1,198 research outputs found
Phase-sensitive correlation optical time-domain reflectometer using quantum phase noise of laser light
Abstract: We propose and experimentally demonstrate a simple approach to realize a phase-sensitive correlation optical time-domain reflectometer (OTDR) suitable for detection and localization of dynamic perturbations along a single-mode optical fiber. It is based on the quantum phase fluctuations of a coherent light emitted by a telecom DFB diode laser. Truly random probe signals are generated by an interferometer with the optical path difference exceeding the coherence length of the laser light. Speckle-like OTDR traces were obtained by calculating cross-correlation functions between the probe light and the light intensity signals returned back from the sensing fiber. Perturbations are detected and localized by monitoring time variations of correlation amplitude along the fiber length. Results of proof-of-concept experimental testing are presented
Mechanical charecterization and analytical modeling of the thermo-viscoplastic behaviour AISI 304 steel under wide ranges of strain rates at room temperature
In this investigation, the thermo-viscoplastic behaviour of the steel AISI 304 has been examined. The experimental characterization of the material has been conducted in tension under wide ranges of strain rates.An analytical description of the macroscopic behaviour of this metal is reported. For such goal, the extended Rusinek-Klepaczko model to viscous drag effects is applied.It allows for proper description of the material behaviour within the whole range of loading conditions considered.In addition, the analytical formulation proposed gathers limited number of material constants and simple calibration procedure
Application of Deep Learning for Quality Assessment of Atrial Fibrillation ECG Recordings
[EN] In the last years, atrial fibrillation (AF) has become one
of the most remarkable health problems in the developed
world. This arrhythmia is associated with an increased
risk of cardiovascular events, being its early detection an
unresolved challenge. To palliate this issue, long-term
wearable electrocardiogram (ECG) recording systems are
used, because most of AF episodes are asymptomatic and
very short in their initial stages. Unfortunately, portable
equipments are very susceptible to be contaminated with
different kind of noises, since they work in highly dynamics
and ever-changing environments. Within this scenario, the
correct identification of free-noise ECG segments results
critical for an accurate and robust AF detection. Hence,
this work presents a deep learning-based algorithm to
identify high-quality intervals in single-lead ECG recordings obtained from patients with paroxysmal AF. The obtained results have provided a remarkable ability to classify between high- and low-quality ECG segments about
92%, only misclassifying around 7% of clean AF intervals
as noisy segments. These outcomes have overcome most
previous ECG quality assessment algorithms also dealing
with AF signals by more than 20%.This research has been supported by the grants DPI2017-83952-C3 from MINECO/AEI/FEDER EU, SBPLY/17/180501/000411 from Junta de Comunidades de Castilla-La Mancha, AICO/2019/036 from Generalitat Valenciana and FEDER 2018/11744.Huerta, A.; Martinez-Rodrigo, A.; Arias, MA.; Langley, P.; Rieta, JJ.; Alcaraz, R. (2020). Application of Deep Learning for Quality Assessment of Atrial Fibrillation ECG Recordings. IEEE. 1-4. https://doi.org/10.22489/CinC.2020.367S1
Self-similar dynamics of morphogen gradients
We discovered a class of self-similar solutions in nonlinear models
describing the formation of morphogen gradients, the concentration fields of
molecules acting as spatial regulators of cell differention in developing
tissues. These models account for diffusion and self-induced degration of
locally produced chemical signals. When production starts, the signal
concentration is equal to zero throughout the system. We found that in the
limit of infinitely large signal production strength the solution of this
problem is given by the product of the steady state concentration profile and a
function of the diffusion similarity variable. We derived a nonlinear boundary
value problem satisfied by this function and used a variational approach to
prove that this problem has a unique solution in a natural setting. Using the
asymptotic behavior of the solutions established by the analysis, we
constructed these solutions numerically by the shooting method. Finally, we
demonstrated that the obtained solutions may be easily approximated by simple
analytical expressions, thus providing an accurate global characterization of
the dynamics in an important class of non-linear models of morphogen gradient
formation. Our results illustrate the power of analytical approaches to
studying nonlinear models of biophysical processes.Comment: 17 pages, 5 figure
Transmit–receive parabolic reflectarray to generate two beams per feed for multispot satellite antennas in Ka-band
This contribution describes the design of a multibeam parabolic reflectarray to produce two adjacent beams per feed in orthogonal circular Polarization (CP) simultaneously at transmit (Tx) and receive (Rx) frequencies in Ka-band. The Variable Rotation Technique (VRT) has been applied to reflectarray cells based on two types of resonant elements, which makes it possible to provide orthogonal beams at Tx and Rx, as well as to implement an in-band optimization procedure to reduce the cross-polarization. A 90-cm parabolic reflectarray has been designed, manufactured and tested to produce multiple adjacent beams in RHCP and LHCP at both 20 and 30 GHz. The results
are satisfactory and validate the concept of generating two spaced beams in orthogonal CP by a single feed, changing the polarization of the beam between Tx and Rx. This concept can be suitable for multispot satellites in Ka-band, enabling to halve the number of onboard antennas and feedsAgencia Estatal de Investigación | Ref. TEC2016-75103-C2-1-RAgencia Estatal de Investigación | Ref. FJCI-2016-29943European Space Agency | Ref. 4000117113/16/NL/A
Sex and gender disparities in patients with advanced gastroesophageal adenocarcinoma: data from the AGAMENON-SEOM registry
Gastroesophageal cancer; Gender; SexCáncer gastroesofágico; Género; SexoCàncer gastroesofàgic; Gènere; SexeBackground
Recommendations for research articles include the use of the term sex when reporting biological factors and gender for identities or psychosocial or cultural factors. There is an increasing awareness of incorporating the effect of sex and gender on cancer outcomes. Thus, these types of analyses for advanced gastroesophageal adenocarcinoma are relevant.
Patients and methods
Patients with advanced gastroesophageal adenocarcinoma from the Spanish AGAMENON-SEOM registry treated with first-line combination chemotherapy were selected. Epidemiology, characteristics of the disease, treatment selection, and results were examined according to sex.
Results
This analysis included 3274 advanced gastroesophageal adenocarcinoma patients treated with combination chemotherapy between 2008 and 2021: 2313 (70.7%) men and 961 (29.3%) women. Tumors in females were more frequently HER2-negative (67.8% versus 60.8%; P < 0.0001), grade 3 (45.4% versus 36.8%; P < 0.001), diffuse (43.3% versus 26.5%; P < 0.0001), and signet ring cell histology (40.5 versus 23.9%; P < 0.0001). Peritoneal spread was more common in women (58.6% versus 38.9%; P < 0.0001), while liver burden was lower (58.9% versus 71.1%; P < 0.0001). There were no significant differences in treatment recommendation. Treatment doses, density, and duration were comparable between sexes. Women experienced more diarrhea (46% versus 37%; P < 0.0001), neutropenia (51% versus 43%; P < 0.0001), and anemia (62% versus 57%; P < 0.0001). After a median 59.6-month follow-up [95% confidence interval (CI) 54.5-70.8], there were no statistically significant differences between the sexes in progression-free survival [6.21 months (95% CI 5.8-6.5 months) versus 6.08 months (95% CI 5.8-6.3 months); log-rank test, χ2 = 0.1, 1 df, P = 0.8] or in overall survival [10.6 months (95% CI 9.8-11.1 months) versus 10.9 months (95% CI 10.4-11.4 months); log-rank test: χ2 = 0.6, 1 df, P = 0.5].
Conclusion
This sex analysis of patients with advanced gastroesophageal adenocarcinoma from the AGAMENON-SEOM registry receiving first-line polychemotherapy found no differences in survival. Although women had worse prognostic histopathology, metastatic disease pattern, and greater toxicity, treatment allocation and compliance were equivalent
Mechanical charecterization and analytical modeling of the thermo-viscoplastic behaviour AISI 304 steel under wide ranges of strain rates at room temperature
In this investigation, the thermo-viscoplastic behaviour of the steel AISI 304 has been examined. The experimental characterization of the material has been conducted in tension under wide ranges of strain rates.An analytical description of the macroscopic behaviour of this metal is reported. For such goal, the extended Rusinek-Klepaczko model to viscous drag effects is applied.It allows for proper description of the material behaviour within the whole range of loading conditions considered.In addition, the analytical formulation proposed gathers limited number of material constants and simple calibration procedure
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The evolution of our understanding of the behavior of oxide nanostructures depends heavily on the structural information obtained from a wide range of physical methods traditionally used in solid state physics, surface science and inorganic chemistry. In this chapter, we describe several techniques that are useful for the characterization of the structural properties of oxide nanostructures: X-ray diffraction (XRD) and scattering, X-ray absorption fine structure (XAFS), Raman spectroscopy, transmission electron microscopy (TEM), scanning tunneling microscopy (STM) and atomic force microscopy (AFM). The ultimate goal is to obtain information about the spatial arrangement of atoms in the nanostructures with precise interatomic distances and bond angles. This may not be possible for complex systems and one may get only partial information about the local geometry or morphology
Effect of the human immunodeficiency virus type 1 reverse transcriptase polymorphism Leu-214 on replication capacity and drug susceptibility
A negative association between polymorphism Leu-214 and type-1 thymidine analogue mutations (TAM1) and a positive association with a clinically favorable virological response to thymidine analogue-based combination antiretroviral therapy have been described. In this study, the impact of Leu-214 on replication capacity and resistance to zidovudine (ZDV) of viruses containing TAM1 or TAM2 was determined. Leu-214 decreased the growth rate of viruses bearing Tyr-215, as well as their resistance to ZDV. This observation was confirmed by structural and molecular modeling data, suggesting a regulatory role for Leu-214 in the emergence and phenotypic resistance of TAM1
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