13,297 research outputs found
Expression of Green Fluorescence Protein (GFP) in Zebrafish Muscle through Injection: A Gene Therapy Model
Expression of the target gene is important for gene therapy. Presently, localized transgenesis is used for gene therapy which can be achieved by a target gene expression. Here, we have reported the plasmid mediated gene therapy to zebrafish model. For this purpose, we have chosen green fluorescent protein (GFP) as a target gene because the expression can be detected easily. GFP was inserted in a plasmid vector, pQE30 to develop the vector pQE30GFP. The plasmid pQE30GFP was constructed form plasmid, pQE30 and pEGFPC2. pQE30GFP injected directly in one group of fish into the muscle where luciferase expression was noted. In another group, after injection electroporation was performed where we have also noted luciferase expression; but, electroporation cause muscle injury to the zebrafish. In our case, the expression was very strong at the site of injection in first group in compare to electroporation group and in both the cases expression was stable more than two weeks
Nd-142/Nd-144 in SNCs and early differentiation of a heterogeneous Martian mantle
Sm/Nd correlated variations in Nd-142/Nd-144 have been observed for mineral phases of achondrites from decay of live Sm-146 in the early solar system. Crystallization ages of shergottites-nakhlites-Chassigny (SNC) meteorites are less than or = 1.3 Ga, so variations of Nd-142/Nd-144 among mineral phases of the SNC's are not expected. However, if SNC's were derived from source reservoirs of differing Sm/Nd ratios, established while Sm-146 was still alive, and which remained isolated except for magma extraction, then variations in Nd-142/Nd-144 would exist among individual SNC meteorites. Rb-Sr and U-Pb isotopic data for the shergottites imply differentiation of their parent planet approximately 4.6 Ga ago. The confirmation of the conclusion that the nakhlites and shergottites were derived from different source regions, and that, consequently, the shergottite parent body (SPB) mantle was heterogeneous is presented
A Critical Examination of Hypernova Remnant Candidates in M101. II. NGC 5471B
NGC 5471B has been suggested to contain a hypernova remnant because of its
extraordinarily bright X-ray emission. To assess its true nature, we have
obtained high-resolution images in continuum bands and nebular lines with the
Hubble Space Telescope, and high-dispersion long-slit spectra with the Kitt
Peak National Observatory 4-m echelle spectrograph. The images reveal three
supernova remnant (SNR) candidates in the giant HII region NGC 5471, with the
brightest one being the 77x60 pc shell in NGC 5471B. The Ha velocity profile of
NGC 5471B can be decomposed into a narrow component (FWHM = 41 km/s) from the
background HII region and a broad component (FWHM = 148 km/s) from the SNR
shell. Using the brightness ratio of the broad to narrow components and the Ha
flux measured from the WFPC2 Ha image, we derive an Ha luminosity of
(1.4+-0.1)x10^39 ergs/s for the SNR shell. The [SII]6716,6731 doublet ratio of
the broad velocity component is used to derive an electron density of ~700
cm^-3 in the SNR shell. The mass of the SNR shell is thus 4600+-500 Mo. With a
\~330 km/s expansion velocity implied by the extreme velocity extent of the
broad component, the kinetic energy of the SNR shell is determined to be
5x10^51 ergs. This requires an explosion energy greater than 10^52 ergs, which
can be provided by one hypernova or multiple supernovae. Comparing to SNRs in
nearby active star formation regions, the SNR shell in NGC 5471B appears truly
unique and energetic. We conclude that the optical observations support the
existence of a hypernova remnant in NGC 5471B.Comment: 27 pages, 9 figures, to appear in May 2002 issue of The Astronomical
Journa
New high-efficiency source of photon pairs for engineering quantum entanglement
We have constructed an efficient source of photon pairs using a
waveguide-type nonlinear device and performed a two-photon interference
experiment with an unbalanced Michelson interferometer. Parametric
down-converted photons from the nonlinear device are detected by two detectors
located at the output ports of the interferometer. Because the interferometer
is constructed with two optical paths of different length, photons from the
shorter path arrive at the detector earlier than those from the longer path. We
find that the difference of arrival time and the time window of the coincidence
counter are important parameters which determine the boundary between the
classical and quantum regime. When the time window of the coincidence counter
is smaller than the arrival time difference, fringes of high visibility
(80 10%) were observed. This result is only explained by quantum theory
and is clear evidence for quantum entanglement of the interferometer's optical
paths.Comment: 4 pages, 4 figures, IQEC200
Additive Expression of Consolidated Memory through Drosophila Mushroom Body Subsets
Associative olfactory memory in Drosophila has two components called labile anesthesia-sensitive memory and consolidated anesthesia-resistant memory (ARM). Mushroom body (MB) is a brain region critical for the olfactory memory and comprised of 2000 neurons that can be classified into alphabeta, alpha'beta', and gamma neurons. Previously we demonstrated that two parallel pathways mediated ARM consolidation: the serotonergic dorsal paired medial (DPM)-alphabeta neurons and the octopaminergic anterior paired lateral (APL)-alpha'beta' neurons. This finding prompted us to ask how this composite ARM is retrieved. Here, we showed that blocking the output of alphabeta neurons and that of alpha'beta' neurons each impaired ARM retrieval, and blocking both simultaneously had an additive effect. Knockdown of radish and octbeta2R in alphabeta and alpha'beta' neurons, respectively, impaired ARM. A combinatorial assay of radish mutant background rsh1 and neurotransmission blockade confirmed that ARM retrieved from alpha'beta' neuron output is independent of radish. We identified MBON-beta2beta'2a and MBON-beta'2mp as the MB output neurons downstream of alphabeta and alpha'beta' neurons, respectively, whose glutamatergic transmissions also additively contribute to ARM retrieval. Finally, we showed that alpha'beta' neurons could be functionally subdivided into alpha'beta'm neurons required for ARM retrieval, and alpha'beta'ap neurons required for ARM consolidation. Our work demonstrated that two parallel neural pathways mediating ARM consolidation in Drosophila MB additively contribute to ARM expression during retrieval
Measurement of the Dynamical Structure Factor of a 1D Interacting Fermi Gas
We present measurements of the dynamical structure factor of an
interacting one-dimensional (1D) Fermi gas for small excitation energies. We
use the two lowest hyperfine levels of the Li atom to form a
pseudo-spin-1/2 system whose s-wave interactions are tunable via a Feshbach
resonance. The atoms are confined to 1D by a two-dimensional optical lattice.
Bragg spectroscopy is used to measure a response of the gas to density
("charge") mode excitations at a momentum and frequency . The
spectrum is obtained by varying , while the angle between two laser
beams determines , which is fixed to be less than the Fermi momentum
. The measurements agree well with Tomonaga-Luttinger theory
Global Energetics of Thirty-Eight Large Solar Eruptive Events
We have evaluated the energetics of 38 solar eruptive events observed by a
variety of spacecraft instruments between February 2002 and December 2006, as
accurately as the observations allow. The measured energetic components
include: (1) the radiated energy in the GOES 1 - 8 A band; (2) the total energy
radiated from the soft X-ray (SXR) emitting plasma; (3) the peak energy in the
SXR-emitting plasma; (4) the bolometric radiated energy over the full duration
of the event; (5) the energy in flare-accelerated electrons above 20 keV and in
flare-accelerated ions above 1 MeV; (6) the kinetic and potential energies of
the coronal mass ejection (CME); (7) the energy in solar energetic particles
(SEPs) observed in interplanetary space; and (8) the amount of free
(nonpotential) magnetic energy estimated to be available in the pertinent
active region. Major conclusions include: (1) the energy radiated by the
SXR-emitting plasma exceeds, by about half an order of magnitude, the peak
energy content of the thermal plasma that produces this radiation; (2) the
energy content in flare-accelerated electrons and ions is sufficient to supply
the bolometric energy radiated across all wavelengths throughout the event; (3)
the energy contents of flare-accelerated electrons and ions are comparable; (4)
the energy in SEPs is typically a few percent of the CME kinetic energy
(measured in the rest frame of the solar wind); and (5) the available magnetic
energy is sufficient to power the CME, the flare-accelerated particles, and the
hot thermal plasma
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