A Review of the Effects of Olive Oil-Cooking on Phenolic Compounds

The fate of phenolic compounds in oil and food during cooking vary according to the type of cooking. From a nutritional point of view, reviews largely suggest a preference for using extra-virgin olive oil at a low temperature for a short time, except for frying and microwaving, for which there appears to be no significant advantages compared to olive oil. However, due to the poorly pertinent use of terminology, the different protocols adopted in studies aimed at the same objective, the different type and quality of oils used in experiments, and the different quality and quantity of PC present in the used oils and in the studied vegetables, the evidence available is mainly contradictory. This review tries to reanalyse the main experimental reports on the fate, accessibility and bioavailability of phenolic compounds in cooking oils and cooked vegetables, by considering different cooking techniques and types of oil and foods, and distinguishing experimental findings obtained using oil alone from those in combination with vegetables. The re-analysis indicates that incomplete and contradictory observations have been published in the last few years and suggests that further research is necessary to clarify the impact of cooking techniques on the phenolic compounds in oil and vegetables during cooking, especially when considering their nutritional properties.     

Diastereoselective aziridination of chiral alpha-carbonyl enoates

Nosyloxycarbamates very efficiently aziridinate optically active alpha-carbonyl enoates with high levels of diastereoselectivity under mild conditions and in a straightforward process.     

Image based visual servoing for robot positioning tasks

Visual servoing has become a popular paradigm for the control of complex robotic systems: this sensor based approach exploits the image informations provided by one ore more cameras in a feedback control loop to drive the system to the desired configuration. Here authors will refers to a monocular system where the camera is mounted on the end effector of a 6-DOF manipulator. Among different Visual Servoing approaches Image Based Visual Servoing (IBVS) has been the most investigated in the literature because of its nice properties of robustness with respect to both robot modeling and camera calibration errors: in IBVS the control loop is in fact directly closed in the image; moreover IBVS doesn’t require the knowledge of the target/scene model (model-free approach). Despite its advantages IBVS may be affected by singularity and local minima problems of the control law: these drawbacks arise especially when the initial and the goal camera images respectively corresponding to the actual and desired system configurations are very different (i.e for large system displacements). To overcome these problems an image path planning can be exploited to ensure system convergence. In this paper author presents an off-line image path planning that can be used to execute system positioning task also in presence of large camera displacements: planning trajectories has been developed such as to make the robot end effector move on a 3D helix, connecting the initial and the desired arm configuration, by generating feasible robot twist-screws and keeping the target in the image field of view. During control execution also 3D target informations are retrieved through an adaptive estimation law. Both simulations and experimental results show the feasibility of the proposed approach.     

Mixing symbolic and numerical approaches for the surface-to-surface intersection problem

This paper shows how the efficiency of the current methodologies applied to the surface-to-surface intersection problem can be improved by combining an algebraic/symbolic framework with efficient and robust numerical techniques. The algebraic/symbolic framework is used to translate the computation of resultants, subresultants, discriminants, etc. to one or several generalized eigenvalue problems and SVD computations. The framework requires only the values of the involved polynomials at some set of points, and it will guide the numerical computations, providing thus a certificate of the topological correctness of the output. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Local desorption of thiols by scanning electrochemical microscopy: patterning and tuning the reactivity of self-assembled monolayers

Self-assembled monolayers (SAMs) are widely used in the field of nanotechnologies and (bio)sensors. The monolayer surface properties are tailored by employing several techniques. A large set of SAM post-modification routes are commonly performed to adapt them to a variety of nano-technological and bio-technological studies as well as to several bio-sensoristic applications. Here, we report a procedure to locally modify SAMs by electrochemical desorption of alkanethiols in order to create microsized spots of bare gold area without affecting the surrounding monolayer stability. The tip of the scanning electrochemical microscope (SECM) was employed to draw microstructured pattern according to a defined geometry. The time stability of the pattern was also tested. Furthermore, the patterned surface was post-functionalized using the same alkanethiol or a ferrocene-terminated thiol, in order to tune the surface reactivity of the microstructure. The local surface properties, including reactivity and electron transfer kinetics toward redox mediator reduction, were characterized by SECM.     

Retention of heavy metal ions on SBA-15 mesoporous silica functionalised with carboxylic groups

Three samples of SBA-15 functionalised with -(CH(2))(3)COOH groups have been prepared by co-condensation, starting from solutions of TEOS and 4-(triethoxysilyl)butyronitrile, acting as -(CH(2))(3)COOH precursor, of different molar compositions. Materials were characterised by X-ray diffraction, nitrogen adsorption, and FT-IR spectroscopy. The pK(a) and the acidic capacity were measured for all samples by potentiometric titration. The acidic capacity increases with increasing amount of -COOH precursor in the synthesis mixture only up to 10% molar of total alkoxysilane. The value for the pK(a)(4.75) is independent of the acidic capacity of the material. The sample prepared starting from an amount of -COOH precursor equal to 10% molar of total alkoxysilane was chosen to test selective interactions with heavy metals of environmental importance (Ag(+), Cd(2+), Fe(3+), Cu(2+), Zn(2+)) at different pH values and ionic strengths. The significant and selective adsorption exhibited by the material has been exploited in a preliminary cation-exchange chromatographic application showing the possibility of eluting the metal ions at different retention times.     

Metal-based Heterogeneous Catalysts for One-Pot Synthesis of Secondary Anilines from Nitroarenes and Aldehydes

Recently, N-substituted anilines have been the object of increasing research interest in the field of organic chemistry due to their role as key intermediates for the synthesis of important compounds such as polymers, dyes, drugs, agrochemicals and pharmaceutical products. Among the various methods reported in literature for the formation of C–N bonds to access secondary anilines, the one-pot reductive amination of aldehydes with nitroarenes is the most interesting procedure, because it allows to obtain diverse N-substituted aryl amines by simple reduction of nitro compounds followed by condensation with aldehydes and subsequent reduction of the imine intermediates. These kinds of tandem reactions are generally catalyzed by transition metal-based catalysts, mainly potentially reusable metal nanoparticles. The rapid growth in the last years in the field of metal-based heterogeneous catalysts for the one-pot reductive amination of aldehydes with nitroarenes demands for a review on the state of the art with a special emphasis on the different kinds of metals used as catalysts and their recyclability features.     

A chromatographic study on the exceptional enantioselectivity of cellulose tris(4-methylbenzoate) towards C5-chiral 4,5-dihydro-(1H)-pyrazole derivatives

A set of ten C5-chiral 4,5-dihydro-(1H)-pyrazole derivatives was synthesized and analyzed by high-performance liquid chromatography (HPLC) on the polysaccharide-based Chiralcel OJ-H chiral stationary phase (CSP). The enantioseparations were carried out using pure ethanol as eluent. Different structural elements of the investigated compounds were recognized for obtaining a very high enantioselectivity. In order to clarify some aspects of the chiral discrimination process, the thermodynamic parameters associated to the enantiorecognition and the enantiomer elution order were established.     

Stereoselective synthesis and ROESY 1H NMR study of bidiaziridines

The bisaziridination reaction of symmetric (E-s-trans-E)-α-diimines using ethyl nosyloxycarbamate as aminating agent yields symmetrically functionalized bidiaziridines, under mild conditions. The reactions take place with very high stereoselectivity giving only bidiaziridines with total retention of the starting α-diimine configuration, as determined by NMR measurements. Moreover, only a single pure diastereomer, derived from attack of the aza-anion on the opposite faces of conjugate system was obtained, starting from chiral substrates. ROESY analyses clearly show that all nitrogens have a stable pyramidal conformation, and the absolute configurations of new chiral centers were assigned.     

Large spin corrections in SYM : Still a linear integral equation

Anomalous dimension and higher conserved charges in the sl(2) sector of SYM for generic spin s and twist L are described by using a novel kind of non-linear integral equation (NLIE). The latter can be derived under typical situations of the SYM sectors, i.e. when the scattering need not depend on the difference of the rapidities and these, in their turn, may also lie on a bounded range. Here the non-linear (finite range) integral terms, appearing in the NLIE and in the dimension formula, go to zero as s→∞. Therefore they can be neglected at least up to the O(s⁰) order, thus implying a linear integral equation (LIE) and a linear dimension/charge formula respectively, likewise the ‘thermodynamic’ (i.e. infinite spin) case. Importantly, these non-linear terms go faster than any inverse logarithm power (lns)⁻ⁿ, n>0, thus extending the linearity validity.