University of Crete

About: University of Crete is a education organization based out in Rethymno, Greece. It is known for research contribution in the topics: Population & Galaxy. The organization has 8681 authors who have published 21684 publications receiving 709078 citations. The organization is also known as: Panepistimio Kritis.

Acute exacerbations of idiopathic pulmonary fibrosis.

Abstract: Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive and ultimately fatal disease, with a highly variable course in individual patients. Episodes of rapid deterioration are not uncommon, often following a period of stability. In cases of uncertain etiology, with typical clinical and high-resolution computed tomography (HRCT) features, the term ‘acute exacerbation of IPF' (AE-IPF) has been coined to describe a combination of diffuse alveolar damage and preexisting usual interstitial pneumonia. In 2007, a consensus definition and diagnostic criteria were proposed. Although the presence of overt infection is currently an exclusion criterion, it appears likely that occult infection, reflux and thoracic surgical procedures are all trigger factors for AE-IPF. The development of new, usually bilateral infiltrates (ground-glass attenuation with variable admixed consolidation) is a defining HRCT feature. The outcome is poor with a short-term mortality in excess of 50% despite therapy. A number of pathophysiologic pathways are activated, with immunologic dysregulation, epithelial damage and circulating fibrocytes all believed to play a pathogenetic role. Acute exacerbations are less prevalent in other fibrotic lung diseases than in IPF and may have a better outcome, with the exception of acute exacerbations of rheumatoid lung. In AE-IPF, the exclusion of alternative causes of rapid deterioration, including heart failure and infection, is the main goal of investigation. Empirical high-dose corticosteroid steroid therapy is generally used in AE-IPF, without proven benefit.

Akt1 and Akt2 protein kinases differentially contribute to macrophage polarization

Abstract: Activated macrophages are described as classically activated or M1 type and alternatively activated or M2 type, depending on their response to proinflammatory stimuli and the expression of genetic markers including iNOS, arginase1, Ym1, and Fizz1. Here we report that Akt kinases differentially contribute to macrophage polarization, with Akt1 ablation giving rise to an M1 and Akt2 ablation resulting in an M2 phenotype. Accordingly, Akt2−/− mice were more resistant to LPS-induced endotoxin shock and to dextran sulfate sodium (DSS)-induced colitis than wild-type mice, whereas Akt1−/− mice were more sensitive. Cell depletion and reconstitution experiments in a DSS-induced colitis model confirmed that the effect was macrophage-dependent. Gene-silencing studies showed that the M2 phenotype of Akt2−/− macrophages was cell autonomous. The microRNA miR-155, whose expression was repressed in naive and in LPS-stimulated Akt2−/− macrophages, and its target C/EBPβ appear to play a key role in this process. C/EBPβ, a hallmark of M2 macrophages that regulates Arg1, was up-regulated upon Akt2 ablation or silencing. Overexpression or silencing of miR-155 confirmed its central role in Akt isoform-dependent M1/M2 polarization of macrophages.

The Detection of a Population of Submillimeter-Bright, Strongly Lensed Galaxies

Abstract: Gravitational lensing is a powerful astrophysical and cosmological probe and is particularly valuable at submillimeter wavelengths for the study of the statistical and individual properties of dusty star-forming galaxies. However, the identification of gravitational lenses is often time-intensive, involving the sifting of large volumes of imaging or spectroscopic data to find few candidates. We used early data from the Herschel Astrophysical Terahertz Large Area Survey to demonstrate that wide-area submillimeter surveys can simply and easily detect strong gravitational lensing events, with close to 100% efficiency.

SAR image denoising via Bayesian wavelet shrinkage based on heavy-tailed modeling

Abstract: Synthetic aperture radar (SAR) images are inherently affected by multiplicative speckle noise, which is due to the coherent nature of the scattering phenomenon. This paper proposes a novel Bayesian-based algorithm within the framework of wavelet analysis, which reduces speckle in SAR images while preserving the structural features and textural information of the scene. First, we show that the subband decompositions of logarithmically transformed SAR images are accurately modeled by alpha-stable distributions, a family of heavy-tailed densities. Consequently, we exploit this a priori information by designing a maximum a posteriori (MAP) estimator. We use the alpha-stable model to develop a blind speckle-suppression processor that performs a nonlinear operation on the data and we relate this nonlinearity to the degree of non-Gaussianity of the data. Finally, we compare our proposed method to current state-of-the-art soft thresholding techniques applied on real SAR imagery and we quantify the achieved performance improvement.

Ultra-low shrinkage hybrid photosensitive material for two-photon polymerization microfabrication.

Abstract: Investigations into the structuring by two-photon polymerization of a nonshrinking, photosensitive, zirconium sol−gel material are presented This hybrid material can be photostructured even when it contains up to 30 mol % of zirconium propoxide (ZPO); by varying the material’s inorganic content, it is possible to modify and tune its refractive index The introduction of ZPO significantly increases the photosensitivity of the resulting photopolymer The fabricated three-dimensional photonic crystal structures demonstrate high resolution and a clear band-stop in the near-IR region In contrast to common practice, no additional effort is required to precompensate for shrinkage or to improve the structural stability of the fabricated photonic crystals; this, combined with the possibility of tuning this material’s optical, mechanical, and chemical properties, makes it suitable for a variety of applications by two-photon polymerization manufacturing