Nitric oxide releasing metal-diazeniumdiolate complexes strongly induce vasorelaxation and endothelial cell proliferation

The preparation, characterization, and NO-releasing properties of metal complexes derived from N-aminoethylpiperazine-N-diazeniumdiolate (HPipNONO), [Cu(PipNONO)Cl] and [Ni(PipNONO)Cl], and the Ni(II) complex derived from the Schiff base between HPipNONO and salicylaldehyde, [Ni(SalPipNONO)], are described. Compounds [Cu(PipNONO)Cl] and [Ni(SalPipNONO)] release NO at a much slower rate than HPipNONO in aqueous buffer in the pH range between 6.8 and 8.0. The kinetics of NO release by [Ni(SalPipNONO)] is complex, with an apparent stepwise release of NO molecules. Both [Cu(PipNONO)Cl] and [Ni(SalPipNONO)] are effective vasorelaxant agents of precontracted rabbit aorta rings, and are active in the nM concentration range. In addition, these complexes promote the proliferation of endothelial cells. Both vascular activities were inhibited by a specific inhibitor of guanylate cyclase, suggesting the involvement of the cGMP pathway. In all biological assays, the reference agent sodium nitroprusside was shown to be 10-1000-fold less potent than the two metal-NONOates.     

A Combined High‐Resolution Mass Spectrometric and in silico Approach for the Characterisation of Small Ligands of β2‐Microglobulin

β₂‐Microglobulin (β₂‐m) is a protein responsible for a severe complication of long‐term hemodialysis, known as dialysis‐related amyloidosis, in which initial β₂‐m misfolding leads to amyloid fibril deposition, mainly in the skeletal tissue. Whereas much attention is paid to understanding the complex mechanism of amyloid formation, the evaluation of small molecules that may bind β₂‐m and possibly inhibit the aggregation process is still largely unexplored mainly because the protein lacks a specific active site. Based on our previous findings, we selected a pilot set of sulfonated molecules that are known to either bind or not to the protein, including binders that are anti‐amyloidogenic. We show how a complementary approach, using high‐resolution mass spectrometry and in silico studies, can offer rapid and precise information on affinity, as well as insight into the structural requisites that favour or disfavour the inhibitory activity. Overall, this approach can be used for predictive purposes and for a rapid screening of fibrillogenesis inhibitors.     

Reliability and accuracy of embedded fiber Bragg grating sensors for strain monitoring in advanced composite structures

This work investigated issues for an efficient and reliable embedding and use of Fiber Bragg Grating (FBG) sensors for strain monitoring of composite structures with particular regard to the manufacturing process of components in the nautical field by means of the vacuum bag technique in autoclave. CFRP material laminates with embedded FBGs were produced and the effect of the curing process parameters on the light transmission characteristics of the optical fibers was initially investigated. Two different types of coating, namely polyimide and acrylate, were tested by measuring the light attenuation by an Optical Time Domain Reflectometer. Tensile specimens were subsequently extracted from the laminas and instrumented also with a surface-mounted conventional electrical strain gage (SG). Comparison between the FBG and SG measurements during static tensile tests allowed the evaluation of the strain monitoring capability of the FBGs, in particular of their sensitivity (i.e., gage factor) when embedded.     

Fine‐Tuning of Catalytic Properties of Catechol 1,2‐Dioxygenase by Active Site Tailoring

Choosing chloro : By reshaping the catalytic pocket of a catechol 1,2‐dioxygenase through a structural route alternative to evolution, novel engineered chlorocatechol dioxygenase‐like enzymes were obtained. Variants show an inversion of specificity with a preference for 4‐chlorocatechol and activity on the rarely recognised substrate 4,5‐dichlorocatechol.

     

Validation of a vector version of the 6S radiative transfer code for atmospheric correction of satellite data. Part I: path radiance

A vector version of the 6S (Second Simulation of a Satellite Signal in the Solar Spectrum) radiative transfer code (6SV1), which enables accounting for radiation polarization, has been developed and validated against a Monte Carlo code, Coulson's tabulated values, and MOBY (Marine Optical Buoy System) water-leaving reflectance measurements. The developed code was also tested against the scalar codes SHARM, DISORT, and MODTRAN to evaluate its performance in scalar mode and the influence of polarization. The obtained results have shown a good agreement of 0.7% in comparison with the Monte Carlo code, 0.2% for Coulson's tabulated values, and 0.001-0.002 for the 400-550 nm region for the MOBY reflectances. Ignoring the effects of polarization led to large errors in calculated top-of-atmosphere reflectances: more than 10% for a molecular atmosphere and up to 5% for an aerosol atmosphere. This new version of 6S is intended to replace the previous scalar version used for calculation of lookup tables in the MODIS (Moderate Resolution Imaging Spectroradiometer) atmospheric correction algorithm.     

Biological response of human bone marrow stromal cells to sandblasted titanium nitride-coated implant surfaces

Titanium nitride (TiN) coating has been proposed as an adjunctive surface treatment aimed to increase the physico-mechanical and aesthetic properties of dental implants. In this study we investigated the biological response of primary human bone marrow stromal cells (BMSC) to TiN-coated sandblasted (TiN-SB) compared to uncoated sandblasted (SB) surfaces. SB and TiN-SB disks were qualitatively and quantitatively analyzed by atomic force microscopy. BMSC were obtained from healthy donors and their adhesion and proliferation on the titanium disks were evaluated by scanning electron microscopy and viability assay. The osteoblastic differentiation, in terms of alkaline phosphatase activity, osteocalcin synthesis, and extracellular mineralization, was assessed by specific immunoenzymatic or spectrophotometric assays. No difference (P > 0.05) between TiN-SB and SB disks was found in terms of any of the investigated parameters. TiN-coating showed to maintain the topographical characteristics of sandblasted titanium surfaces and their biological affinity toward bone precursors.     

QoS in Wireless LAN: A comparison between feedback-based and earliest due-date approaches

The Hybrid Coordination Function is a very powerful mechanism to provide differentiated services in IEEE 802.11 WLANs. In recent years, its adoption in conjunction with centralized scheduling algorithms has lead to many interesting solutions to support services with very sharp delay constraints. Notably, two main approaches have been proposed to face real-time service provisioning, i.e., using the well known earliest due date scheme or feedback control theory. Unfortunately, it is still missing a deep comparison among them. To bridge this gap, we propose herein a novel feedback-based mechanism for infrastructure WLANs and compare it with respect to the most important delay-EDD algorithm, in complex scenarios with video, voice, and best effort flows. Simulation results, obtained using ns-2, demonstrate that (i) both algorithms are able to guarantee upper bounded packet delays, (ii) a more efficient bandwidth usage and a higher network throughput is achieved using the feedback based approach. In particular, it has been shown that the feedback based approach allows a throughput gain ranging from 10% to 20% with respect to delay-EDD.     

Mechatronic design of the Twente humanoid head

This paper describes the mechatronic design of the Twente humanoid head, which has been realized in the purpose of having a research platform for human-machine interaction. The design features a fast, four degree of freedom neck, with long range of motion, and a vision system with three degrees of freedom, mimicking the eyes. To achieve fast target tracking, two degrees of freedom in the neck are combined in a differential drive, resulting in a low moving mass and the possibility to use powerful actuators. The performance of the neck has been optimized by minimizing backlash in the mechanisms, and using gravity compensation. The vision system is based on a saliency algorithm that uses the camera images to determine where the humanoid head should look at, i.e. the focus of attention computed according to biological studies. The motion control algorithm receives, as input, the output of the vision algorithm and controls the humanoid head to focus on and follow the target point. The control architecture exploits the redundancy of the system to show human-like motions while looking at a target. The head has a translucent plastic cover, onto which an internal LED system projects the mouth and the eyebrows, realizing human-like facial expressions.