| 1. |
- Malina, Tamás, et al.
(författare)
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Individual variability of venom from the European adder (Vipera berus berus) from one locality in Eastern Hungary
- 2017
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Ingår i: Toxicon. - : Elsevier BV. - 0041-0101 .- 1879-3150. ; 135, s. 59-70
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Tidskriftsartikel (refereegranskat)abstract
- We have revealed intra-population variability among venom samples from several individual European adders (Vipera berus berus) within a defined population in Eastern Hungary. Individual differences in venom pattern were noticed, both gender-specific and age-related, by one-dimensional electrophoresis. Gelatin zymography demonstrated that these individual venoms have different degradation profiles indicating varying protease activity in the specimens from adders of different ages and genders. Some specimens shared a conserved region of substrate degradation, while others had lower or extremely low protease activity. Phospholipase A(2) activity of venoms was similar but not identical. Interspecimen diversity of the venom phospholipase A(2)-spectra (based on the components' molecular masses) was detected by MALDI-TOF MS. The lethal toxicity of venoms (LD50) also showed differences among individual snakes. Extracted venom samples had varying neuromuscular paralysing effect on chick biventer cervicis nerve-muscle preparations. The paralysing effect of venom was lost when calcium in the physiological salt solution was replaced by strontium; indicating that the block of twitch responses to nerve stimulation is associated with the activity of a phospholipase-dependent neurotoxin. In contrast to the studied V.b. berus venoms from different geographical regions so far, this is the first V.b berus population discovered to have predominantly neurotoxic neuromuscular activity. The relevance of varying venom yields is also discussed. This study demonstrates that individual venom variation among V.b. berus living in particular area of Eastern Hungary might contribute to a wider range of clinical manifestations of V.b. hems envenoming than elsewhere in Europe.
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| 2. |
- Preobrajenski, Alexei, et al.
(författare)
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Influence of chemical interaction at the lattice-mismatched h-BN∕Rh(111) and h-BN∕Pt(111) interfaces on the overlayer morphology
- 2007
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 75:24, s. 245412-
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Tidskriftsartikel (refereegranskat)abstract
- The atomic and electronic structure of the lattice-mismatched h-BN/Pt(111) and h-BN/Rh(111) interfaces formed by pyrolitic reactions with vaporized borazine has been studied by low-energy electron diffraction, scanning tunneling microscopy, x-ray-absorption spectroscopy, and core-level and valence-band photoemission. It has been found that on Pt(111), h-BN forms a nearly flat monolayer, insignificantly corrugated across the supercell. On Rh(111), h-BN grows in form of a nanomesh, as originally observed by Corso [Science 303, 217 (2004)]. The structural difference between the h-BN/Pt(111) and h-BN/Rh(111) interfaces is associated with the strength of chemical interaction between h-BN and the substrate surface. A stronger orbital hybridization on Rh(111) results in a stronger attraction of the monolayer to the metal surface at favorable adsorption sites resulting in a highly corrugated structure (nanomesh). It has been shown that the electronic structure of the outer (elevated) and inner (attracted to the surface) nanomesh sites is very different as a result of different chemical bonding to the substrate (weak and strong, respectively).
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