unparalleled capabilities. PHENIX measures electron and muon pairs, photons, and hadrons with excellent energy and momentum resolution. The detector consists of a large number of subsystems that are discussed in other papers in this volume. The overall design parameters of the detector are presented. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 9. |
- Adler, SS, et al.
(författare)
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PHENIX on-line systems
- 2003
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 499:2-3, s. 560-592
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Tidskriftsartikel (refereegranskat)abstract
- The PHENIX On-Line system takes signals from the Front End Modules (FEM) on each detector subsystem for the purpose of generating events for physics analysis. Processing of event data begins when the Data Collection Modules (DCM) receive data via fiber-optic links from the FEMs. The DCMs format and zero suppress the data and generate data packets. These packets go to the Event Builders (EvB) that assemble the events in final form. The Level-1 trigger (LVL1) generates a decision for each beam crossing and eliminates uninteresting events. The FEMs carry out all detector processing of the data so that it is delivered to the DCMs using a standard format. The FEMs also provide buffering for LVL1 trigger processing and DCM data collection. This is carried out using an architecture that is pipelined and deadtimeless. All of this is controlled by the Master Timing System (MTS) that distributes the RHIC clocks. A Level-2 trigger (LVL2) gives additional discrimination. A description of the components and operation of the PHENIX On-Line system is given and the solution to a number of electronic infrastructure problems are discussed. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 10. |
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| 11. |
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| 12. |
- Andersen, Toril, et al.
(författare)
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Chitosan-Based Nanomedicine to Fight Genital Candida Infections : Chitosomes
- 2017
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Ingår i: Marine Drugs. - : MDPI. - 1660-3397. ; 15:3
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Tidskriftsartikel (refereegranskat)abstract
- Vaginal infections are associated with high recurrence, which is often due to a lack of efficient treatment of complex vaginal infections comprised of several types of pathogens, especially fungi and bacteria. Chitosan, a mucoadhesive polymer with known antifungal effect, could offer a great improvement in vaginal therapy; the chitosan-based nanosystem could both provide antifungal effects and simultaneously deliver antibacterial drugs. We prepared chitosan-containing liposomes, chitosomes, where chitosan is both embedded in liposomes and surface-available as a coating layer. For antimicrobial activity, we entrapped metronidazole as a model drug. To prove that mucoadhesivness alone is not sufficient for successful delivery, we used Carbopol-containing liposomes as a control. All vesicles were characterized for their size, zeta potential, entrapment efficiency, and in vitro drug release. Chitosan-containing liposomes were able to assure the prolonged release of metronidazole. Their antifungal activity was evaluated in a C. albicans model; chitosan-containing liposomes exhibited a potent ability to inhibit the growth of C. albicans. The presence of chitosan was crucial for the system's antifungal activity. The antifungal efficacy of chitosomes combined with antibacterial potential of the entrapped metronidazole could offer improved efficacy in the treatment of mixed/complex vaginal infections.
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| 13. |
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| 14. |
- Bamia, C., et al.
(författare)
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Fruit and vegetable consumption in relation to hepatocellular carcinoma in a multi-centre, European cohort study
- 2015
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Ingår i: British Journal of Cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 112:7, s. 1273-1282
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Tidskriftsartikel (refereegranskat)abstract
- Background:Vegetable and/or fruit intakes in association with hepatocellular carcinoma (HCC) risk have been investigated in case-control studies conducted in specific European countries and cohort studies conducted in Asia, with inconclusive results. No multi-centre European cohort has investigated the indicated associations. Methods: In 486 799 men/women from the European Prospective Investigation into Cancer and nutrition, we identified 201 HCC cases after 11 years median follow-up. We calculated adjusted hazard ratios (HRs) for HCC incidence for sex-specific quintiles and per 100 g d(-1) increments of vegetable/fruit intakes. Results: Higher vegetable intake was associated with a statistically significant, monotonic reduction of HCC risk: HR (100 g d(-1) increment): 0.83; 95% CI: 0.71-0.98. This association was consistent in sensitivity analyses with no apparent heterogeneity across strata of HCC risk factors. Fruit intake was not associated with HCC incidence: HR (100 g d(-1) increment): 1.01; 95% CI: 0.92-1.11. Conclusions: Vegetable, but not fruit, intake is associated with lower HCC risk with no evidence for heterogeneity of this association in strata of important HCC risk factors. Mechanistic studies should clarify pathways underlying this association. Given that HCC prognosis is poor and that vegetables are practically universally accessible, our results may be important, especially for those at high risk for the disease.
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| 15. |
- Bjorkander, J, et al.
(författare)
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Normal and abnormal mucosal antibody mediated immunity.
- 1991
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Ingår i: Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology. - 0954-7894. ; 21 Suppl 1, s. 199-204
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Tidskriftsartikel (refereegranskat)
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| 16. |
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| 17. |
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| 18. |
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| 19. |
- Ericson, Mats O, et al.
(författare)
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Muscular activity during ergometer cycling.
- 1985
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Ingår i: Scandinavian Journal of Rehabilitation Medicine. - 0036-5505 .- 1940-2228. ; 17:2, s. 53-61
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to quantify the activity as recorded by electromyography during ergometer cycling in eleven different muscles of the lower extremity. Eleven healthy subjects rode in twelve different ways at different work-load, pedalling rate, saddle height and pedal foot position. Vastus medialis and lateralis, gastrocnemius medialis and lateralis and the soleus muscle were the most activated muscles. Changes in muscle activity during different calibrations were studied in eight of the eleven muscles. An increase in work-load significantly increased the mean maximum activity in all the eight muscles investigated. An increase of the pedalling rate increased the activity in the gluteus maximus, gluteus medius, vastus medialis, medial hamstring, gastrocnemius medialis and soleus muscles. An increase of the saddle height increased the muscle activity in the gluteus medius, medial hamstring and gastrocnemius medialis muscles. Use of a posterior pedal foot position increased the activity in the gluteus medius and rectus femoris muscles, and decreased the activity in the soleus muscle.
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| 20. |
- Ericson, Mats O, et al.
(författare)
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Power output and work in different muscle groups during ergometer cycling.
- 1986
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Ingår i: European Journal of Applied Physiology and Occupational Physiology. - 0301-5548 .- 1432-1025. ; 55:3, s. 229-35
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to calculate the magnitude of the instantaneous muscular power output at the hip, knee and ankle joints during ergometer cycling. Six healthy subjects pedalled a weight-braked bicycle ergometer at 120 watts (W) and 60 revolutions per minute (rpm). The subjects were filmed with a cine camera, and pedal reaction forces were recorded from a force transducer mounted in the pedal. The muscular work at the hip, knee and ankle joint was calculated using a model based upon dynamic mechanics described elsewhere. The mean peak concentric power output was, for the hip extensors, 74.4 W, hip flexors, 18.0 W, knee extensors, 110.1 W, knee flexors, 30.0 W and ankle plantar flexors, 59.4 W. At the ankle joint, energy absorption through eccentric plantar flexor action was observed, with a mean peak power of 11.4 W and negative work of 3.4 J for each limb and complete pedal revolution. The energy production relationships between the different major muscle groups were computed and the contributions to the total positive work were: hip extensors, 27%; hip flexors, 4%; knee extensors, 39%; knee flexors, 10%; and ankle plantar flexors 20%.
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| 21. |
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| 22. |
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| 23. |
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| 24. |
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| 25. |
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| 26. |
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| 27. |
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| 28. |
- Fedirko, V., et al.
(författare)
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Consumption of fish and meats and risk of hepatocellular carcinoma: the European Prospective Investigation into Cancer and Nutrition (EPIC)
- 2013
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Ingår i: Annals of Oncology. - : Elsevier BV. - 1569-8041 .- 0923-7534. ; 24:8, s. 2166-2173
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Tidskriftsartikel (refereegranskat)abstract
- While higher intake of fish and lower consumption of red/processed meats have been suggested to play a protective role in the etiology of several cancers, prospective evidence for hepatocellular carcinoma (HCC) is limited, particularly in Western European populations. The associations of fish and meats with HCC risk were analyzed in the EPIC cohort. Between 1992 and 2010, 191 incident HCC were identified among 477 206 participants. Baseline diet was assessed using validated dietary questionnaires. A single 24-h diet recall from a cohort subsample was used for calibration. Multivariable proportional hazard regression was utilized to estimate hazard ratios (HR) and 95% confidence intervals (CI). In a nested case-control subset (HCC = 122), HBV/HCV status and liver function biomarkers were measured. HCC risk was inversely associated with intake of total fish (per 20 g/day increase, HR = 0.83, 95% CI 0.74-0.95 and HR = 0.80, 95% CI 0.69-0.97 before and after calibration, respectively). This inverse association was also suggested after adjusting for HBV/HCV status and liver function score (per 20-g/day increase, RR = 0.86, 95% CI 0.66-1.11 and RR = 0.74, 95% CI 0.50-1.09, respectively) in a nested case-control subset. Intakes of total meats or subgroups of red/processed meats, and poultry were not associated with HCC risk. In this large European cohort, total fish intake is associated with lower HCC risk.
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| 29. |
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| 30. |
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| 31. |
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| 32. |
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| 33. |
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| 34. |
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| 35. |
- Hjelmevoll, Stig Ove, et al.
(författare)
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A fast real-time polymerase chain reaction method for sensitive and specific detection of the Neisseria gonorrhoeae porA pseudogene
- 2006
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Ingår i: Journal of Molecular Diagnostics. - : Elsevier BV. - 1525-1578 .- 1943-7811. ; 8:5, s. 574-581
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Tidskriftsartikel (refereegranskat)abstract
- Ever since the advent of molecular methods, the diagnostics of Neisseria gonorrhoeae has been troubled by false negative and false positive results compared with culture. Commensal Neisseria species and Neisseria meningitidis are closely related to N. gonorrhoeae and may cross-react when using molecular tests comprising too-low specificity. We have devised a real-time polymerase chain reaction (PCR), including an internal amplification control, that targets the N. gonorrhoeae porA pseudogene. DNA was automatically isolated on a BioRobot M48. Our subsequent PCR method amplified all of the different N. gonorrhoeae international reference strains (n = 34) and N. gonorrhoeae clinical isolates (n = 176) but not isolates of the 13 different nongonococcal Neisseria species (n = 68) that we tested. Furthermore, a panel of gram-negative bacterial (n = 18), gram-positive bacterial (n = 23), fungal (n = 1), and viral (n = 4) as well as human DNA did not amplify. The limit of detection was determined to be less than 7.5 genome equivalents/PCR reaction. In conclusion, the N. gonorrhoeae porA pseudogene real-time PCR developed in the present study is highly sensitive, specific, robust, rapid and reproducible, making it suitable for diagnosis of N. gonorrhoeae infection.
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| 36. |
- Hjelmevoll, Stig Ove, et al.
(författare)
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Appropriate Time for Test-of-Cure when Diagnosing Gonorrhoea with a Nucleic Acid Amplification Test
- 2012
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Ingår i: Acta Dermato-Venereologica. - Uppsala : Acta Dermato-Venereologica. - 0001-5555 .- 1651-2057. ; 92:3, s. 316-319
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Tidskriftsartikel (refereegranskat)abstract
- Culture is commonly regarded as the gold standard for diagnosis of Neisseria gonorrhoeae. However, nucleic acid amplification tests (NAATs) have rapidly replaced culture for diagnostics in many settings. The aim of the present study was to investigate the appropriate time for test-of-cure (TOC) when NAATs are used for diagnosis of gonorrhoea. In total, 30 patients (28 men and 2 women) provided urethral, cervical, rectal or pharyngeal specimens for TOC. All included patients, except one who did not return for second TOC before day 19, tested negative within 2 weeks after treatment with cefixime 400 mg x 1. Antimicrobial susceptibility testing showed that 68% of the culture-positive strains were resistant to ciprofloxacin. Thus, the recommended empirical treatment with ciprofloxacin in Norway should be changed immediately. TOC can be performed 2 weeks after treatment when NAATs are used for diagnosis of gonorrhoea.
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| 37. |
- Hjelmevoll, Stig Ove, et al.
(författare)
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Clinical validation of a real-time polymerase chain reaction detection of Neisseria gonorrheae porA pseudogene versus culture techniques
- 2008
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Ingår i: Sexually Transmitted Diseases. - Philadelphia : American Venereal Disease Association. - 0148-5717 .- 1537-4521. ; 35:5, s. 517-520
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Tidskriftsartikel (refereegranskat)abstract
- Background: Diagnosing Neisseria gonorrheae using nucleic acid amplification tests (NAATs) might increase the sensitivity, compared to cultivation. However, using NAATs has also been problematic mainly due to the close genetic relationships between different Neisseria species, resulting in false positive diagnoses. This study was conducted to clinically validate a previously published real-time polymerase chain reaction (PCR) method targeting the porA pseudogene in N. gonorrheae in comparison to culture techniques.Methods: In total, 360 samples, urethra (n = 109), rectum (n = 84), pharynx (n = 119), and cervix (n = 48) from 185 males and 57 females, were analyzed using porA pseudogene PCR and cultivation. Sequencing of the entire porA pseudogene and the 16S rRNA gene were used to resolve discrepant results.Results: Of the 360 samples, 37 were positive by both culture and PCR, however, the PCR identified 15 additional confirmed positive samples. The PCR method showed a sensitivity, specificity, positive predictive value, and negative predictive value of 100% in a preselected population. The preselected population had a true gonorrhea prevalence of 17.4%.Conclusions: The present porA pseudogene real-time PCR comprises a valuable supplement to the traditional culture techniques for diagnosis of N. gonorrheae, especially for samples from extragenital sites such as pharynx and rectum.
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| 38. |
- Jarmar, T., et al.
(författare)
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Cross-sectional transmission electron microscopy study of the influence of niobium on the formation of titanium silicide in small-feature contacts
- 2003
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 93:8, s. 4480-4484
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Tidskriftsartikel (refereegranskat)abstract
- The influence of a Nb layer between Si and Ti on the formation of TiSi2 in small-feature contacts and of the substrate doping level has been studied using transmission electron microscopy in combination with convergent-beam electron diffraction. For an As dose of 2.5x10(16) cm(-2), a mixture of C49 and partially agglomerated C54 TiSi2 grains was found in some of the 5x5 mum(2) contact windows, while only C49 existed in the 0.7x0.7 mum(2) windows. Agglomeration is shown to lead to possible C49-C54 coexistence, as well as erroneous interpretation of the C54 nucleation density. Decreasing the As dose to 5x10(15) cm(-2) leads to a thicker TiSi2 layer, but does not have a major influence on phase formation in the small windows, although only C54 TiSi2 was found in the large ones. In the presence of a thin Nb layer between Ti and poly-Si, C40 (Ti,Nb)Si-2 was consistently found in all contacts, indicating that formation does not depend on the contact size at least down to 0.5 mum(2). Surprisingly, Ti was found on both sides of the (Ti,Nb)Si-2 layer and the silicide near the interface to Si was relatively rich in Ti instead of Nb.
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| 39. |
- Jarmar, T., et al.
(författare)
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Germanium-induced texture and preferential orientation of NiSi1-xGex layers on Si1-xGex
- 2004
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 70:23, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- NiSi1-xGex films on compressively strained as well as relaxed undoped Si1-xGex epitaxially grown substrates with x=0.06-0.30 on Si(001) wafers have been studied with respect to the relative orientation of film and substrate after annealing at temperatures in the range 400-850 degreesC. Using x-ray diffraction, transmission electron microscopy, and pole-figure measurements, it was found that only the monogermanosilicide phase formed above 450 degreesC and was the only phase still at 850 degreesC. New information regarding the effects of Ge on the silicidation of Ni was also found. Thus, the preferred plane parallel to the surface is (013). Compared to NiSi, Ge suppresses the development of the other planes parallel to the surface except (013). Within this plane, the orientations of the grains pile up in such a way that the configuration NiSi1-xGex[100]//Si1-xGex[100] is avoided, which in the pole-figures leads to broad peaks in-between the substrate [100] and [010]. In addition, peaks indicating the epitaxial alignment NiSi0.8Ge0.2(+/-21-1) or (+/-2-11)//Si0.8Ge0.2(+/-2+/-20) coupled with NiSi0.8Ge0.2(+/-100)approximate to//Si0.8Ge0.2(+/-100) or (0+/-10) were found. Fine structure in the broad peaks is found to be due to lateral epitaxial alignments between grains along their common grain boundary. Based on the nonexistence of NiGe2, the observations are interpreted in terms of Ge preventing the formation of certain Ni-Ge bonds at the interface between NiSi1-xGex and the Si1-xGex substrate.
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| 40. |
- Jarmar, T., et al.
(författare)
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Influence of germanium on the formation of NiSi1-xGex on (111)-oriented Si1-xGex
- 2005
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 98:5
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Tidskriftsartikel (refereegranskat)abstract
- The formation of NiSi1-xGex on Si1-xGex(111) substrates with x=0, 0.05, and 0.20 at an annealing temperature of 500 degrees C has been studied by x-ray diffraction, transmission electron microscopy, and pole-figure measurements. NiSi formed preferentially oriented on Si, with (100), (001), and (102) parallel to Si(111) and NiSi[010]parallel to Si < 211 >. In NiSi0.95Ge0.05, (001) and (102) maintained their preferential orientations, whereas NiSi0.95Ge0.05(100) was rotated by 30 degrees, so that NiSi0.95Ge0.05[010]parallel to Si0.95Ge0.05< 011 >. An epitaxial alignment in the form of a double axiotaxy, with NiSi0.95Ge0.05(2 +/- 11) as well as (20-2)parallel to Si0.95Ge0.05{220}, simultaneously with NiSi0.95Ge0.05(0 +/- 13) as well as (020)parallel to Si0.95Ge0.05{022}, caused NiSi0.95Ge0.05(100) to tilt over the range of 0 degrees-7.5 degrees. The Ge addition also enhanced the preferentially oriented structure by reinforcing NiSi0.95Ge0.05(123)parallel to Si0.95Ge0.05(111) through the axiotaxial alignments, NiSi0.95Ge0.05(211) and (-112)parallel to Si0.95Ge0.05{220}. Observed was also the presence of NiSi0.95Ge0.05(011)parallel to Si0.95Ge0.05(111), with NiSi0.95Ge0.05[100]parallel to Si0.95Ge0.05< 011 >. In the case of NiSi0.80Ge0.20, the preferential orientations were sharply reduced in favor of NiSi0.80Ge0.20(100)parallel to Si0.80Ge0.20(111), with NiSi0.80Ge0.20[010]parallel to Si0.80Ge0.20< 011 > and the 30 degrees rotation thus preserved. The observed Ge influence is shown to be consistent with a model suggested earlier for Si1-xGex(001) substrates, which is based on the nonexistence of Ni(Si1-xGex)(2) for all except the smallest values of x. High-resolution transmission electron microscopy was used to show that the surface steps typical of molecular-beam-deposited epitaxial Si1-xGex substrate films do not influence the growth of the NiSi1-xGex.
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| 41. |
- Jarmar, T., et al.
(författare)
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Morphological and phase stability of nickel-germanosilicide on Si1-xGex under thermal stress
- 2002
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 92:12, s. 7193-7199
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Tidskriftsartikel (refereegranskat)abstract
- Continuous and uniform Ni(Si,Ge) layers are formed on polycrystalline Si and Si0.42Ge0.58 substrate films at 500 degreesC by rapid thermal processing. The germanosilicide is identified as NiSi0.42Ge0.58, i.e., with the same Si-to-Ge ratio as in the substrate. The NiSi0.42Ge0.58 layer has agglomerated at 600 degrees C. This is accompanied by a diffusion of Ge out from the germanosilicide grains and the growth of a Ge-rich SiGe region in their close vicinity. These changes cause a slight variation in the atomic composition of Ni(Si,Ge) detectable for individual grains by means of energy dispersive spectroscopy. Above 600 degreesC, substantial outdiffusion of Ge from the Ni(Si,Ge) grains occurs concurrently with the migration of the grains into the substrate film away from the surface area leaving a Ge-rich SiGe region behind. These observations can be understood with reference to calculated Ni-Si-Ge ternary phase diagrams with and without the inclusion of NiSi2. When Ge is present, the Ni-based self-aligned silicide process presents a robust technique with respect to device applications.
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| 42. |
- Lek, M, et al.
(författare)
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A homeodomain feedback circuit underlies step-function interpretation of a Shh morphogen gradient during ventral neural patterning
- 2010
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Ingår i: Development (Cambridge, England). - : The Company of Biologists. - 1477-9129 .- 0950-1991. ; 137:23, s. 4051-4060
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Tidskriftsartikel (refereegranskat)abstract
- The deployment of morphogen gradients is a core strategy to establish cell diversity in developing tissues, but little is known about how small differences in the concentration of extracellular signals are translated into robust patterning output in responding cells. We have examined the activity of homeodomain proteins, which are presumed to operate downstream of graded Shh signaling in neural patterning, and describe a feedback circuit between the Shh pathway and homeodomain transcription factors that establishes non-graded regulation of Shh signaling activity. Nkx2 proteins intrinsically strengthen Shh responses in a feed-forward amplification and are required for ventral floor plate and p3 progenitor fates. Conversely, Pax6 has an opposing function to antagonize Shh signaling, which provides intrinsic resistance to Shh responses and is important to constrain the inductive capacity of the Shh gradient over time. Our data further suggest that patterning of floor plate cells and p3 progenitors is gated by a temporal switch in neuronal potential, rather than by different Shh concentrations. These data establish that dynamic, non-graded changes in responding cells are essential for Shh morphogen interpretation, and provide a rationale to explain mechanistically the phenomenon of cellular memory of morphogen exposure.
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- Narahashi, T, et al.
(författare)
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Mechanisms of alcohol-nicotine interactions: alcoholics versus smokers.
- 2001
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Ingår i: Alcoholism, clinical and experimental research. - 0145-6008. ; 25:5 Suppl ISBRA
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Forskningsöversikt (refereegranskat)abstract
- This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were Toshio Narahashi and Bo Söderpalm. The presentations were (1) Nicotinic mechanisms and ethanol reinforcement: Behavioral and neurochemical studies, by Bo Söderpalm, M. Ericson, P. Olausson, and J. A. Engel; (2) Chronic nicotine and ethanol: Differential regulation in gene expression of nicotinic acetylcholine receptor subunits, by X. Zhang and A. Nordberg; (3) Nicotine-ethanol interactions at neuronal nicotinic acetylcholine receptors, by Toshio Narahashi, William Marszalec, and Gary L. Aistrup; (4) Relapse prevention in alcoholics by cigarette smoking? Treatment outcome in an observational study with acamprosate, by L.G. Schmidt, U. Kalouti, M. Smolka, and M. Soyka; and (5) Effect of nicotine on voluntary ethanol intake and development of alcohol dependence in male rats, by L. Hedlund and G. Wahlström.
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- Paulsen, Marianne H., et al.
(författare)
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An amphipathic cyclic tetrapeptide scaffold containing halogenated β2,2-amino acids with activity against multiresistant bacteria
- 2018
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Ingår i: Journal of Peptide Science. - : John Wiley & Sons. - 1075-2617 .- 1099-1387. ; 24:10
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Tidskriftsartikel (refereegranskat)abstract
- The present study describes the synthesis and biological studies of a small series of head-to-tail cyclic tetrapeptides of the general structure c(Lys‐β2,2‐Xaa‐Lys) containing one lipophilic β2,2-amino acid and Lys, Gly, Ala, or Phe as the Xaa residue in the sequence. The peptides were investigated for antimicrobial activity against gram-positive and gram-negative reference strains and 30 multiresistant clinical isolates including strains with extended spectrum β-lactamase-carbapenemase (ESBL-CARBA) production. Toxicity was determined against human red blood cells. The most potent peptides showed high activity against the gram-positive clinical isolates with minimum inhibitory concentrations of 4-8μg/mL and low haemolytic activity. The combination of high antimicrobial activity and low toxicity shows that these cyclic tetrapeptides containing lipophilic β2,2-amino acids form a valuable scaffold for designing novel antimicrobial agents.
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