Studies on the Biosynthesis of Some Furocoumarins Present in Ruta graveolens

The biosynthesis of some furocoumarins present in Ruta graveolens has been studied administering labeled psoralen, xanthotoxin, rutaretin, marmesin and 7-hydroxycoumarin-derivatives. The results obtained indicate that the biosynthetic pathway involves not only psoralen, but also xanthotoxin and bergapten, by means of methoxylation or demethoxylation reactions. Moreover results achieved from administering rutaretin demonstrate that this substance is a new very effective natural precursor for xanthotoxin; in a parallel way marmesin is incorporated into psoralen. The reported results indicate that also at the stage of natural 4′,5′-dihydrofurocoumarins intermediates an interconversion can occur. Finally the essential role of umbelliferone in the biosynthesis of furocoumarins has been confirmed

Contribution of polymorphic variation of inositol hexakisphosphate kinase 3 (IP6K3) gene promoter to the susceptibility to late onset Alzheimer's disease

Maintenance of electric potential and synaptic transmission are energetically demanding tasks that neuronal metabolism must continually satisfy. Inability to fulfil these energy requirements leads to the development of neurodegenerative disorders, including Alzheimer's disease. A prominent feature of Alzheimer's disease is in fact neuronal glucose hypometabolism. Thus understanding the fine control of energetic metabolism might help to understand neurodegenerative disorders. Recent research has indicated that a novel class of signalling molecules, the inositol pyrophosphates, act as energy sensors. They are able to alter the balance between mitochondrial oxidative phosphorylation and glycolytic flux, ultimately affecting the cellular level of ATP. The neuronal inositol pyrophosphate synthesis relies on the activity of the neuron enriched inositol hexakisphosphate kinase 3 (IP6K3) enzyme. To verify an involvement of inositol pyrophosphate signalling in neurodegenerative disorders, we performed tagging single nucleotide polymorphism (SNP) analysis of the IP6K3 gene in patients with familial and sporadic late onset Alzheimer's disease (LOAD). Two SNPs in the 5'-flanking promoter region of the IP6K3 gene were found to be associated with sporadic LOAD. Characterizing the functionality of the two polymorphisms by luciferase assay revealed that one of them (rs28607030) affects IP6K3 promoter activity, with the G allele showing an increased activity. As the same allele has a beneficial effect on disease risk, this may be related to upregulation of IP6K3 expression, with a consequent increase in inositol pyrophosphate synthesis. In conclusion, we provide the first evidence for a contribution of genetic variability in the IP6K3 gene to LOAD pathogenesis

Comparison of Reconstruction Algorithms for Brain Stroke Microwave Imaging

The aim of this paper is to describe and compare the performances of three image reconstruction algorithms that can be used for brain stroke microwave imaging. The algorithms belong to the class of non-linear iterative algorithms and are capable of providing a quantitative map of the imaged scenario. The first algorithm is the Contrast Source Inversion (CSI) method, which uses the Finite Element Method (FEM) to discretize the domain of interest. The second one is the Subspace-Based Optimization Method (SOM) that has some properties in common with the CSI method, and it also uses FEM to discretize the domain. The last one is the Distorted Born Iterative Method with the inverse solver Two-step Iterative Shrinkage/Thresholding (DBIM-TwIST), which exploits the forward Finite Difference Time Domain (FDTD) solver. The reconstruction examples are created with 3-D synthetic data modelling realistic brain tissues with the presence of a blood region, representing the stroke area in the brain, whereas the inversion step is carried out using a 2-D model

Assessing a Microwave Imaging System for Brain Stroke Monitoring via High Fidelity Numerical Modelling

This work presents the outcomes of a numerical analysis based on a 3-D high fidelity model of a realistic microwave imaging system for the clinical follow-up of brain stroke. The analysis is meant as a preliminary step towards the full experimental characterization of the system, with the aim of assessing the achievable results and highlight possible critical points. The system consists of an array of twenty-four printed monopole antennas, placed conformal to the upper part of the head; each monopole is immersed into a semi-solid dielectric brick with custom permittivity, acting as coupling medium. The whole system, including the antennas and their feeding mechanism, has been numerically modeled via a custom full-wave software based on the finite element method. The numerical model generates reliable electromagnetic operators and accurate antenna scattering parameters, which provide the input data for the implemented imaging algorithm. In particular, the numerical analysis assesses the capability of the device of reliably monitoring the evolution of hemorrhages and ischemias, considering the progression from a healthy statet o an early-stage stroke

Preliminary In-Line Microwave Imaging Experimental Assessment for Food Contamination Monitoring

Food producers must deal with contaminants (wood, plastic, glass) inside packaged products that could lead to customer dissatisfaction. The assessed technologies fail to detect some of these contaminants, leading to the need for new technologies with different signal qualities, such as microwave sensing. This paper presents a preliminary result of a microwave imaging system designed for industrial applications. The measurement system was designed for and works on an industrial conveyor belt where packaged products are scanned. The scanned signals are processed to obtain an accurate 3D image of the size and position of the contaminant inside the food package. In addition to the results, we describe the implemented system and some considerations on data acquisition

Non-Destructive Characterization of Magnetic Polymeric Scaffolds using Terahertz Time-of-Flight Imaging

Magnetic Scaffolds MagS are 3D composite materials, in which magnetic nanoparticles (MNPs) are used to load a polymeric matrix. Due to their wide use in various medical applications, there is an increasing demand of advanced techniques for non-destructive quality assessment procedures aimed at verifying the absence of defects and, more generally, dedicated to the characterization of MagS. In this framework, the use of TeraHertz (THz) waves for the non-destructive characterization of multifunctional scaffolds represents an open challenge for the scientific community. This paper deals with an approach for the characterization of MagS by means of a THz time-domain system used in reflection mode. THz analyses are performed on poly($\epsilon$ - capprolactone) (PCL) scaffolds magnetized with iron oxide (Fe $_{3}$ O$_{4}$) MNPs through a drop-casting deposition and tuned to obtain different distributions of MNP in the biomaterial. The proposed data processing approach allows a quantitative characterization MagS, in terms of their (estimated) thickness and refractive index. Moreover, the proposed procedure allows to identify the areas of the scaffold wherein MNP are mainly concentrated and thus, it gives us information about MNP spatial distribution

Microwave imaging technology for in-line food contamination monitoring

Foreign body contamination in food is one of the major sources of complaints against food manufacturers, and it can lead to injury, loss of brand loyalty and large recall expenses. Different technologies, such as X-ray or infrared techniques, are currently applied to detection systems used for food inspection, but physical contamination, with e.g. wood, plastic, metal and glass fragments, is still present in food. For this reason, there is the interest to develop new technologies able to address the still unmet needs of food industry. In this paper, we report about preliminary investigations of the use of the microwave imaging technology for food contamination monitoring. Numerical results show the feasibility of the proposed approach. The realization of prototype measurement system is under development

Wearable Microwave Imaging System for Brain Stroke Imaging

This paper presents the experimental validation of the detection capabilities of a low complexity wearable system designed for the imaging-based detection of brain stroke. The system approaches the electromagnetic inverse problem via a 3-D imaging algorithm based on the Born approximation and the Truncated Singular Value Decomposition (TSVD). For testing, flexible antennas with custom-made coupling-medium are prototyped and assessed in mimicked hemorrhagic and ischemic stroke conditions. The experiment emulates the clinical scenario using a single-tissue anthropomorphic head phantom and strokes with both 20 cm 3 and 60 cm 3 ellipsoid targets. The imaging kernel is computed via full-wave simulation of a virtual twin model. The results demonstrate the capabilities for detecting and estimating the stroke-affected area

A Portable Microwave Scanner for Brain Stroke Monitoring: Design, Implementation and Experimental Validation

This paper presents the design, the realization, and the experimental assessment of a novel portable microwave scanner prototype for brain stroke monitoring. The device employs a 22-antenna-array, placed conformal to the upper head part, composed of compact, flexible, and custom-made antennas working at around 1 GHz. The validation includes the monitoring of an experimentally emulated evolving hemorrhagic stroke. The progression of the medical condition is emulated via a non-static phantom (custom-shape balloon), derived from medical images, and a single-cavity 3-D anthropomorphic head phantom. The phantoms are filled with liquids mimicking the dielectric properties of the hemorrhage and the average brain tissues, respectively. The imaging-based follow-up is approached using a differential scheme that receives the scattering matrices, taken at two different instants, and exploits the distorted Born approximation to form the image in real-time. The kernel of the imaging algorithm is computed through accurate numerical models. The results verify the capabilities of the system to assess the continuous evolution of the stroke

Microwave imaging device prototype for brain stroke 3D monitoring

This paper summarizes the development and the experimental testing of a scanning device, in the microwave range, to monitor brain stroke. The device comprehends 4 main sections: a sensors helmet, a switching matrix, a data acquisition part, and a control/processing core. The sensors in the helmet are 22 custom-made flexible antennas working around 1 GHz, placed conformally to the upper head part. A first validation of the system consists in the detection of a target in the head region. Experimental testing is performed on a single-cavity head phantom, while the target is a balloon mimicking the stroke. The shape of the balloon and phantom are extracted from medical images, and tissues properties are emulated with liquids that resemble their dielectric properties. A differential measurement approach senses the field on the antennas in two different situations, and from their difference computes a 3-D image through a singular value decomposition of the discretized scattering operator obtained from an accurate numerical model. The results verify the capabilities of the system on detecting and monitoring stroke evolution