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| 2. |
- Ayerden, N.P., et al.
(författare)
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Design, fabrication and characterization of LVOF-based IR microspectrometers
- 2014
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. - 9781628410785 ; 9130
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Konferensbidrag (refereegranskat)abstract
- This paper presents the design, fabrication and characterization of a linear variable optical filter (LVOF) that operates in the infrared (IR) spectral range. An LVOF-based microspectrometer is a tapered-cavity Fabry-Perot optical filter placed on top of a linear array of detectors. The filter transforms the optical spectrum into a lateral intensity profile, which is recorded by the detectors. The IR LVOF has been fabricated in an IC-compatible process flow using a resist reflow and is followed by the transfer etching of this resist pattern into the optical resonator layer. This technique provides the possibility to fabricate a small, robust and high-resolution micro-spectrometer in the IR spectral range directly on a detector chip. In these designs, the LVOF uses thin-film layers of sputtered Si and SiO 2 as the high and low refractive index materials respectively. By tuning the deposition conditions and analyzing the optical properties with a commercial ellipsometer, the refractive index for Si and SiO2 thin-films was measured and optimized for the intended spectral range. Two LVOF microspectrometers, one operating in the 1.8-2.8 μm, and the other in the 3.0-4.5 μm wavelength range, have been designed and fabricated on a silicon wafer. The filters consist of a Fabry-Perot structure combined with a band-pass filter to block the out-of-band transmission. Finally, the filters were fully characterized with an FTIR spectrometer and the transmission curve widening was investigated. The measured transmittance curves were in agreement with theory. The characterization shows a spectral resolution of 35-60 nm for the short wavelength range LVOF and 70 nm for the long wavelength range LVOF, which can be further improved using signal processing algorithms.
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| 3. |
- Brinkfeldt, Klas, et al.
(författare)
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Microshutters for MEMS-based time-of-flight measurements in space
- 2011
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Ingår i: Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS). - 1084-6999. - 9781424496327 ; , s. 597-600
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Konferensbidrag (refereegranskat)abstract
- This paper reports on the fabrication, integration and first operation of a mechanical microshutter in a time-of-flight (TOF) based ion detector in space. The microshutter is fabricated from a silicon on insulator (SOI) wafer and operated in a resonance mode, 306 kHz. Open time of the shutter is 100 ns. The microshutters are integrated in the PRIMA instrument, which is part of the payload on the Swedish PRISMA mission. PRISMA was successfully launched into low Earth orbit on June 15, 2010.
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| 5. |
- Brinkfelt, Klas, 1976, et al.
(författare)
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Microshutters for space physics time of flight applications
- 2010
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Ingår i: 21st Micromechanics and Micro systems Europe workshop, 26-29 September 2010, Enschede, The Netherlands. ; , s. 140-143
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Konferensbidrag (refereegranskat)abstract
- In present time-of-flight (TOF) mass and energy spectrometers in experimental space plasmaphysics applications, the resolution is limited by the fact that the particle to be measured loses part of its energyin the generation of the start pulse. To improve the resolution, a fast micromechanical shutter system togenerate the start signal has been developed. The microshutter is included in the PRIMA (PRIsma MassAnalyzer) ion detector on-board the Swedish PRISMA mission, which will be launched into low Earth orbit onJune 15, 2010.
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| 6. |
- Enoksson, M, et al.
(författare)
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Human cord blood-derived mast cells are activated by the Nod1 agonist M-TriDAP to release pro-inflammatory cytokines and chemokines
- 2011
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Ingår i: Journal of innate immunity. - : S. Karger AG. - 1662-8128 .- 1662-811X. ; 3:2, s. 142-149
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Tidskriftsartikel (refereegranskat)abstract
- Mast cells are among the first cells of our immune system to encounter exogenous danger. Intracellular receptors such as nucleotide-binding oligomerization domain (Nod) play an important role in responding to invading pathogens. Here, we have investigated the response of human mast cells to the Nod1 ligand M-TriDAP. Human cord blood-derived mast cells (CBMCs) were activated with M-TriDAP alone, or in combination with the Toll-like receptor (TLR) ligands lipopolysaccharide (LPS) and zymosan. Release of pro-inflammatory chemokines and cytokines was measured by ELISA, cytometric bead array and LUMINEX, and degranulation was evaluated by analysis of histamine release. M-TriDAP induced a dose-dependent release of IL-8, MIP-1α, MIP-1β and TNF. In contrast, degranulation could not be observed. When cells were treated with M-TriDAP in combination with the TLR4 agonist LPS, but not with TLR2 agonist zymosan, the secretion of cytokines was augmented. We here present results demonstrating that human CBMCs are stimulated by the Nod1 agonist M-TriDAP alone and in combination with LPS to produce pro-inflammatory cytokines and chemokines. Our results add to the concept that mast cells constitute an important part of our host defense, as they are equipped with several types of important pattern recognition receptors, including TLRs and Nod.
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| 7. |
- Enoksson, M, et al.
(författare)
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Mast cells as sensors of cell injury through IL-33 recognition
- 2011
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Ingår i: Journal of immunology (Baltimore, Md. : 1950). - : The American Association of Immunologists. - 1550-6606 .- 0022-1767. ; 186:4, s. 2523-2528
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Tidskriftsartikel (refereegranskat)abstract
- In response to cell injury, caused, for example, by trauma, several processes must be initiated simultaneously to achieve an acute inflammatory response designed to prevent sustained tissue damage and infection and to restore and maintain tissue homeostasis. Detecting cell injury is facilitated by the fact that damaged cells release intracellular molecules not normally present in the extracellular space. However, potential underlying mechanisms for the recognition of endogenous danger signals released upon cell injury have yet to be elucidated. In this study, we demonstrate that mast cells, potent promoters of acute inflammation, play a key role in responding to cell injury by recognizing IL-33 released from necrotic structural cells. In an in vitro model of cell injury, this recognition was shown to involve the T1/ST2 receptor and result in the secretion of proinflammatory leukotrienes and cytokines by mouse mast cells. Remarkably, of all of the components released upon necrosis, our results show that IL-33 alone is a key component responsible for initiating proinflammatory responses in mast cells reacting to cell injury. Our findings identify IL-33 as a key danger signal released by necrotic structural cells capable of activating mast cells, thus providing novel insights concerning the role of mast cells as sensors of cell injury.
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| 8. |
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| 9. |
- Enoksson, Tomas, et al.
(författare)
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Nucleus accumbens D2- and D1-receptor expressing medium spiny neurons are selectively activated by morphine withdrawal and acute morphine, respectively
- 2012
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Ingår i: Neuropharmacology. - : Elsevier BV. - 0028-3908 .- 1873-7064. ; 62:8, s. 2463-2471
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Tidskriftsartikel (refereegranskat)abstract
- Opioids are effective analgesic agents but serious adverse effects such as tolerance and withdrawal contribute to opioid dependence and limit their use. Opioid withdrawal involves numerous brain regions and includes suppression of dopamine release and activation of neurons in the ventral striatum. By contrast, acute opioids increase dopamine release. Like withdrawal, acute opioids also activate neurons in the ventral striatum, suggesting that different populations of ventral striatal neurons may be activated by withdrawal and acute opioid actions. Here, immunofluorescence for the activity-related immediate-early gene, c-Fos, was examined in transgenic reporter mouse lines by confocal microscopy to study the specific populations of ventral striatal neurons activated by morphine withdrawal and acute morphine. After chronic morphine, naloxone-precipitated withdrawal strongly increased expression of c-Fos immunoreactivity, predominantly in D2-receptor (D2R) medium-sized spiny neurons (MSNs) of the nucleus accumbens (NAc) core and shell regions. By contrast, a single injection of morphine exclusively activated c-Fos immunoreactivity in D1-receptor expressing (D1R) MSNs of the core and shell of the NAc. These results reveal a striking segregation of neuronal responses occurring in the two populations of MSNs of the NAc in response to morphine withdrawal and acute morphine.
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| 10. |
- Ghaderi, M., et al.
(författare)
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Design, fabrication and characterization of infrared LVOFs for measuring gas composition
- 2014
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Ingår i: Journal of Micromechanics and Microengineering. - : IOP Publishing. - 1361-6439 .- 0960-1317. ; 24:8, s. Art. no. 084001-
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the design, fabrication and characterization of a linear-variable optical-filter (LVOF) that will be used in a micro-spectrometer operating in infrared (IR) for natural gas composition measurement. An LVOF is placed on top of an array of detectors and transforms the optical spectrum into a lateral intensity profile, which is recorded by the detectors. The IR LVOF was fabricated in an IC-compatible process using a photoresist reflow technique, followed by transfer etching of the photoresist into the optical resonator layer. The spectral range between 3 to 5 mu m contains the absorption peaks for hydrocarbons, carbon-monoxide and carbon-dioxide. The resulting optical absorption is utilized to measure the gas concentrations in a sample volume. Two LVOF structures were designed and fabricated on silicon wafers using alternate layers of sputtered silicon and silicon-dioxide as the high- and low- refractive index materials. These filters consist of a Fabry-Perot resonator combined with a band-pass filter designed to block out-of-band transmissions. Finally, the filters were fully characterized with an FTIR spectrometer and showed satisfactory agreement with the optical thin-film simulations. The characterization showed a spectral resolution of 100 nm, which can be further improved with signal processing algorithms. This method makes it possible to fabricate small and robust LVOFs with high resolving power in the IR spectral range directly on the detector array chip.
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