1,707 research outputs found
On a Basis for the Framed Link Vector Space Spanned by Chord Diagrams
In view of the result of Kontsevich, now often called ``the fundamental
theorem of Vassiliev theory'', identifying the graded dual of the associated
graded vector space to the space of Vassiliev invariants filtered by degree
with the linear span of chord diagrams modulo the ``4T-relation'' (and in the
unframed case, the ``1T-'' or ``isolated chord relation''), it is a problem of
some interest to provide a basis for the space of chord diagrams modulo the
4T-relation.
We construct the basis for the vector space spanned by chord diagrams with n
chords and m distinguishable link components, modulo 4T relations for n less
than or equal to 5.Comment: 25 papers, numerous png figure
Generation of spin-wave dark solitons with phase engineering
We generate experimentally spin-wave envelope dark solitons from rectangular
high-frequency dark input pulses with externally introduced phase shifts in
yttrium-iron garnet magnetic fims. We observe the generation of both odd and
even numbers of magnetic dark solitons when the external phase shift varies.
The experimental results are in a good qualitative agreement with the theory of
the dark-soliton generation in magnetic films developed earlier [Phys. Rev.
Lett. 82, 2583 (1999)].Comment: 6 pages, including 7 figures, submitted to Phys. Rev.
Robust nanopatterning by laser-induced dewetting of metal nanofilms
We have observed nanopattern formation with robust and controllable spatial
ordering by laser-induced dewetting in nanoscopic metal films. Pattern
evolution in Co film of thickness 1\leq h\leq8 nm on SiO_{2} was achieved under
multiple pulse irradiation using a 9 ns pulse laser. Dewetting leads to the
formation of cellular patterns which evolve into polygons that eventually break
up into nanoparticles with monomodal size distribution and short range ordering
in nearest-neighbour spacing R. Spatial ordering was attributed to a
hydrodynamic thin film instability and resulted in a predictable variation of R
and particle diameter D with h. The length scales R and D were found to be
independent of the laser energy. These results suggest that spatially ordered
metal nanoparticles can be robustly assembled by laser-induced dewetting
Direct comparison of a radioiodinated intact chimeric anti-CEA MAb with its F(ab')2 fragment in nude mice bearing different human colon cancer xenografts.
Tumour localisation and tumour to normal tissue ratios of a chimeric anti-carcinoembryonic antigen (CEA) monoclonal antibody (MAb), in intact form and as an F(ab')2 fragment labelled with 125I and 131I, were compared in groups of nude mice bearing four different colon cancer xenografts, T380, Co112 or LoVo, of human origin, or a rat colon cancer transfected with human CEA cDNA, called '3G7'. For each tumour, three to four mice per time point were analysed 6, 12, 24, 48 and 96 h after MAb injection. In the different tumours, maximal localisation of intact MAb was obtained at 24 to 48 h, and of F(ab')2 fragment 12 to 24 h after injection. Among the different tumours, localisation was highest with colon cancer T380, with 64% of the injected dose per gram (% ID/g) for the intact MAb and 57% for its F(ab')2 fragment, while in the three other tumours, maximal localisation ranged from 14 to 22% ID g-1 for the intact MAb and was about 11% for the F(ab')2. Tumour to normal tissue ratios of intact MAb increased rapidly until 24 h after injection and remained stable or showed only a minor increase thereafter. In contrast, for the F(ab')2 fragment, the tumour to normal tissue ratios increased steadily up to 4 days after injection reaching markedly higher values than those obtained with intact MAb. For the four different xenografts, tumour to blood ratios of F(ab')2 were about 2, 3 and 5 to 16 times higher than those of intact antibodies at 12, 24 and 96 h after injection, respectively
- …