Reduction of computational cost in DFT implementation of FIR digital filters

The influence on the computational cost of the transformation of a FIR digital filter into cyclic convolutions is analysed in the letter. An optimal choice of the length of the cyclic convolutions is suggested and illustrated.     

Protein-disulfide isomerase-mediated reduction of the A subunit of cholera toxin in a human intestinal cell line

A key step in the action of cholera toxin (CT) is the reduction of its A subunit to the A1 peptide. The latter is an ADP-ribosyltransferase, which activates the alpha-subunit of the stimulatory G protein of adenylyl cyclase. In this study, the enzymatic reduction of membrane-bound CT in CaCo-2 human intestinal epithelial cells was characterized. Whereas diphtheria toxin was found to be reduced by a cell surface population of protein-disulfide isomerase (PDI) and its cytotoxicity was inhibited by p-chloromercuribenzenesulfonic acid, bacitracin, or anti-PDI antibodies, these inhibitors had no effect on CT reduction or activity in intact cells. In contrast, the reduction of CT in vitro by either postnuclear supernatants (PNS) or microsomal membranes in the presence of Triton X-100 was significantly inhibited by p-chloromercuribenzenesulfonic acid and bacitracin. Anti-PDI monoclonal antibodies likewise inhibited the in vitro reduction of CT and also were effective in depleting reductase activity from PNS. Since inhibition and depletion were not observed in the absence of detergent, these results suggested that the reductase activity was a soluble component localized to the lumen of microsomal vesicles and correlated with the presence of protein-disulfide isomerase. This was further confirmed by showing a corresponding depletion of reductase activity and PDI in alkali-treated microsomes. This activity was restored when purified bovine PDI was added back to alkali-treated microsomes in a redox buffer that reflected conditions found in the lumen of the endoplasmic reticulum (ER). When the CT-related reductase activity was assayed in subcellular fractions of PNS-derived membranes isolated on a 9-30% Iodixanol gradient, the activity, as measured by CT-A1 peptide formation localized to those fractions containing PDI. Likewise CT-A1 peptide formed in intact cells co-localized to those membrane fractions containing the majority of cellular PDI. Furthermore, the banding density corresponded to a region of the gradient containing ER-derived membranes. These results indicated that CT was a substrate for PDI-catalyzed reduction in intact cells and supported the hypothesis that CT reduction and activation occurs in the ER.     

Challenges and opportunities in renovating public sector information by enabling linked data and analytics

Linked Data has become the current W3C recommended approach for publishing data on the World Wide Web as it is sharable, extensible, and easily re-usable. An ecosystem of linked data hubs in the Public Sector has the potential to offer significant benefits to its consumers (other public offices and ministries, as well as researchers, citizens and SMEs), such as increased accessibility and re-use value of their data through the use of web-scale identifiers and easy interlinking with datasets of other public data providers. The power and flexibility of the schema-defying Linked Data, however, is counterbalanced by inborn factors that diminish the potential for cost-effective and efficient adoption by the Public Sector. The paper analyzes these challenges in view of the current state-of-the-art in linked data technologies and proposes a technical framework that aims to hide the underlying complexity of linked data while maintaining and promoting the interlinking capabilities enabled by the Linked Data Paradigm. The paper presents the innovations behind our proposed solutions as well as their advantages, especially for the non-expert users.     

Gradient evaluation for neural-networks-based electromagneticoptimization procedures

This paper extends the use of a neural network (NN) approximating a function, to the evaluation of the gradient of the same function. This is done without any extra training of the network. The evaluation of the function's gradient is used in NN-based optimization procedures in order to speed up the convergence and to maintain the overall accuracy     

Ferroelectric Response and Induced Biaxiality in the Nematic Phase of Bent‐Core Mesogens

The still undiscovered fluid ferroelectric nematic phase is expected to exhibit a much faster and easier response to an external electric field compared to conventional ferroelectric smectic liquid crystals; therefore, the discovery of such a phase could open new avenues in electro‐optic device technology. Here, experimental evidence of a ferroelectric response to a switching electric field in a low molar mass nematic liquid crystal is reported and connected with field‐induced biaxiality. The fluid is made of bent‐core polar molecules and is nematic over a range of 120 °C. Combining repolarization current measurements, electro‐optical characterizations, X‐ray diffraction and computer simulations, ferroelectric switching is demonstrated and it is concluded that the response is due to field‐induced reorganization of polar cybotactic groups within the nematic phase. This work represents significant progress toward the realization of ferroelectric fluids that can be aligned at command with a simple electric field.     

EMI reduction in switched power converters using frequency Modulation techniques

Frequency-modulation techniques have been used to reduce electromagnetic interference (EMI) produced by the clock of digital systems working in the range of hundreds of megahertz. The working principle consists of modulating the original constant clock frequency in order to spread the energy of each single harmonic into a certain frequency band, thus reducing the peak amplitude of EMI at harmonic frequencies. Nowadays, the switching frequency of power converters has increased up to values that make interesting the application of such techniques to reduce EMI emissions due to switching of power circuits. This paper presents the theoretical principles of frequency modulation using deterministic profiles for the modulating function. It shows the effectiveness of such methods in terms of EMI reduction for different modulation profiles and other parameters. The method is compared with other methods using random modulation. Tests carried out on a buck converter are presented for experimental validation of the method. A short discussion on optimal modulation profiles and parameters is also included.     

MCAM/MUC18/CD146 as a Multifaceted Warning Marker of Melanoma Progression in Liquid Biopsy

Human malignant melanoma shows a high rate of mortality after metastasization, and its incidence is continuously rising worldwide. Several studies have suggested that MCAM/MUC18/CD146 plays an important role in the progression of this malignant disease. MCAM/MUC18/CD146 is a typical single-spanning transmembrane glycoprotein, existing as two membrane isoforms, long and short, and an additional soluble form, sCD146. We previously documented that molecular MCAM/MUC18/CD146 expression is strongly associated with disease progression. Recently, we showed that MCAM/MUC18/CD146 and ABCB5 can serve as melanoma-specific-targets in the selection of highly primitive circulating melanoma cells, and constitute putative proteins associated with disease spreading progression. Here, we analyzed CD146 molecular expression at onset or at disease recurrence in an enlarged melanoma case series. For some patients, we also performed the time courses of molecular monitoring. Moreover, we explored the role of soluble CD146 in different cohorts of melanoma patients at onset or disease progression, rather than in clinical remission, undergoing immune therapy or free from any clinical treatment. We showed that MCAM/MUC18/CD146 can be considered as: (1) a membrane antigen suitable for identification and enrichment in melanoma liquid biopsy; (2) a highly effective molecular “warning” marker for minimal residual disease monitoring; and (3) a soluble protein index of inflammation and putative response to therapeutic treatments.     

Eye pattern evaluation in high-speed digital systems analysis byusing MTL modeling

A method for simulating the eye pattern of high-speed digital signals propagated on printed circuit boards using multiconductor transmission-line modeling is proposed in this paper. The approach takes into account the frequency-dependent properties of the dielectric materials of the board and of the conductors. The validation is performed by comparing the modeling with measurements taken from the literature, and directly performed on test boards specially design for this study     

Impact of partial element accuracy on PEEC model stability

This paper details the impact of partial element accuracy on quasi-static partial element equivalent circuit (PEEC) model stability in the time domain. The potential sources of inaccurate partial element values are found to be poor geometrical meshing and the use of unsuitable partial element calculation routines. The impact on PEEC model stability of erroneous partial element values, and the coefficients of potential and partial inductances, are shown as theoretical constraints and practical results. Projection meshing, which is a discretization strategy suitable for the PEEC method, is shown to improve calculated partial element values for the same number of unknowns, thus improving model stability.