| 1. |
- Dunham, I, et al.
(författare)
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The DNA sequence of human chromosome 22
- 1999
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 402:6761, s. 489-495
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Tidskriftsartikel (refereegranskat)
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| 2. |
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| 3. |
- Chan, H C, et al.
(författare)
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Angiotensin II receptor type I-regulated anion secretion in cystic fibrosis pancreatic duct cells.
- 1997
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Ingår i: The Journal of membrane biology. - 0022-2631. ; 156:3, s. 241-9
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Tidskriftsartikel (refereegranskat)abstract
- The beta-adrenergic (cAMP-dependent) regulation of Cl- conductance is defective in cystic fibrosis (CF). The present study explored alternative regulation of anion secretion in CF pancreatic ductal cells (CFPAC-1) by angiotensin II (AII) using the short-circuit current (ISC) technique. An increase in ISC could be induced in CFPAC-1 cells by basolateral or apical application of AII in a concentration-dependent manner (EC50 at 3 microm and 100 nm, respectively). Angiotensin receptor subtypes were identified using specific antagonists, losartan and PD123177, for AT1 and AT2 receptors, respectively. It was found that losartan (1 microm) could completely inhibit the AII-induced ISC, whereas, PD123177 exerted insignificant effect on the ISC, indicating predominant involvement of AT1 receptors. The presence of AT1 receptors in CFPAC-1 cells was also demonstrated by immunohistochemical studies using specific antibodies against AT1 receptors. Confocal microscopic study demonstrated a rise in intracellular Ca2+ upon stimulation by AII indicating a role of intracellular Ca2+ in mediating the AII response. Depletion of intracellular but not extracellular pool of Ca2+ diminished the AII-induced ISC. Treatment of the monolayers with a Cl- channel blocker, DIDS, markedly reduced the ISC, indicating that a large portion of the AII-activated ISC was Cl--dependent. AII-induced ISC was also observed in monolayers whose basolateral membranes had been permeabilized by nystatin, suggesting that the ISC was mediated by apical Cl- channels. Our study indicates an AT1-mediated Ca2+-dependent regulatory mechanism for anion secretion in CF pancreatic duct cells which may be important for the physiology and pathophysiology of the pancreas.
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| 4. |
- Leung, P S, et al.
(författare)
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Angiotensin II receptors: localization of type I and type II in rat epididymides of different developmental stages.
- 1997
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Ingår i: The Journal of membrane biology. - 0022-2631. ; 157:1, s. 97-103
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Tidskriftsartikel (refereegranskat)abstract
- Previous studies from our laboratory have provided evidence for the existence of a local renin-angiotensin system in the rat epididymis. Evidence has also accumulated, indicating that locally formed angiotensin II from the rat epididymis may play a paracrine and/or autocrine role in regulating epididymal electrolyte and fluid transport. In the present study, specific anti-peptide antibodies against the second extracellular loops of angiotensin II type I (AT1) and type II (AT2) receptors were used to localize immunocytochemically these receptors in the rat cauda epididymides of three developmental stages, namely, immature (2-week), early mature (6-week) and fully mature (10-week). The immunostaining intensity for AT1 receptors was found to be stronger than that for AT2 receptors throughout rat epididymides of all stages. However, the immunostaining for both AT1 and AT2 receptors observed in the fully mature rat epididymis was much more intense than that observed in the epididymides of the two younger stages. While the immunostaining for both AT1 and AT2 receptors in the younger rat epididymides appeared to be distributed in both basal and apical regions, the immunostaining in the fully mature epididymis was predominantly localized in the basal region. The present finding of the differential patterns of angiotensin II receptor immunoreactivity in three different stages of the rat epididymis may reflect the fine tuning of rat epididymal function by angiotensin II, acting as a paracrine or autocrine agent, during the course of development.
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| 7. |
- Zetterling, Carl-Mikael, et al.
(författare)
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Formation and high frequency CV-measurements of aluminum/aluminum nitride/6H silicon carbide structures
- 1996
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Ingår i: Materials Research Society Symposium - Proceedings. - San Francisco, CA, USA. ; , s. 667-672
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Konferensbidrag (refereegranskat)abstract
- Undoped single crystalline aluminum nitride films were grown by metal organic chemical vapor deposition (MOCVD) at 1200 °C. The precursors used were trimethylaluminum (TMA) and ammonia (NH3) in a hydrogen carrier flow, at a pressure of 10 Torr. Silicon carbide substrates of the 4H or the 6H polytype with an epilayer on the silicon face, were used to grow the 200 nm thick AlN films. Aluminum was evaporated and subsequently patterned to form MIS capacitors for high frequency (400 kHz) capacitance voltage measurements at room temperature. It was possible to measure the structure and characterize accumulation, depletion and deep depletion. However, it was not possible to invert the low doped SiC epilayer at room temperature. From an independent optical thickness measurement the relative dielectric constant of aluminum nitride was calculated to be 8.4. The films were stressed up to 50 Volts (2.5 MV/cm) without breakdown or excessive leakage currents. These results indicate the possibility to replace silicon dioxide with aluminum nitride in SiC field effect transistors.
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| 8. |
- Zetterling, Carl-Mikael, et al.
(författare)
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Investigation of aluminum nitride grown by metal-organic chemical-vapor deposition on silicon carbide
- 1997
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 82:6, s. 2990-2995
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Tidskriftsartikel (refereegranskat)abstract
- Undoped single crystalline aluminum nitride films were grown on 4H and 6H SiC substrates using metal-organic chemical-vapor deposition at 1200°C. From in situ reflection high-energy electron diffraction, x-ray diffraction rocking curves, and cathodoluminescence spectra, the crystallinity of the films was confirmed. Atomic force microscopy showed that some films were substantially dominated by island growth, rather than step flow growth. Aluminum was evaporated to form metal-insulator-semiconductor (MIS) capacitors for high-frequency capacitance voltage measurements carried out at room temperature. Low leakage made it possible to measure the structures and characterize accumulation, depletion, deep depletion, and, in some cases, inversion. From independent optical thickness measurements, the relative dielectric constant of aluminum nitride was confirmed at 8.4. The flatband voltage of the AlN MIS capacitors on p-type SiC was close to the theoretical value expected. The films were stressed up to 60 V (3 MV/cm) without breakdown, but excessive leakage currents (>0.1 A/cm2), probably dominated by grain-boundary conduction, shifted the flatband voltage of the capacitors. These results indicate the possibility of replacing silicon dioxide with aluminum nitride in SiC field effect transistors using insulated gates.
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| 9. |
- Zetterling, Carl-Mikael, et al.
(författare)
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UV-ozone precleaning and forming gas annealing applied to wet thermal oxidation of p-type silicon carbide
- 1999
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Ingår i: Materials Science in Semiconductor Processing. - 1369-8001 .- 1873-4081. ; 2:1, s. 23-27
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Tidskriftsartikel (refereegranskat)abstract
- MOS capacitors using wet thermal oxidation of p-type 4H and 6H silicon carbide have been investigated using capacitance-voltage (CV) measurements. The interface state density was determined from displacements in the CV curves at room temperature after optical generation of carriers. Forming gas annealing at 400 °C after metallization was found to reduce the amount of deep interface states, and in combination with UV-ozone precleaning of the SiC substrates in a commercial system, the fixed oxide charge was also reduced.
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