Effect of different extraction and precipitation methods on yield and quality of pectin

An experimental study has been conducted to determine the combined effects of different extraction conditions and precipitation method on the yield and quality of high methoxyl pectin from lemon peels. Pectin was extracted using different mineral acids (HCl, HNO₃ and H₂SO₄) at four concentration levels (0.025; 0.05; 0.1 and 0.2  m ), at 70 °C for 4 h. The soluble pectin was precipitated by iso-propanol or by an aluminium sulphate, Al₂(SO₄)₃, solution at pH 4. The extraction with HCl and HNO₃, at the highest concentrations investigated, followed by aluminium precipitation led to the best results in terms of yield (22–25%), quality and gelling power of pectin with a remarkable decrease of alcohol consumption as compared to the alcoholic precipitation under the same extracting conditions.     

Development and applications of a software tool for diarthrodial joint analysis

This paper describes a new software environment for advanced analysis of diarthrodial joints. The new tool provides a number of elaboration functions to investigate the joint kinematics, bone anatomy, and ligament and tendon properties. In particular, the shapes and the contact points of the articulating surfaces can be displayed and analysed through 2D user-defined sections and fittings (lines or conics). Ligament behaviour can be evaluated during joint movement, through the computation of elongations, orientations, and fiber strain. Motion trajectories can be also analysed through the calculation of helical axes, instantaneous rotations, and displacements in specific user-chosen coordinate reference frames. The software has an user-friendly graphical interface to display four-dimensional data (time-space data) obtained from medical images, navigation systems, spatial linkages or digitalizers, and can also generate printable reports and multiple graphs as well as ASCII files that can be imported to spreadsheet programs such as Microsoft Excel.     

Procedure for calibrating an ultrasonic sensor for online monitoring of conversion in latex reactors

In order to estimate online conversion and polymer composition through sound velocity measurements, a mathematical model for calculating sound velocity in emulsion polymerization has been developed. With respect to previous modeling approaches, its main features are as follows: (1) the application to three‐phase, reacting systems of Urick equation (usually adopted for estimating sound velocity in multiphase, dispersed, unreacting systems, such as emulsions and suspensions); and (2) the development of an empirical relationship for estimating particle compressibility as a function of conversion during the reaction. The model has been validated through several sets of experimental data of batch and semibatch homo‐ and copolymerizations involving styrene, butyl acrylate, vinyl acetate, and methyl methacrylate. In most of the examined cases, the performances of the calibration model are satisfactory. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1451–1477, 1999     

An Efficient Aequorea victoria Green Fluorescent Protein for Stimulated Emission Depletion Super-Resolution Microscopy

In spite of their value as genetically encodable reporters for imaging in living systems, fluorescent proteins have been used sporadically for stimulated emission depletion (STED) super-resolution imaging, owing to their moderate photophysical resistance, which does not enable reaching resolutions as high as for synthetic dyes. By a rational approach combining steady-state and ultrafast spectroscopy with gated STED imaging in living and fixed cells, we here demonstrate that F99S/M153T/V163A GFP (c3GFP) represents an efficient genetic reporter for STED, on account of no excited state absorption at depletion wavelengths <600 nm and a long emission lifetime. This makes c3GFP a valuable alternative to more common, but less photostable, EGFP and YFP/Citrine mutants for STED imaging studies targeting the green-yellow region of the optical spectrum.     

Measurements of monomer partitioning in emulsion copolymerization systems

A new apparatus to measure the equilibrium solvent activity in a multiphase system containing a particulated polymer is presented. An experimental procedure to determine the monomer partitioning in typical emulsion copolymerization systems is developed; the method is devised in a way that no phase separation between water and swollen polymer particles is required in order to determine the monomer content in each phase. The analytical technique used is quantitative gas chromatography, either of the vapor or of the liquid phases. Different monomers (styrene, methyl methacrylate, and vinyl acetate) and polymeric matrices (polystyrene and methyl methacrylate–vinyl acetate copolymer) are examined both above and below saturation conditions (corresponding to intervals II and III of an emulsion polymerization process). The experimental results are compared with predictions of a literature model. © 1996 John Wiley & Sons, Inc.     

Performance Evaluation of 3D Keypoint Detectors

In the past few years detection of repeatable and distinctive keypoints on 3D surfaces has been the focus of intense research activity, due on the one hand to the increasing diffusion of low-cost 3D sensors, on the other to the growing importance of applications such as 3D shape retrieval and 3D object recognition. This work aims at contributing to the maturity of this field by a thorough evaluation of several recent 3D keypoint detectors. A categorization of existing methods in two classes, that allows for highlighting their common traits, is proposed, so as to abstract all algorithms to two general structures. Moreover, a comprehensive experimental evaluation is carried out in terms of repeatability, distinctiveness and computational efficiency, based on a vast data corpus characterized by nuisances such as noise, clutter, occlusions and viewpoint changes.     

A multimodal imaging approach to the evaluation of post-traumatic epilepsy

Object

Electroencephalography-functional magnetic resonance imaging (EEG-fMRI) coregistration and high-density EEG (hdEEG) can be combined to map noninvasively abnormal brain activation elicited by epileptic processes. By combining noninvasive imaging techniques in a multimodal approach, we sought to investigate pathophysiological mechanisms underlying epileptic activity in seven patients with severe traumatic brain injury.

Materials and methods

Standard EEG and fMRI data were acquired during a single scanning session. The EEG-fMRI data were analyzed using the general linear model and independent component analysis. Source localization of interictal epileptiform discharges (IEDs) was performed using 256-channel hdEEG. Blood oxygenation level dependent (BOLD) localizations were then compared to EEG source reconstruction.

Results

On hdEEG, focal source localization was detected in all seven patients; in six out of seven it was concordant with the expected epileptic activity as defined by EEG data and clinical evaluation; and in four out of seven in whom IEDs were recorded, BOLD signal changes were observed. These activities were partially concordant with the source localization.

Conclusion

Multimodal integration of EEG-fMRI and hdEEG combining two different methods to localize the same epileptic foci appears to be a promising tool to noninvasively map abnormal brain activation in patients with post-traumatic brain injury.     

Kinetics of multimonomer emulsion polymerization. The pseudo-homopolymerization approach

By generalizing the Smith–Ewart theory, a system of polymer particle population balances is developed for describing the kinetics of emulsion polymerization processes involving any number of monomer species. Each population is characterized by the number of active radicals of each type present inside each particle, and described through a size distribution function. An approximation procedure is proposed for reducing the original system to that typical of homopolymerization processes, thus characterizing each population-only through the overall number of radicals, without any significant loss of accuracy. The reliability of such “pseudo-homopolymerization approach” is tested by comparison with polymer composition vs. monomer conversion experimental data for the ternary system acrylonitrile–styrene–methyl methacrylate.     

The torcular Herophili: the diagnostic pitfalls in TOF 3D magnetic resonance angiography

The authors report on a diagnostic pitfall which is often observed in magnetic resonance angiography (MRA) of intracranial vessels (time-of-flight 3D)--i.e., the absence of one of the two transverse sinuses. Fifty patients underwent MRA of the intracranial vessels with the TOF 3D (FISP) and the TOF 2D (FISP) techniques. Five patients were affected with sinus stenosis. MRA was performed with a 1.5-T superconductive magnet and a circular head coil. All patients underwent Magnetic Resonance Angiography with FISP 2D sequences (FA 40 degrees, TR 40 ms, TE 12 ms) acquired on coronal plane as well as FISP 3D (FA 15 degrees, TR 30 ms, TE 7 ms) acquired on axial plane. In the patients in whom FISP 2D sequences correctly demonstrated the whole confluence of sinuses, FISP 3D sequences always depicted the upper sagittal sinus, while the right transverse sinus was seen in 84.4% (38/45) of cases and the left transverse sinus in 24.2% (11/45) of cases. In the patients with a stenosis in the confluence of sinuses, FISP 3D sequences demonstrated two false-positive cases with respect to FISP 2D. The statistical analysis (McNemar test) of the results demonstrated the difference between 2D and 3D sequences in the detection of the two transverse sinuses to be statistically significant: p < 0.01 for the right transverse sinus and p < 0.001 for the left transverse sinus. In the study of the intracranial vessels (TOF 3D technique) the absence of one of the two transverse sinuses is suggestive of a diagnostic pitfall; the combination of 3D and 2D sequences answers this diagnostic question.