Phase transitions in wetting films at the surface of Ga–Pb alloys

Surface phase transitions at Ga-rich liquid surfaces have been investigated in Ga–Pb alloys with low lead content. In the region of the liquid–liquid miscibility gap, the Pb-rich liquid phase completely wets the surface of the Ga-rich phase at coexistence. Observations have been made of demixing and solidification of the Pb-rich liquid film. Ga-rich alloys, which are single-phase below the monotectic temperature, can be undercooled below the liquidus, as far as the metastable binodal line where the Pb-rich wetting liquid film forms and solidifies into thin {111} Pb crystals. These films completely redissolve upon reheating to the liquidus temperature. Freezing occurs at surfaces because of complete wetting of the liquid rich in the high melting point component and the hysteretic character of the solidification transformation. Such “surface” experiments allow assessment of the stable and metastable liquidus lines of the Ga–Pb phase diagram in the vicinity of the monotectic temperature.     

Reactive navigation through multiscroll systems: from theory to real-time implementation

In this paper a new reactive layer for multi-sensory integration applied to robot navigation is proposed. The new robot navigation technique exploits the use of a chaotic system able to be controlled in real-time towards less complex orbits, like periodic orbits or equilibrium points, considered as perceptive orbits. These are subject to real-time modifications on the basis of environment changes acquired through a distributed sensory system. The strategy is inspired to the olfactory bulb neural activity observed in rabbits subject to external stimuli. The mathematical details of the approach are given including simulation results in a virtual environment. Furthermore the proposed strategy has been tested on an experimental environment consisting of an FPGA-based hardware driving an autonomous roving robot. The obtained results demonstrate the capability to perform a real-time navigation control.     

TMABoost: an integrated system for comprehensive management of tissue microarray data.

In the last decade, high-throughput technologies such as DNA and tissue microarrays (TMAs) have become a means of large-scale investigation of gene expression, providing a plethora of new biomedical data in a relatively short time. Data collection and organization are critical aspects in this process to ensure the quality and reliability of future data interpretation. In this work, we propose a comprehensive approach to handle TMA data with the aim of supporting and promoting biomarker development. We describe a web-based system for the complete management of tissue microarray data in the field of pathology. The system has been in use since June, 2003. Our approach includes automatic localization and identification of tissue microarray samples, and quantitative image analysis that allows high-throughput screening of TMAs by ensuring nonsubjective measures and novel prognosis associations. In this paper, we present the architecture and the components of this system.     

A reversible first-order dispersive model of parametric instability

A general purpose instability model is derived for the variation of device parameters which is related to the activation–deactivation of statistically independent microscopic defects, with reversible first-order reaction kinetics and distributed rate constants. The model is aimed at predicting the parametric instability of electronic devices under periodic AC stimulus of arbitrary waveform over a wide time-scale range covering the whole device lifetime. As a practical application, we extracted a model for the negative-bias temperature instability of a p-channel type silicon MOSFET, including both the recovery effects and the voltage–temperature dependence. The model can be implemented in commercially available tools for the compact simulation of integrated circuits.     

Autophagy in Prostate Cancer and Androgen Suppression Therapy

The role of autophagy is known to be highly complex and context-dependent, leading to both cancer suppression and progression in several tumors including melanoma, breast and prostate cancer. In the present review, recent advances in an understanding of the involvement of autophagy in prostate cancer treatment are described. The regulatory effects of androgens on prostate cancer cell autophagy are particularly discussed in order to highlight the effects of autophagy modulation during androgen deprivation. A critical evaluation of the studies examined in the present review suggests the attractive possibility of autophagy inhibition combined with hormonal therapy as a promising approach for prostate cancer treatment.     

A broadband RF 65 nm CMOS front-end for cable TV reception

A novel broadband RF front-end in 65 nm CMOS technology is presented. The front-end serves to precondition the incoming RF spectrum for further processing in a cable TV receiver architecture where RF channel selection and down conversion are done in digital domain. The analog front-end consists of a broadband highly linear low-noise amplifier followed by a variable gain RF amplifier. An original broadband circuit topology for the amplifiers is adopted.The fabricated front-end exhibits a bandwidth of 50-1050 MHz, a variable gain, which spans from 12 to 37 dB with a 0.2 dB step, an OIP3 of 28.4 dBm (77.5 dBmV), an OIP2 of 65 dBm (114 dBmV), and a noise figure of 5.8 dB, dissipating 125 mW at 1.2 V supply, and a core silicon area of 0.4 mm².     

Durability of steel FRCM-masonry joints: effect of water and salt crystallization

Fiber-reinforced cementitious matrix (FRCM) composites have been recently employed as a strengthening system to retrofit historic masonry structures, since they are more compatible with masonry, less subject to ageing, and compliant with conservation criteria for cultural heritage than fiber-reinforced polymer composites. However, the durability of FRCMs, such as the resistance to salt attack, has not been deeply investigated yet. In this paper, the mechanical behavior of steel FRCM strips bonded to fired-clay brick masonry blocks is studied experimentally. Single-lap shear tests are conducted in laboratory on control FRCM-masonry joints and on additional joints that underwent artificial weathering cycles in a solution of sodium sulfate decahydrate. Peak loads, slips at failure at the loaded end as well as failure modes are investigated. Pore size distribution of the constituent materials and the amount and distribution of salt within the specimens are reported and discussed in order to evaluate the transport and crystallization mechanisms of sulfate in masonry elements strengthened with externally bonded FRCM strips.     

The Biomolecular Basis of Adipogenic Differentiation of Adipose-Derived Stem Cells

There is considerable attention regarding the role of receptor signaling and downstream-regulated mediators in the homeostasis of adipocytes, but less information is available concerning adipose-derived stem cell (ASC) biology. Recent studies revealed that the pathways regulating ASC differentiation involve the activity of receptor tyrosine kinases (RTKs), including fibroblast growth factor, vascular endothelial growth factor, ErbB receptors and the downstream-regulated serine/threonine protein kinase B (Akt) and phosphatase and tensin homolog (PTEN) activity. RTKs are cell surface receptors that represent key regulators of cellular homeostasis but also play a critical role in the progression of cancer. Many of the metabolic effects and other consequences of activated RTKs are mediated by the modulation of Akt and extracellular signal-regulated protein kinases 1 (Erk-1) signaling. Akt activity sustains survival and the adipogenic differentiation of ASCs, whereas Erk-1 appears downregulated. The inhibition of FGFR-1, EGFR and ErbB2 reduced proliferation, but only FGFR-1 inihibition reduced Akt activity and adipogenesis. Adipogenesis and neovascularization are also chronologically and spatially coupled processes and RTK activation and downstream targets are also involved in ASC-mediated angiogenesis. The potentiality of ASCs and the possibility to modulate specific molecular pathways underlying ASC biological processes and, in particular, those shared with cancer cells, offer new exciting strategies in the field of regenerative medicine.     

Polymerization,grafting and adsorption in the presence of inorganic substrates: Thermal polymerization of styrene with untreated and γ-irradiated silica gel as a case study

The search for innovative and well-defined organic–inorganic hybrid materials demands that the interplay between polymerization reactions, chemical reactivity, and physical adsorption be fully understood. We examine the case study of the thermal polymerization of styrene in the presence of silica, and the effect of pre-irradiation of silica with γ-rays. The effect of adsorption of styrene-derived radical species on the silica support and polymerization conditions on free and grafted (unextractable) polystyrenes and on polymerization mechanism is discussed on the basis of previous literature findings and new data. Evidence is provided of silica derivatization with various species besides polystyrene (¹³C CPMAS NMR), including products from a β-scission of the adsorbed radical intermediates ensuing oxygen donation from the silica network. The polymerization mechanism can be cationic as well as radical, depending on reaction conditions, and the cationic route prevails in the grafting of polystyrene from silica, resulting in a bimodal molecular weight distribution.