QoS Provisioning in Wireless IP Networks

This paper deals with quality of service (QoS) provision in wireless IP networks. QoS provision is particularly challenging in wireless networks, where network resources are generally limited, variable over time and shared. In the design of possible measures to assure QoS one should consider that standardization is well established for the network layer Internet Protocol and for many underlying technologies of frequent use (e.g. IEEE 802.11, BLUETOOTH or HIPERLAN II). Therefore, as far as research on QoS is concerned, there is little room in both the IP and the link-layers for improved IP over wireless interfaces. In this paper we illustrate a solution in which an intermediate Wireless Adaptation Layer (WAL) is transparently interposed between the IP layer and specific link-layer technologies as a solution to provide QoS. The WAL addresses two main issues: (i) compensation for channel impairments in different platforms in order to enhance wireless channel reliability and (ii) implementation of traffic control and packet scheduling mechanisms to satisfy bandwidth and delay requirements, as well as to enforce a general principle of fairness among the IP associations contending for network resources and achieve optimal exploitation of transmission capacity. The WAL consists of a set of modules, each one in charge of a specific task, which can be enabled or disabled depending on the specific network environment. The novelty of the WAL approach is its capability of adapting itself to different wireless interfaces selecting performance enhancing modules for specific networks. This requires to modify the standard TCP/IP protocol stack by introducing an intermediate layer between the IP layer and the Data Link layer, with performance enhancement purposes. This paper focuses on two modules in particular, namely a traffic control module, which is in charge of performing congestion control and channel state dependent scheduling (CSD) packet scheduling, and a forward error correction (FEC) module, which compensates for channel impairments. This paper presents the proposed architecture provided with these modules and reports some measurements and simulations highlighting benefits resulting from the use of such modules.     

Efficient Neuroprotective Rescue of Sacsin-Related Disease Phenotypes in Zebrafish

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a multisystem hereditary ataxia associated with mutations in SACS, which encodes sacsin, a protein of still only partially understood function. Although mouse models of ARSACS mimic largely the disease progression seen in humans, their use in the validation of effective therapies has not yet been proposed. Recently, the teleost Danio rerio has attracted increasing attention as a vertebrate model that allows rapid and economical screening, of candidate molecules, and thus combines the advantages of whole-organism phenotypic assays and in vitro high-throughput screening assays. Through CRISPR/Cas9-based mutagenesis, we generated and characterized a zebrafish sacs-null mutant line that replicates the main features of ARSACS. The sacs-null fish showed motor impairment, hindbrain atrophy, mitochondrial dysfunction, and reactive oxygen species accumulation. As proof of principle for using these mutant fish in high-throughput screening studies, we showed that both acetyl-DL-leucine and tauroursodeoxycholic acid improved locomotor and biochemical phenotypes in sacs^−/− larvae treated with these neuroprotective agents, by mediating significant rescue of the molecular functions altered by sacsin loss. Taken together, the evidence here reported shows the zebrafish to be a valuable model organism for the identification of novel molecular mechanisms and for efficient and rapid in vivo optimization and screening of potential therapeutic compounds. These findings may pave the way for new interventions targeting the earliest phases of Purkinje cell degeneration in ARSACS.     

Angiogenin and Copper Crossing in Wound Healing

Angiogenesis plays a key role in the wound healing process, involving the migration, growth, and differentiation of endothelial cells. Angiogenesis is controlled by a strict balance of different factors, and among these, the angiogenin protein plays a relevant role. Angiogenin is a secreted protein member of the ribonuclease superfamily that is taken up by cells and translocated to the nucleus when the process of blood vessel formation has to be promoted. However, the chemical signaling that activates the protein, normally present in the plasma, and the transport pathways through which the protein enters the cell are still largely unclear. Copper is also an angiogenic factor that regulates angiogenin expression and participates in the activation of common signaling pathways. The interaction between angiogenin and copper could be a relevant mechanism in regulating the formation of new blood vessel pathways and paving the way to the development of new drugs for chronic non-healing wounds.     

CeF<Subscript>3</Subscript>-ZnO scintillating nanocomposite for self-lighted photodynamic therapy of cancer

We report on the synthesis and characterization of a composite nanostructure based on the coupling of cerium fluoride (CeF₃) and zinc oxide (ZnO) for applications in self-lighted photodynamic therapy. Self-lighted photodynamic therapy is a novel approach for the treatment of deep cancers by low doses of X-rays. CeF₃ is an efficient scintillator: when illuminated by X-rays it emits UV light by fluorescence at 325?nm. In this work, we simulate this effect by exciting directly CeF₃ fluorescence by UV radiation. ZnO is photo-activated in cascade, to produce reactive oxygen species. This effect was recently demonstrated in a physical mixture of distinct nanoparticles of CeF₃ and ZnO [Radiat. Meas. (2013) 59:139–143]. Oxide surface provides a platform for rational functionalization, e.g., by targeting molecules for specific tumors. Our composite nanostructure is stable in aqueous media with excellent optical coupling between the two components; we characterize its uptake and its good cell viability, with very low intrinsic cytotoxicity in dark.     

Deflocculation of Concentrated Aqueous Clay Suspensions with Sodium Polymethacrylates

The ability of sodium polymethacrylate salts with various molecular weights (1200 to 30000 g·mol⁻¹) to deflocculate concentrated aqueous suspensions (58 wt%) of two clays, widely used for stoneware ceramic tile production, was investigated. Rheological measurements were made in distilled water or in water containing calcium ions (0 to 6 × 10⁻³ mol·dm⁻³) to evaluate the practical applications of these salts as deflocculants in the ceramic tile industry. All slips presented a non-Newtonian behavior. Polymethacrylates with low molecular weights were the most efficient deflocculants for clay suspensions. The salts acted by an essentially electrosteric stabilization mechanism, in combination with a high sequestering ability toward flocculating cations. For their efficient deflocculating capabilities toward concentrated aqueous clay suspensions, sodium(I) polymethacrylates may be considered for practical industrial application, in particular for the preparation of liquid deflocculants.     

Raman Characterization of Ambient Airborne Soot and Associated Mineral Phases

Airborne particulate matter samples were collected in an urban and a rural–suburban monitoring stations of the city of Rome, Italy, and the particles were analyzed through the Raman microspectroscopy. A careful examination of the spectral bands, performed with a five-(Voigt) curve deconvolution model previously described by the literature and here adapted to the purpose, lead to the characterization of the graphitic and carbonaceous material plus the identification of the mineral particles associated with it. Statistical analysis of the full-width at half-maximum (FWHM) values of the bands, as well as of their intensity ratio, revealed the presence of two classes of soot particles that can be ascribed to a different degree of crystallinity. The population of soot collected at the urban site, where the vehicular emission component prevails, exhibits mostly crystalline characteristics (with a D1 FWHM of 150–155 cm^?1), whereas the population collected at the rural–suburban site, particularly the coarse fraction, shows a prevailing amorphous nature (with a D1 FWHM of ～175 cm^?1). A similar aspect emerges for the pure black carbon particles, mainly crystalline, and the black carbon particles associated with minerals, generally disordered. These results add useful information and characterization of the soot, a relevant component of the ambient air, and its different features with respect to the urban or rural–suburban areas.

Copyright 2014 American Association for Aerosol Research     

Development of functionalized Fe–Al–Cr alloy fibers as innovative catalytic oxidation devices

Catalytic devices play a very important role to drastically reduce the noxious contaminants released by the combustion engines. Common devices consist of functionalized ceramic monoliths; an interesting alternative can be realized with a support material made of a high temperature compatible metal alloy, like FeCrAl. In the present study the FeAlCr fibers used to make a device similar to the ceramic monolith were thermally treated to obtain alumina whiskers, which were homogenously covered with alumina or ceria–zirconia–alumina washcoats. Pt or Pt and Pd have been loaded over the functionalized fibers obtaining an innovative oxidation catalyst. The systems were characterized by BET surface area measurements, hydrogen chemisorption and tested under high space velocity and fast heating run-up cycles, for hydrocarbon and CO conversion and particulate filtration ability. The good catalytic activity after severe aging treatments confirms the possibility of use of these innovative functionalized metallic stacks in air pollution control applications.