1,261 research outputs found
Bi-directional light transmission properties assessment for venetian blinds : Computer simulations compared to photogoniometer measurements
An accurate evaluation of daylight distribution through advanced fenestration systems (complex glazing, solar shading systems) requires the knowledge of their Bi-directional light Transmission Distribution Function (BTDF). An innovative equipment for the experimental assessment of these bi-directional functions has been developed, based on a digital imaging detection system. An extensive set of BTDF measurements was performed with this photogoniometer on venetian blinds presenting curved slats with a mirror coating on the upper side. In this paper, the measured data are compared with ray-tracing results achieved with a virtual copy of the device, that was constructed with a commercial ray-tracing software. The model of the blind was created by implementing the measured reflection properties of the slats coatings in the ray-tracing calculations. These comparisons represent an original and objective validation methodology for detailed bi-directional properties for a complex system; the good agreement between the two methods, yet presenting very different parameters and assessment methodologies, places reliance both on the digital-imaging detection system and calibration, and on the potentiality of a flexible calculation method combining ray-tracing simulations with simple components measurements
The prognostic significance of transforming growth factors in human breast cancer.
Transforming growth factor alpha (TGF alpha) and Transforming growth factor beta-1 (TGF-beta 1) are growth regulatory for breast cancer cell lines in vitro and several studies have suggested that levels of the receptor for TGF alpha, the epidermal growth factor (EGFR) in tumour biopsies predict relapse and survival. We have examined the prognostic significance of TGF alpha, TGF-beta 1 and EGFR mRNA expression in a series of patients with primary breast cancer with a median follow up period of 60 months. In 167 patients the expression of TGF-beta 1 was inversely correlated with node status (P = 0.065) but not ER status, tumour size or menopausal status. Patients with high levels of TGF-beta 1 had a longer disease free interval with a significantly longer probability of survival at 80 months although the overall relapse free survival was not increased. EGFR mRNA expression was measured in 106 patients and was inversely correlated with ER status (P = 0.018). EGFR levels did not predict for early relapse or survival. TGF alpha mRNA levels were measured in 104 patients, no correlation was seen tumour size, node status, Er status, or clinical outcome
Effects of endocrine therapy on steroid-receptor content of breast cancer.
In order to determine the mechanisms of relapse following response to endocrine therapy, we have measured the oestrogen receptor (RE) content of biopsies of breast cancer in patients receiving various types of endocrine treatment. RE content fell in responding (means of 260.2 to 12 fmol/mg protein) and in nonresponding (means of 155.1 to 31.8 fmol/mg protein) patients who had measurable receptor at the start of treatment. Some of these patients, and a further group of responders to endocrine therapy, were monitored until relapse. Tumour biopsies at the time of relapse showed that 10/14 tumour samples contained significant RE (mean of 86.7 fmol/mg protein; range less than 10-271 fmol/mg protein) after successful endocrine therapy. No relationship could be found between RE content and plasma gonadotrophin or steroid-hormone concentration, but the fall in RE content correlated with reduced numbers of tumour cells in the biopsy. These results indicate that relapse following successful endocrine therapy in breast cancer does not appear to be due to the emergence of RE-negative tumour cells. The fall in RE content during response to endocrine therapy may be due to reduced tumour-cell content of the biopsy
Evidence for a vortex-glass transition in superconducting Ba(FeCo)As
Measurements of magneto-resistivity and magnetic susceptibility were
performed on single crystals of superconducting
Ba(FeCo)As close to the conditions of optimal
doping. The high quality of the investigated samples allows us to reveal a
dynamic scaling behaviour associated with a vortex-glass phase transition in
the limit of weak degree of quenched disorder. Accordingly, the dissipative
component of the ac susceptibility is well reproduced within the framework of
Havriliak-Negami relaxation, assuming a critical power-law divergence for the
characteristic correlation time of the vortex dynamics. Remarkably, the
random disorder introduced by the FeCo chemical substitution is
found to act on the vortices as a much weaker quenched disorder than previously
reported for cuprate superconductors such as, e.g.,
YPrBaCuO.Comment: 10 pages, 8 figure
He II 4686 emission from the massive binary system in Car: constraints to the orbital elements and the nature of the periodic minima
{\eta} Carinae is an extremely massive binary system in which rapid spectrum
variations occur near periastron. Most notably, near periastron the He II
line increases rapidly in strength, drops to a minimum value,
then increases briefly before fading away. To understand this behavior, we
conducted an intense spectroscopic monitoring of the He II
emission line across the 2014.6 periastron passage using ground- and
space-based telescopes. Comparison with previous data confirmed the overall
repeatability of EW(He II ), the line radial velocities, and the
timing of the minimum, though the strongest peak was systematically larger in
2014 than in 2009 by 26%. The EW(He II ) variations, combined
with other measurements, yield an orbital period d. The observed
variability of the EW(He II ) was reproduced by a model in which
the line flux primarily arises at the apex of the wind-wind collision and
scales inversely with the square of the stellar separation, if we account for
the excess emission as the companion star plunges into the hot inner layers of
the primary's atmosphere, and including absorption from the disturbed primary
wind between the source and the observer. This model constrains the orbital
inclination to -, and the longitude of periastron to
-. It also suggests that periastron passage occurred on
d. Our model also reproduced EW(He II )
variations from a polar view of the primary star as determined from the
observed He II emission scattered off the Homunculus nebula.Comment: The article contains 23 pages and 17 figures. It has been accepted
for publication in Ap
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