Use of bremsstrahlung radiation to identify hidden weak beta- sources: feasibility and possible use in radio-guided surgery

The recent interest in beta- radionuclides for radio-guided surgery derives from the feature of the beta radiation to release energy in few millimeters of tissue. Such feature can be used to locate residual tumors with a probe located in its immediate vicinity, determining the resection margins with an accuracy of millimeters. The drawback of this technique is that it does not allow to identify tumors hidden in more than few mm of tissue. Conversely, the bremsstrahlung X-rays emitted by the interaction of the beta- radiation with the nuclei of the tissue are relatively penetrating. To complement the beta- probes, we have therefore developed a detector based on cadmium telluride, an X-ray detector with a high quantum efficiency working at room temperature. We measured the secondary emission of bremsstrahlung photons in a target of Polymethylmethacrylate (PMMA) with a density similar to living tissue. The results show that this device allows to detect a 1 ml residual or lymph-node with an activity of 1 kBq hidden under a layer of 10 mm of PMMA with a 3:1 signal to noise, i.e. with a five sigma discrimination in less than 5 s

Speciation of different forms of Se in bovine blood by enzymatic extraction and HPLC/Photo-Reduction/HG-ICP-OES.

Selenium is essential for the vital functions of the human and animal organism, such as growth, reproduction, prevention, and the protection of its muscular integrity. Although this dependence is well characterized, aspects related to selenium speciation still need to be studied further. This work describes the development of an alternative method for selenium speciation in bovine blood samples using a hyphenated analytical system (HPLC-UV-HG-ICP-OES). The influence of the main parameters related to the detection of Se species, such as separation efficiency, photo-reduction and hydride generation, were studied. Enzymatic reaction with proteinase-K (1 day at 37ºC) was employed for sample preparation. An on-line UV reduction system was adopted to convert the different species of Se to Se(IV). For the chromatographic system, equipped with an anionic exchange column, a phosphate-buffer of 40 mmol L-1 in the pH of 6.0 was used as the mobile phase (flow rate of 1 mL min-1 ) for separation of the different Se species. To increase the sensitivity, hydride generation was used, followed by inductively coupled plasma optical emission spectrometry (ICP-OES) analysis. The developed method for Se speciation in bovine blood samples was performed completely on-line. The limits of detection (LODs) were 9.5, 7.2, 5.8, 3.1, 4.4 ?g L-1 and the limits of quantification (LOQs) were 31.4, 23.9, 20.1, 10.5, and 14.5 ?g L-1 for selenomethylselenocysteine, seleno-DL-methionine, Se(IV), and Se(VI), respectively. The recoveries obtained were 96% for Se(IV), 98% for Se(VI), 91% for selenocystamine, 89% for seleno-cysteine, and 84% for seleno-methionine

Antioxidant and Anti-Inflammatory Profiles of Spent Coffee Ground Extracts for the Treatment of Neurodegeneration

Spent coffee grounds (SCGs), waste products of coffee beverage production, are rich in organic compounds such as phenols. Different studies have demonstrated phenol beneficial effects in counteracting neurodegenerative diseases. These diseases are associated with oxidative stress and neuroinflammation, which initiates the degeneration of neurons by overactivating microglia. Unfortunately, to date, there are no pharmacological therapies to treat these pathologies. The aim of this study was to evaluate the phenolic content of 4 different SCG extracts and their ability to counteract oxidative stress and neuroinflammation. Caffeine and 5-O-caffeoylquinic acid were the most abundant compounds in all extracts, followed by 3-O-caffeoylquinic acid and 3,5-O-dicaffeoylquinic acid. The four extracts demonstrated a different ability to counteract oxidative stress and neuroinflammation in vitro. In particular, the methanol extract was the most effective in protecting neuron-like SH-SY5Y cells against H2O2-induced oxidative stress by upregulating endogenous antioxidant enzymes such as thioredoxin reductase, heme oxygenase 1, NADPH quinone oxidoreductase, and glutathione reductase. The water extract was the most effective in counteracting lipopolysaccharide-induced neuroinflammation in microglial BV-2 cells by strongly reducing the expression of proinflammatory mediators through the modulation of the TLR4/NF-kappa B pathway. On these bases, SCG extracts could represent valuable nutraceutical sources for the treatment of neurodegeneratio

Analysis of dynamic wireless power transfer systems based on behavioral modeling of mutual inductance

This paper proposes a system-level approach suitable to analyze the performance of a dynamic Wireless Power Transfer System (WPTS) for electric vehicles, accounting for the uncertainty in the vehicle trajectory. The key-point of the approach is the use of an analytical behavioral model that relates mutual inductance between the coil pair to their relative positions along the actual vehicle trajectory. The behavioral model is derived from a limited training data set of simulations, by using a multi-objective genetic programming algorithm, and is validated against experimental data, taken from a real dynamic WPTS. This approach avoids the massive use of computationally expensive 3D finite element simulations, that would be required if this analysis were performed by means of look-up tables. This analytical model is here embedded into a system-level circuital model of the entire WPTS, thus allowing a fast and accurate analysis of the sensitivity of the performance as the actual vehicle trajectory deviates from the nominal one. The system-level analysis is eventually performed to assess the sensitivity of the power and efficiency of the WPTS to the vehicle misalignment from the nominal trajectory during the dynamic charging process