Two-dimensional photonic crystal slab with embedded silicon nanocrystals: Efficient photoluminescence extraction:

A two-dimensional photonic crystal (PhC) slab was fabricated from a luminescent planar waveguide, formed by a (800 nm thick) layer of silicon nanocrystals (SiNCs) embedded in a polished silica plate. Dimensions of the PhC were designed so that light emitted by SiNCs under excitation with an external UV source can, during its propagation in the layer, interact with the periodicity and be Bragg-diffracted into air. This approach leads to up to 8-fold vertical extraction enhancement of SiNCs luminescence from the PhC slab compared to the bare planar layer. Results of the experiment are supported by the computer simulation. (C) 2013 AIP Publishing LLC

Luminescence of free-standing versus matrix-embedded oxide-passivated silicon nanocrystals: The role of matrix-induced strain:

We collect a large number of experimental data from various sources to demonstrate that free-standing (FS) oxide-passivated silicon nanocrystals (SiNCs) exhibit considerably blueshifted emission, by 200 meV on average, compared to those prepared as matrix-embedded (ME) ones of the same size. This is suggested to arise from compressive strain, exerted on the nanocrystals by their matrix, which plays an important role in the light-emission process; this strain has been neglected up to now as opposed to the impact of quantum confinement or surface passivation. Our conclusion is also supported by the comparison of low-temperature behavior of photoluminescence of matrix-embedded and free-standing silicon nanocrystals

SPHEROIDAL MODELS OF MAGNETIC CLOUDS AND THEIR COMPARISON WITH SPACECRAFT MEASUREMENTS

We present here magnetic force-free solutions for spherical, oblate, and prolate clouds and show their magnetic field configurations. It is shown that spheroidal models can fit observed clouds as well as the cylindrical model. The spherical model is free of the limitation of the cylindrical model that allows only reduced increase of the magnetic field to 2 x of the boundary value following from properties of the Bessel functions. For the tested cases, the cloud diameters following from the fit are generally larger for the spherical model than for the cylindrical one. An analysis of 14 cases shows that the fit using the spherical model is of a comparable accuracy in comparison with the cylindrical model. Generally, no exact determination of the cloud boundaries has been given up to now. We try to estimate cloud boundaries from the plasma data as an independent check, and compare them with cloud boundaries following from models of magnetic clouds. The boundaries given by the spheroidal models are near irregular temperature increases, and we suggest taking these increases as a possible indicator of the cloud physical boundaries

EVIDENCE FOR A SPHEROIDAL STRUCTURE OF MAGNETIC CLOUDS

We have analysed 14 cases of magnetic clouds identified by R. M. Lepping et al. [1990], who have fitted them with the cylindrical model. We treated cloud magnetic field profiles and compared them with the spheroidal models. We argue that all cases exhibit features of spheroidal clouds, namely, the complete sinusoidal profile of magnetic field components inside the cloud, double-peak and/or plateau-type magnetic field magnitude profiles

Selections and suborderability

We extend van Mill--Wattel's results and show that each countably compact completely regular space with a continuous selection on couples is suborderable. The result extends also to pseudocompact spaces if they are either scattered or first countable, or connected. An infinite pseudocompact topological group with such a continuous selection is homeomorphic to the Cantor set. Zero-selection is a selection on the hyperspace of closed sets, which chooses always an isolated point of a set. Extending Fujii--Nogura results, we show that an almost compact space with a continuous zero-selection is homeomorphic to some ordinal space and a (locally compact) pseudocompact space with a continuous zero-selection is an (open) subspace of some space of ordinals. Under the Diamond Principle, we construct several counterexamples, \eg\ a locally compact locally countable monotonically normal space with a continuous zero-selection which is not suborderable

Silicon nanocrystal-based photonic crystal slabs with broadband and efficient directional light emission

Light extraction from a thin planar layer can be increased by introducing a two-dimensional periodic pattern on its surface. This structure, the so-called photonic crystal (PhC) slab, then not only enhances the extraction efficiency of light but can direct the extracted emission into desired angles. Careful design of the structures is important in order to have a spectral overlap of the emission with extraction (leaky) modes. We show that by fabricating PhC slabs with optimized dimensions from silicon nanocrystals (SiNCs) active layers, the extraction efficiency of vertical light emission from SiNCs at a particular wavelength can be enhanced similar to 11 times compared to that of uncorrugated SiNCs-rich layer. More importantly, increased light emission can be obtained in a broad spectral range and, simultaneously, the extracted light can stay confined within relatively narrow angle around the normal to the sample plane. We demonstrate experimentally and theoretically that the physical origin of the enhancement is such that light originating from SiNCs first couples to leaky modes of the PhCs and is then efficiently extracted into the surrounding.This work was supported by the GA CR project No. 16-09692Y and by a postdoc support from the ASCR. A.K. acknowledges support from the MSMT project No. LD15003 within the frame of the COST Action MP1403 “Nanoscale Quantum Optics”. J.V. acknowledges support by the Visegrad Group-Japan Joint Research Project on Advanced Materials (MSMT Project No. 8F15001, co-financed by the International Visegrad Fund)

Survival of patients with kidney cancer in central and northern Denmark, 1998–2009

Tau Pelant1,2, Erik Højkjær Larsen1,2, Lars Lund3, Michael Borre4, Rune Erichsen1, Mette Nørgaard1, Jacob Bonde Jacobsen11Department of Clinical Epidemiology, Aarhus University Hospital, Denmark; 2Department of Urology, Aarhus University Hospital, Aalborg, Denmark; 3Department of Urology, Viborg Hospital, Denmark; 4Department of Urology, Aarhus University Hospital, Skejby, DenmarkObjective: For decades, kidney cancer patients in Denmark have had lower survival than patients in the other Scandinavian countries. Our aim was to study possible changes in survival of patients with kidney cancer after implementation of two national Danish cancer plans.Study design and setting: From 1998 through 2009 we included all patients (N = 2659) with an incident diagnosis of kidney cancer in two Danish regions (population 1.8 million). Data were retrieved from the Danish National Registry of Patients. We computed survival after 1, 3, and 5 years, stratified by age, and estimated mortality rate ratios (MRRs) using Cox regression to assess changes over time, controlling for age and gender. We lacked data on stage distribution. Among patients who had a nephrectomy we also computed 30-day mortality and 30-day MRRs.Results: During the study period, we identified 2659 patients with kidney cancer. The annual number of patients increased from 583 in the period 1998–2000 to 853 in the period 2007–2009. The median age at diagnosis was 69 years throughout the study period. The overall 1-year survival improved from 56% (1998–2000) to 63% (2007–2009), corresponding to an adjusted MRR of 0.78 (95% confidence interval [CI] 0.66–0.93). We predicted the 3-year survival to increase from 40% to 51% and the 5-year survival to increase from 33% to 42%, corresponding to predicted MRRs of 0.76 (95% CI 0.66–0.87) and 0.77 (95% CI 0.68–0.89), respectively. Survival increased in all age groups (15–59 years, 60–74 years, 75+ years) and in both genders, except for men below 60 years, for whom the 1-year survival declined from 76% to 69%. The 30-day mortality after nephrectomy declined from 4% to 2% during the study period.Conclusion: We observed an improvement in the survival and relative mortality in kidney cancer patients, although not in men younger than 60 years.Keywords: kidney neoplasm, outcome research, mortality rate ratio, MR

Stimulated emission of optically excited MOVPE grown ZnCdSe-ZnSe GRINSCH quantum well

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