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- Aspholm-Hurtig, Marina, et al.
(author)
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Functional adaptation of BabA, the H. pylori ABO blood group antigen binding adhesin.
- 2004
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In: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 305:5683, s. 519-22
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Journal article (peer-reviewed)abstract
- Adherence by Helicobacter pylori increases the risk of gastric disease. Here, we report that more than 95% of strains that bind fucosylated blood group antigen bind A, B, and O antigens (generalists), whereas 60% of adherent South American Amerindian strains bind blood group O antigens best (specialists). This specialization coincides with the unique predominance of blood group O in these Amerindians. Strains differed about 1500-fold in binding affinities, and diversifying selection was evident in babA sequences. We propose that cycles of selection for increased and decreased bacterial adherence contribute to babA diversity and that these cycles have led to gradual replacement of generalist binding by specialist binding in blood group O-dominant human populations.
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- Lind, Erik, et al.
(author)
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A resonant tunneling permeable base transistor with Al-free tunneling barriers
- 2002
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In: Device Research Conference (Cat. No.02TH8606). - 0780373170 ; , s. 155-156
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Conference paper (peer-reviewed)abstract
- Summary form only given. Resonant tunneling based devices are an intriguing set of devices with promising high speed, low power and high functionality capabilities. We have developed an technology to embed metallic features on the nm-scale inside a semiconductor. By combining such metallic features and heterostructures we have developed a new type of tunneling transistor, the so called Resonant Tunneling Permeable Base Transistor (RT-PBT), where a double barrier heterostructure is placed in close vicinity to a metal grating. A three step fabrication process is described
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10. |
- Lind, Erik, et al.
(author)
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Stacking of heterostructures and metallic elements for a submicron resonant tunneling transistor
- 2002
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In: 7th International Conference on Nanometer-Scale Science and Technology and 21st European Conference on Surface Science.
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Conference paper (peer-reviewed)abstract
- We have successfully embedded a metal gate in-between two resonant tunneling double barrier heterostructures (RTD), thus realizing a three dimensional resonant tunneling transistor. The gate is placed 30 nm above and 100 below the two RTD's, respectively. The asymmetric gate allows for a unique control of the current-voltage characteristics, not only controlling the peak current but also the peak voltage. We have modeled the transistor with Cadence, a standard simulation package for circuit simulations, achieving good agreement with experimental data
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