3 cases of post-stapedectomy labyrinthine fistula

Three cases are presented of labyrinthine fistula which suddenly arose in patients who had undergone stapedectomy interposing a vein graft from the back of the hand. These patients had all enjoyed 12-15 years apparently problem free period before the fistula occurred. In all three cases the fistula was accompanied by objective dizziness and varying degrees of sensorineural or mixed hearing loss. The patients underwent revision surgery which identified the fistula and the endolymph oozing out of the graft from the previously installed prosthesis. The authors present the cases, describe how the symptoms arose and the results obtained with revision surgery. Finally, they discuss the need to first perform stapedotomy with a platinar hole; they indicate that the number of cases of total or partial stapedectomy should be limited only to those cases characterized by anatomical variations and/or whenever complications arise during surgery.     

Investigation of the mechanisms governing doxorubicin and irinotecan release from drug-eluting beads: mathematical modeling and experimental verification

Drug-eluting beads (DEBs) are embolising devices in clinical use for the treatment of liver cancer by transarterial chemoembolisation. In this study, release kinetics of doxorubicin (DOX) and irinotecan (IRI) were investigated by experimental evaluations and mathematical modeling, based on Langmuir isotherm and two phenomenological models (Boyd/Bhaskar) developed to determine the actual mechanisms controlling drug release rate. The model was validated through release studies, in particular by assessing how drug loading, ionic strength of the release medium and device swelling during release influence drug release kinetics. Results demonstrated that IRI is released much faster than DOX, and that DEB volume strongly depends upon drug loading and fractional release. This effect was properly taken into account in developing the mathematical model. Experimental results were well fit by numerical simulations, and two different rate-controlling mechanisms were found to govern DOX and IRI delivery.     

Proteins from extremophiles as stable tools for advanced biotechnological applications of high social interest

Extremophiles are micro-organisms adapted to survive in ecological niches defined as 'extreme' for humans and characterized by the presence of adverse environmental conditions, such as high or low temperatures, extreme values of pH, high salt concentrations or high pressure. Biomolecules isolated from extremophiles possess extraordinary properties and, in particular, proteins isolated from extremophiles represent unique biomolecules that function under severe conditions, comparable to those prevailing in various industrial processes. In this article, we will review some examples of recent applications of thermophilic proteins for the development of a new class of fluorescence non-consuming substrate biosensors for monitoring the levels of two analytes of high social interest, such as glucose and sodium.     

Emerging chemical sensor technologies for use in on-line applications

Advances in instrumentation and process control capabilities are being driven by the increased sensitivity of analytical chemistry methods, the commoditization and ruggedization of instruments and associated electronics, and changing consumer concerns and expectations, as well as government regulations. The emergence of biotechnology methods for the detection of contaminants, and the miniaturization and ruggedization of more standard analytical instruments based on mass spectrometry and infrared spectroscopy will be discussed as related to on-line process monitoring.     

A new competitive fluorescence assay for the detection of patulin toxin

Patulin is a toxic secondary metabolite of a number of fungal species belonging to the genera Penicillum and Aspergillus. It has been mainly isolated from apples and apple products contaminated with the common storage-rot fungus of apples, Penicillum expansum, but it has also been extracted from rotten fruits, moldy feeds, and stored cheese. Human exposure to patulin can lead to serious health problems, and according to a long-term investigation in rats, the World Health Organization has set a tolerable weekly intake of 7 ppb body weight. The content of patulin in foods has been restricted to 50 ppb in many countries. Conventional analytical detection methods involve chromatographic analyses, such as HPLC, GC, and, more recently, techniques such as LC/MS and GC/MS. However, extensive protocols of sample cleanup are required prior to the analysis, and to accomplish it, expensive analytical instrumentation is necessary. An immunochemical analytical method, based on highly specific antigen-antibody interactions, would be desirable, offering several advantages compared to conventional techniques, i.e., low cost per sample, high selectivity, high sensitivity, and high throughput. In this paper, the synthesis of two new derivatives of patulin is described, along with their conjugation to the bovine serum albumin for the production of polyclonal antibodies. Finally, a fluorescence competitive immunoassay was developed for the on-line detection of patulin.     

An algorithm for fast rendezvous seeking of wireless networked robotic systems

The recent development of wireless network architecture and distributed control algorithm allows the onset of large scale robotic application such as monitoring, formation control and flocking, coordination, exploration of unknown environments, and surveillance. In such applications there are many autonomous robots which have capabilities of sensing and acting on the environment and that can communicate with the other robot by wireless communication network defining a Wireless Networked Robotic Systems (in the follows briefly WNR). Usually a robot implements a cooperative algorithm to get some common WNR objective. A widely studied cooperative algorithm allows every robot automatically converge to a common position (consensus or rendezvous) using only local information received from its one hop neighboring robots. Therefore WNR brings together the cooperative control algorithm and the communication capabilities. Despite of a large body of research produced by robotics research community, it is a challenging problem to explore the analysis, the design and evaluation of cooperative algorithm in a more realistic scenario of wireless networked robotic application where the networking and protocol features might affect the overall closed loop WNR performance. In this direction the paper deals with the analysis and design of m-order cooperative control algorithm for fast rendezvous seeking over WNR. Specifically we give a sufficient stability condition of the control algorithm in the presence of heterogeneous time delays affecting the communication through the hops of the WNR. Moreover we analyze the effect of the packet collision phenomena and the presence of background disturbance traffic on the resulting WNR performance. The above sufficient stability condition and analysis, joining with the implementation issues can give a guideline about the design of the rendezvous control algorithm and wireless protocol parameters when we deal with a realistic network environment of WNR. Simulation experiments carried out by a realistic simulation confirm the theoretical findings.     

Modular experimental setup for real‐time analysis of emergent behavior in networks of Chua's circuits

This paper describes the design, realization and use of an analogical, fully reconfigurable experimental setup to analyze the complex dynamics of networks of chaotic circuits. It reports details of the implementation and characterization of the setup, together with representative results, showing its flexibility and potential. The setup allows to choose arbitrarily the coupling strength and interconnection structure among the circuits, the type of link and to select the parameters of the node dynamics. It has a modular structure, and it can accommodate up to 32 nodes interconnected by at most 32 links. The collective dynamics of a relatively large set of different network structures and configurations has been investigated using the setup. Synchronization, pattern formation and other interesting collective phenomena were observed experimentally, their evidence being reported here as an illustration of the potential of the proposed setup. Copyright © 2015 John Wiley & Sons, Ltd.     

Stimuli-responsive chitosan/poly (<Emphasis Type="Italic">N</Emphasis>-isopropylacrylamide) semi-interpenetrating polymer networks: effect of pH and temperature on their rheological and swelling properties

The aim of this work was to synthesize semi-interpenetrating polymer networks (semi-IPNs) by free radical polymerization of N-isopropylacrylamide [poly (NIPAAm)], in the presence of chitosan (CHI), and to study the effect of pH and temperature changes on their rheological and swelling properties. The semi-IPNs are thermally stable up to about 400 °C and the presence of CHI increases the thermal degradation rate compared to bare poly (NIPAAm). The prepared systems presents a well-defined porosity and proved to be non-toxic, in vitro, on human embryonic skin fibroblast, thus offering appropriate support for cell proliferation. The semi-IPNs present, at physiological pH, swelling degrees well below those of the pure poly (NIPAAm). Differently, at acidic pH, the CHI macromolecules are protonated and become much more permeable to the diffusion of water giving a swelling degree that approaches that of bare poly (NIPAAm). The viscoelastic moduli of the semi-IPNs increase as a function of pH while the LCST remain unchanged. Moreover, the semi-IPNs viscoelastic moduli increase with the increase of CHI content and, in particular, the difference between the elastic modulus before and after the sol/gel transition is higher for the semi-IPN than for bare poly (NIPAAm) just at about physiological conditions.     

Electrophoretic co-deposition of Fe2O3 and Mn1,5Co1,5O4: Processing and oxidation performance of Fe-doped Mn-Co coatings for solid oxide cell interconnects

Fe-doped Mn_1,5Co_1,5O₄ coatings on Crofer22APU were processed by an electrophoretic co-deposition method and the corrosion resistance was tested at 750 °C up to 2000 h.The “in-situ” Fe-doping of the manganese cobalt spinel was achieved by electrophoretic co-deposition of Mn_1,5Co_1,5O₄ and Fe₂O₃ powders followed by a two-step reactive sintering treatment. The effects on the coating properties of two different Fe-doping levels (5 and 10 wt.% respectively) and two different temperatures of the reducing treatment (900 and 1000 °C) are discussed. Samples with Fe-doped coatings demonstrated a lower parabolic oxidation rate and thinner oxide scale in comparison with both the undoped Mn_1,5Co_1,5O₄ spinel coating and bare Crofer 22 APU. The best corrosion protection was achieved with the combined effect of Fe-doping and a higher temperature of the reducing step at 1000 °C.