393 research outputs found
Biphasic Electrical Currents Stimulation Promotes both Proliferation and Differentiation of Fetal Neural Stem Cells
The use of non-chemical methods to differentiate stem cells has attracted
researchers from multiple disciplines, including the engineering and the
biomedical fields. No doubt, growth factor based methods are still the most
dominant of achieving some level of proliferation and differentiation control -
however, chemical based methods are still limited by the quality, source, and
amount of the utilized reagents. Well-defined non-chemical methods to
differentiate stem cells allow stem cell scientists to control stem cell biology
by precisely administering the pre-defined parameters, whether they are
structural cues, substrate stiffness, or in the form of current flow. We have
developed a culture system that allows normal stem cell growth and the option of
applying continuous and defined levels of electric current to alter the cell
biology of growing cells. This biphasic current stimulator chip employing ITO
electrodes generates both positive and negative currents in the same culture
chamber without affecting surface chemistry. We found that biphasic electrical
currents (BECs) significantly increased the proliferation of fetal neural stem
cells (NSCs). Furthermore, BECs also promoted the differentiation of fetal NSCs
into neuronal cells, as assessed using immunocytochemistry. Our results clearly
show that BECs promote both the proliferation and neuronal differentiation of
fetal NSCs. It may apply to the development of strategies that employ NSCs in
the treatment of various neurodegenerative diseases, such as Alzheimer's
and Parkinson's diseases
Biphasic Electrical Currents Stimulation Promotes both Proliferation and Differentiation of Fetal Neural Stem Cells
The use of non-chemical methods to differentiate stem cells has attracted
researchers from multiple disciplines, including the engineering and the
biomedical fields. No doubt, growth factor based methods are still the most
dominant of achieving some level of proliferation and differentiation control -
however, chemical based methods are still limited by the quality, source, and
amount of the utilized reagents. Well-defined non-chemical methods to
differentiate stem cells allow stem cell scientists to control stem cell biology
by precisely administering the pre-defined parameters, whether they are
structural cues, substrate stiffness, or in the form of current flow. We have
developed a culture system that allows normal stem cell growth and the option of
applying continuous and defined levels of electric current to alter the cell
biology of growing cells. This biphasic current stimulator chip employing ITO
electrodes generates both positive and negative currents in the same culture
chamber without affecting surface chemistry. We found that biphasic electrical
currents (BECs) significantly increased the proliferation of fetal neural stem
cells (NSCs). Furthermore, BECs also promoted the differentiation of fetal NSCs
into neuronal cells, as assessed using immunocytochemistry. Our results clearly
show that BECs promote both the proliferation and neuronal differentiation of
fetal NSCs. It may apply to the development of strategies that employ NSCs in
the treatment of various neurodegenerative diseases, such as Alzheimer's
and Parkinson's diseases
Anti-angiogenesis: making the tumor vulnerable to the immune system
Ongoing angiogenesis has been shown to possess immune suppressive activity through several mechanisms. One of these mechanisms is the suppression of adhesion receptors, such as intercellular adhesion molecule-1, vascular cell adhesion molecule-1 and E-selectin—adhesion molecules involved in leukocyte interactions—on the vascular endothelium. This phenomenon, when happening to the tumor endothelium, supports tumor growth due to escape from immunity. Since angiogenesis has this immune suppressive effect, it has been hypothesized that inhibition of angiogenesis may circumvent this problem. In vitro and in vivo data now show that several angiogenesis inhibitors are able to normalize endothelial adhesion molecule expression in tumor blood vessels, restore leukocyte vessel wall interactions, and enhance the inflammatory infiltrate in tumors. It is suggested that such angiogenesis inhibitors can make tumors more vulnerable for the immune system and may therefore be applied to facilitate immunotherapy approaches for the treatment of cancer
Search for a Technicolor omega_T Particle in Events with a Photon and a b-quark Jet at CDF
If the Technicolor omega_T particle exists, a likely decay mode is omega_T ->
gamma pi_T, followed by pi_T -> bb-bar, yielding the signature gamma bb-bar. We
have searched 85 pb^-1 of data collected by the CDF experiment at the Fermilab
Tevatron for events with a photon and two jets, where one of the jets must
contain a secondary vertex implying the presence of a b quark. We find no
excess of events above standard model expectations. We express the result of an
exclusion region in the M_omega_T - M_pi_T mass plane.Comment: 14 pages, 2 figures. Available from the CDF server (PS with figs):
http://www-cdf.fnal.gov/physics/pub98/cdf4674_omega_t_prl_4.ps
FERMILAB-PUB-98/321-
Measurement of the B0 anti-B0 oscillation frequency using l- D*+ pairs and lepton flavor tags
The oscillation frequency Delta-md of B0 anti-B0 mixing is measured using the
partially reconstructed semileptonic decay anti-B0 -> l- nubar D*+ X. The data
sample was collected with the CDF detector at the Fermilab Tevatron collider
during 1992 - 1995 by triggering on the existence of two lepton candidates in
an event, and corresponds to about 110 pb-1 of pbar p collisions at sqrt(s) =
1.8 TeV. We estimate the proper decay time of the anti-B0 meson from the
measured decay length and reconstructed momentum of the l- D*+ system. The
charge of the lepton in the final state identifies the flavor of the anti-B0
meson at its decay. The second lepton in the event is used to infer the flavor
of the anti-B0 meson at production. We measure the oscillation frequency to be
Delta-md = 0.516 +/- 0.099 +0.029 -0.035 ps-1, where the first uncertainty is
statistical and the second is systematic.Comment: 30 pages, 7 figures. Submitted to Physical Review
Search for New Particles Decaying to top-antitop in proton-antiproton collisions at squareroot(s)=1.8 TeV
We use 106 \ipb of data collected with the Collider Detector at Fermilab to
search for narrow-width, vector particles decaying to a top and an anti-top
quark. Model independent upper limits on the cross section for narrow, vector
resonances decaying to \ttbar are presented. At the 95% confidence level, we
exclude the existence of a leptophobic \zpr boson in a model of
topcolor-assisted technicolor with mass M_{\zpr} 480 \gev for natural
width = 0.012 M_{\zpr}, and M_{\zpr} 780 \gev for =
0.04 M_{\zpr}.Comment: The CDF Collaboration, submitted to PRL 25-Feb-200
A Measurement of the Differential Dijet Mass Cross Section in p-pbar Collisions at sqrt{s}=1.8 TeV
We present a measurement of the cross section for production of two or more
jets as a function of dijet mass, based on an integrated luminosity of 86 pb^-1
collected with the Collider Detector at Fermilab. Our dijet mass spectrum is
described within errors by next-to-leading order QCD predictions using CTEQ4HJ
parton distributions, and is in good agreement with a similar measurement from
the D0 experiment.Comment: 18 pages including 2 figures and 3 tables. Submitted to Phys. Rev. D
Rapid Communication
Search for Kaluza-Klein Graviton Emission in Collisions at TeV using the Missing Energy Signature
We report on a search for direct Kaluza-Klein graviton production in a data
sample of 84 of \ppb collisions at = 1.8 TeV, recorded
by the Collider Detector at Fermilab. We investigate the final state of large
missing transverse energy and one or two high energy jets. We compare the data
with the predictions from a -dimensional Kaluza-Klein scenario in which
gravity becomes strong at the TeV scale. At 95% confidence level (C.L.) for
=2, 4, and 6 we exclude an effective Planck scale below 1.0, 0.77, and 0.71
TeV, respectively.Comment: Submitted to PRL, 7 pages 4 figures/Revision includes 5 figure
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