265 research outputs found
Photoemission of a doped Mott insulator: spectral weight transfer and qualitative Mott-Hubbard description
The spectral weight evolution of the low-dimensional Mott insulator TiOCl
upon alkali-metal dosing has been studied by photoelectron spectroscopy. We
observe a spectral weight transfer between the lower Hubbard band and an
additional peak upon electron-doping, in line with quantitative expectations in
the atomic limit for changing the number of singly and doubly occupied sites.
This observation is an unconditional hallmark of correlated bands and has not
been reported before. In contrast, the absence of a metallic quasiparticle peak
can be traced back to a simple one-particle effect.Comment: 4 pages, 4 figures, related theoretical work can be found in
arXiv:0905.1276; shortene
Synthesis and biodistribution of immunoconjugates of a human IgM and polymeric drug carriers
The synthesis and purification of radiolabelled immunoconjugates, composed of a human IgM monoclonal antibody directed against an intracellular tumour-associated antigen and either poly (alpha-L-glutamic acid) (PGA) or poly[N5-(2-hydroxyethyl)-L-glutamine] (PHEG) is described. Coupling of polymers to the antibody was performed through disulfide bond formation involving a single thiol group at the C-terminus of the polymer chain and 2-pyridyldisulfide groups introduced onto the antibody. The antibody was iodinated with 131I before conjugation. The polymers contained tyrosinamide in a low degree of substitution and were radiolabelled with 125I. 125I-labelled PGA and PHEG were found to be stable for at least 3 days in murine and human plasma. The biodistribution in mice of the doubly labelled immunoconjugates was studied and was compared with the pharmacokinetics of the individual components.\ud
\ud
PHEG showed a relatively slow blood clearance, the half-life being approximately 10 h with low uptake in liver, kidneys and spleen. PGA was rapidly cleared from the circulation and was significantly taken up in liver, kidneys and spleen. The biodistribution of both immunoconjugates was indistinguishable from that of the IgM proper, with plasma half-lives of approximately 6 h, indicating that the pharmacokinetic properties of the immunoconjugates are largely determined by the antibody part
Recommended from our members
High-resolution VUV spectroscopy: New results from the Advanced Light Source
Third-generation synchrotron light sources are providing photon beams of unprecedented brightness for researchers in atomic and molecular physics. Beamline 9.0.1, an undulator beamline at the Advanced Light Source (ALS), produces a beam in the vacuum-ultraviolet (VUV) region of the spectrum with exceptional flux and spectral resolution. Exciting new results from experiments in atomic and molecular VUV spectroscopy of doubly excited autoionizing states of helium, hollow lithium, and photoelectron spectroscopy of small molecules using Beamline 9.0.1 at the ALS are reported
Charge Transfer Of Hydrogen Ions And Atoms In Metal Vapors
Cross sections and equilibrium fractions for energetic H+, H−, and H0 in collisions with metal vapor targets have been compiled and evaluated. Both experimental and theoretical results are reported. Sources of errors are discussed, and recommended values for the data are presented. © 1985, American Institute of Physics for the National Institute of Standards and Technology. All rights reserved
High transport currents in mechanically reinforced MgB2 wires
We prepared and characterized monofilamentary MgB2 wires with a mechanically
reinforced composite sheath of Ta(Nb)/Cu/steel, which leads to dense filaments
and correspondingly high transport currents up to Jc = 10^5 A/cm^2 at 4.2 K,
self field. The reproducibility of the measured transport currents was
excellent and not depending on the wire diameter. Using different precursors,
commercial reacted powder or an unreacted Mg/B powder mixture, a strong
influence on the pinning behaviour and the irreversibility field was observed.
The critical transport current density showed a nearly linear temperature
dependency for all wires being still 52 kA/cm^2 at 20 K and 23 kA/cm^2 at 30 K.
Detailed data for Jc(B,T) and Tc(B) were measured.Comment: 21 pages, 13 figures, revised version, to be published in Supercond.
Sci. Techno
Test of a DC-HTS Busbar Demonstrator for Power Distribution in Hybrid-Electric Propulsion Systems for Aircraft
In the framework of the German project TELOS (Thermo-Electrically Optimised
Aircraft Propulsion Systems) a high-temperature superconducting 40 MVA DC demonstrator
busbar for hybrid-electric propulsion systems for aircraft has been developed. The design current
for a temperature below 25 K is 13.3 kA and the rated voltage is 3 kV. The 2-pole busbar contains
2 stacks of REBCO coated conductors which are supported by a 3D-printed structure allowing
compensation of thermal length changes of the superconductor. It fits in a cryostat tube with an
inner diameter of 25 mm. A special focus has been put on low-resistive joints that are necessary
to connect single elements of the busbar system. The special layout of the joints allows an
effective current redistribution between the different tapes in a stack. We present results for the
test of the DC busbar demonstrator in liquid nitrogen at 77 K. The design current for this
temperature is 3.3 kA which corresponds to a rated power of 10 MW. We applied currents up to
3.5 kA and measured the I-V characteristics and contact resistances of 90° and 180° joints in a
virgin and in a strained state thus simulating thermal length changes. We also present results of
Lorentz-Force tests with short AC current pulses up to 20 kA to demonstrate the viability of the
design for application with currents up to 13.3 k
Synthesis and biological evaluation of immunoconjugates of adriamycin and a human IgM linked by poly[N5-(2-hydroxyethyl)-l-glutamine
The synthesis and purification of radiolabelled immunoconjugates, composed of a human IgM monoclonal antibody (IgM 16.88) directed against an intracellular tumour-associated antigen, the drug carrier poly[N5-(2-hydroxyethyl)--glutamine] (PHEG) and the cytostatic drug adriamycin (ADR) are described. The immunoconjugates were constructed to allow selective release of ADR in the putatively acidic environment of the tumour through a novel acid-labile maleamic acid linker. The conjugate of PHEG and the acid-labile ADR derivative effectively released ADR in cytotoxic amounts at a pH of 6.0 as judged from incubation in buffer and from inhibition of the growth of HT-29 colon tumour cells in vitro. Immunoconjugates were prepared by coupling of PHEG-ADR having a hydrolytically stable amide bond with 131I-labelled antibody through thioether bond formation involving a single thiol group at the C-terminus of the polymer chain and maleimido groups introduced onto th
- …