2,856 research outputs found
Recoverin Regulates Light-dependent Phosphodiesterase Activity in Retinal Rods
The Ca2+-binding protein recoverin may regulate visual transduction in retinal rods and cones, but its functional role and mechanism of action remain controversial. We compared the photoresponses of rods from control mice and from mice in which the recoverin gene was knocked out. Our analysis indicates that Ca2+-recoverin prolongs the dark-adapted flash response and increases the rod's sensitivity to dim steady light. Knockout rods had faster Ca2+ dynamics, indicating that recoverin is a significant Ca2+ buffer in the outer segment, but incorporation of exogenous buffer did not restore wild-type behavior. We infer that Ca2+-recoverin potentiates light-triggered phosphodiesterase activity, probably by effectively prolonging the catalytic activity of photoexcited rhodopsin
How different Fermi surface maps emerge in photoemission from Bi2212
We report angle-resolved photoemission spectra (ARPES) from the Fermi energy
() over a large area of the () plane using 21.2 eV and 32 eV
photons in two distinct polarizations from an optimally doped single crystal of
BiSrCaCuO (Bi2212), together with extensive
first-principles simulations of the ARPES intensities. The results display a
wide-ranging level of accord between theory and experiment and clarify how
myriad Fermi surface (FS) maps emerge in ARPES under various experimental
conditions. The energy and polarization dependences of the ARPES matrix element
help disentangle primary contributions to the spectrum due to the pristine
lattice from those arising from modulations of the underlying tetragonal
symmetry and provide a route for separating closely placed FS sheets in low
dimensional materials.Comment: submitted to PR
Selected topics on Hadrons in Nuclei
In this talk we report on selected topics on hadrons in nuclei. The first
topic is the renormalization of the width of the in a nuclear
medium. This is followed by a short update of the situation of the in
the medium. The investigation of the properties of in the nuclear
medium from the study of the reaction is also addressed, as
well as properties of X,Y,Z charmed and hidden charm resonances in a nuclear
medium. Finally we address the novel issue of multimeson states.Comment: Talk at the International Nuclear Physics Conference, Vancouver, July
201
Slow-Moving Landslide Damage Assessment of Historic Masonry Churches: Some Case-Studies in Italy
This paper presents a contribution for the damage assessment of historic masonry churches exposed to slow-moving landslides. In particular, the authors identified four global damage mechanisms, which are presented here by means of the critical damage assessment of four case studies located in the Liguria region (Italy) in areas affected by slow-moving landslides. For each church, a correlation between the damage patterns observed on-site and the ground movements induced by landslide phenomena was sought by means of visual inspections and crack interpretation. As a result, each damage mechanism was associated to a different pattern of ground movements produced by slow-moving landslides
Measurement of 1323 and 1487 keV resonances in 15N({\alpha}, {\gamma})19F with the recoil separator ERNA
The origin of fluorine is a widely debated issue. Nevertheless, the
^{15}N({\alpha},{\gamma})^{19}F reaction is a common feature among the various
production channels so far proposed. Its reaction rate at relevant temperatures
is determined by a number of narrow resonances together with the DC component
and the tails of the two broad resonances at E_{c.m.} = 1323 and 1487 keV.
Measurement through the direct detection of the 19F recoil ions with the
European Recoil separator for Nuclear Astrophysics (ERNA) were performed. The
reaction was initiated by a 15N beam impinging onto a 4He windowless gas
target. The observed yield of the resonances at Ec.m. = 1323 and 1487 keV is
used to determine their widths in the {\alpha} and {\gamma} channels. We show
that a direct measurement of the cross section of the
^{15}N({\alpha},{\gamma})^{19}F reaction can be successfully obtained with the
Recoil Separator ERNA, and the widths {\Gamma}_{\gamma} and {\Gamma}_{\alpha}
of the two broad resonances have been determined. While a fair agreement is
found with earlier determination of the widths of the 1487 keV resonance, a
significant difference is found for the 1323 keV resonance {\Gamma}_{\alpha} .
The revision of the widths of the two more relevant broad resonances in the
15N({\alpha},{\gamma})19F reaction presented in this work is the first step
toward a more firm determination of the reaction rate. At present, the residual
uncertainty at the temperatures of the ^{19}F stellar nucleosynthesis is
dominated by the uncertainties affecting the Direct Capture component and the
364 keV narrow resonance, both so far investigated only through indirect
experiments.Comment: 8 pages, 11 figures. Accepted for publication in PR
Tratamiento de la escoliosis idiopática mediante artrodesis anterior e instrumentación de Zielke
—Hemos revisado 16 pacientes afectos de escoliosis toracolumbar y lumbar tratados
mediante artrodesis anterior e instrumentación de Zielke. La corrección de la curva en el
plano anteroposterior ha sido del 68%. La escoliosis torácica asociada se ha corregido de forma
espontánea un 30%. La lordosis global final ha sido de 40°, sin embargo la instrumentación
provoca un aumento de la cifosis regional de 10°. Las complicaciones de la serie han sido
3 roturas de barra, una progresión de la curva torácica y un derrame pleural.The authors showed the clinical outcome of 16 patients with thoracolumbar
and lumbar curvatures treated by Zielke instrumentation and anterior fusion. The correction
obtained in the primary curvature was 68%. The average correction in the compensatory thoracic
curvature was 30%. The average lordosis correction at follow was 40°. However the Zielke's
system lead to an increase of 10° of kyphotic at the instrumented levels. Complications
included 3 browen rods, a progression of the thoracic curve and one pleural spilling
Tallimustine in advanced previously untreated colorectal cancer, a phase II study.
Tallimustine is a novel benzoyl mustard derivative from distamycin A with a unique mode of action. It is a DNA minor groove binder and produces highly sequence-specific alkylations. Previous studies have shown significant anti-tumour effects in animal models. We performed a phase II study in previously untreated patients with advanced colorectal cancer, using a schedule of i.v. bolus infusions of 900 microgram m-2 once every 4 weeks. Seventeen patients were enrolled, and no responses were documented in 14 evaluable patients. Toxicity mainly consisted a highly selective neutropenia, which warrants further investigation of this agent in combination with myeloid growth factors
Magnetic properties and energy absorption of CoFe2O4 nanoparticles for magnetic hyperthermia
We have studied the magnetic and power absorption properties of three samples
of CoFe2O4 nanoparticles with sizes from 5 to 12 nm prepared by thermal
decomposition of Fe (acac)3 and Co(acac)2 at high temperatures. The blocking
temperatures TB estimated from magnetization M(T) curves spanned the range 180
< TB < 320 K, reflecting the large magnetocrystalline anisotropy of these
nanoparticles. Accordingly, high coercive fields HC \approx 1.4 - 1.7 T were
observed at low temperatures. Specific Power Absorption (SPA) experiments
carried out in ac magnetic fields indicated that, besides particle volume, the
effective magnetic anisotropy is a key parameter determining the absorption
efficiency. SPA values as high as 98 W/g were obtained for nanoparticles with
average size of \approx12 nm.Comment: 4 pages, 3 figure
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