Lossless Tapers, Gaussian Beams, Free-Space Modes: Standing Waves Versus Through-Flowing Waves

It was noticed in the past that, to avoid physical inconsistencies, in Marcatili's lossless tapers through-flowing waves must be drastically different from standing waves. First, we reconfirm this by means of numerical results based on an extended BPM algorithm. Next, we show that this apparently surprising behavior is a straightforward fallout of Maxwell's equations. Very similar remarks apply to Gaussian beams in a homogeneous medium. As a consequence, Gaussian beams are shown to carry reactive powers, and their active power distributions depart slightly from their standard pictures. Similar conclusions hold for free-space modes expressed in terms of Bessel functions.Comment: 19 pages and 6 figure

On the construction of Dialectical Databases

Argumentation systems have substantially evolved in the past few years, resulting in adequate tools to model some forms of common sense reasoning. This has sprung a new set of argument-based applications in diverse areas. In previous work, we defined how to use precompiled knowledge to obtain significant speed-ups in the inference process of an argument-based system. This development is based on a logic programming system with an argumentationdriven inference engine, called Observation Based Defeasible Logic Programming (ODeLP). In this setting was first presented the concept of dialectical databases, that is, data structures for storing precompiled knowledge. These structures provide precompiled information about inferences and can be used to speed up the inference process, as TMS do in general problem solvers. In this work, we present detailed algorithms for the creation of dialectical databases in ODeLP and analyze these algorithms in terms of their computational complexity

TGF-β2 dictates disseminated tumour cell fate in target organs through TGF-β-RIII and p38α/β signalling

In patients, non-proliferative disseminated tumour cells (DTCs) can persist in the bone marrow (BM) while other organs (such as lung) present growing metastasis. This suggested that the BM might be a metastasis ‘restrictive soil’ by encoding dormancy-inducing cues in DTCs. Here we show in a head and neck squamous cell carcinoma (HNSCC) model that strong and specific transforming growth factor-β2 (TGF-β2) signalling in the BM activates the MAPK p38α/β, inducing an (ERK/p38)low signalling ratio. This results in induction of DEC2/SHARP1 and p27, downregulation of cyclin-dependent kinase 4 (CDK4) and dormancy of malignant DTCs. TGF-β2-induced dormancy required TGF-β receptor-I (TGF-β-RI), TGF-β-RIII and SMAD1/5 activation to induce p27. In lungs, a metastasis ‘permissive soil’ with low TGF-β2 levels, DTC dormancy was short-lived and followed by metastatic growth. Importantly, systemic inhibition of TGF-β-RI or p38α/β activities awakened dormant DTCs, fuelling multi-organ metastasis. Our work reveals a ‘seed and soil’ mechanism where TGF-β2 and TGF-β-RIII signalling through p38α/β regulates DTC dormancy and defines restrictive (BM) and permissive (lung) microenvironments for HNSCC metastasis.Fil: Bragado, Paloma. Mount Sinai School of Medicine. Tisch Cancer Institute; Estados UnidosFil: Estrada, Yeriel. Mount Sinai School of Medicine. Tisch Cancer Institute; Estados UnidosFil: Parikh, Falguni. Mount Sinai School of Medicine. Tisch Cancer Institute; Estados UnidosFil: Krause, Sarah. University Hospital of Schleswig-Holstein; AlemaniaFil: Capobianco, Carla Sabrina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Farina, Hernán Gabriel. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Oncología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Schewe, Denis M.. Mount Sinai School of Medicine. Tisch Cancer Institute; Estados UnidosFil: Aguirre Ghiso, Julio A.. Mount Sinai School of Medicine. Tisch Cancer Institute; Estados Unido

Graphene-assisted control of coupling between optical waveguides

The unique properties of optical waveguides electrically controlled by means of graphene layers are investigated. We demonstrate that, thanks to tunable losses induced by graphene layers, a careful design of silicon on silica ridge waveguides can be used to explore passive PT-symmetry breaking in directional couplers. We prove that the exceptional point of the system can be probed by varying the applied voltage and we thus propose very compact photonic structures which can be exploited to control coupling between waveguides and to tailor discrete diffraction in arrays

Luminosity- and morphology-dependent clustering of galaxies

How does the clustering of galaxies depend on their inner properties like morphological type and luminosity? We address this question in the mathematical framework of marked point processes and clarify the notion of luminosity and morphological segregation. A number of test quantities such as conditional mark-weighted two-point correlation functions are introduced. These descriptors allow for a scale-dependent analysis of luminosity and morphology segregation. Moreover, they break the degeneracy between an inhomogeneous fractal point set and actual present luminosity segregation. Using the Southern Sky Redshift Survey~2 (da Costa et al. 1998, SSRS2) we find both luminosity and morphological segregation at a high level of significance, confirming claims by previous works using these data (Benoist et al. 1996, Willmer et al. 1998). Specifically, the average luminosity and the fluctuations in the luminosity of pairs of galaxies are enhanced out to separations of 15Mpc/h. On scales smaller than 3Mpc/h the luminosities on galaxy pairs show a tight correlation. A comparison with the random-field model indicates that galaxy luminosities depend on the spatial distribution and galaxy-galaxy interactions. Early-type galaxies are also more strongly correlated, indicating morphological segregation. The galaxies in the PSCz catalog (Saunders et al. 2000) do not show significant luminosity segregation. This again illustrates that mainly early-type galaxies contribute to luminosity segregation. However, based on several independent investigations we show that the observed luminosity segregation can not be explained by the morphology-density relation alone.Comment: aastex, emulateapj5, 20 pages, 13 figures, several clarifying comments added, ApJ accepte

Radial Velocity Studies of Close Binary Stars.VIII

Radial-velocity measurements and sine-curve fits to the orbital velocity variations are presented for the seventh set of ten close binary systems: V410 Aur, V523 Cas, QW Gem, V921 Her, V2357 Oph, V1130 Tau, HN UMa, HX UMa, HD 93917, NSV 223. All systems, but three (V523 Cas, HD 93917, NSV 223), were discovered photometrically by the Hipparcos mission. All systems are double-lined (SB2) binaries and all, but the detached, very close system V1130 Tau, are contact binaries. The broadening-function permitted improvement of the orbital elements for V523 Cas, which was the only system observed before for radial velocity variations. Spectroscopic/visual companions were detected for V410 Aur and HX UMa.Comment: AASTeX5, 4 figures, 3 tables, to appear AJ, June 200

Frequency addressing of nano-objects by electrical tuning of optical antennas

We first analyze the equivalent circuit parameters of linear wire optical nano-antennas in uniaxial anisotropic media. We then exploit the electro-optic response of a bipolar nematic liquid crystal to demonstrate tuning of an optical antenna using a low frequency external electric field as the control mechanism

Proteome analysis of human amniotic mesenchymal stem cells (hA-MSCs) reveals impaired antioxidant ability, cytoskeleton and metabolic functionality in maternal obesity.

Maternal obesity increases the risk of obesity and/or obesity-related diseases in the offspring of animal models. The aim of this study was to identify metabolic dysfunctions that could represent an enhanced risk for human obesity or obesity-related diseases in newborn or in adult life, similar to what occurs in animal models. To this aim, we studied the proteome of 12 obese (Ob-) and 6 non-obese (Co-) human amniotic mesenchymal stem cells (hA-MSCs) obtained from women at delivery by cesarean section (pre-pregnancy body mass index [mean ± SD]: 42.7 ± 7.7 and 21.3 ± 3.3 kg/m(2), respectively). The proteome, investigated by two-dimensional fluorescence difference gel electrophoresis/mass spectrometry, revealed 62 differently expressed proteins in Ob- vs Co-hA-MSCs (P < 0.05), nine of which were confirmed by western blotting. Bioinformatics analysis showed that these 62 proteins are involved in several statistically significant pathways (P < 0.05), including the stress response, cytoskeleton and metabolic pathways. Oxidative stress was shown to be an early triggering factor of tissue fat accumulation and obesity-related disorders in the offspring of obese animal models. Our finding of a reduced stress response in Ob-hA-MSCs suggests that a similar mechanism could occur also in humans. Long-term follow-up studies of newborns of obese mothers are required to verify this hypothesis

A novel compound of triphenyltin(IV) with N-tert-butoxycarbonyl-L-ornithine causes cancer cell death by inducing a p53-dependent activation of the mitochondrial pathway of apoptosis

The triphenyltin(IV) compound with N-tert-butoxycarbonyl-L-ornithine (Boc-Orn-OH), [Ph3Sn(Boc-Orn-O)], was synthesized and characterized by elemental analysis, FT-IR, solution1H,13C and119Sn NMR and ESI mass spectrometry. The organotin(IV) compound inhibited at very low micromolar concentrations the growth of human tumor cell lines HepG2 (hepatocarcinoma cells), MCF-7 (mammary cancer) and HCT116 (colorectal carcinoma) while it did not affect the viability of non-malignant human-derived hepatic cells Chang. The mechanism of the antiproliferative effect of Ph3Sn(Boc-Orn-O), investigated on human hepatoma HepG2 cells, was pro-apoptotic, being associated with externalization of plasma membrane phosphatidylserine, chromatin condensation or fragmentation and mitochondrial dysfunction as well as with increase of p53 levels.The triphenyltin(IV) compound with N-tert-butoxycarbonyl-L-ornithine (Boc-Orn-OH), [Ph3Sn(Boc-Orn-O)], was synthesized and characterized by elemental analysis, FT-IR, solution 1H, 13C and 119Sn NMR and ESI mass spectrometry. The organotin(IV) compound inhibited at very low micromolar concentrations the growth of human tumor cell lines HepG2 (hepatocarcinoma cells), MCF-7 (mammary cancer) and HCT116 (colorectal carcinoma) while it did not affect the viability of non-malignant human-derived hepatic cells Chang. The mechanism of the antiproliferative effect of Ph3Sn(Boc-Orn-O), investigated on human hepatoma HepG2 cells, was pro-apoptotic, being associated with externalization of plasma membrane phosphatidylserine, chromatin condensation or fragmentation and mitochondrial dysfunction as well as with increase of p53 levels