2,481 research outputs found
Carbon nanotube net as a conductive and transparent film for solar energy conversion
Vertically aligned silicon nanowires arrays have been grown through a metal-assisted chemical etching method, giving a heavily absorbing surface. Over this surface, a transparent and conductive net of carbon nanotubes has been formed by chemical vapour deposition. The optical characterisation of the net has been performed by the study of its hemispherical reflectance, and the electrical properties have been obtained by four-point probe method. A high transmittance of the net (over 99%) in the 300-900 nm range is reported. Also, a good sheet resistance value has been obtained (around 3 kΩ/□) for such a thin carbon nanotube netThis work was supported by MINECO research Project ENE2014-57977-C2-1-
Development and application of two novel monoclonal antibodies against overexpressed CD26 and integrin α3 in human pancreatic cancer.
Monoclonal antibody (mAb) technology is an excellent tool for the discovery of overexpressed cell surface tumour antigens and the development of targeting agents. Here, we report the development of two novel mAbs against CFPAC-1 human pancreatic cancer cells. Using ELISA, flow cytometry, immunoprecipitation, mass spectrometry, Western blot and immunohistochemistry, we found that the target antigens recognised by the two novel mAbs KU44.22B and KU44.13A, are integrin α3 and CD26 respectively, with high levels of expression in human pancreatic and other cancer cell lines and human pancreatic cancer tissue microarrays. Treatment with naked anti-CD26 mAb KU44.13A did not have any effect on the growth and migration of cancer cells nor did it induce receptor downregulation. In contrast, treatment with anti-integrin α3 mAb KU44.22B inhibited growth in vitro of Capan-2 cells, increased migration of BxPC-3 and CFPAC-1 cells and induced antibody internalisation. Both novel mAbs are capable of detecting their target antigens by immunohistochemistry but not by Western blot. These antibodies are excellent tools for studying the role of integrin α3 and CD26 in the complex biology of pancreatic cancer, their prognostic and predictive values and the therapeutic potential of their humanised and/or conjugated versions in patients whose tumours overexpress integrin α3 or CD26
Molecular Dynamics Simulation of Polymer-Metal Bonds
Molecular simulation is becoming a very powerful tool for studying dynamic phenomena in materials. The simulation yields information about interaction at length and time scales unattainable by experimental measurements and unpredictable by continuum theories. This is especially meaningful when referring to bonding between a polymer and a metal substrate. A very important characteristic of polymers is that their physical properties do not rely on the detailed chemical structure of the molecular chains but only on their flexibility, and accordingly they will be able to adopt different conformations. In this paper, a molecular simulation of the bonding between vinyl ester polymer and steel is presented. Four different polymers with increasing chain lengths have been studied. Atomic co-ordinates are adjusted in order to reduce the molecular energy. Conformational changes in the macromolecules have been followed to obtain the polymer pair correlation function. Radius of gyration and end-to-end distance distributions of the individual chains have been used as a quantitative measurement of their flexibility. There exists a correlation between flexibility of the molecular chains and the energy of adhesion between the polymer and the metal substrate. Close contacts between the two materials are established at certain points but every atom up to a certain distance from the interface contributes to the total value of the adhesion energy of the system
A Multi-Wavelength Analysis of Dust and Gas in the SR 24S Transition Disk
We present new Atacama Large Millimeter/sub-millimeter Array (ALMA) 1.3 mm
continuum observations of the SR 24S transition disk with an angular resolution
(12 au radius). We perform a multi-wavelength investigation by
combining new data with previous ALMA data at 0.45 mm. The visibilities and
images of the continuum emission at the two wavelengths are well characterized
by a ring-like emission. Visibility modeling finds that the ring-like emission
is narrower at longer wavelengths, in good agreement with models of dust
trapping in pressure bumps, although there are complex residuals that suggest
potentially asymmetric structures. The 0.45 mm emission has a shallower profile
inside the central cavity than the 1.3 mm emission. In addition, we find that
the CO and CO (J=2-1) emission peaks at the center of the
continuum cavity. We do not detect either continuum or gas emission from the
northern companion to this system (SR 24N), which is itself a binary system.
The upper limit for the dust disk mass of SR 24N is , which gives a disk mass ratio in dust between the two
components of . The current ALMA observations may imply that either
planets have already formed in the SR 24N disk or that dust growth to mm-sizes
is inhibited there and that only warm gas, as seen by ro-vibrational CO
emission inside the truncation radii of the binary, is present.Comment: Accepted for publication in Ap
Workplace wellbeing programmes and their impact on employees and their employing organisations: a scoping review of the evidence base
This report constitutes a scoping literature review that identifies and critically examines the evidence base surrounding health and wellbeing programmes conducted in the workplace and their impact on employees and their employing organisations. The review drew on a broad range of sources covering multiple sectors. However, the report additionally highlights evidence that relates specifically to the retail and construction industries. The review offers an analysis of the current evidence base and discusses the implications of implementing different types of workplace health and wellbeing schemes. Some recommendations for supporting and promoting the health and wellbeing of employees in organisations are made on the basis of this review and, where gaps in knowledge are identified, recommendations for further research are made
Scattered light images of spiral arms in marginally gravitationally unstable discs with an embedded planet
Scattered light images of transition discs in the near-infrared often show
non-axisymmetric structures in the form of wide-open spiral arms in addition to
their characteristic low-opacity inner gap region. We study self-gravitating
discs and investigate the influence of gravitational instability on the shape
and contrast of spiral arms induced by planet-disc interactions.
Two-dimensional non-isothermal hydrodynamical simulations including viscous
heating and a cooling prescription are combined with three-dimensional dust
continuum radiative transfer models for direct comparison to observations. We
find that the resulting contrast between the spirals and the surrounding disc
in scattered light is by far higher for pressure scale height variations, i.e.
thermal perturbations, than for pure surface density variations. Self-gravity
effects suppress any vortex modes and tend to reduce the opening angle of
planet-induced spirals, making them more tightly wound. If the disc is only
marginally gravitationally stable with a Toomre parameter around unity, an
embedded massive planet (planet-to-star mass ratio of ) can trigger
gravitational instability in the outer disc. The spirals created by this
instability and the density waves launched by the planet can overlap resulting
in large-scale, more open spiral arms in the outer disc. The contrast of these
spirals is well above the detection limit of current telescopes.Comment: Accepted for publication in MNRAS; 13 pages, 8 figure
Visible spectroscopy of the new ESO Large Program on trans-Neptunian objects and Centaurs: final results
A second large programme (LP) for the physical studies of TNOs and Centaurs,
started at ESO Cerro Paranal on October 2006 to obtain high-quality data, has
recently been concluded. In this paper we present the spectra of these pristine
bodies obtained in the visible range during the last two semesters of the LP.
We investigate the spectral behaviour of the TNOs and Centaurs observed, and we
analyse the spectral slopes distribution of the full data set coming from this
LP and from the literature. We computed the spectral slope for each observed
object, and searched for possible weak absorption features. A statistical
analysis was performed on a total sample of 73 TNOs and Centaurs to look for
possible correlations between dynamical classes, orbital parameters, and
spectral gradient. We obtained new spectra for 28 bodies, 15 of which were
observed for the first time. All the new presented spectra are featureless,
including 2003 AZ84, for which a faint and broad absorption band possibly
attributed to hydrated silicates on its surface has been reported. The data
confirm a wide variety of spectral behaviours, with neutral--grey to very red
gradients. An analysis of the spectral slopes available from this LP and in the
literature for a total sample of 73 Centaurs and TNOs shows that there is a
lack of very red objects in the classical population. We present the results of
the statistical analysis of the spectral slope distribution versus orbital
parameters. In particular, we confirm a strong anticorrelation between spectral
slope and orbital inclination for the classical population. A strong
correlation is also found between the spectral slope and orbital eccentricity
for resonant TNOs, with objects having higher spectral slope values with
increasing eccentricity.Comment: 11 pages, 9 figure
Testing particle trapping in transition disks with ALMA
We present new Atacama Large Millimeter/submillimeter Array (ALMA) continuum
observations at 336GHz of two transition disks, SR21 and HD135344B. In
combination with previous ALMA observations from Cycle 0 at 689GHz, we compare
the visibility profiles at the two frequencies and calculate the spectral index
(). The observations of SR21 show a clear shift in the
visibility nulls, indicating radial variations of the inner edge of the cavity
at the two wavelengths. Notable radial variations of the spectral index are
also detected for SR21 with values of in the
inner region ( AU) and outside. An
axisymmetric ring (which we call the ring model) or a ring with the addition of
an azimuthal Gaussian profile, for mimicking a vortex structure (which we call
the vortex model), is assumed for fitting the disk morphology. For SR21, the
ring model better fits the emission at 336GHz, conversely the vortex model
better fits the 689GHz emission. For HD135344B, neither a significant shift in
the null of the visibilities nor radial variations of are
detected. Furthermore, for HD135344B, the vortex model fits both frequencies
better than the ring model. However, the azimuthal extent of the vortex
increases with wavelength, contrary to model predictions for particle trapping
by anticyclonic vortices. For both disks, the azimuthal variations of
remain uncertain to confirm azimuthal trapping. The
comparison of the current data with a generic model of dust evolution that
includes planet-disk interaction suggests that particles in the outer disk of
SR21 have grown to millimetre sizes and have accumulated in a radial pressure
bump, whereas with the current resolution there is not clear evidence of radial
trapping in HD135344B, although it cannot be excluded either.Comment: Minor changes after language edition. Accepted for publication in A&A
(abstract slightly shortened for arXiv
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