| 1. |
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| 2. |
- Bergström, L, et al.
(författare)
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Spectroscopic ellipsometry characterisation and estimation of the Hamaker constant of cellulose
- 1999
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Ingår i: Cellulose. - 0969-0239 .- 1572-882X. ; 6, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Calculations of Hamaker constants using Lifshitz theory require the availability of accurate dielectric data, especially in the visible-ultraviolet region. We present spectroscopic ellipsometry data on well defined cellulose films of a limited thickness range (100–140 layers) deposited on an oxidised and hydrophobised silicon substrate. The spectral data, representing measurements from a perpendicular orientation to the fibre deposition direction, was used for estimates of the necessary spectral parameters, i.e. the oscillator strengths and characteristic frequencies in the UV-range. Our calculations show that cellulose has a relatively low Hamaker constant in air (58 zJ) and water (8.0 zJ). The implications for the surface energy estimates of cellulose and colloidal interactions between cellulose and various types of fillers and coating colours were discussed.
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| 3. |
- Braun, Stefan, et al.
(författare)
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Small footprint knife gate microvalves for large flow control
- 2005
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Ingår i: The 13th International Conference on Solid-State Sensors, Actuators and Microsystems conference (IEEE TRANSDUCERS 2005). - NEW YORK : IEEE conference proceedings. ; , s. 329-332
-
Konferensbidrag (refereegranskat)abstract
- This paper introduces the first area-optimized micromachined knife gate microvalve. In comparison to recent microvalves the pressure-flow performance is increased using out-of-plane actuators and an out-of-plane orifice. Three different actuator-gate designs and their fabrication are described. The valve features integrated therinal silicon/aluminum bimorph actuators where the aluminum layer forins the resistive heater as well as the bimorph material. The characterization of the actuators and of the pressure-flow perfon-nance is presented. The valve allows a flow change of Delta Q=3.4 1/min at 100 kPa on an active chip area of only 2.3 x 3.7 mm(2).
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| 4. |
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| 5. |
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| 6. |
- Buchmann, Sebastian, et al.
(författare)
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Probabilistic cell seeding and non-autofluorescent 3D-printed structures as scalable approach for multi-level co-culture modeling
- 2023
-
Ingår i: Materials Today Bio. - : Elsevier BV. - 2590-0064. ; 21, s. 100706-100706
-
Tidskriftsartikel (refereegranskat)abstract
- To model complex biological tissue in vitro, a specific layout for the position and numbers of each cell type isnecessary. Establishing such a layout requires manual cell placement in three dimensions (3D) with micrometricprecision, which is complicated and time-consuming. Moreover, 3D printed materials used in compartmentalizedmicrofluidic models are opaque or autofluorescent, hindering parallel optical readout and forcing serial charac-terization methods, such as patch-clamp probing. To address these limitations, we introduce a multi-level co-culture model realized using a parallel cell seeding strategy of human neurons and astrocytes on 3D structuresprinted with a commercially available non-autofluorescent resin at micrometer resolution. Using a two-stepstrategy based on probabilistic cell seeding, we demonstrate a human neuronal monoculture that forms net-works on the 3D printed structure and can establish cell-projection contacts with an astrocytic-neuronal co-cultureseeded on the glass substrate. The transparent and non-autofluorescent printed platform allows fluorescence-based immunocytochemistry and calcium imaging. This approach provides facile multi-level compartmentaliza-tion of different cell types and routes for pre-designed cell projection contacts, instrumental in studying complextissue, such as the human brain.
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| 7. |
- Dubois, Valentin J., et al.
(författare)
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Massively parallel fabrication of crack-defined gold break junctions featuring sub-3 nm gaps for molecular devices
- 2018
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Break junctions provide tip-shaped contact electrodes that are fundamental components of nano and molecular electronics. However, the fabrication of break junctions remains notoriously time-consuming and difficult to parallelize. Here we demonstrate true parallel fabrication of gold break junctions featuring sub-3 nm gaps on the wafer-scale, by relying on a novel self-breaking mechanism based on controlled crack formation in notched bridge structures. We achieve fabrication densities as high as 7 million junctions per cm(2), with fabrication yields of around 7% for obtaining crack-defined break junctions with sub-3 nm gaps of fixed gap width that exhibit electron tunneling. We also form molecular junctions using dithiol-terminated oligo(phenylene ethynylene) (OPE3) to demonstrate the feasibility of our approach for electrical probing of molecules down to liquid helium temperatures. Our technology opens a whole new range of experimental opportunities for nano and molecular electronics applications, by enabling very large-scale fabrication of solid-state break junctions.
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| 8. |
- Enrico, Alessandro, et al.
(författare)
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Ultrafast and Resist-Free Nanopatterning of 2D Materials by Femtosecond Laser Irradiation
- 2023
-
Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 17:9, s. 8041-8052
-
Tidskriftsartikel (refereegranskat)abstract
- The performance of two-dimensional (2D) materials is promising for electronic, photonic, and sensing devices since they possess large surface-to-volume ratios, high mechanical strength, and broadband light sensitivity. While significant advances have been made in synthesizing and transferring 2D materials onto different substrates, there is still the need for scalable patterning of 2D materials with nanoscale precision. Conventional lithography methods require protective layers such as resist or metals that can contaminate or degrade the 2D materials and deteriorate the final device performance. Current resist-free patterning methods are limited in throughput and typically require custom-made equipment. To address these limitations, we demonstrate the noncontact and resist-free patterning of platinum diselenide (PtSe2), molybdenum disulfide (MoS2), and graphene layers with nanoscale precision at high processing speed while preserving the integrity of the surrounding material. We use a commercial, off-the-shelf two-photon 3D printer to directly write patterns in the 2D materials with features down to 100 nm at a maximum writing speed of 50 mm/s. We successfully remove a continuous film of 2D material from a 200 μm × 200 μm substrate area in less than 3 s. Since two-photon 3D printers are becoming increasingly available in research laboratories and industrial facilities, we expect this method to enable fast prototyping of devices based on 2D materials across various research areas.
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| 9. |
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| 10. |
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| 11. |
- Forsberg, Fredrik, et al.
(författare)
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CMOS-integrated Si/SiGe quantum-well infrared microbolometer focal plane arrays manufactured with very large-scale heterogeneous 3-d integration
- 2015
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - : Institute of Electrical and Electronics Engineers Inc.. - 0792-1233 .- 1077-260X .- 1558-4542. ; 21:4
-
Tidskriftsartikel (refereegranskat)abstract
- We demonstrate infrared focal plane arrays utilizing monocrystalline silicon/silicon-germanium (Si/SiGe) quantum-well microbolometers that are heterogeneously integrated on top of CMOS-based electronic read-out integrated circuit substrates. The microbolometers are designed to detect light in the long wavelength infrared (LWIR) range from 8 to 14 μm and are arranged in focal plane arrays consisting of 384 × 288 microbolometer pixels with a pixel pitch of 25 μm × 25 μm. Focal plane arrays with two different microbolometer designs have been implemented. The first is a conventional single-layer microbolometer design and the second is an umbrella design in which the microbolometer legs are placed underneath the microbolometer membrane to achieve an improved pixel fill-factor. The infrared focal plane arrays are vacuum packaged using a CMOS compatible wafer bonding and sealing process. The demonstrated heterogeneous 3-D integration and packaging processes are implemented at wafer-level and enable independent optimization of the CMOS-based integrated circuits and the microbolometer materials. All manufacturing is done using standard semiconductor and MEMS processes, thus offering a generic approach for integrating CMOS-electronics with complex miniaturized transducer elements
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| 12. |
- Haasl, S., et al.
(författare)
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Arrays of monocrystalline silicon micromirrors fabricated using CMOS compatible transfer bonding
- 2003
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Ingår i: Proc. MEMS-03 Kyoto Micro Electro Mechanical Systems IEEE The Sixteenth Annual Int. Conf. ; , s. 271-274
-
Konferensbidrag (refereegranskat)abstract
- In this paper, we present CMOS compatible fabrication of monocrystalline silicon micromirror arrays using membrane transfer bonding. To fabricate the micromirrors, a thin monocrystalline silicon device layer is transferred from a standard silicon-on-insulator (SOI) wafer to a target wafer (e.g. a CMOS wafer) using low temperature adhesive wafer bonding. In this way, very flat, uniform and low stress micromirror membranes made of monocrystalline silicon can be directly fabricated on top of CMOS circuits. The mirror fabrication does not contain any bond alignment between the wafers; thus, the mirror dimensions and alignment accuracies are only limited by the photolithographic steps. Micromirror arrays with 4×4 pixels and a pitch size of 16 μm ×16 μm have been fabricated.
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| 13. |
- Haasl, Sjoerd, et al.
(författare)
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Out-of-Plane Knife-Gate Microvalves for Controlling Large Gas Flows
- 2006
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Ingår i: Journal of microelectromechanical systems. - : IEEE Press. - 1057-7157 .- 1941-0158. ; 15:5, s. 1281-1288
-
Tidskriftsartikel (refereegranskat)abstract
- This paper considers design issues for microvalves for large gas flow control. It introduces out-of-plane knife-gate microvalves as a novel design concept and a proportional microvalve concept for pressure control applications. The design of three different actuator-gate configurations and first prototypes are presented. The first valve prototypes feature thermal silicon-aluminum bimorph actuators and the pressure-flow performance per chip area of the demonstrator valve presented is greatly increased using out-of-plane actuation and an out-of-plane orifice. The characterization of the actuators and of the pressure-flow performance is presented. The prototype valve allows for a flow change of Delta Q = 3.4 standard liters per minute (SLPM) at a pressure change of Delta P = 95 kPa (P-in = 196.3 kPa, P-out = 101.3 kPa) on an active chip area of only 2.3 x 3.7 mm(2).
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| 14. |
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| 15. |
- Hansson, GK, et al.
(författare)
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Autoimmunity in atherosclerosis
- 1997
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Ingår i: ATHEROSCLEROSIS. - 0021-9150. ; 134:1-2, s. 289-289
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 16. |
- Hansson, H A, et al.
(författare)
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Evidence indicating trophic importance of IGF-I in regenerating peripheral nerves
- 1986
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Ingår i: Acta Physiologica Scandinavica. - : Wiley. - 0001-6772 .- 1365-201X. ; 126:4, s. 14-609
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Tidskriftsartikel (refereegranskat)abstract
- The mechanisms influencing regeneration of peripheral nerves are incompletely known, but growth factors are supposed to play a key role. In the present study, we demonstrate, with the aid of immunohistochemical methods, that somatomedin C (Sm-C/insulin-like growth factor I/IGF-I) rapidly increased from low to high concentrations, reaching peak values in 2 weeks, in regenerating sciatic nerves of adult rats. In addition, IGF-I was demonstrated extracellularly, never observed in the control nerves. Reactive Schwann cells appeared to be the major source for IGF-synthesis. Higher concentrations were seen in tubulated nerves as compared to sutured ones. It is proposed that IGF-I exerts important growth supporting effects on regenerating peripheral nerves.
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| 17. |
- Holmberg, M, et al.
(författare)
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Surface force studies of Langmuir-Blodgett cellulose films
- 1997
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Ingår i: Journal of Colloid and Interface Science. - 0021-9797 .- 1095-7103. ; 186, s. 369-381
-
Tidskriftsartikel (refereegranskat)abstract
- The interactions between cellulose surfaces, between chitosan coated surfaces and between one cellulose surface and one chitosan coated surface have been studied using the interferometric surface forces apparatus (SFA). The cellulose surfaces were prepared by depositing trimethylsilyl cellulose on hydrophobized mica using the Langmuir-Blodgett technique. The surfaces were desilylated in humid HCl atmosphere to obtain regenerated cellulose. ESCA measurements and wetting studies demonstrated that the desilylation process was effective. AFM studies showed the cellulose surfaces to be smooth with a root mean square roughness of 0.16 nm. Surface force and ellipsometry measurements illustrate that the cellulose film swells considerably in humid air and in water, suggesting that it is mostly amorphous. The interaction between two cellulose surfaces is dominated by a steric repulsion caused by a few dangling tails. On separation an attractive force was present both between two cellulose surfaces and between one cellulose surface and one chitosan surface. The long-range interaction between cellulose and chitosan was shown to be attractive.
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| 18. |
- Huang, Po-Han, et al.
(författare)
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3d Printing of Silica-HSQ Composites with Sub-Micrometer Resolution and Selectively Generated Silicon Nanocrystals
- 2023
-
Ingår i: 2023 22nd International Conference on Solid-State Sensors, Actuators and Microsystems, Transducers 2023. - : Institute of Electrical and Electronics Engineers Inc.. ; , s. 433-436
-
Konferensbidrag (refereegranskat)abstract
- Silica glass is a high-performance material that has become essential in modern life. Functionalization of silica glass is critically important for its optical applications such as in lenses and filters, which is however challenging to realize and manipulate in 3D-printed silica glass. Here, we report 3D printing of solid composites of silica glass and hydrogen silsesquioxane (HSQ) with sub-micrometer resolution. This is achieved by encapsulating HSQ inside silica glass by selectively transforming HSQ to silica glass by multi-photon absorption using a femtosecond laser. Furthermore, we demonstrated selective generation of photoluminescent silicon nanocrystals in the HSQ regions inside the composites by annealing. This is based on our experimental observation that the silica glass transformed from HSQ by multi-photon absorption, unlike HSQ, does not generate silicon nanocrystals upon annealing.
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| 19. |
- Huang, Po-Han, et al.
(författare)
-
Three-dimensional printing of silica glass with sub-micrometer resolution
- 2023
-
Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 14:1
-
Tidskriftsartikel (refereegranskat)abstract
- Silica glass is a high-performance material used in many applications such as lenses, glassware, and fibers. However, modern additive manufacturing of micro-scale silica glass structures requires sintering of 3D-printed silica-nanoparticle-loaded composites at similar to 1200 degrees C, which causes substantial structural shrinkage and limits the choice of substrate materials. Here, 3D printing of solid silica glass with sub-micrometer resolution is demonstrated without the need of a sintering step. This is achieved by locally crosslinking hydrogen silsesquioxane to silica glass using nonlinear absorption of sub-picosecond laser pulses. The as-printed glass is optically transparent but shows a high ratio of 4-membered silicon-oxygen rings and photoluminescence. Optional annealing at 900 degrees C makes the glass indistinguishable from fused silica. The utility of the approach is demonstrated by 3D printing an optical microtoroid resonator, a luminescence source, and a suspended plate on an optical-fiber tip. This approach enables promising applications in fields such as photonics, medicine, and quantum-optics.
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| 20. |
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| 21. |
- Lenk, Gabriel, et al.
(författare)
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Evaluation of a Volumetric Dried Blood Spot Card Using a Gravimetric Method and a Bioanalytical Method with Capillary Blood from 44 Volunteers
- 2019
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 91:9, s. 5558-5565
-
Tidskriftsartikel (refereegranskat)abstract
- Dried blood spot (DBS) sampling is a promising method for collection of microliter blood samples. However, hematocrit-related bias in combination with subpunch analysis can result in inaccurate quantification of analytes in DBS samples. In this study we use a microfluidic DBS card, designed to automatically collect fixed volume DBS samples irrespective of the blood hematocrit, to measure caffeine concentration in normal finger prick samples obtained from 44 human individuals. Caffeine levels originating from blood drops of unknown volume collected on the volumetric microfluidic DBS card were compared to volume-controlled pipetted DBS samples from the same finger prick. Hematocrit independence and volumetric sampling performances were also verified on caffeine-spiked blood samples in vitro, using both LC-MS/MS and gravimetric methods, on hematocrits from 26 to 62%. The gravimetric measurements show an excellent metering performance of the microfluidic DBS card, with a mean blood sample volume of 14.25 μL ± 3.0% (n = 51). A measured mean bias below 2.9% compared to normal hematocrit (47%) demonstrates that there is no significant hematocrit-induced bias. LC-MS/MS measurements confirm low CV and hematocrit independence of the sampling system and exhibit no substantial mean bias compared to pipetted DBS. Tests with 44 individuals demonstrated applicability of the microfluidic DBS card for direct finger prick blood sampling, and measured caffeine concentrations show a good agreement with measurements of pipetted DBS. The presented concept demonstrates a good volumetric performance which can help to improve the accuracy of DBS analysis by analyzing a whole spot, equivalent to a defined volume of liquid blood.
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| 22. |
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| 23. |
- Mitchell, G., et al.
(författare)
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Measurement of the turbulence intensities in a flat plate boundary layer
- 2003
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Ingår i: Proc. of Turbulence, Heat and Mass Transfer, 4th Int. Symp., Antalya, Turkey. ; , s. 261-268
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Detailed information on the flow in the vicinity of the wall is of particular interest for various types of flow and heat transfer predictions and of basic importance for turbulence modelling. The time-averaged value can be determined accurately by a number of methods, however time resolved part is rather more difficult to measure. In this work, the results of measurements of the wall shear stress fluctuations in a turbulent boundary layer are presented. Described experiments are performed for the case of zero-pressure gradient flow on a flat plate at Reynolds number, Reθ, ranging from about 1000 to 6000. A main feature of this work is that the miniature wall mounted hot wires fabricated with very high accuracy were implemented in the measurements.
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| 24. |
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| 25. |
- Quellmalz, Arne, et al.
(författare)
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Large-area integration of two-dimensional materials and their heterostructures by wafer bonding
- 2021
-
Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 12:1
-
Tidskriftsartikel (refereegranskat)abstract
- Integrating two-dimensional (2D) materials into semiconductor manufacturing lines is essential to exploit their material properties in a wide range of application areas. However, current approaches are not compatible with high-volume manufacturing on wafer level. Here, we report a generic methodology for large-area integration of 2D materials by adhesive wafer bonding. Our approach avoids manual handling and uses equipment, processes, and materials that are readily available in large-scale semiconductor manufacturing lines. We demonstrate the transfer of CVD graphene from copper foils (100-mm diameter) and molybdenum disulfide (MoS2) from SiO2/Si chips (centimeter-sized) to silicon wafers (100-mm diameter). Furthermore, we stack graphene with CVD hexagonal boron nitride and MoS2 layers to heterostructures, and fabricate encapsulated field-effect graphene devices, with high carrier mobilities of up to 4520 cm2V-1s-1. Thus, our approach is suited for backend of the line integration of 2D materials on top of integrated circuits, with potential to accelerate progress in electronics, photonics, and sensing. The existing integration approaches for 2D materials often degrade material properties and are not compatible with industrial processing. Here, the authors devise an adhesive wafer bonding strategy to transfer and stack monolayers, suitable for back end of the line integration of 2D materials.
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| 26. |
- Quellmalz, Arne, et al.
(författare)
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Large-Area Integration of Two-Dimensional Materials and Their Heterostructures Using Wafer Bonding
- 2021
-
Ingår i: Nature Communications. - 2041-1723. ; 12, s. 917-
-
Tidskriftsartikel (refereegranskat)abstract
- Integrating two-dimensional (2D) materials into semiconductor manufacturing lines is essential to exploit their material properties in a wide range of application areas. However, current approaches are not compatible with high-volume manufacturing on wafer level. Here, we report a generic methodology for large-area integration of 2D materials by adhesive wafer bonding. Our approach avoids manual handling and uses equipment, processes, and materials that are readily available in large-scale semiconductor manufacturing lines. We demonstrate the transfer of CVD graphene from copper foils (100-mm diameter) and molybdenum disulfide (MoS2) from SiO2/Si chips (centimeter-sized) to silicon wafers (100-mm diameter). Furthermore, we stack graphene with CVD hexagonal boron nitride and MoS2 layers to heterostructures, and fabricate encapsulated field-effect graphene devices, with high carrier mobilities of up to 4520cm2V−1s−14520cm2V−1s−1. Thus, our approach is suited for backend of the line integration of 2D materials on top of integrated circuits, with potential to accelerate progress in electronics, photonics, and sensing.
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| 27. |
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| 28. |
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| 29. |
- Stemme, S, et al.
(författare)
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Effect of colloidal silica and electrolyte on the structure of an adsorbed cationic polyelectrolyte layer
- 1999
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Ingår i: Colloids and Surfaces A. - 0927-7757 .- 1873-4359. ; 155, s. 145-154
-
Tidskriftsartikel (refereegranskat)abstract
- The interactions between an adsorbed high molecular weight cationic polyacrylamide (C-PAM) and anionic components have been investigated by ellipsometry. The anionic components used were non-aggregated and microaggregated anionic colloidal silica particles (ACS) and an anionic polyacrylamide (A-PAM). The C-PAM was adsorbed to a silica surface and the different anionic components were then added to the system. The effect of adding an electrolyte (NaCl) to some of these systems was also investigated. The thickness of the adsorbed layer, the adsorbed amount and some kinetic aspects of the adsorption and desorption processes were studied. A three-fold expansion was observed for the C-PAM layer when non-aggregated and microaggregated ACS was added. When large amounts of NaCl are added there is a great decrease in layer thickness for a system with non-aggregated ACS. A system with microaggregated ACS particles is less affected by an increase in the electrolyte concentration. More ACS is adsorbed to a C-PAM layer in the presence of NaCl than in its absence. When A-PAM is added to the C-PAM layer, the thickness and adsorbed amount is much less influenced than if ACS is added. A small increase in adsorption and in layer thickness is first observed and then a desorption process starts. Information about the conformation of the adsorbed cationic polyacrylamide has also been obtained. The ellipsometry measurements indicate that the structure of the adsorbed layer changes as the adsorption process proceeds. The polymers adsorbed first to the surface give a more dense layer than the polymers adsorbed last.
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| 30. |
- Stemme, S
(författare)
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Plaque T-cell activity: not so specific?
- 2001
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Ingår i: Arteriosclerosis, thrombosis, and vascular biology. - : Ovid Technologies (Wolters Kluwer Health). - 1524-4636 .- 1079-5642. ; 21:7, s. 1099-1101
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 31. |
- STEMME, S, et al.
(författare)
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T lymphocytes from human atherosclerotic plaques recognize oxidized low density lipoprotein
- 1995
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 92:9, s. 3893-3897
-
Tidskriftsartikel (refereegranskat)abstract
- Atherosclerosis, an underlying cause of myocardial infarction, stroke, and other cardiovascular diseases, consists of focal plaques characterized by cholesterol deposition, fibrosis, and inflammation. The presence of activated T lymphocytes and macrophages and high expression of HLA class II molecules are indicative of a local immunologic activation in the atherosclerotic plaque, but the antigen(s) involved has not yet been identified. We established T-cell clones from human atherosclerotic plaques using polyclonal mitogens as stimuli and exposed the clones to potential antigens in the presence of autologous monocytes as antigen-presenting cells. Four of the 27 CD4+ clones responded to oxidized low density lipoprotein (oxLDL) by proliferation and cytokine secretion; this response was dependent on autologous antigen-presenting cells and restricted by HLA-DR. All clones that responded to oxLDL secreted interferon gamma upon activation, but only one produced interleukin 4, suggesting that the response to oxLDL results in immune activation and inflammation but may not be a strong stimulus to antibody production. No significant response to oxLDL could be detected in CD4+ T-cell clones derived from the peripheral blood of the same individuals. Together, the present data suggest that the inflammatory infiltrate in the atherosclerotic plaque is involved in a T-cell-dependent, autoimmune response to oxLDL.
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| 32. |
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| 33. |
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| 34. |
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| 35. |
- Svensson, Per-Arne, 1969, et al.
(författare)
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Regulation and splicing of scavenger receptor class B type I in human macrophages and atherosclerotic plaques
- 2005
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Ingår i: BMC Cardiovasc Disord. - : Springer Science and Business Media LLC. - 1471-2261. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The protective role of high-density lipoprotein (HDL) in the cardiovascular system is related to its role in the reverse transport of cholesterol from the arterial wall to the liver for subsequent excretion via the bile. Scavenger receptor class B type I (SR-BI) binds HDL and mediates selective uptake of cholesterol ester and cellular efflux of cholesterol to HDL. The role of SR-BI in atherosclerosis has been well established in murine models but it remains unclear whether SR-BI plays an equally important role in atherosclerosis in humans. The aim of this study was to investigate the expression of SR-BI and its isoforms in human macrophages and atherosclerotic plaques. METHODS: The effect of hypoxia and minimally modified low-density lipoprotein (mmLDL), two proatherogenic stimuli, on SR-BI expression was studied in human monocyte-derived macrophages from healthy subjects using real-time PCR. In addition, SR-BI expression was determined in macrophages obtained from subjects with atherosclerosis (n = 15) and healthy controls (n = 15). Expression of SR-BI isoforms was characterized in human atherosclerotic plaques and macrophages using RT-PCR and DNA sequencing. RESULTS: SR-BI expression was decreased in macrophages after hypoxia (p < 0.005). In contrast, SR-BI expression was increased by exposure to mmLDL (p < 0.05). There was no difference in SR-BI expression in macrophages from patients with atherosclerosis compared to controls. In both groups, SR-BI expression was increased by exposure to mmLDL (p < 0.05). Transcripts corresponding to SR-BI and SR-BII were detected in macrophages. In addition, a third isoform, referred to as SR-BIII, was discovered. All three isoforms were also expressed in human atherosclerotic plaque. Compared to the other isoforms, the novel SR-BIII isoform was predicted to have a unique intracellular C-terminal domain containing 53 amino acids. CONCLUSION: We conclude that SR-BI is regulated by proatherogenic stimuli in humans. However, we found no differences between subjects with atherosclerosis and healthy controls. This indicates that altered SR-BI expression is not a common cause of atherosclerosis. In addition, we identified SR-BIII as a novel isoform expressed in human macrophages and in human atherosclerotic plaques.
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| 36. |
- van der Wijngaart, Wouter, et al.
(författare)
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A MICROMACHINED KMFE GATE VALVE FOR HIGH-FLOW PRESSURE REGULATION APPLICATIONS
- 2003
-
Ingår i: 12th IEEE International Conference on Solid-State Sensors, Actuators and Microsystems Conference (IEEE TRANSDUCERS 2003). - NEW YORK : IEEE conference proceedings. - 0780377311 ; , s. 1931-1934
-
Konferensbidrag (refereegranskat)abstract
- Cross-flow pressure regulating valve structures are attractive for high-flow pressure control applications due to the decreased actuation force required and the reduced device footprint area. A knife gate valve was fabricated, controlling a flow of 1.3 Nl/min at a supply pressure of 1.5 bar. The valve was microfabricated using deep reactive ion etching (DRIE) and silicon fusion bonding. The use of micromachined knife gate valves in pressure control systems enhances performance and cost savings can be realized.
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| 37. |
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| 38. |
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| 39. |
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| 40. |
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| 41. |
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