250 research outputs found
Constructing optimal entanglement witnesses. II
We provide a class of optimal nondecomposable entanglement witnesses for 4N x
4N composite quantum systems or, equivalently, a new construction of
nondecomposable positive maps in the algebra of 4N x 4N complex matrices. This
construction provides natural generalization of the Robertson map. It is shown
that their structural physical approximations give rise to entanglement
breaking channels.Comment: 6 page
Evidence that the caudal portion of the neural tube develops by cavitation of a neural cord in the caudal eminence of human embryos
The formation of the secondary neural tube was traced in serial sections of human
embryos of developmental stages 13 to 17 (32-41 days after fertilisation). It was
found that the secondary neural tube formation begins with cavitation of the
neural cord. The minute cavities are seen in embryos at stages 13 and 15. At
stages 16 and 17 the numerous cavities coalesce to form a single central canal
Constructing new optimal entanglement witnesses
We provide a new class of indecomposable entanglement witnesses. In 4 x 4
case it reproduces the well know Breuer-Hall witness. We prove that these new
witnesses are optimal and atomic, i.e. they are able to detect the "weakest"
quantum entanglement encoded into states with positive partial transposition
(PPT). Equivalently, we provide a new construction of indecomposable atomic
maps in the algebra of 2k x 2k complex matrices. It is shown that their
structural physical approximations give rise to entanglement breaking channels.
This result supports recent conjecture by Korbicz et. al.Comment: 9 page
White communicating rami in human embryos at the end of the fifth week
White communicating rami were traced in 8 human embryos of developmental
stages 14 and 15 (aged 33 and 36 postovulatory days, respectively). In
embryos at stage 14 the white communicating rami were found in the spinal
nerves T1 to T9. In embryos at stage 15 the white communicating rami were
present at the spinal cord levels T1 to L3. (Folia Morphol 2010; 69, 2: 75-77
The thickness of the ventral midline of the spinal cord in human embryos during the fifth week
The thickness of the ventral midline of the spinal cord was determined in
9 human embryos aged five weeks (developmental stages 13-15). This part of
the spinal cord consists of floor plate, mantle and marginal layers. The floor
plate ependymal cells form pseudostratified columnar epithelium. The thickness
of the investigated structure varied from 20 to 50 micrometers at different
levels of the spinal cord
Optimal entanglement witnesses from generalized reduction and Robertson maps
We provide a generalization of the reduction and Robertson positive maps in
matrix algebras. They give rise to a new class of optimal entanglement
witnesses. Their structural physical approximation is analyzed. As a byproduct
we provide a new examples of PPT (Positive Partial Transpose) entangled states.Comment: 14 page
Breeding for Ukrainian table grape varieties
Research Not
Enzymatic Characterization of ER Stress-Dependent Kinase, PERK, and Development of a High-Throughput Assay for Identification of PERK Inhibitors
PERK is serine/threonine kinase localized to the endoplasmic reticulum (ER) membrane. PERK is activated and contributes to cell survival in response to a variety of physiological stresses that affect protein quality control in the ER, such as hypoxia, glucose depravation, increased lipid biosynthesis, and increased protein translation. Pro-survival functions of PERK are triggered by such stresses, suggesting that development of small-molecule inhibitors of PERK may be efficacious in a variety of disease scenarios. Hence, we have conducted a detailed enzymatic characterization of the PERK kinase to develop a high-throughput-screening assay (HTS) that will permit the identification of small-molecule PERK inhibitors. In addition to establishing the Km of PERK for both its primary substrate, eIF2?, and for adenosine triphosphate, further mechanistic studies revealed that PERK targets its substrate via either a random/steady-state ordered mechanism. For HTS, we developed a time-resolved fluorescence resonance energy transferâbased assay that yielded a robust Z? factor and percent coefficient of variation value, enabling the successful screening of 79,552 compounds. This approach yielded one compound that exhibited good in vitro and cellular activity. These results demonstrate the validity of this screen and represent starting points for drug discovery efforts
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