G-quartet biomolecular nanowires

We present a first-principle investigation of quadruple helix nanowires, consisting of stacked planar hydrogen-bonded guanine tetramers. Our results show that long wires form and are stable in potassium-rich conditions. We present their electronic bandstructure and discuss the interpretation in terms of effective wide-bandgap semiconductors. The microscopic structural and electronic properties of the guanine quadruple helices make them suitable candidates for molecular nanoelectronics.Comment: 7 pages, 3 figures, to be published in Applied Physics Letters (2002

Modulation of galactic protons in the heliosphere during the unusual solar minimum of 2006 to 2009

The last solar minimum activity period, and the consequent minimum modulation conditions for cosmic rays, was unusual. The highest levels of galactic protons were recorded at Earth in late 2009 in contrast to expectations. Proton spectra observed for 2006 to 2009 from the PAMELA cosmic ray detector on-board the Resurs-DK1 satellite are presented together with the solutions of a comprehensive numerical model for the solar modulation of cosmic rays. The model is used to determine what mechanisms were mainly responsible for the modulation of protons during this period, and why the observed spectrum for 2009 was the highest ever recorded. From mid-2006 until December 2009 we find that the spectra became significantly softer because increasingly more low energy protons had reached Earth. To simulate this effect, the rigidity dependence of the diffusion coefficients had to decrease significantly below ~3 GeV. The modulation minimum period of 2009 can thus be described as relatively more "diffusion dominated" than previous solar minima. However, we illustrate that drifts still had played a significant role but that the observable modulation effects were not as well correlated with the waviness of the heliospheric current sheet as before. Protons still experienced global gradient and curvature drifts as the heliospheric magnetic field had decreased significantly until the end of 2009, in contrast to the moderate decreases observed during previous minimum periods. We conclude that all modulation processes contributed to the observed increases in the proton spectra for this period, exhibiting an intriguing interplay of these major mechanisms

Optical spectra of nitride quantum dots: Quantum confinement and electron-hole coupling

We calculate the optical properties of nitride-based quantum dots by taking into account quantum confinement as well as electron-hole interaction. We analyze model structures simulating In_xGa_{1−x}N dots in In_yGa_{1−y}N layers with different alloy compositions. We discuss the trends with the dot size and show that quantum confined excitations exist for a broad range of sizes down to the smallest observed dots. Our results allow us to identify the strong role of Coulomb correlations in the optical spectra and to predict a strong influence of photoexcitation power on selection rules in polarized samples. The signature of quantum confinement can be utilized for a critical interpretation of measured optical spectra

First principle theory of correlated transport through nano-junctions

We report the inclusion of electron-electron correlation in the calculation of transport properties within an ab initio scheme. A key step is the reformulation of Landauer's approach in terms of an effective transmittance for the interacting electron system. We apply this framework to analyze the effect of short range interactions on Pt atomic wires and discuss the coherent and incoherent correction to the mean-field approach.Comment: 5 pages, 3 figure

Habitat Patch Diversity Evaluation for Sustainability: a Case Study of a Rural Area in Central Italy

Landscape analysis is regarded as a new tool for monitoring and judging land use patterns in terms of sustainability of human activity systems at local level. A case study of evaluation for sustainability based on habitat patch diversity in an ecoregion of Central Italy is presented. In this region, ongoing land use patterns reflect both historical adaptation to local environmental constraints and positive, social-oriented management. More protective land use patterns are mostly widespread in fragile physiographic conditions like those of the mountain areas, where woodland, shrub, and grassland patches are larger and cover more than 90% of the land. This situation is regarded as a positive outcome of the traditional public ownership regime, because public lands amount to more than 70% in the mountain areas. The hilly areas, where public property drops to 28%, presents landscape metrics showing a well balanced situation between agricultural land use and protective native woods and grasslands, which provides a fine-grained and harmonious Mediterranean landscape. In the low-land areas, with anthropic pressure and more favourable conditions for crop productivity, there is much more agricultural land, even if some mitigation in terms of biodiversity maintenance is offered by the presence of hedgerow ecotones. In these areas, landscape analysis is not able to supply meaningful information about cropping system design and practices which can maintain a sustainable level of soil fertility and quality of natural resources and processes, and further analysis at cropping system level should be carried out

Self-assembled guanine ribbons as wide-bandgap semiconductors

We present a first principle study about the stability and the electronic properties of a new biomolecular solid-state material, obtained by the self-assembling of guanine (G) molecules. We consider hydrogen-bonded planar ribbons in isolated and stacked configurations. These aggregates present electronic properties similar to inorganic wide-bandgap semiconductors. The formation of Bloch-type orbitals is observed along the stacking direction, while it is negligible in the ribbon plane. Global band-like conduction may be affected by a dipole-field which spontaneously arises along the ribbon axis. Our results indicate that G-ribbon assemblies are promising materials for biomolecular nanodevices, consistently with recent experimental results.Comment: 7 pages, 3 figures, to be published in Physica

The major allergen of the Parietaria pollen contains an LPS-binding region with immuno-modulatory activity

Background: The major allergens in Parietaria pollen, Par j 1 and Par j 2, have been identified as lipid transfer proteins. The family of the Par j 1 allergens is composed of two isoforms, which differ by the presence of a 37 amino acid peptide (Par37) exclusive to the Par j 1.0101 isoform. The goal of this study was to elucidate the biological properties of the Par37 peptide. Methods: In silico analysis, spectrofluorimetric experiments and in vitro cell culture assays were used to identify the biological properties of Par37. In addition, a mouse model of sensitization was used to study the influence of Par37 in the murine immune response. Results: In silico analysis predicted that Par37 displays characteristics of a host defence peptide. Spectrofluorimetric analysis, real-time PCR and ELISA assays demonstrated that Par37 possesses an LPS-binding activity influencing cell signalling in vitro. In RAW264.7 cells, LPS-induced IL-6 and TNF-a transcription and translation were inhibited after preincubation with Par37. Consistent with these data, inhibition of IFN-c secretion was observed in murine spleen cells and in human PBMC. Finally, mice immunized with the two Par j 1 isoforms differing in the presence or absence of the Par37 peptide showed different immunological behaviours in vivo. Conclusions: This study demonstrates that the Par j 1.0101 allergen displays LPSbinding activity due to the presence of a 37 amino acid COOH-terminal region and that this region is capable of influencing cytokine and antibody responses in vitro and in vivo

IMP-3 expression in keratoacanthomas and squamous cell carcinomas of the skin: an immunohistochemical study

<p>The protein insulin-like growth factor II mRNA binding protein 3 (IMP3) is an important factor for cell migration and adhesion in malignancies. Recent studies have shown a remarkable overexpression of IMP3 in different human malignant neoplasms and also revealed it as an important prognostic marker in some tumor entities. The purpose of this study is to compare IMP3 immunostaining in squamous cellular skin tumor and determine whether IMP3 can aid in the differential diagnosis of these lesions. To our knowledge, IMP3 expression has not been investigated in skin squamous cell proliferations thus far. Immunohistochemical staining for IMP3 was performed on slides organized by samples from 67 patients, 34 with keratoacanthoma and 33 with primary squamous cell carcinoma (16 invasive and 17 <em>in</em><em> situ</em>). The majority of our KAs (25/34) were negative for IMP-3 staining. The majority of SCCs (19/33) are positive for IMP3 staining. The percentage of IMP3 positive cells increases significantly in group SCC (p=0.0111), and in particular in the SCC <em>in situ</em> group (p=0.0021) with respect to the KA group.  IMP3 intensity staining increases significantly in SCCs (p=0.0213), and particularly in SCCs (p=0.008) with respect to KA. Our data show that IMP3 expression is different in keratoacanthomas with respect to squamous cell carcinoma. IMP3 assessment and staining pattern, together with a careful histological study, can be useful in the differential diagnosis between KA e SCC.</p

Joint Power Control and Structural Health Monitoring in Industry 4.0 Scenarios using Eclipse Arrowhead and Web of Things

The integration of legacy IoT ecosystems in Industry 4.0 scenarios requires human effort to adapt single devices. This process would highly benefit from features like device lookup, loose coupling and late binding. In this paper, we tackle the issue of integrating legacy monitoring systems and actuation systems in an industrial scenario, by looking into the Web of Things (WoT) as a communication standard and the Eclipse Arrowhead Framework (AHF) as a service orchestrator. More specifically, we propose a general architectural approach to enable closed-loop automation between the above mentioned legacy systems by leveraging the adaptation of the WoT to the AHF. Then, we develop a rule-based engine that enables the control of the actuation based on sensor values. Finally, we present a proof-of-concept use case where we integrate a Structural Health Monitoring (SHM) scenario with a power control actuation subsystem using the developed component