Coherence and synchronization in diode-laser arrays with delayed global coupling

The dynamics of a semiconductor-laser array whose individual elements are coupled in a global way through an external mirror is numerically analysed. A coherent in-phase solution is seen to be preferred by the system at intermediate values of the feedback coupling strength. At low values of this parameter, a strong amplification of the spontaneous emission noise is observed. A tendency towards chaos synchronization is also observed at large values of the feedback strength.Comment: 8 pages, LaTeX, 6 PS figures, to appear in International Journal of Bifurcation and Chao

Niobia supported on silica as a catalyst for Biodiesel production from waste oil

AbstractThe activity and stability of niobia supported on silica catalyst have been tested in continuous micro-pilot reactors, for biodiesel production starting from acid vegetable oils. A catalyst was prepared by the impregnation of silica pellets with a loading of 12% of Nb and was extensively characterized. The activity of this catalyst in both esterification and transesterification was tested in a continuous micro-pilot laboratory plant in which acid oil was fed (FFA 10% w/w) at a temperature of 220°C and at a pressure of 60 bar. The niobia based catalyst resulted in a very active catalyst in both esterification (FFA conversion = 95-90%) and transesterification reactions (FAME yield = 80-90%), and the activity remained quite constant for more than 100 h on stream. Notwithstanding this stability, a non-negligible leaching phenomena has been detected, in the case of long-time continuous runs, as the Nb concentration on the spent catalyst resulted lower than that on the fresh one. The obtained result confirms that the leaching of the active specie is one of the most strong problem in heterogeneous catalysis for biodiesel production

Use of aequorin-based indicators for monitoring Ca2+ in acidic organelles

Over the last years, there is accumulating evidence that acidic organelles can accumulate and release Ca2+ upon cell activation. Hence, reliable recording of Ca2+ dynamics in these compartments is essential for understanding the physiopathological aspects of acidic organelles. Genetically encoded Ca2+ indicators (GECIs) are valuable tools to monitor Ca2+ in specific locations, although their use in acidic compartments is challenging due to the pH sensitivity of most available fluorescent GECIs. By contrast, bioluminescent GECIs have a combination of features (marginal pH sensitivity, low background, no phototoxicity, no photobleaching, high dynamic range and tunable affinity) that render them advantageous to achieve an enhanced signal-to-noise ratio in acidic compartments. This article reviews the use of bioluminescent aequorin-based GECIs targeted to acidic compartments. A need for more measurements in highly acidic compartments is identified

Molecular gyroscopes and biological effects of weak ELF magnetic fields

Extremely-low-frequency magnetic fields are known to affect biological systems. In many cases, biological effects display `windows' in biologically effective parameters of the magnetic fields: most dramatic is the fact that relatively intense magnetic fields sometimes do not cause appreciable effect, while smaller fields of the order of 10--100 $\mu$T do. Linear resonant physical processes do not explain frequency windows in this case. Amplitude window phenomena suggest a nonlinear physical mechanism. Such a nonlinear mechanism has been proposed recently to explain those `windows'. It considers quantum-interference effects on protein-bound substrate ions. Magnetic fields cause an interference of ion quantum states and change the probability of ion-protein dissociation. This ion-interference mechanism predicts specific magnetic-field frequency and amplitude windows within which biological effects occur. It agrees with a lot of experiments. However, according to the mechanism, the lifetime $\Gamma^{-1}$ of ion quantum states within a protein cavity should be of unrealistic value, more than 0.01 s for frequency band 10--100 Hz. In this paper, a biophysical mechanism has been proposed that (i) retains the attractive features of the ion interference mechanism and (ii) uses the principles of gyroscopic motion and removes the necessity to postulate large lifetimes. The mechanism considers dynamics of the density matrix of the molecular groups, which are attached to the walls of protein cavities by two covalent bonds, i.e., molecular gyroscopes. Numerical computations have shown almost free rotations of the molecular gyros. The relaxation time due to van der Waals forces was about 0.01 s for the cavity size of 28 angstr\"{o}ms.Comment: 10 pages, 7 figure

Spatial Division Multiplexed Microwave Signal processing by selective grating inscription in homogeneous multicore fibers

[EN] The use of Spatial Division Multiplexing for Microwave Photonics signal processing is proposed and experimentally demonstrated, for the first time to our knowledge, based on the selective inscription of Bragg gratings in homogeneous multicore fibers. The fabricated devices behave as sampled true time delay elements for radiofrequency signals offering a wide range of operation possibilities within the same optical fiber. The key to processing flexibility comes from the implementation of novel multicavity configurations by inscribing a variety of different fiber Bragg gratings along the different cores of a 7-core fiber. This entails the development of the first fabrication method to inscribe high-quality gratings characterized by arbitrary frequency spectra and located in arbitrary longitudinal positions along the individual cores of a multicore fiber. Our work opens the way towards the development of unique compact fiber-based solutions that enable the implementation of a wide variety of 2D (spatial and wavelength diversity) signal processing functionalities that will be key in future fiber-wireless communications scenarios. We envisage that Microwave Photonics systems and networks will benefit from this technology in terms of compactness, operation versatility and performance stability.We thank Prof. Jose Capmany for the thoughtful discussions and recommendations that greatly contribute to this work. This research was supported by the Spanish MINECO Projects TEC2014-60378-C2-1-R and TEC2015-62520-ERC, the Valencian Research Excellency Award Program GVA PROMETEO 2013/012, the Spanish MECD FPU Scholarship (FPU13/04675) for J. Hervas, and the Spanish MINECO Ramon y Cajal Program (RYC-2014-16247) for I. Gasulla.Gasulla Mestre, I.; Barrera Vilar, D.; Hervás-Peralta, J.; Sales Maicas, S. (2017). Spatial Division Multiplexed Microwave Signal processing by selective grating inscription in homogeneous multicore fibers. Scientific Reports. 7(41727):1-10. https://doi.org/10.1038/srep41727S110741727Samsung Electronics Co, “5G Vision”, available at http://www.samsung.com/global/business-images/insights/2015/Samsung-5G-Vision-0.pdf (2015).Technology Focus on Microwave Photonics. Nat. Photonics 5, 723 (2011).J. Capmany, J. Mora, I. Gasulla, J. Sancho, J. Lloret & S. Sales . Microwave photonic signal processing. IEEE J. Lightw. Technol. 31, 571–586 (2013).Y. Long & J. Wang . Ultra-high peak rejection notch microwave photonic filter using a single silicon microring resonator. Opt. Express 23, 17739–17750 (2015).Y. Long & J. Wang . All-optical tuning of a nonlinear silicon microring assisted microwave photonic filter: theory and experiment. Opt. Express 23, 17758–17771 (2015).Y. Long, L. Zhou & J. Wang . Photonic-assisted microwave signal multiplication and modulation using a silicon Mach–Zehnder modulator. Sci. Reports 6, 20215 (2016).J. Sancho, J. Bourderionnet, J. Lloret, S. Combrié, I. Gasulla, S. Xavier, S. Sales, P. Colman, G. Lehoucq, D. Dolfi, J. Capmany & A. De Rossi . Integrable microwave filter based on a photonic crystal delay line. Nat. Commun. 3, 1075 (2012).F. Ohman, K. Yvind & J. Mørk . Slow Light in a Semiconductor Waveguide for True-Time Delay Applications in Microwave Photonics. IEEE Photon. Technol. Lett. 19, 1145–1157 (2007).P. A. Morton & J. B. Khurgin. Microwave photonic delay line with separate tuning of the optical carrier. IEEE Photon. Technol. Lett. 21, 1686–1688 (2009).D. Marpaung, C. Roeloffzen, R. Heideman, A. Leinse, S. Sales & J. Capmany . Integrated microwave photonics. Lasers Photon. Rev. 7, 506–538 (2013).I. Gasulla & J. Capmany . Microwave photonics applications of multicore fibers. Photonics J. 4, 877–888 (2012).S. Garcia & I. Gasulla . Design of Heterogeneous Multicore fibers as sampled True Time Delay Lines. Opt. Lett. 40, 621–624 (2015).F. Zeng & J. Yao . All-optical microwave filters using uniform fiber Bragg gratings with identical reflectivities. IEEE J. Lightw. Technol. 23, 1410 (2005).C. Wang & J. Yao . Fiber Bragg gratings for microwave photonics subsystems. Opt. Express 21, 22868–22884 (2013).I. Gasulla, D. Barrera & S. Sales . Microwave photonic devices based on multicore fibers. 16th International Conference on Transparent Optical Networks (ICTON), Graz, Austria, 2014.I. Gasulla, D. Barrera, J. Hervás, S. García & S. Sales . Multi-cavity Microwave Photonics devices built upon multicore fibres. 18th International Conference on Transparent Optical Networks (ICTON), Trento (Italy), pp. 1–4, 2016.K. O. Hill & G. Meltz . Fiber Bragg grating technology fundamentals and overview. IEEE J. Lightw. Technol. 15, 1263–1276 (1997).T. Erdogan . Fiber grating spectra. IEEE J. Lightw. Technol. 15, 1277–1294 (1997).D. Barrera, I. Gasulla & S. Sales . Multipoint two-dimensional curvature optical fiber sensor based on a non-twisted homogeneous four-core fiber. IEEE J. Lightw. Technol. 33, 2445–2450 (2015).T. Birks, B. Mangan, A. Diez, J. Cruz, S. Leon-Saval, J. Bland-Hawthorn & D. Murphy . Multicore optical fibres for astrophotonics. In CLEO/Europe and EQEC 2011 Conference Digest, OSA Technical Digest (CD)d (Optical Society of America, 2011), paper JSIII2_1.C. Wang, Z. Yan, Q. Sun, Z. Sun, C. Mou, J. Zhang, A. Badmos & L. Zhang . Fibre Bragg gratings fabrication in four core fibres. Proc. SPIE 9886, Micro-Structured and Specialty Optical Fibres IV, 98860H (2016).M. J. Cole, W. H. Loh, R. I. Laming, M. N. Zervas & S. Barcelos . Moving fibre/phase mask-scanning beam technique for enhanced flexibility in producing fibre gratings with uniform phase mask. Electron. Lett. 31, 1488–1490 (1995).M. Gallagher & U. Österberg . Time resolved 3.10 eV luminescence in germanium-doped silica glass. Appl. Phys. Lett. 63, 2987–2988 (1993).T. Komukai & M. Nakazawa . Fabrication of high-quality long fiber Bragg grating by monitoring 3.1 eV radiation (400 nm) from GeO defects. IEEE Photon. Tech. Lett. 8, 1495–1497 (1996).R. R. Thomson, H. T. Bookey, N. D. Psaila, A. Fender, S. Campbell, W. N. MacPherson, J. S. Barton, D. T. Reid & A. K. Kar . Ultrafast-laser inscription of a three dimensional fan-out device for multicore fiber coupling applications. Opt. Express 15, 11691–11697 (2007)

Microenvironmental hCAP-18/LL-37 promotes pancreatic ductal adenocarcinoma by activating its cancer stem cell compartment

This is the peer reviewed version of the following article: Microenvironmental hCAP-18/LL-37 promotes pancreatic ductal adenocarcinoma by activating its cancer stem cell compartment. Gut 64.12 (2015): 1921-1935 and which has been published in final form at http://dx.doi.org/10.1136/gutjnl-2014-308935OBJECTIVES: The tumour stroma/microenvironment not only provides structural support for tumour development, but more importantly it provides cues to cancer stem cells (CSCs) that regulate their self-renewal and metastatic potential. This is certainly true for pancreatic ductal adenocarcinomas (PDAC), where tumour-associated fibroblasts, pancreatic stellate cells and immune cells create an abundant paracrine niche for CSCs via microenvironment-secreted factors. Thus understanding the role that tumour stroma cells play in PDAC development and CSC biology is of utmost importance. DESIGN: Microarray analyses, tumour microarray immunohistochemical assays, in vitro co-culture experiments, recombinant protein treatment approaches and in vivo intervention studies were performed to understand the role that the immunomodulatory cationic antimicrobial peptide 18/LL-37 (hCAP-18/LL-37) plays in PDAC biology. RESULTS: We found that hCAP-18/LL-37 was strongly expressed in the stroma of advanced primary and secondary PDAC tumours and is secreted by immune cells of the stroma (eg, tumour-associated macrophages) in response to tumour growth factor-β1 and particularly CSC-secreted Nodal/ActivinA. Treatment of pancreatic CSCs with recombinant LL-37 increased pluripotency-associated gene expression, self-renewal, invasion and tumourigenicity via formyl peptide receptor 2 (FPR2)- and P2X purinoceptor 7 receptor (P2X7R)-dependent mechanisms, which could be reversed by inhibiting these receptors. Importantly, in a genetically engineered mouse model of K-Ras-driven pancreatic tumourigenesis, we also showed that tumour formation was inhibited by either reconstituting these mice with bone marrow from cathelicidin-related antimicrobial peptide (ie, murine homologue of hCAP-18/LL-37) knockout mice or by pharmacologically inhibiting FPR2 and P2X7R. CONCLUSIONS: Thus, hCAP-18/LL-37 represents a previously unrecognised PDAC microenvironment factor that plays a critical role in pancreatic CSC-mediated tumourigenesis.CH: ERC Advanced Investigator Grant (Pa-CSC 233460), European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 256974 (EPC-TM-NET) and n° 602783 (CAM-PaC), the Subdirección General de Evaluación y Fomento de la Investigación, Fondo de Investigación Sanitaria (PS09/02129 & PI12/02643) and the Programa Nacional de Internacionalización de la I+D, Subprogramma: FCCI 2009 (PLE2009-0105; both Ministerio de Economía y Competitividad (es), Spain), BSJr: Rámon y Cajal Merit Award from the Ministerio de Economía y Competitividad, Spain and Clinic and Laboratory Integration Program (CLIP) grant from the Cancer Research Institute, NY, NY. MC: La Caixa Predoctoral Fellowshi

Construcción de un índice de privación por zona básica de salud en Aragón a partir de datos de censo de 2011

Fundamentos: La medición de las desigualdades mediante indicadores compuestos facilita la priorización y puesta en marcha de acciones de salud pública. La fuente de información más comúnmente utilizada para ello ha sido el Censo de Población y viviendas de 2011 (CPV_2011). El objetivo fue validar la utilización del CPV_2011 por Zona de Salud (ZBS) y construir un índice de privación (IP) por ZBS así como analizar su asociación con la mortalidad en Aragón. Métodos: Estudio ecológico por ZBS. El CPV_2011, con diseño muestral, se validó mediante un test de homogeneidad de Chi_cuadrado y se calcularon 26 indicadores socioeconómicos. Se obtuvo el coeficiente de correlación de Spearman entre indicadores socioeconómicos y Razones de Mortalidad Estandarizadas (REM). Se realizó un análisis de componentes principales (ACP) con los indicadores correlacionados significativamente, extrayendo los componentes con autovalores mayores a 1 y se obtuvo la matriz rotada (Varimax). Se realizaron ACP con las variables de cada componente extrayendo un único factor. Se agruparon las ZBS en cuartiles, según el factor calculando tasas de mortalidad ajustadas a población estándar europea por edad, sexo y cuartil. El factor que más discrimina por cuartiles se consideró IP y se recalculó para ZBS urbanas con idénticas variables. Resultados: La validación de la muestra del CPV_2011, detectó cuatro ZBS infrarrepresentadas. 17 indicadores socioeconómicos se correlacionaron con REM. Del primer ACP se extrajeron 3 componentes, eligiendo como IP, el formado por %Desempleo, %Asalariados eventuales, %Instrucción Insuficiente 16-64 años y %Extranjeros. Las varianzas explicadas fueron 59,7% y 73,8% en el IP urbano. En hombres, la mortalidad en el cuartil menos privado (544,7 por 105; IC95%:515,8-573,6), fue inferior a la del más privado (618,7 por 105; IC95%:589,4,648,0). Conclusiones: El IP permite identificar ZBS desfavorecidas constituyendo una herramienta para evidenciar desigualdades y planificar intervenciones según necesidades. Background: The measurement of inequalities using composite indicators facilitates the prioritization and implementation of public health actions. The most commonly source of information used for this has been the Population and Housing Census of 2011 (PCH_2011). The objective of this study was to evaluate the use of PHC_2011 and develop a deprivation index (DI) by Basic Healthcare Area (BHA) and to analyse its association with mortality in Aragon. Methods: Ecological study by BHA. Since PHC_2011 was a sample of the population it was validated by the Chi-square test for homogeneity. 26 socioeconomic indicators were calculated. Spearman correlation coefficients were used to evaluate the relationship between socioeconomic indicators and Standardized Mortality Ratios (SMR). Principal Component Analyses (PCA) were conducted using the indicators in which a significant correlation was found. Components with eigenvalues higher than 1 were extracted, and the rotated matrix (Varimax) was obtained. PCA from each component were conducted, extracting only one factor. BHA were grouped into, according to the deprivation index values. Mortality rates adjusted to the European Standard Population by age, sex and quartile were calculated. The most discriminant factor by quartiles was considered DI. A different DI for urban areas was obtained from the same variables. Results: The validation of PHC sample detected 4 underrepresented BHA. 17 socioeconomic indicators were significatively correlated with SMR. From the first PCA, 3 components were obtained. The DI included % unemployment, % eventual workers, % insufficient education 16-64 years old and % foreigners. The % of variance explained by the DI was 59.7% and 73.8% in urban areas. In men, mortality in the quartile with the lowest deprivation (544, 7 per 105; CI95%: 515, 8-573, 6) was significatively lower than in the most deprivated areas(618, 7 per 105; CI95%: 589, 4-648, 0). Conclusions: This new DI allows us to identify deprived BHA. This is a useful tool to bring to light health inequalities and to plan interventions according to population's needs

Mean first passage times of processes driven by white shot noise

The systems driven by white shot noise are analyzed based on mean first passage times. The shot noise has exponentially distributed jump heights. The the linkage between the results and the steady state probability density function of the process are presented