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| 3. |
- Green, Richard E., et al.
(författare)
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Three crocodilian genomes reveal ancestral patterns of evolution among archosaurs
- 2014
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 346:6215, s. 1335-
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Tidskriftsartikel (refereegranskat)abstract
- To provide context for the diversification of archosaurs-the group that includes crocodilians, dinosaurs, and birds-we generated draft genomes of three crocodilians: Alligator mississippiensis (the American alligator), Crocodylus porosus (the saltwater crocodile), and Gavialis gangeticus (the Indian gharial). We observed an exceptionally slow rate of genome evolution within crocodilians at all levels, including nucleotide substitutions, indels, transposable element content and movement, gene family evolution, and chromosomal synteny. When placed within the context of related taxa including birds and turtles, this suggests that the common ancestor of all of these taxa also exhibited slow genome evolution and that the comparatively rapid evolution is derived in birds. The data also provided the opportunity to analyze heterozygosity in crocodilians, which indicates a likely reduction in population size for all three taxa through the Pleistocene. Finally, these data combined with newly published bird genomes allowed us to reconstruct the partial genome of the common ancestor of archosaurs, thereby providing a tool to investigate the genetic starting material of crocodilians, birds, and dinosaurs.
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| 4. |
- Rashid, S. J., et al.
(författare)
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Modelling of single-crystal diamond Schottky diodes for high-voltage applications
- 2006
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Ingår i: Diamond and related materials. - : Elsevier BV. - 0925-9635 .- 1879-0062. ; 15, s. 317-323
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Tidskriftsartikel (refereegranskat)abstract
- The modelling of Schottky m-i-p(+) (SMIP) diodes fabricated on chemical vapour deposited (CVD) single crystal (SC) diamond intrinsic layers grown on highly boron doped CVD diamond Substrates is reported. Variations in intrinsic layer thickness, Schottky metal type and operating temperature have been included in the analysis. Numerical models that take into account the activation of dopants, concentration and temperature dependant mobility and avalanche coefficients have been derived to successfully simulate experimental diamond devices.
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| 6. |
- Rashid, S. J., et al.
(författare)
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Numerical Parameterization of Chemical-Vapor-Deposited (CVD) Single-Crystal Diamond for Device Simulation and Analysis
- 2008
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Ingår i: IEEE Transactions on Electron Devices. - 0018-9383 .- 1557-9646. ; 55:10, s. 2744-2756
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Tidskriftsartikel (refereegranskat)abstract
- High-quality electronic-grade intrinsic chemical-vapor-deposited (CVD) single-crystal diamond layers having exceptionally high carrier mobilities have been reported by Isberg et al. This makes the realization of novel electronic devices in diamond, particularly for high-voltage and high-temperature applications, a viable proposition. As such, material models which can capture the particular features of diamond as a semiconductor are required to analyze, optimize, and quantitatively design new devices. For example, the incomplete ionization of boron in diamond and the transition to metallic conduction in heavily boron-doped layers require accurate carrier freeze-out models to be included in the simulation of diamond devices. Models describing these phenomena are proposed in this paper and include numerical approximation of intrinsic diamond which is necessary to formulate doping- and temperature-dependent mobility models. They enable a concise numerical description of single-crystal diamond which agrees with data obtained from material characterization. The models are verified by application to new Schottky m-i-p(+) diode structures in diamond. Simulated forward characteristics show excellent correlation with experimental measurements. In spite of the lack of impact ionization data for single-crystal diamond, approximation of avalanche coefficient parameters from other wide-bandgap semiconductors has also enabled the reverse blocking characteristics of diamond diodes to be simulated. Acceptable agreement with breakdown voltage from experimental devices made with presently available single-crystal CVD diamond is obtained.
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- Balmer, R. S., et al.
(författare)
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Unlocking diamond's potential as an electronic material
- 2008
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Ingår i: Philosophical Transactions. Series A. - London : Royal Society of London. - 1364-503X .- 1471-2962. ; 366:1863, s. 251-265
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we review the suitability of diamond as a semiconductor material for high-performance electronic applications. The current status of the manufacture of synthetic diamond is reviewed and assessed. In particular, we consider the quality of intrinsic material now available and the challenges in making doped structures suitable for practical devices. Two practical applications are considered in detail. First, the development of high-voltage switches capable of switching voltages in excess of 10kV. Second, the development of diamond MESFETs for high-frequency and high-power applications. Here device data are reported showing a current density of more than 30mAmm -1 along with small-signal RF measurements demonstrating gigahertz operation. We conclude by considering the remaining challenges which will need to be overcome if commercially attractive diamond electronic devices are to be manufactured.
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| 8. |
- Gabrysch, Markus, et al.
(författare)
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Formation of secondary electron cascades in single-crystalline plasma-deposited diamond upon exposure to femtosecond x-ray pulses
- 2008
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 103:6
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Tidskriftsartikel (refereegranskat)abstract
- Secondary electron cascades were measured in high purity single-crystalline chemical vapor deposition (CVD) diamond, following exposure to ultrashort hard x-ray pulses (140 fs full width at half maximum, 8.9 keV energy) from the Sub-Picosecond Pulse Source at the Stanford Linear Accelerator Center. We report measurements of the pair creation energy and of drift mobility of carriers in two CVD diamond crystals. This was done for the first time using femtosecond x-ray excitation. Values for the average pair creation energy were found to be 12.17 +/- 0.57 and 11.81 +/- 0.59 eV for the two crystals, respectively. These values are in good agreement with recent theoretical predictions. The average drift mobility of carriers, obtained by the best fit to device simulations, was mu(h)= 2750 cm(2)/V s for holes and was mu(e)= 2760 cm(2) / V s for electrons. These mobility values represent lower bounds for charge mobilities due to possible polarization of the samples. The results demonstrate outstanding electric properties and the enormous potential of diamond in ultrafast x-ray detectors.
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| 10. |
- Iorizzo, L., et al.
(författare)
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Proposed cutoff for fetal scalp blood lactate in intrapartum fetal surveillance based on neonatal outcomes: a large prospective observational study
- 2022
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Ingår i: BJOG: An International Journal of Obstetrics and Gynaecology. - : Wiley. - 1470-0328 .- 1471-0528. ; 129:4, s. 636-646
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Determination of lactate in fetal scalp blood (FBS) during labour has been recognised since the 1970s. The internationally accepted cutoff of >4.8mmol/l indicating fetal acidosis is exclusive for the point-of-care device (POC) LactatePro™, which is no longer in production. The aim of this study was to establish a new cutoff for scalp lactate based on neonatal outcomes with the use of the StatstripLactate®/StatstripXpress® Lactate system, the only POC designed for hospital use. Design: Observational study. Setting: January 2016 to March 2020 labouring women with indication for FBS were prospectively included from seven Swedish and one Australian delivery unit. Population: Inclusion criteria: singleton pregnancy, vertex presentation, ≥35+0weeks of gestation. Method: Based on the optimal correlation between FBS lactate and cord pH/lactate, only cases with ≤25minutes from FBS to delivery were included in the final calculations. Main outcome measures: Metabolic acidosis in cord blood defined as pH <7.05 plus BDecf >10mmol/l and/or lactate >10mmol/l. Results: A total of 3334 women were enrolled of whom 799 were delivered within 25minutes. The areas under the receiver operating characteristics curves (AUC) and corresponding optimal cutoff values were as follows; metabolic acidosis AUC 0.87 (95% CI 0.77–0.97), cutoff 5.7mmol/l; pH <7.0 AUC 0.83 (95% CI 0.68–0.97), cutoff 4.6mmol/l; pH <7.05 plus BDecf ≥12mmol/l AUC 0.97 (95% CI 0.92–1), cutoff 5.8mmol/l; Apgar score <7 at 5minutes AUC 0.74 (95% CI 0.63–0.86), cutoff 5.2mmol/l; and pH <7.10 plus composite neonatal outcome AUC 0.76 (95% CI 0.67–0.85), cutoff 4.8mmol/l. Conclusion: A scalp lactate level <5.2mmol/l using the StatstripLactate®/StatstripXpress® system will safely rule out fetal metabolic acidosis. Tweetable abstract: Scalp blood lactate <5.2mmol/l using the StatstripLactate®/StatstripXpress system has an excellent ability to rule out fetal acidosis.
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