Using C/X-band SAR interferometry and GNSS measurements for the Assisi landslide analysis

This work presents an analysis of the applicability of synthetic aperture radar (SAR) interferometry to landslide monitoring. This analysis was carried out by using different interferometric approaches, different spaceborne SAR data (both in the C-band and in the X-band), and in situ global navigation satellite system (GNSS) measurements. In particular, we investigated both the reliability of displacement monitoring and the issues of the cross-comparison and validation of the interferometric synthetic aperture radar (InSAR) results. The work was focused on the slow-moving landslide that affects a relevant part of the urban area of the historical town of Assisi (Italy).

A C-band ENVISAT advanced synthetic aperture radar (ENVISAT ASAR) dataset acquired between 2003 and 2010 was processed by using two different interferometric techniques, to allow cross-comparison of the obtained displacement maps. Good correspondence between the results was found, and a deeper analysis of the movement field was possible. Results were further compared to a set of GNSS measurements with a 7 year overlap with SAR data. A comparison was made for each GNSS marker with the surrounding SAR scatterers, trying to take into account local topological effects, when possible.

Further, the high-resolution X-band acquired on both ascending and descending tracks by the COSMO-SkyMed (CSK) constellation was processed. The resultant displacement fields show good agreement with C-band and GNSS measurements and a sensible increase in the density of measurements.     

On sets of numbers accepted by P/T systems composed by join

Recently, some studies linked the computational power of abstract computing systems based on multiset rewriting to models of Petri nets and the computation power of these nets to their topology. In turn, the computational power of these abstract computing devices can be understood by just looking at their topology, that is, information flow.Here we continue this line of research by introducing J languages and proving that they can be accepted by place/transition systems whose underlying net is composed only by join. Moreover, we study how J languages relate to other families of formal languages.     

DynaMICs: Comprehensive Support for Run-Time Monitoring

Software engineering strives to enable the economic construction of software systems that behave reliably, predictably, and safely. In other engineering disciplines, safety is assured in part by detailed monitoring of processes. In software, we may achieve some level of confidence in the operation of programs by monitoring their execution. DynaMICs is a software tool that facilitates the collection and use of constraints for software systems. In addition, it supports traceability by mapping constraints to system artifacts. Constraint specifications are stored separately from code; constraint-monitoring code is automatically generated from the specifications and inserted into the program at appropriate places; and constraints are verified at execution time. These constraint checks are triggered by changes made to variable values. We describe the architecture of DynaMICs, discuss alternative verification techniques, and outline research directions for the DynaMICs project.     

Degradative transport of cationic amphiphilic drugs across phospholipid bilayers

Drug molecules must cross multiple cell membrane barriers to reach their site of action. We present evidence that one of the largest classes of pharmaceutical drug molecules, the cationic amphiphilic drugs (CADs), does so via a catalytic reaction that degrades the phospholipid fabric of the membrane. We find that CADs partition rapidly to the polar-apolar region of the membrane. At physiological pH, the protonated groups on the CAD catalyse the acid hydrolysis of the ester linkage present in the phospholipid chains, producing a fatty acid and a single-chain lipid. The single-chain lipids rapidly destabilize the membrane, causing membranous fragments to separate and diffuse away from the host. These membrane fragments carry the drug molecules with them. The entire process, from drug adsorption to drug release within micelles, occurs on a time-scale of seconds, compatible with in vivo drug diffusion rates. Given the rate at which the reaction occurs, it is probable that this process is a significant mechanism for drug transport.     

Studies on the synthesis of diacetyl over oxidation zeolite catalysts

Diacetyl (2,3-butanedione) synthesis from methyl ethyl ketone over oxidation zeolites using O₂ as oxidant was studied. Various zeolites with Fe, V and Ti as active sites were employed. VS-1, Ti-NCL, Ti-MCM-41 and FeBEA type materials were synthesized and characterized by BET, FTIR, XRD, pyridine adsorption and template desorption. The detailed study of the effect of reaction temperature, the effect of concentration of oxygen and the addition of water was realized. The most active catalyst was zeolites with V as oxidation center.     

Hydroxypropylmethylcellulose surface activity at equilibrium and adsorption dynamics at the air–water and oil–water interfaces

The surface behaviour of hydroxypropylmethylcelluloses (HPMC) was studied at the air–water (A/W) and oil–water (O/W) interfaces. At the A/W interface, the π-C isotherms were sigmoidal and presented inflexions as the HPMC bulk concentration increases, related with different structural patterns adopted by the biopolymer segments. The behaviour of these biopolymers at the O/W interface resulted different. No inflections in the adsorption isotherm were observed, denoting the absence of any change in the structure of the adsorbed monolayer. The order in the interfacial activity was different at the two interfaces.The dynamics of adsorption showed that the surface pressure (π) values and the rate of adsorption/penetration were lower at the O/W interface.Analogously to π values, the surface dilatational modulus was smallest at the O/W interface, however at long-term adsorption strong viscoelastic films are formed at the O/W interface.     

Serendipitous Identification of a Covalent Activator of Liver Pyruvate Kinase

Enzymes are effective biological catalysts that accelerate almost all metabolic reactions in living organisms. Synthetic modulators of enzymes are useful tools for the study of enzymatic reactions and can provide starting points for the design of new drugs. Here, we report on the discovery of a class of biologically active compounds that covalently modifies lysine residues in human liver pyruvate kinase (PKL), leading to allosteric activation of the enzyme (EC₅₀=0.29 μM). Surprisingly, the allosteric activation control point resides on the lysine residue K282 present in the catalytic site of PKL. These findings were confirmed by structural data, MS/MS experiments, and molecular modelling studies. Altogether, our study provides a molecular basis for the activation mechanism and establishes a framework for further development of human liver pyruvate kinase covalent activators.     

Current advances in the non‐chromatographic fractionation and characterization of PEGylated proteins

For more than 30 years, PEGylation has been used to improve the physicochemical properties of several proteins and therapeutic drugs having a major impact in the biopharmaceutical industry. The purification of PEGylated proteins usually involves two basic challenges: (1) the separation of PEG‐proteins from other reaction products; and (2) the sub‐fractionation of PEG‐proteins on the basis of their degree of PEGylation and positional isomerism. Currently, most PEGylated protein purification processes are based on chromatographic techniques, especially size exclusion chromatography (SEC) and ion exchange chromatography (IEX). Nonetheless, other less frequently used strategies based on non‐chromatographic techniques such as ultrafiltration, electrophoresis, capillary electrophoresis, and aqueous two‐phase systems have been developed in order to fractionate and analyze PEGylated derivates. This review presents current advances in some of the most widely used non‐chromatographic strategies for the fractionation and analysis of PEG‐protein conjugates. Copyright © 2010 Society of Chemical Industry     

Ligand Binding Promiscuity of Human Liver Fatty Acid Binding Protein: Structural and Dynamic Insights from an Interaction Study with Glycocholate and Oleate

Human liver fatty acid binding protein (hL‐FABP) has been reported to act as an intracellular shuttle of lipid molecules, thus playing a central role in systemic metabolic homeostasis. The involvement of hL‐FABP in the transport of bile salts has been postulated but scarcely investigated. Here we describe a thorough NMR investigation of glycocholate (GCA) binding to hL‐FABP. The protein molecule bound a single molecule of GCA, in contrast to the 1:2 stoichiometry observed with fatty acids. GCA was found to occupy the large internal cavity of hL‐FABP, without requiring major conformational rearrangement of the protein backbone; rather, this led to increased stability, similar to that estimated for the hL‐FABP:oleate complex. Fast‐timescale dynamics appeared not to be significantly perturbed in the presence of ligands. Slow motions (unlike for other proteins of the family) were retained or enhanced upon binding, consistent with a requirement for structural plasticity for promiscuous recognition.     

High-Stable Mesoporous Ni-Ce/Clay Catalysts for Syngas Production

Abstract  

A mesoporous-type catalytic support was synthesized through the modification of a smectite with polyvinyl alcohol (PVA) and microwaves. Texture and micro-morphology of the support was determined. Several techniques were employed in order to describe the chemical environment of active species on the surface. Ni⁰ particle sizes were dependent on the structural site of reducible species. High stable Ni-Ce catalysts (calcined at 800 °C) were evaluated in the CO₂ reforming of methane reaction at 700 °C (WHSV = 96 L g⁻¹ h⁻¹, without dilution gas and pre-reduction). The catalysts have presented CH₄ conversions between 40 and 65%, CO₂ conversion between 35 and 65% and H₂/CO ratios between 0.2 and 0.4.