| 1. |
- Kunkel, E J, et al.
(författare)
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Lymphocyte CC chemokine receptor 9 and epithelial thymus-expressed chemokine (TECK) expression distinguish the small intestinal immune compartment: Epithelial expression of tissue-specific chemokines as an organizing principle in regional immunity
- 2000
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Ingår i: Journal of Experimental Medicine. - 1540-9538. ; 192:5, s. 761-768
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Tidskriftsartikel (refereegranskat)abstract
- The immune system has evolved specialized cellular and molecular mechanisms for targeting and regulating immune responses at epithelial surfaces. Here we show that small intestinal intraepithelial lymphocytes and lamina propria lymphocytes migrate to thymus-expressed chemokine (TECK). This attraction is mediated by CC chemokine receptor (CCR)9, a chemoattractant receptor expressed at high levels by essentially all CD4(+) and CD8(+) T lymphocytes in the small intestine. Only a small subset of lymphocytes in the colon are CCR9(+), and lymphocytes from other tissues including tonsils, lung, inflamed liver, normal or inflamed skin, inflamed synovium and synovial fluid, breast milk, and seminal fluid are universally CCR9(-). TECK expression is also restricted to the small intestine: immunohistochemistry reveals that intense anti-TECK reactivity characterizes crypt epithelium in the jejunum and ileum, but not in other epithelia of the digestive tract (including stomach and colon), skin, lung, or salivary gland. These results imply a restricted role for lymphocyte CCR9 and its ligand TECK in the small intestine, and provide the first evidence for distinctive mechanisms of lymphocyte recruitment that may permit functional specialization of immune responses in different segments of the gastrointestinal tract. Selective expression of chemokines by differentiated epithelium may represent an important mechanism for targeting and specialization of immune responses.
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| 2. |
- Buyanova, Irina, 1960-, et al.
(författare)
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Optical study of spin injection dynamics in InGaN/GaN quantum wells with GaMnN injection layers
- 2004
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Ingår i: Journal of Vacuum Science & Technology B. - : American Vacuum Society. - 1071-1023 .- 1520-8567. ; 22:6, s. 2668-2672
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Tidskriftsartikel (refereegranskat)abstract
- The spin injection dynamics of GaMnN/InGaN multiquantum well (MQW) light emitting diodes (LEDs) grown by molecular beam epitaxy were examined using picosecond-transient and circularly polarized photoluminescence (PL) measurements. Even with the presence of a room temperature ferromagnetic GaMnN spin injector, the LEDs are shown to exhibit very low efficiency of spin injection. Based on resonant optical orientation spectroscopy, the spin loss in the structures is shown to be largely due to fast spin relaxation within the InGaN MQW, which itself destroys any spin polarization generated by optical spin orientation or electrical spin injection. Typical photoluminescence decay times were 20-40 ns in both commercial GaN MQW LEDs with emission wavelengths between 420-470 nm and in the GaMnN/InGaN multi-quantum well MQW LEDs. In the wurtzite InGaN/GaN system, biaxial strain at the interfaces give rise to large piezoelectric fields directed along the growth axis. This built-in piezofield breaks the reflection symmetry of confining potential leading to the presence of a large Rashba term in the conduction band Hamiltonian which is responsible for the short spin relaxation times.
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| 3. |
- Buyanova, Irina, 1960-, et al.
(författare)
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On spin injection in GaMnN/InGaN Light-Emitting Diodes
- 2004
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Ingår i: 3rd International Conference on Physics and Applications of Spin-Related Phenomena in Semiconductors PASPS III,2004.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Buyanova, Irina, 1960-, et al.
(författare)
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On the origin of spin loss in GaMnN/InGaN Light-Emitting Diodes
- 2004
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 84, s. 2599-
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Tidskriftsartikel (refereegranskat)abstract
- Spin polarization of GaMnN/InGaN light-emitting diodes grown by molecular beam epitaxy is analyzed. In spite of the ferromagnetic behavior of the GaMnN spin injector, the diodes are shown to exhibit very low efficiency of spin injection. Based on resonant optical orientation spectroscopy, the spin loss in the structures is shown to be largely due to fast spin relaxation within the InGaN spin detector, which itself destroys any spin polarization generated by optical spin orientation or electrical spin injection.
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| 5. |
- Buyanova, Irina, 1960-, et al.
(författare)
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Optical and electrical characterization of (Ga,Mn)N/InGaN multiquantum well light-emitting diodes
- 2004
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Ingår i: Journal of Electronic Materials. - : Springer Science and Business Media LLC. - 0361-5235 .- 1543-186X. ; 33:5, s. 467-471
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Tidskriftsartikel (refereegranskat)abstract
- (Ga,Mn)/N/InGaN multiquantum well (MQW) diodes were grown by molecular beam epitaxy (MBE). The current-voltage characteristics of the diodes show the presence of a parasitic junction between the (Ga,Mn)N and the n-GaN in the top contact layer due to the low conductivity of the former layer. Both the (Ga,Mn)N/InGaN diodes and control samples without Mn doping show no or very low (up to 10% at the lowest temperatures) optical (spin) polarization at zero field or 5 T, respectively. The observed polarization is shown to correspond to the intrinsic optical polarization of the InGaN MQW, due to population distribution between spin sublevels at low temperature, as separately studied by resonant optical excitation with a photon energy lower than the bandgap of both the GaN and (Ga,Mn)N. This indicates efficient losses in the studied structures of any spin polarization generated by optical spin orientation or electrical spin injection. The observed vanishing spin injection efficiency of the spin light-emitting diode (LED) is tentatively attributed to spin losses during the energy relaxation process to the ground state of the excitons giving rise to the light emission.
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| 6. |
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| 7. |
- Polyakov, A. Y., et al.
(författare)
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Electrical and luminescent properties and the spectra of deep centers in GaMnN/InGaN light-emitting diodes
- 2004
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Ingår i: Journal of Electronic Materials. - : Springer Science and Business Media LLC. - 0361-5235 .- 1543-186X. ; 33:3, s. 241-247
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Tidskriftsartikel (refereegranskat)abstract
- Electrical and electroluminescent properties were studied for GaN/InGaN light-emitting diodes (LEDs) with the n-GaN layer up and with the top portion of the n layer made of undoped GaMnN to allow polarization modulation by applying an external magnetic field (so-called -spin-LEDs-). The contact annealing temperature was kept to 750°C, which is the thermal stability limit for retaining room-temperature magnetic ordering in the GaMnN layer. Measurable electroluminescence (EL) was obtained in these structures at threshold voltages of ∼15 V, with a lower EL signal compared to control LEDs without Mn. This is related to the existence of two parasitic junctions between the metal and the lower contact p-type layer and between the GaMnN and the n-GaN in the top contact layer.
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| 8. |
- Csernok, E, et al.
(författare)
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Evaluation of capture ELISA for detection of antineutrophil cytoplasmic antibodies directed against proteinase 3 in Wegener's granulomatosis: first results from a multicentre study
- 2004
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Ingår i: Rheumatology. - : Oxford University Press (OUP). - 1462-0332 .- 1460-2172. ; 43:2, s. 174-180
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To evaluate the performance characteristics of direct and capture ELISA for the detection of PR3-ANCA in Wegener's granulomatosis (WG) in international ANCA reference laboratories. Methods: Serum samples were derived from patients with histological and clinical diagnosis of WG (n = 60), rheumatoid arthritis (RA) (n = 30) and healthy controls (n = 30). Each of them was tested for the presence of ANCA by indirect immunofluorescence technique (IFT), direct and capture ELISA in six international reference laboratories (Massachusetts General Hospital, Boston; Wieslab AB, Lund; University of Maastricht; University Hospital Groningen; Mayo Clinic, Rochester; Rheumaklinik Bad Bramstedt/University of Schleswig-Holstein Campus Lubeck). Each centre tested the sera according to their house protocols of IFT and ELISA. The diagnostic performance of each test was estimated by receiver operating characteristic curve analysis and sensitivity and specificity in detection of ANCA/PR3-ANCA were calculated for the respective methods. Results: In patients histologically and clinically known as WG, the detection of ANCA by IFT varied between 52 and 83% among the participating centres. PR3-ANCA positivity with the different ELISAs ranged from 53 to 80% in direct ELISA and from 72 to 76% in capture ELISA. While most capture ELISAs successfully detected PR3-ANCA, there were significant differences between IFT and direct ELISA results between laboratories. ROC curve analysis demonstrated that in five of six laboratories the overall diagnostic performance of capture ELISA was superior to IFT and direct ELISA, respectively. Conclusion: Capture ELISA is a highly sensitive assay for detection of PR3-ANCA in WG and should be used in conjunction with compatible clinical picture and histological evidence.
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| 9. |
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| 10. |
- Mustafa, K., et al.
(författare)
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Electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy analysis of titanium surfaces cultured with osteoblast-like cells derived from human mandibular bone
- 2002
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Ingår i: Journal of Biomedical Materials Research. - : Wiley. - 0021-9304 .- 1097-4636. ; 59:4, s. 655-664
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Tidskriftsartikel (refereegranskat)abstract
- Variations in the oxide films on titanium surfaces blasted with TiO2 particles of various sizes were analyzed after cultures with cells derived from human mandibular bone. Turned titanium surfaces and surfaces blasted with 63-90-, 106-180-, and 180-300-mum TiO2 particles were cultured with osteoblast-like cells. The surfaces were characterized before and after the cell culture with electrochemical impedance spectroscopy (EIS). The surface chemical composition of selected samples was analyzed with X-ray photoelectron spectroscopy (XPS). EIS revealed that with respect to the turned surfaces, the effective surface area was about 5, 6, and 4 times larger on the surfaces blasted with 63-90-, 106-180-, and 180-300-mum particles, respectively. After 28 days of the cell culture, the corrosion resistance on all sample types was unaffected. The impedance characteristics suggest a considerable effect of ion incorporation and precipitation during culturing. XPS revealed that before the cell culture, a typical surface layer consisted of TiO2. After the culture, the surface oxide film contained both phosphorus and calcium, along with large amounts of oxidized carbon (carbonate) and nitrogen. There were lower concentrations of carbon and nitrogen on the blasted surfaces. We concluded that the effective surface area was several times higher on blasted surfaces than on turned surfaces. Cells derived from human mandibular bone affected ion incorporation into the implant surface.
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| 11. |
- Pan, M., et al.
(författare)
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Crustal movements in Skane, Sweden, between 1992 and 1998 as observed by GPS
- 2001
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Ingår i: Journal of Geodynamics. - 0264-3707 .- 1879-1670. ; 31:3, s. 311-322
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Tidskriftsartikel (refereegranskat)abstract
- We estimate a network of crustal deformations in Skane, southern Sweden, using observations of the Global Positioning System (GPS) from 1992, 1996 and 1998. The network straddles the Tornquist zone, potentially one of the most active fault zones in Sweden. In addition to two stations of the Swedish permanent GPS network (Onsala and Hassleholm), it includes seven GPS sites spaced approximately 80 km apart. The precisions of the relative horizontal components for these stations are described by repeatabilities with approximately 3 mm in the north-south direction and about 2 mm in the east-west direction in the campaigns in the reference frame ITRF96. About 70% of the GPS integer carrier phase ambiguities were resolved for the three campaigns. Three stations south of the Tornquist zone moved with a rate of 5+/-0.2 mm/a toward the SW-SE, and two other stations further to the east with a rate of 2+/-0.2 mm/a toward the SE, relative to station Onsala. The displacements mean that a lateral strike-slip transtensional fault exists within the Tornquist zone, and the relative motion between the two sides along the zone was about 2 mm/a. The old fault is still active, which is consistent with geological results. The station Stavershult closest to Onsala moved NE with about 1.5+/-0.8 mm/a relative to the station Onsala. This may imply a transtensional fault between Stavershult and Onsala. If we assume that Stavershult represents the Baltic shield, Onsala has moved 1.5 mm/a toward the southwest with respect to the Baltic shield, which was confirmed by data of Very Long Baseline Interferometry (VLBI) and Satellite Laser Ranging (SLR) from 1976 to 1997 (Argus, D.F., Peltier, W.R., Watkins, M.M. Glacial isostatic adjustment observed by Very Long Baseline Interferometry and Satellite Laser Ranging geodesy. JGR 1999;104(B12);29077-93).
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| 12. |
- Pan, Q, et al.
(författare)
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Lack of IgA in C(mu)-deficient patients
- 2002
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Ingår i: Nature immunology. - : Springer Science and Business Media LLC. - 1529-2908 .- 1529-2916. ; 3:7, s. 595-595
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 13. |
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| 14. |
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| 15. |
- Ren, J, et al.
(författare)
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Expression of sphingosine kinase gene in the interactions between human gastric carcinoma cell and vascular endothelial cell
- 2002
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Ingår i: World Journal of Gastroenterology. - 1007-9327. ; 8:4, s. 602-607
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Tidskriftsartikel (refereegranskat)abstract
- AIM: To study the interactions between human gastric carcinoma cell (HGCC) and human vascular endothelial cell (HVEC), and if the expression of sphingosine kinase (SPK) gene was involved in these interactions. METHODS: The specific inhibitor to SPK, dimethyl sphingosine (DMS), was added acting on HGCC and HVEC, then the cell proliferation was measured by MTT. The conditioned mediums (CMs) of HGCC and HVEC were prepared. The CM of one kind of cell was added to the other kind of cell, and the cell proliferation was measured by MTT. After the action of CM, the cellular expression of SPK gene in mRNA level was detected with in situ hybridization (ISH). RESULTS: DMS could almost completely inhibit the proliferation of HGCC and HVEC. The growth inhibitory rates could amount to 97.21%, 83.42%, respectively (P<0.01). The CM of HGCC could stimulate the growth of HVEC (2.70 +/- 0.01, P<0.01) while the CM of HVEC could inhibit the growth of HGCC (52.97 +/- 0.01%, P<0.01). There was no significant change in the mRNA level of SPK gene in one kind of cell after the action of the CM of the other kind of cell. CONCLUSION: SPK plays a key role in regulating the proliferation of HGCC and HVEC. There exist complicated interactions between HGCC and HVEC. HGCC can significantly stimulate the growth of HVEC while HVEC can significantly inhibit the growth of HGCC. The expression of SPK gene is not involved in the interactions.
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| 16. |
- Ren, J, et al.
(författare)
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The role of KDR in the interactions between human gastric carcinoma cell and vascular endothelial cell
- 2002
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Ingår i: World Journal of Gastroenterology. - 1007-9327. ; 8:4, s. 596-601
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Tidskriftsartikel (refereegranskat)abstract
- AIM:To study the interactions between human gastric carcinoma cell (HGCC) and human vascular endothelial cell (HVEC), and the role of KDR in these interactions. METHODS:Antisense oligodexynucleotide(ASODN) specific to KDR gene was devised and added to the culture medium of HGCC and HVEC. After the action of ASODN, the proliferation of two cells was measured by MTT method. The role of KDR in regulating the proliferation of two kinds of cells was known through observing the effect of ASODN on them. The conditioned mediums (CMs) of HGCC and HVEC were prepared. The CM of one kind of cell was added acting on the other kind of cell, then the cell proliferation was measured by MTT. After the action of ASODN or CM, the cellular expression of KDR gene was detected with in situ hybridization(ISH) for mRNA level and with immunohistochemical staining for protein level. ABC-ELISA was used to detect hVEGF in the CMs of two cells. RESULTS: KDR ASODN could specifically inhibit the proliferation of HGCC and HVEC significantly. The growth inhibitory rate amounted to 55.35 % and 54.83 %, respectively (P <0.01). HGCC and HVEC could secret a certain level of hVEGF(92.06 +/- 1.69 ng/L, 77.70 +/- 8.04 ng/L. The CM of HGCC could significantly stimulate the growth(2.70 +/- 0.01 times) and KDR gene expression of HVEC( P<0.01) while the CM of HVEC could significantly inhibit the growth(52.97 +/- 0.01%) and KDR gene expression of HGCC (P <0.01). CONCLUSION: KDR plays a key role in regulating the proliferation of HGCC and HVEC. There exist complicated interactions between HGCC and HVEC. HGCC can significantly stimulate the growth of HVEC while HVEC can significantly inhibit the growth of HGCC. KDR is involved in the interactions between them.
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