373 research outputs found
Modeling Hematological Diseases and Cancer With Patient-Specific Induced Pluripotent Stem Cells
The advent of induced pluripotent stem cells (iPSCs) together with recent advances in genome editing, microphysiological systems, tissue engineering and xenograft models present new opportunities for the investigation of hematological diseases and cancer in a patient-specific context. Here we review the progress in the field and discuss the advantages, limitations, and challenges of iPSC-based malignancy modeling. We will also discuss the use of iPSCs and its derivatives as cellular sources for drug target identification, drug development and evaluation of pharmacological responses
A camera for photographing bathythermograph slides
The instrument described here is a simple portable device that quickly produces accurate and permanent 2¼ x 3¼ photographic prints of bathythermograph data, both smoked slide and calibration grid being photographed simultaneously…
M\"ossbauer, nuclear inelastic scattering and density functional studies on the second metastable state of Na2[Fe(CN)5NO]2H2O
The structure of the light-induced metastable state SII of
Na2[Fe(CN)5NO]2H2O 14 was investigated by transmission M\"ossbauer
spectroscopy (TMS) in the temperature range 15 between 85 and 135 K, nuclear
inelastic scattering (NIS) at 98 K using synchrotron 16 radiation and density
functional theory (DFT) calculations. The DFT and TMS results 17 strongly
support the view that the NO group in SII takes a side-on molecular orientation
18 and, further, is dynamically displaced from one eclipsed, via a staggered,
to a second 19 eclipsed orientation. The population conditions for generating
SII are optimal for 20 measurements by TMS, yet they are modest for
accumulating NIS spectra. Optimization 21 of population conditions for NIS
measurements is discussed and new NIS experiments on 22 SII are proposed
Unraveling the mechanism of NO ligand photoisomerism by time-resolved infrared spectroscopy
International audienceUV-Vis- and infrared femtosecond spectroscopy makes it possible to reveal all different steps of photochemical reactions after the electronic excitation. The electronic relaxations are observed in the UV-Vis spectral range whereas the nuclear motions are monitored in the infrared spectral range. We used femtosecond time-resolved infrared spectroscopy to demonstrate the photoisomerization of the NO ligand photoinduced by a visible femtosecond pulse in a Na2[Fe(CN)5NO]*2H2O single crystal occurs in about 350 fs. The analysis of data makes it possible to unravel the mechanism leading to the photoisomerization of the NO ligand
Genomic imprinting defect in Zfp57 mutant iPS cell lines
AbstractZFP57 maintains genomic imprinting in mouse embryos and ES cells. To test its roles during iPS reprogramming, we derived iPS clones by utilizing retroviral infection to express reprogramming factors in mouse MEF cells. After analyzing four imprinted regions, we found that parentally derived DNA methylation imprint was largely maintained in the iPS clones with Zfp57 but missing in those without maternal or zygotic Zfp57. Intriguingly, DNA methylation imprint was lost at the Peg1 and Peg3 but retained at the Snrpn and Dlk1-Dio3 imprinted regions in the iPS clones without zygotic Zfp57. This finding will be pursued in future studies
Evidence for a soft-phonon-mode-driven Peierls-type distortion in ScCoC
We provide experimental and theoretical evidence for the realization of the
Peierls-type structurally distorted state in the quasi-one-dimensional
superconductor ScCoC by a phonon-softening mechanism. The transition
from the high- to the final low-temperature phase below 80K proceeds via an
extended intermediate temperature regime between 80K and 150K characterized by
phonon-driven atom displacements. In support of the low-dimensional character
of the title compound we find a highly anisotropic correlation-length of these
dynamic distortions.Comment: 9 pages, 7 figures and supporting informatio
Structural properties in Sr0.61a0.39Nb2O6 in the temperature range 10 K to 500 K investigated by high-resolution neutron powder diffraction and specific heat measurements
We report high-resolution neutron powder diffraction on Sr0.61Ba0.39Nb2O6,
SBN61, in the temperature range 15-500 K. The results indicate that the
low-temperature anomalies (T<100K) observed in the dielectric dispersion are
due to small changes in the incommensurate modulation of the NbO6-octahedra, as
no structural phase transition of the average structure was observed. This
interpretation is supported by specific heat measurements, which show no latent
heat, but a glass-like behavior at low temperatures. Furthermore we find that
the structural changes connected with the ferroelectric phase transition at Tc
approx. 350K start already at 200K, explaining the anisotropic thermal
expansion in the temperature range 200-300K observed in a recent x-ray
diffraction study.Comment: Accepted by PRB (2006
Pas de Deux of an NO Couple: Synchronous Photoswitching from a Double-Linear to a Double-Bent Ru(NO)(2) Core under Nitrosyl Charge Conservation
The {Ru(NO)(2)}(10) dinitrosylruthenium complex [Ru(NO)(2)(PPh3)(2)] (1) shows photo-induced linkage isomerism (PLI) of a special kind: the two NO ligands switch, on photo-excitation, synchronously from the ground state (GS) with two almost linear RuNO functions to a metastable state (MS) which persists up to 230 K and can be populated to approximate to 50 %. The MS was experimentally characterised by photo-crystallography, IR spectroscopy and DS-calorimetry as a double-bent variant of the double-linear GS. The experimental results are confirmed by computation which unravels the GS/MS transition as a disrotatory synchronous 50 degrees turn of the two nitrosyl ligands. Although 1 shows the usual redshift of the N-O stretch on bending the MNO unit, there is no increased charge transfer from Ru to NO along the GS-to-MS path. In terms of the effective-oxidation-state (EOS) method, both isomers of 1 and the transition state are Ru-II(NO+)(2) species
Multiple light-induced NO linkage isomers in the dinitrosyl complex [RuCl(NO)₂(PPh₃)₂]BF₄ nravelled by photocrystallographic and IR analysis
Multiple light-induced reversible metastable NO linkage isomers (PLIs) have been detected in the dinitrosyl compound [RuCl(NO)(2)(PPh3)(2)]BF4 by a combination of photocrystallographic and IR analysis. The IR signature of three PLI states has been clearly identified, with estimated populations of 59% (PLI-1), 8% (PLI-2) and 5% (PLI-3) for a total population of the metastable state of 72%. The structural configuration of the major component (PLI-1) has been derived by X-ray photocrystallography. In the ground state, the structure is characterized by a bent and a linear nitrosyl, the bent one being oriented towards the linear equatorial nitrosyl with an Ru-N-O angle of 133.88 (9)degrees. X-ray Fourier difference maps indicate a selectivity of the photo-isomerization process in PLI-1: only the bent NO ligand changes its position, while the linear NO is unaffected. After irradiation at 405 nm, the orientation is changed by rotation towards the Cl ligand opposite the linear NO, with an Ru-N-O angle in this new position of 109 (1)degrees. The photocrystallographic analysis provides evidence that, in the photo-induced metastable state, the bent NO group is attached to the Ru atom through the N atom (Ru-N-O),rather than in an isonitrosyl Ru-O-N binding mode. In the IR spectra, the asymmetric NO vibrational band shifts by -33 cm(-1) to a lower value, whereas the symmetric band splits and shifts by 5 cm(-1) to a higher value and by -8 cm(-1) to a lower value. The down shift is a clear indication of the structural change, and the small upward shift in response to the new electronic configuration of the metastable structure. Variable-temperature IR kinetic measurements in the range 80-114 K show that the decay of the PLI-1 state follows an Arrhenius behaviour with an activation energy of 0.22 eV
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