| 1. |
- Rakov, V. A., et al.
(författare)
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New insights into lightning processes gained from triggered-lightning experiments in Florida and Alabama
- 1998
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Ingår i: Journal of Geophysical Research - Atmospheres. - 2169-897X .- 2169-8996. ; 103:D12, s. 14117-14130
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Tidskriftsartikel (refereegranskat)abstract
- Analyses of electric and magnetic fields measured at distances from tens to hundreds of meters from the ground strike point of triggered lightning at Camp Blanding, Florida, and at 10 and 20 m at Fort McClellan, Alabama, in conjunction with currents measured at the lightning channel base and with optical observations, allow us to make new inferences on several aspects of the lightning discharge and additionally to verify the recently published “two-wave†mechanism of the lightning M component. At very close ranges (a few tens of meters or less) the time rate of change of the final portion of the dart leader electric field can be comparable to that of the return stroke. The variation of the close dart leader electric field change with distance is somewhat slower than the inverse proportionality predicted by the uniformly charged leader model, perhaps because of a decrease of leader charge density with decreasing height associated with an incomplete development of the corona sheath at the bottom of the channel. There is a positive linear correlation between the leader electric field change at close range and the succeeding return stroke current peak at the channel base. The formation of each step of a dart-stepped leader is associated with a charge of a few millicoulombs and a current of a few kiloamperes. In an altitude-triggered lightning the downward negative leader of the bidirectional leader system and the resulting return stroke serve to provide a relatively low-impedance connection between the upward moving positive leader tip and the ground, the processes that follow likely being similar to those in classical triggered lightning. Lightning appears to be able to reduce, via breakdown processes in the soil and on the ground surface, the grounding impedance which it initially encounters at the strike point, so at the time of channel-base current peak the reduced grounding impedance is always much lower than the equivalent impedance of the channel. At close ranges the measured M-component magnetic fields have waveshapes that are similar to those of the channel-base currents, whereas the measured M-component electric fields have waveforms that appear to be the time derivatives of the channel-base current waveforms, in further confirmation of the “two-wave†M-component mechanism.
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| 2. |
- Chen, Q, et al.
(författare)
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Identification of Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) as the rosetting ligand of the malaria parasite P. falciparum
- 1998
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Ingår i: The Journal of experimental medicine. - : Rockefeller University Press. - 0022-1007 .- 1540-9538. ; 187:1, s. 15-23
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Tidskriftsartikel (refereegranskat)abstract
- Severe Plasmodium falciparum malaria is characterized by excessive sequestration of infected and uninfected erythrocytes in the microvasculature of the affected organ. Rosetting, the adhesion of P. falciparum–infected erythrocytes to uninfected erythrocytes is a virulent parasite phenotype associated with the occurrence of severe malaria. Here we report on the identification by single-cell reverse transcriptase PCR and cDNA cloning of the adhesive ligand P. falciparum erythrocyte membrane protein 1 (PfEMP1). Rosetting PfEMP1 contains clusters of glycosaminoglycan-binding motifs. A recombinant fusion protein (Duffy binding-like 1–glutathione S transferase; Duffy binding-like-1–GST) was found to adhere directly to normal erythrocytes, disrupt naturally formed rosettes, block rosette reformation, and bind to a heparin-Sepharose matrix. The adhesive interactions could be inhibited with heparan sulfate or enzymes that remove heparan sulfate from the cell surface whereas other enzymes or similar glycosaminoglycans of a like negative charge did not affect the binding. PfEMP1 is suggested to be the rosetting ligand and heparan sulfate, or a heparan sulfate–like molecule, the receptor both for PfEMP1 binding and naturally formed erythrocyte rosettes.
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| 3. |
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| 4. |
- Rakov, VA, et al.
(författare)
-
New insights into lightning processes gained from triggered-lightning experiments in Florida and Alabama
- 1998
-
Ingår i: JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES. - : AMER GEOPHYSICAL UNION. - 0747-7309. ; 103:D12, s. 14117-14130
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Tidskriftsartikel (refereegranskat)abstract
- Analyses of electric and magnetic fields measured at distances from tens to hundreds of meters from the ground strike point of triggered lightning at Camp Blanding, Florida, and at 10 and 20 m at Fort McClellan, Alabama, in conjunction with currents measu
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| 5. |
- Barral, Anna-Maria, et al.
(författare)
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Cell–cell adherence as a selection method for the generation of anti-melanoma monoclonal antibodies
- 1997
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Ingår i: Journal of Immunological Methods. - 0022-1759. ; 203:1, s. 103-109
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to obtain monoclonal antibodies (mAbs) recognising human melanoma-associated antigens after immunisation of BALB/c mice with a 70–150 kDa membrane fraction from melanoma tumour tissues. Screening of specific antibody- producing hybridomas was performed using a novel cell–cell adherence method with the melanoma cell line M-14. Three mAbs of IgG1 isotype were selected: Mel-1, Mel-2 and Mel-3 which recognised the immunogen by ELISA and stained several melanoma cell lines positive in immunofluorescence. The molecular weight of the antigen was studied by different methods; a 170-kDa band was identified following immunoblotting of tumour lysate and a 72-kDa band was observed following immunoaffinity purification. Cell–cell adherence appears to be a reliable procedure for the generation of mAbs against native cellular antigens.
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| 6. |
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| 7. |
- Fernandez-Mateos, P, et al.
(författare)
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Point mutations and deletion responsible for the Bombay H null and the Reunion H weak blood groups.
- 1998
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Ingår i: Vox sanguinis. - 0042-9007. ; 75:1, s. 37-46
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Definition of the molecular basis of the Reunion and the Bombay red cell and salivary H-deficient phenotypes. METHODS: Sequence and expression of FUT1 and FUT2 genes from H-deficient individuals. Family segregation analysis of the mutations responsible for the fucosyltransferase defects of H, secretor and Lewis systems. RESULTS: The Indian red cell H null Bombay phenotype depends on a new mutation of the FUT1 gene. T725-->G changing Leu242-->Arg. Their salivary nonsecretor phenotype is secondary to a complete deletion of the FUT2 gene. The red cell H weak Reunion phenotype depends on another new mutation of FUT1, C349-->T which induces a change of His117-->Tyr. Their salivary nonsecretor phenotype is due to the known Caucasian inactivating mutation G428-->A. CONCLUSION: Single prevalent FUT1 and FUT2 point mutations and a deletion are responsible for the Indian Bombay H null and the Reunion H weak phenotypes found on Reunion island. This is in contrast with other H-deficient phenotypes where sporadic nonprevalent inactivating mutations are the rule.
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| 8. |
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| 9. |
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| 10. |
- Richard, G., et al.
(författare)
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Multi Modal Verification for Teleservices and Security Applications (M2VTS)
- 1999
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Ingår i: IEEE International Conference on Multimedia Computing and Systems. - Los Alamitos : IEEE. - 0769502539 ; , s. 1061-1064
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents the European ACTS project M2VTS which stands for Multi Modal Verification for Teleservices and Security Applications. The primary goal of this project is to address the issue of secured access to local and centralised services in a multimedia environment. The main objective is to extend the scope of application of network-based services by adding novel and intelligent functionalities, enabled by automatic verification systems combining multimodal strategies (secured access based on speech, image or other information). The objectives of the project are also to show that limitations of individual technologies (speaker verification, frontal face authentication, profile identification,...) can be overcome by relying on multi-modal decisions (combination or fusion of these technologies).
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