פרסומים

Efficient mode division multiplexing using the spatial aperture sampled concept from single-modefibers to a few-mode fiber is extended to circular step index fibers supporting up to ten spatial modes and to annular refractive index profile fibers supporting nine optical orbital angular momentum modes (mode counts double when considering polarization states for each case). Each sampling beam aperture is spatially shaped for lower average coupling losses and mode dependent losses or a balance thereof. The optimization demonstrates the scalability and consistent low losses for the aperture-sampled mode multiplexer for increasing mode counts, as opposed to the phase hologram-based mode conversion technique. The aperture-sampling approach is also found to be robust to small input fiber alignment errors and fiber geometrical distortions.

Efficient mode division multiplexing using the spatial aperture sampled concept from single-modefibers to a few-mode fiber is extended to circular step index fibers supporting up to ten spatial modes and to annular refractive index profile fibers supporting nine optical orbital angular momentum modes (mode counts double when considering polarization states for each case). Each sampling beam aperture is spatially shaped for lower average coupling losses and mode dependent losses or a balance thereof. The optimization demonstrates the scalability and consistent low losses for the aperture-sampled mode multiplexer for increasing mode counts, as opposed to the phase hologram-based mode conversion technique. The aperture-sampling approach is also found to be robust to small input fiber alignment errors and fiber geometrical distortions.

Rogue waves are observed as light propagates in the extreme nonlinear regime that occurs when a photorefractive ferroelectric crystal is undergoing a structural phase transition. The transmitted spatial light distribution contains bright localized spots of anomalously large intensity that follow a signature long-tail statistics that disappears as the nonlinearity is weakened. The isolated wave events form as out-of-equilibrium response and disorder enhance the Kerr-saturated nonlinearity at the critical point. Self-similarity associable to the individual observed filaments and numerical simulations of the generalized nonlinear Schrodinger equation suggests that dynamics of soliton fusions and scale invariance can microscopically play an important role in the observed rogue intensities and statistics.

A model is proposed in which building contractors have regional preferences so that housing construction in different regions are imperfect substitutes. The model hypothesizes spatial and national spillovers in construction. Although the government does not engage directly in housing construction, it influences regional housing markets by auctioning land to contractors. Contractors are hypothesized to use housing-under-construction as a buffer between starts and completions. Spatial panel data for Israel are used to test the model and investigate the determinants of regional housing construction. Because the spatial panel data are nonstationary, we use spatial panel cointegration methods to estimate the model. The estimated model is used to calculate impulse responses which propagate over time and across space.

The invention relates to a light-absorbing element coated on at least a region of its surface with a film of at least one light-absorbing material, the light-absorbing material being assocd. with at least one binder material, the film being 1 - 20 μm thick and having light absorption of at least 90%. The invention also relates to a device comprising a light-absorbing element. The invention also claims a thermosolar device comprising a light-absorbing element. The invention also relates to a method of fabricating a light-absorbing film on a surface region of a substrate, the method comprising: (a) forming on a surface region at least one absorbing layer comprising: (I) a light-absorbing material; and (II) a polymerizable binder resin; (b) heating the at least one absorbing layer to induce polymn. of the binder resin; and (c) optionally forming at least one IR radiation reflecting layer on the polymd. binder. [on SciFinder(R)]

The invention relates to a light-absorbing element coated on at least a region of its surface with a film of at least one light-absorbing material, the light-absorbing material being assocd. with at least one binder material, the film being 1 - 20 μm thick and having light absorption of at least 90%. The invention also relates to a device comprising a light-absorbing element. The invention also claims a thermosolar device comprising a light-absorbing element. The invention also relates to a method of fabricating a light-absorbing film on a surface region of a substrate, the method comprising: (a) forming on a surface region at least one absorbing layer comprising: (I) a light-absorbing material; and (II) a polymerizable binder resin; (b) heating the at least one absorbing layer to induce polymn. of the binder resin; and (c) optionally forming at least one IR radiation reflecting layer on the polymd. binder. [on SciFinder(R)]

We report on the noise spectrum experienced by few nanometer deep nitrogen-vacancy centers in diamond as a function of depth, surface coating, magnetic field and temperature. Analysis reveals a double-Lorentzian noise spectrum consistent with a surface electronic spin bath in the low frequency regime, along with a faster noise source attributed to surface-modified phononic coupling. These results shed new light on the mechanisms responsible for surface noise affecting shallow spins at semiconductor interfaces, and suggests possible directions for further studies. We demonstrate dynamical decoupling from the surface noise, paving the way to applications ranging from nanoscale NMR to quantum networks.

The design of Pt(IV) pro-drugs as anticancer agents is predicated on the assumption that they will not undergo substitution reactions before entering the cancer cell. Attempts to improve the cytotoxic properties of Pt(IV) pro-drugs included the use of haloacetato axial ligands. Herein, we demonstrate that Pt(IV) complexes with trifluoroacetato (TFA) or dichloroacetato (DCA) ligands can be unstable under biologically relevant conditions and readily undergo hydrolysis, which results in the loss of the axial TFA or DCA ligands. The half-lives for Pt(IV) complexes with two TFA or DCA ligands at pH 7 and 37 °C range from 6 to 800 min, which is short relative to the duration of cytotoxicity experiments that last 24-96 h. However, complexes with two monochloroacetato (MCA) or acetato axial ligands are stable under biologically relevant conditions. The loss of the axial ligands depends primarily on the electron-withdrawing strength of the axial ligands, but also upon the nature of the equatorial ligands. We were unable to find obvious correlations between the structures of the Pt(IV) complexes and the rates of decay of the parent compounds. The X-ray crystal structures of the bis-DCA and bis-MCA Pt(IV) derivatives of oxaliplatin did not reveal any significant structural differences that could explain the observed differences in stability.

Experimental biology is providing the distribution of numerous different biological molecules inside cells and in body fluids of patients. Statistical methods of analysis have very successfully examined these rather large databases. We seek to use a thermodynamic analysis to provide a physical understanding and quantitative characterization of human cancers and other pathologies within a molecule-centered approach. The key technical development is the introduction of a Lagrangian. By imposing constraints the minimal value of the Lagrangian defines a thermodynamically stable state of the cellular system. The minimization also allows using experimental data measured at a number of different conditions to evaluate the steady-state distribution of biomolecules such as messenger RNAs. Thereby the number of effectively accessible quantum states of biomolecules is determined from the experimentally measured expression levels. With the increased resolution provided by the minimization of the Lagrangian one can differentiate between normal and diseased patients and further between disease subtypes. Each such refinement corresponds to imposing an additional constraint of biological origin. The constraints are the unbalanced ongoing biological processes in the system. MicroRNA expression level data for control and diseased lung cancer patients are analyzed as an example.

Abstract The regio- and stereoselective formation of stereodefined polysubstituted silyl ketene aminals is easily achieved through selective combined carbometalation?oxidation?silylation reactions. These substrates are ideal candidates for Mukaiyama aldol reactions with aliphatic aldehydes as they give the aldol products with a quaternary carbon stereocenter α to the carbonyl groups in outstanding diastereoselectivities.