1,769 research outputs found
Characterization of the monocyte-specific esterase (MSE) gene
Carboxylic esterases are widely distributed in hematopoietic cells. Monocytes express the esterase isoenzyme (termed 'monocyte-specific esterase', MSE) that can be inhibited by NaF in the alpha-naphthyl acetate cytochemical staining. We examined the expression of MSE in normal cells and primary and cultured leukemia-lymphoma cells. The MSE protein was demonstrated by isoelectric focusing (IEF); MSE mRNA expression was investigated by Northern blotting and reverse transcriptase-polymerase chain reaction (RT-PCR). The following samples were positive for MSE protein and Northern mRNA expression: 20/24 monocytic, 4/32 myeloid, and 1/20 erythroid-megakaryocytic leukemia cell lines, but none of the 112 lymphoid leukemia or lymphoma cell lines; of the normal purified cell populations only the monocytes were positive whereas, T, B cells, and granulocytes were negative; of primary acute (myelo) monocytic leukemia cells (CD14-positive, FAB M4/M5 morphology) 14/20 were Northern mRNA and 11/14 IEF protein positive. RT-PCR revealed MSE expression in 29/49 Northern-negative lymphoid leukemia-lymphoma cell lines. The RT-PCR signals in monocytic cell lines were on average 50-fold stronger than the mostly weak trace expression in lymphoid specimens. On treatment with various biomodulators, only all-trans retinoic acid significantly upregulated MSE message and protein levels but could not induce new MSE expression in several leukemia cell lines; lipopolysaccharide and interferon-gamma increased MSE expression in normal monocytes. Analysis of DNA methylation with sensitive restriction enzymes showed no apparent regulation of gene expression by differential methylation; the MSE gene is evolutionarily conserved among mammalian species; the half-life of the human MSE transcripts was about 5-6 h. The extent of MSE expression varied greatly among different monocytic leukemia samples. However, the MSE overexpression in a significant number of specimens was not associated with gene amplification, gross structural rearrangements or point mutations within the cDNA region. Taken together, the results suggest that MSE expression is not absolutely specific for, but strongly associated with cells of the monocytic lineage; MSE is either not expressed at all or expressed at much lower levels in cells from other lineages. The biological significance, if any, of rare MSE messages in lymphoid cells detectable only by the hypersensitive RT-PCR remains unclear. Further studies on the regulation of this gene and on the physiological function of the enzyme will no doubt be informative with respect to its striking overexpression in some malignant cells and to a possible role in the pathobiology of monocytic leukemias
Automatic segmentation and classification methods using optical coherence tomography angiography (Octa): A review and handbook
Optical coherence tomography angiography (OCTA) is a promising technology for the non-invasive imaging of vasculature. Many studies in literature present automated algorithms to quantify OCTA images, but there is a lack of a review on the most common methods and their comparison considering multiple clinical applications (e.g., ophthalmology and dermatology). Here, we aim to provide readers with a useful review and handbook for automatic segmentation and classification methods using OCTA images, presenting a comparison of techniques found in the literature based on the adopted segmentation or classification method and on the clinical application. Another goal of this study is to provide insight into the direction of research in automated OCTA image analysis, especially in the current era of deep learning
Reconfigurable antenna pattern verification
A method of verifying programmable antenna configurations is disclosed. The method comprises selecting a desired antenna configuration from a plurality of antenna configuration patterns, with the selected antenna configuration forming at least one reconfigurable antenna from reconfigurable antenna array elements. The method validates the formation of the selected antenna configuration to determine antenna performance of the at least one reconfigurable antenna
Ionic conductivity in Li2O-Al2O3-SiO2 based glasses and glass ceramics
The complex conductivity of lithium aluminosilicate based glasses and glass-ceramics (Zerodur from Schott) has been investigated in a broad range of temperatures (200 K < T < 700 K) and frequencies (10 mHz<v<2.5 THz). The data are presented in terms of the conductivity and the electrical modulus formalisms. The width of the modulus loss peak as measured for the ceramic sample is broader than that determined for its precursor glass. This result is shown to be associated with the considerably smaller dc conductivity of this material.</jats:p
Quantum gears: a simple mechanical system in the quantum regime
Abstract. The quantum mechanics of a simple mechanical system is considered. A group of gears can serve as a model for several different systems such as an artifically constructed nanomechanical device or a group of ring molecules. It is shown that the classical motion of the gears in which the angular velocities are locked together does not correspond to
Reconstructing the Optical Parameters of a Layered Medium with Optical Coherence Elastography
In this work we consider the inverse problem of reconstructing the optical
properties of a layered medium from an elastography measurement where optical
coherence tomography is used as the imaging method. We hereby model the sample
as a linear dielectric medium so that the imaging parameter is given by its
electric susceptibility, which is a frequency- and depth-dependent parameter.
Additionally to the layered structure (assumed to be valid at least in the
small illuminated region), we allow for small scatterers which we consider to
be randomly distributed, a situation which seems more realistic compared to
purely homogeneous layers. We then show that a unique reconstruction of the
susceptibility of the medium (after averaging over the small scatterers) can be
achieved from optical coherence tomography measurements for different
compression states of the medium.Comment: 19 pages, 1 figur
Antenna reconfiguration verification and validation
A method of testing the electrical functionality of an optically controlled switch in a reconfigurable antenna is provided. The method includes configuring one or more conductive paths between one or more feed points and one or more test point with switches in the reconfigurable antenna. Applying one or more test signals to the one or more feed points. Monitoring the one or more test points in response to the one or more test signals and determining the functionality of the switch based upon the monitoring of the one or more test points
Spin polarized electric currents in semiconductor heterostructures induced by microwave radiation
We report on microwave (mw) radiation induced electric currents in
(Cd,Mn)Te/(Cd,Mg)Te and InAs/(In,Ga)As quantum wells subjected to an external
in-plane magnetic field. The current generation is attributed to the
spin-dependent energy relaxation of electrons heated by mw radiation. The
relaxation produces equal and oppositely directed electron flows in the spin-up
and spin-down subbands yielding a pure spin current. The Zeeman splitting of
the subbands in the magnetic field leads to the conversion of the spin flow
into a spin-polarized electric current.Comment: 3 pages, 4 figure
Molecular Motor Constructed from a Double-Walled Carbon Nanotube Driven by Axially Varying Voltage
A new molecular motor is conceptually constructed from a double-walled carbon
nanotube (DWNT) consisting of a long inner single-walled carbon nanotube (SWNT)
and a short outer SWNT with different chirality. The interaction between inner
and outer tubes is the sum of the Lennard-Jones potentials between carbon atoms
in inner tube and those in outer one. Within the framework of
Smoluchowski-Feynman ratchet, it is theoretically shown that this system in an
isothermal bath will exhibit a unidirectional rotation in the presence of a
varying axial electrical voltage.Comment: 11 pages + 3 figure
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