| 1. |
- Norell-Clarke, Annika, 1979-, et al.
(författare)
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Sleep-related cognitive processes and the incidence of insomnia over time : Does anxiety and depression impact the relationship?
- 2021
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Ingår i: Frontiers in Psychology. - : Frontiers Media S.A.. - 1664-1078. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Aim: According to the Cognitive Model of Insomnia, engaging in sleep-related cognitive processes may lead to sleep problems over time. The aim was to examine associations between five sleep-related cognitive processes and the incidence of insomnia, and to investigate if baseline anxiety and depression influence the associations. Methods: Two thousand three hundred and thirty-three participants completed surveys on nighttime and daytime symptoms, depression, anxiety, and cognitive processes at baseline and 6 months after the first assessment. Only those without insomnia at baseline were studied. Participants were categorized as having or not having incident insomnia at the next time point. Baseline anxiety and depression were tested as moderators. Results: Three cognitive processes predicted incident insomnia later on. Specifically, more safety behaviors and somatic arousal at Time 1 increased the risk of developing insomnia. When investigating changes in the cognitive processes over time, reporting an increase of worry and safety behaviors also predicted incident insomnia. Depressive symptoms moderated the association between changes in worry and incident insomnia. Conclusion: These findings provide partial support for the hypothesis that cognitive processes are associated with incident insomnia. In particular, safety behaviors, somatic arousal, and worry increase the risk for incident insomnia. Preventative interventions and future research are discussed.
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| 2. |
- Ahlroth, Mikael, et al.
(författare)
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Bark and wood powder firing in the recovery boiler for maximum power generation
- 2017
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Ingår i: International chemical recovery conference, May 24-26, 2017, Halifax, Canada. - : PAPTAC.
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Konferensbidrag (refereegranskat)abstract
- The effect of co-firing bark or wood powder in a recovery boiler is studied. The effect of increased NPEs in the liquor and lime cycles, the FMT and sticky dust and the smelt composition is assessed by using simulation tools. The results indicate that generating an additional 22-39% HP steam for power production by firing wood powder in the recovery boiler is a viable option, if Cl and K are purged from the ESP dust by a treatment unit. The smelt is enriched with the same proportion of NPEs as the as-fired liquor.
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| 3. |
- Benson, Mikael, 1954, et al.
(författare)
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Gene profiling reveals decreased expression of uteroglobin and other anti-inflammatory genes in nasal fluid cells from patients with intermittent allergic rhinitis
- 2005
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Ingår i: Clin Exp Allergy. - : Wiley. ; 35:4, s. 473-478
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Intermittent allergic rhinitis (IAR) results from interactions between a large number of pro- and anti-inflammatory mediators. Little is known about anti-inflammatory mediators in IAR. DNA microarrays allow simultaneous analysis of the whole transcriptome in a sample. OBJECTIVE: To identify anti-inflammatory transcripts in nasal fluid cells from patients with IAR during season and from healthy controls. METHODS: Nasal lavage fluids were obtained from 15 patients with symptomatic birch/and or grass pollen-induced IAR and 28 healthy controls. RNA was extracted from the nasal fluid cells and pooled into one patient- and one control pool. These were analysed with DNA microarrays containing more than 44,927 genes and variants. RESULTS: Seventeen thousand three hundred and fifty three genes were expressed in the controls and 17 928 in the patients. One thousand five hundred and seventy nine of the genes had higher expression in patients than in controls, and 1570 had lower expression in patients. Out of 189 up-regulated inflammatory genes, 187 were pro-inflammatory and two were anti-inflammatory. These genes regulated key steps of inflammation, ranging from influx of leukocytes to immunoglobulin production. By comparison, out of 49 down-regulated inflammatory genes, 36 were pro-inflammatory and 13 were anti-inflammatory. The anti-inflammatory gene that decreased most in expression in the patients was uteroglobin (also known as Clara Cell protein 16, CC16). The nasal fluid concentrations of uteroglobin protein were significantly lower in patients than in controls, 5.43+/-1.53 and 12.93+/-2.53 ng/mL, respectively (P<0.05). CONCLUSION: IAR is associated with decreased expression of uteroglobin and other anti-inflammatory genes.
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| 4. |
- Fransson, Mattias, et al.
(författare)
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Expression of Toll-like receptor 9 in nose, peripheral blood and bone marrow during symptomatic allergic rhinitis.
- 2007
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Ingår i: Respiratory research. - : Springer Science and Business Media LLC. - 1465-993X .- 1465-9921. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Allergic rhinitis is an inflammatory disease of the upper airway mucosa that also affects leukocytes in bone marrow and peripheral blood. Toll-like receptor 9 (TLR9) is a receptor for unmethylated CpG dinucleotides found in bacterial and viral DNA. The present study was designed to examine the expression of TLR9 in the nasal mucosa and in leukocytes derived from different cellular compartments during symptomatic allergic rhinitis. METHODS: The study was based on 32 patients with seasonal allergic rhinitis and 18 healthy subjects, serving as controls. Nasal biopsies were obtained before and after allergen challenge. Bone marrow, peripheral blood and nasal lavage fluid were sampled outside and during pollen season. The expression of TLR9 in tissues and cells was analyzed using immunohistochemistry and flow cytometry, respectively. RESULTS: TLR9 was found in several cell types in the nasal mucosa and in different leukocyte subpopulations derived from bone marrow, peripheral blood and nasal lavage fluid. The leukocyte expression was generally higher in bone marrow than in peripheral blood, and not affected by symptomatic allergic rhinitis. CONCLUSION: The widespread expression of TLR9 in the nasal mucosa along with its rich representation in leukocytes in different compartments, demonstrate the possibility for cells involved in allergic airway inflammation to directly interact with bacterial and viral DNA.
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| 5. |
- Karlsson, Dennis, et al.
(författare)
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Binder jetting of the AlCoCrFeNi alloy
- 2019
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Ingår i: Additive Manufacturing. - : Elsevier. - 2214-8604 .- 2214-7810. ; 27, s. 72-79
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Tidskriftsartikel (refereegranskat)abstract
- High density components of an AlCoCrFeNi alloy, often described as a high-entropy alloy, were manufactured by binder jetting followed by sintering. Thermodynamic calculations using the CALPHAD approach show that the high-entropy alloy is only stable as a single phase in a narrow temperature range below the melting point. At all other temperatures, the alloy will form a mixture of phases, including a sigma phase, which can strongly influence the mechanical properties. The phase stabilities in built AlCoCrFeNi components were investigated by comparing the as-sintered samples with the post-sintering annealed samples at temperatures between 900 °C and 1300 °C. The as-sintered material shows a dominant B2/bcc structure with additional fcc phase in the grain boundaries and sigma phase precipitating in the grain interior. Annealing experiments between 1000 °C and 1100 °C inhibit the sigma phase and only a B2/bcc phase with a fcc phase is observed. Increasing the temperature further suppresses the fcc phase in favor for the B2/bcc phases. The mechanical properties are, as expected, dependent on the annealing temperature, with the higher annealing temperature giving an increase in yield strength from 1203 MPa to 1461 MPa and fracture strength from 1996 MPa to 2272 MPa. This can be explained by a hierarchical microstructure with nano-sized precipitates at higher annealing temperatures. The results enlighten the importance of microstructure control, which can be utilized in order to tune the mechanical properties of these alloys. Furthermore, an excellent oxidation resistance was observed with oxide layers with a thickness of less than 5 μm after 20 h annealing at 1200 °C, which would be of great importance for industrial applications.
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| 6. |
- Lee, S. K., et al.
(författare)
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Electrical characterization of TiC ohmic contacts to aluminum ion implanted 4H-silicon carbide
- 2000
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 77:10, s. 1478-1480
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Tidskriftsartikel (refereegranskat)abstract
- We report on the investigation of epitaxial TiC ohmic contacts to Al ion implanted 4H-SiC. TiC ohmic contacts were formed by coevaporation of Ti and C-60 at low temperature (< 500 degrees C). A sacrificial silicon nitride (Si3N4) layer was deposited on the silicon carbide substrate prior to Al implantation in order to reach a high Al dopant concentration at the surface while maintaining a low dose. The combination of epitaxially grown TiC and the silicon nitride layer resulted in a promising scheme to make low resistivity ohmic contacts. The lowest contact resistivity (rho(C)) and sheet resistance (R-s) of the implanted layer at 25 degrees C were as low as 2 x 10(-5) Ohm cm(2) and 0.6 k Ohm/square, respectively.
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| 7. |
- Lee, S. K., et al.
(författare)
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Low resistivity ohmic contacts on 4H-silicon carbide for high power and high temperature device applications
- 2002
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Ingår i: Microelectronic Engineering. - 0167-9317 .- 1873-5568. ; 60:1-2, s. 261-268
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Tidskriftsartikel (refereegranskat)abstract
- We investigated titanium based ohmic contacts using co-evaporated epitaxial titanium carbide (TiC) on highly doped n(+)- and p(+)-type epilayers as well as Al ion implanted layers for high power and high temperature device application. Epitaxially grown TiC ohmic contacts on epilayers as well as Al implanted layers of 4H-SiC were formed by UHV co-evaporation with Ti and C-60 at low substrate temperature. The specific contact resistance (rho(C)) was as low as 5 x 10(-6), 2 x 10(-5), and 2 x 10(-5) Omegacm(2) for TiC contacts on n(+), on p(+) epilayer, and on Al implanted layer, respectively, using a linear TLM measurement. In addition to TiC, we also investigated TiW (weight ratio 30:70) ohmic contacts to p- and n-type 4H-SiC for the purpose of long-term reliability tests at high temperature. The average rho(C) of sputtered TiW contacts was 4 x 10(-5) for p(+) and n(+) epilayer. We also found that an evaporated top layer (Au or Pt) helps to protect from degradation of the contacts under long-term reliability tests with temperatures of up to 600degreesC in a vacuum chamber.
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| 8. |
- Lee, S. K., et al.
(författare)
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Low resistivity ohmic titanium carbide contacts to n- and p-type 4H-silicon carbide
- 2000
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Ingår i: Solid-State Electronics. - 0038-1101 .- 1879-2405. ; 44:7, s. 1179-1186
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Tidskriftsartikel (refereegranskat)abstract
- Low resistivity Ohmic contacts of epitaxial titanium carbide to highly doped n- (1.3 x 10(19) cm(-3)) and p- (>10(20) cm(-3)) type epilayer on 4H-SiC were investigated. The titanium carbide contacts were epitaxially grown using coevaporation with an e-beam for Ti and a Knudsen cell for C-60 in a UHV system. A comparison of epitaxial evaporated Ti Ohmic contacts on p(+) epilayer of 4H-SiC is also given. The as-deposited TiC Ohmic contacts showed a good Ohmic behavior and the lowest contact resistivity (rho(C)) was 7.4 x 10(-7) Ohm cm(2) at 200 degrees C for n-type, and 1.1 x 10(-4) Ohm cm(2) at 25 degrees C for p-type contacts. Annealing at 950 degrees C did not improve the Ohmic contact to n-type 4H-SiC, but instead resulted in an increase in rho(C) to 4.01 x 10(-5) Ohm cm(2) at 25 degrees C. In contrast to n-type, after annealing at 950 degrees C the specific rho(C) for p-type SiC reached its lowest value of 1.9 x 10(-5) Ohm cm(2) at 300 degrees C. Our results indicate that co-evaporated TiC contacts to n- and p-type epilayers of 4H-SiC should not require a higher post-annealing temperature, contrary to earlier works. Material characteristics, utilizing X-ray diffraction, Low energy electron diffraction, Rutherford backscattering spectrometry, transmission electron microscopy, and X-ray photoelectron spectroscopy measurements are also discussed.
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| 9. |
- Lee, S. -K, et al.
(författare)
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The formation and characterization of epitaxial titanium carbide contacts to 4H-SiC
- 2000
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Ingår i: Materials Research Society Symposium - Proceedings. - San Francisco, CA. ; , s. T691-T696
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Konferensbidrag (refereegranskat)abstract
- Epitaxial TiC Ohmic and Schottky contacts to 4H-SiC were formed by a new deposition method, UHV co-evaporation with Ti and C60, at low temperature (< 500°C). We achieved a contact resistivity of 2 × 10-5 Ωcm2 at 25°C for as deposited Ohmic contacts on Al ion implanted 4H-Silicon carbide. The rectifying behavior of TiC Schottky contacts was also investigated using I-V and C-V. The measured Schottky barrier height (SBH) was 1.26 eV for n-type and 1.65 eV for p-type 4H-SiC using C-V measurements for frequencies ranging from 1kHz to 1MHz. LEED, RBS, XPS, and XRD measurements were performed to analyze composition ratio, interface reaction, and structural properties of the TiC epitaxial layer.
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| 10. |
- Lundberg, N., et al.
(författare)
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CVD-based tungsten carbide Schottky contacts to 6H-SiC for very high-temperature operation
- 2000
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Ingår i: Journal of Electronic Materials. - : Springer Science and Business Media LLC. - 0361-5235 .- 1543-186X. ; 29:3, s. 372-375
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Tidskriftsartikel (refereegranskat)abstract
- In this study, tungsten carbide, with its hardness, chemical inertness, thermal stability and low resistivity (25 mu Omega cm)(1) is shown as a reliable contact material to n- and p-type 6H-SiC for very high temperature applications. WC films with thicknesses of 100-150 nm were deposited by chemical vapor deposition (CVD) from a WF6/C3H8/H-2 mixture at 1173 K. A method to pattern CVD-tungsten carbide is suggested. TEM analysis of as deposited samples displayed a clear and unreacted interface. The electrical investigations of the p-type 6H-SiC Schottky contacts revealed a high rectification ratio and a low reverse current density (6.1 x 10(-5) A cm(-2), -10 V) up to 713 K. On n-type, a low barrier (Phi(Bn) = 0.79 eV) at room temperature was observed. The low Phi(Bn) value suggests WC to be promising as an ohmic contact material on highly doped n-type epi-layers. We will show a temperature dependence for the barrier height of tungsten carbide contacts that can be related to the simultaneous change in the energy bandgap, which should be considered when designing SiC devices intended for high temperature operation.
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