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| 2. |
- Davanco, M., et al.
(författare)
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Directional coupler wavelength filters based on waveguides exhibiting electromagnetically induced transparency
- 2003
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Ingår i: IEEE Journal of Quantum Electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9197 .- 1558-1713. ; 39:4, s. 608-613
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Tidskriftsartikel (refereegranskat)abstract
- We describe the principle and analyze the operation of an integrated optics directional coupler filter based on coupling between a regular waveguide and one, that exhibits electromagnetically induced transparency. Bandwidth length products on the order of 2 pm x mm are obtainable, as an example, using this approach.
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| 3. |
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| 4. |
- Holmstrom, P., et al.
(författare)
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Proposal of an optical modulator based on resonant tunneling and intersubband transitions
- 2001
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Ingår i: IEEE Journal of Quantum Electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9197 .- 1558-1713. ; 37:2, s. 224-230
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Tidskriftsartikel (refereegranskat)abstract
- We propose and analyze an optical modulator based on intersubband transitions. The absorption is modulated by modulating the carrier density in the ground state of a quantum well (QW). Electrons are injected resonantly into this subband from a QW reservoir subband through a single barrier. When the two states are tuned out of resonance, the electrons are rapidly evacuated by means of the optical held, A waveguide based on surface plasmons is assumed in order to have a high optical mode overlap. Calculations are performed for a cascaded structure with four periods, assuming InGaAs-InAlAs QWs, The considered modulator structure operates at lambda =6.0 mum and is RC limited to 27 GHz, An extinction ratio of it is obtained with a low applied voltage of 0.6 V, At larger applied voltages, the absorption is bistable, Absorption at shorter/longer wavelengths can be obtained by using materials with a larger/smaller conduction band offset. We also assess resonant tunneling from a 2-D electron gas reservoir into an array of quantum dots and compare it to the 2-D-2-D tunneling resonance.
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| 6. |
- Jacobson, SH, et al.
(författare)
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Monocyte-related determinants of inflammation in patients on peritoneal dialysis
- 2001
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Ingår i: American journal of nephrology. - : S. Karger AG. - 0250-8095 .- 1421-9670. ; 21:1, s. 40-46
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Tidskriftsartikel (refereegranskat)abstract
- <i>Aims:</i> We studied markers of monocyte activation, i.e., the cell surface expression of CD11b and CD62L, and the serum concentrations of monocyte chemotactic protein 1 (MCP-1; a monocyte-specific chemoattractant) and soluble vascular cell adhesion molecule 1 (sVCAM-1; an adhesion molecule involved in monocyte recruitment) in 20 patients on peritoneal dialysis (PD), in 25 patients with chronic renal insufficiency, and in 27 healthy subjects. <i>Results:</i> Monocytes obtained from the peripheral blood of PD patients had a significantly higher expression of CD62L (p = 0.02) as compared with monocytes from healthy subjects and a lower CD11b/CD18 expression as compared with monocytes collected from healthy subjects (p < 0.001) and from patients with renal insufficiency (p < 0.001). Monocytes from PD patients had, however, the capacity to increase the expression of CD11b following stimulation with a potent chemotactic factor. The serum concentrations of MCP-1 and sVCAM-1 were higher in PD patients (575 ± 51 and 1,517 ± 89 ng/ml) than in healthy subjects (225 ± 17 and 668 ± 64 ng/ml, respectively; p < 0.001 for both comparisons). There was a correlation between the levels of sVCAM-1 and MCP-1 (r = 0.48, p < 0.05) in patients on PD, but neither correlated with the monocyte expression of CD11b/CD18 or CD62L. The concentration of C-reactive protein was higher in patients on PD as compared with healthy subjects and correlated significantly with the concentration of sVCAM-1 (r = 0.63, p < 0.01). <i>Conclusions:</i> Monocytes in the peripheral circulation of patients on PD have a CD62L<sup>high</sup>/CD11b<sup>low</sup> phenotype, indicating that they have not undergone complete differentiation. Patients also have an increase in the systemic chemotactic activity for monocytes in combination with increased levels of sVCAM-1 and C-reactive protein. These inflammatory aberrations may play a pathophysiological role in the response to inflammatory and infectious diseases in patients on PD.
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| 7. |
- Jacobson, SH, et al.
(författare)
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Three monocyte-related determinants of atherosclerosis in haemodialysis
- 2000
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Ingår i: Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association. - : Oxford University Press (OUP). - 0931-0509. ; 15:9, s. 1414-1419
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Tidskriftsartikel (refereegranskat)
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| 8. |
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| 9. |
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| 10. |
- Moshfegh, A, et al.
(författare)
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Impact of hemodialysis membrane and permeability on neutrophil transmigration in vitro
- 2002
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Ingår i: Nephron. - : S. Karger AG. - 1660-8151 .- 2235-3186. ; 91:4, s. 659-665
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Tidskriftsartikel (refereegranskat)abstract
- <i>Background/Aim:</i> The impact of dialysis membrane permeability on neutrophil transmigration properties in vitro was examined in the present study. This issue has not been fully scrutinized before. <i>Methods:</i> We studied the capacity of neutrophils collected from a group of dialysis patients randomly treated with cuprophan, low- or high-flux polysulfone, to transmigrate in vitro through a membrane covered with fibronectin (a main constituent of the endothelial basement membrane). The hemodialysis-induced quantitative changes in expression of adhesion molecules were examined in parallel. <i>Results:</i> At the end of dialysis, neutrophils collected from patients treated with high-flux polysulfone dialyzers had a significantly higher transmigration index than neutrophils from patients treated with low-flux polysulfone membrane (p < 0.01) or cuprophan membrane (p < 0.01), and approached the level of transmigration observed in neutrophils collected from healthy controls. In the groups treated with low-flux polysulfone and cuprophan dialyzers, the transmigration capacity was significantly lower (p < 0.02) compared to neutrophils from healthy subjects. We also noted that differences between low- and high-flux polysulfone dialysis, in the context of transmigration properties, were not mirrored by changes in adhesion phenotype, which strengthens the view that there is no strict relationship between these two features. <i>Conclusion:</i> The study demonstrates that high-flux polysulfone dialysis, as opposed to low-flux polysulfone and cuprophan treatment, improves the transmigration properties of circulating neutrophils, despite similar effects on adhesion molecule phenotypes. A plausible mechanism is that potentially toxic middle range molecules that inhibit neutrophil migration are more efficiently eliminated during high-flux polysulfone dialysis, but this explanation requires further support.
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| 11. |
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| 14. |
- Thylen, P, et al.
(författare)
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Modulation of CD11b/CD18 on monocytes and granulocytes following hemodialysis membrane interaction in vitro
- 1996
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Ingår i: The International journal of artificial organs. - : SAGE Publications. - 0391-3988 .- 1724-6040. ; 19:3, s. 156-163
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Tidskriftsartikel (refereegranskat)abstract
- We studied the generation of CD11b/CD18 mobilizing factors in serum after incubation with dialysis membrane fragments of different chemical composition. We also evaluated the relative importance of the alternative and classical pathways of the complement system in the generation of such factors. Monocytes and granulocytes from healthy blood donors were incubated in normal human serum (NHS) and in NHS that had been preincubated with Cuprophan (CU) membrane (NHS-CU), Hemophan (HE) (NHS-HE) or polysulfone (PS) (NHS-PS). NHS-CU caused the highest up-regulation of the CD11b/CD18 receptor on monocytes and granulocytes. The rank in capacity to mobilize CD11b/CD18 on granulocytes was CU>HE>PS (p<0.001), CU>HE (p<0.05) and HE>PS (p<0.001). The rank in capacity to mobilize CD11b/CD18 on monocytes was CU>HE>PS (p<0.001), CU>HE (p<0.05) and HE>PS (p<0.01). NHS-PS induced a lower up-regulation of CD11b/CD18 compared to NHS which indicates that serum factors with the ability to mobilize the CD11b/CD18 receptor on monocytes and granulocytes are deposited on or adsorbed by PS. In order to study the relative contribution of the alternative and classical pathways of the complement system in the generation of CD11b/CD18 mobilizing factors in serum, three different serum preparations (1. both pathways intact. 2. only the alternative intact and 3. only the classical pathway intact) were used. The CU membrane activated the classical pathway to a larger extent than the PS membrane (p<0.01). When only the alternative pathway was intact no difference in the generation of CD11b/CD18 mobilizing factors between the CU and PS membranes was observed. These studies show that CD11b/CD18 mobilizing serum factors are generated after incubation with CU membranes and that such factors are probably adsorbed by PS. The classical pathway of complement activation seems to contribute to the generation of CD11b/CD18 mobilizing factors in serum.
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| 18. |
- Wosinska, Lena, et al.
(författare)
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Large-capacity strictly nonblocking optical cross-connects based on microelectrooptomechanical systems (MEOMS) switch matrices : Reliability performance analysis
- 2001
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 19:8, s. 1065-1075
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, the reliability performance of 128 x 128 optical cross-connects (OXCs) based on microelectrooptomechanical systems (MEOMS) switch matrices is considered. First, we compare a strictly nonblocking wavelength selective switch with a strictly nonblocking three-stage Clos architecture. The probability of maintenance of free operation has been investigated for both OXC structures. We present our calculation results for such commonly used reliability measures as mean time between failures (MTBF), mean downtime (MDT) per year, and steady-state unavailability. It is shown that the reliability performances of the considered OXCs are far from that requested. In this paper, we also investigate possibilities of improving the reliability performance of the considered OXCs by introducing shared redundancy of the MEOMS matrices. We propose two different protection schemes: one for the wavelength selective switch [1] and another for the three-stage Clos architecture. It is shown that the proposed protection schemes significantly improve the reliability performance for both cases. Finally, we compare the performance of the all-optical version of the OXC based on MEOMS matrices with the optoelectronic version of the OXC based on electronic cross-point switch matrices. It is shown that from a reliability viewpoint, the optical cross-connect based on MEOMS matrices is better than that with electrical cross-point switches. The influence of capacity expansion on the system reliability is discussed.
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| 19. |
- Yu, Y. C., et al.
(författare)
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Enhanced linear dynamic range of asymmetric Fabry-Perot modulator/detector
- 2006
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Ingår i: IEEE Photonics Technology Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1041-1135 .- 1941-0174. ; 18:12-sep, s. 1040-1042
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Tidskriftsartikel (refereegranskat)abstract
- An InGaAsP multiple-quantum-well asymmetric Fabry-Wrot modulator/detector has been developed for radio-over-fiber systems. The measured bandwidth is more than 6 GHz and the total insertion loss is 7.1 dB. The property of nonlinearity and spurious-free dynamic range (SFDR) has been studied theoretically. By optimizing the operation optical wavelength and bias voltage based on the numerical simulation, fifth-order nonlinearity dominates the intermodulation distortion and an SFDR of 101 dB center dot Hz(4/5) has been achieved experimentally.
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| 20. |
- Yu, Y. C., et al.
(författare)
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Enhanced linear dynamic range of asymmetric Fabry-Perot modulator/detector
- 2006
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Ingår i: IEEE Photonics Technology Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1041-1135 .- 1941-0174. ; 18:08-maj, s. 770-772
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Tidskriftsartikel (refereegranskat)abstract
- An InGaAsP multiple-quantum-well asymmetric Fabry-Perot modulator/detector has been developed for radioover-fiber systems. The measured bandwidth is more than 6 GHz and the total insertion loss is 7.1 dB. The property of nonlinearity and spurious-free dynamic range (SFDR) has been studied theoretically. By optimizing the operation optical wavelength and bias voltage based on the numerical simulation, fifth-order nonlinearity dominates the intermodulation distortion and an SFDR of 101 dB. Hz(4/5) has been achieved experimentally.
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| 21. |
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