357 research outputs found

    Radiation and magnetic field effects on new semiconductor power devices for HL-LHC experiments

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    The radiation hardness of commercial Silicon Carbide and Gallium Nitride power MOSFETs is presented in this paper, for Total Ionizing Dose effects and Single Event Effects, under gamma, neutrons, protons and heavy ions. Similar tests are discussed for commercial DC-DC converters, also tested in operation under magnetic field

    Surface Periodic Poling in Lithium Niobate and Lithium Tantalate

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    Periodic Poling of Lithium Niobate crystals (PPLN) by means of electric field has revealed the best technique for finely tailoring PPLN structures and parameters, which play a central role in many current researches in the field of nonlinear integrated optics. Besides the most studied technique of bulk poling, recently a novel technique where domain inversion occurs just in a surface layer using photoresist or silica masks has been devised and studied. This surface periodic poling (SPP) approach is best suited when light is confined in a thin surface guiding layer or stripe, as in the case of optical waveguide devices. Also, we found that SPP respect to bulk poling offers two orders of magnitude reduction on the scale of periodicity, so that even nanostructures can be obtained provided an high resolution holographic mask writing technique is adopted. We were able to demonstrate 200 nm domain size, and also good compatibility with alpha-phase proton exchange channel waveguide fabrication. Our first experiments on Lithium Tantalate have also shown that the SPP technology appears to be applicable to this crystal (SPPLT), whose properties can allow to overcome limitations such as optical damage or UV absorption still present in PPLN devices. Finally, the issue of SPP compatibility with proton exchange waveguide fabrication will be addresse

    A methodology for assessing the impact of salinity gradient power generation in urban contexts

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    The paper proposes a methodology to assess the potential impact of salinity gradient power technology in urban contexts. The idea to employ such energy source in urban contexts derives from the observation that, among the energy districts outputs, low-salinity treated wastewater can be used to produce electricity if a suitable source of high salinity feed (seawater of a salt-works) is also available. The methodology uses the HOMER software for assessing the district’s electric energy production, consumption and exchange with the main grid. Then, starting from the total gross surface and the number of inhabitants of the district, some possible realistic scenarios characterized by different wastewater flow rate are defined. Finally, for each scenario the size and the yearly energy production of the salinity gradient power system are calculated thanks to a simulator carried out by the same authors. An application example, considering three different scenarios, shows that urban density plays a crucial role in the process and that the most promising realistic scenarios are those including treated wastewater and brine and unlimited seawater and brine. The economic feasibility of the salinity gradient power technology is evaluated by a comparison with classical renewable technologies such as photovoltaic and wind systems

    Next-Generation Probiotics for Inflammatory Bowel Disease

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    Engineered probiotics represent a cutting-edge therapy in intestinal inflammatory disease (IBD). Genetically modified bacteria have provided a new strategy to release therapeutically operative molecules in the intestine and have grown into promising new therapies for IBD. Current IBD treatments, such as corticosteroids and immunosuppressants, are associated with relevant side effects and a significant proportion of patients are dependent on these therapies, thus exposing them to the risk of relevant long-term side effects. Discovering new and effective therapeutic strategies is a worldwide goal in this research field and engineered probiotics could potentially provide a viable solution. This review aims at describing the proceeding of bacterial engineering and how genetically modified probiotics may represent a promising new biotechnological approach in IBD treatment

    A new hexapeptide from the leader peptide of rMnSOD enters cells through the oestrogen receptor to deliver therapeutic molecules

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    A 24-amino acid leader peptide of a new human recombinant manganese superoxide dismutase can enter cells and carry molecules. Here, we demonstrated that six of the 24 amino acids penetrate cells through a particular gate represented by a specific amino acid sequence of the oestrogen receptor (ER). We analysed the internalization of the synthetic hexapeptide and the cytotoxic activity of the hexapeptide conjugated to cisplatin on a cell line panel. In most cell lines, the hexapeptide delivered an amount of cisplatin that was 2 to 8 times greater than that released by cisplatin when the drug was used alone. This increased delivery increases the therapeutic index of cisplatin and reduces side effects caused by a high dosage or long-term treatment times. We may consider this hexapeptide a new molecular carrier to deliver molecules with therapeutic activity into ER+ cells for diagnostic purposes and clinical or immune therapy

    Dietary treatment of urinary risk factors for renal stone formation. A review of CLU Working Group

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    OBJECTIVE: Diet interventions may reduce the risk of urinary stone formation and its recurrence, but there is no conclusive consensus in the literature regarding the effectiveness of dietary interventions and recommendations about specific diets for patients with urinary calculi. The aim of this study was to review the studies reporting the effects of different dietary interventions for the modification of urinary risk factors in patients with urinary stone disease. MATERIALS AND METHODS: A systematic search of the Pubmed database literature up to July 1, 2014 for studies on dietary treatment of urinary risk factors for urinary stone formation was conducted according to a methodology developed a priori. Studies were screened by titles and abstracts for eligibility. Data were extracted using a standardized form and the quality of evidence was assessed. RESULTS: Evidence from the selected studies were used to form evidence-based guideline statements. In the absence of sufficient evidence, additional statements were developed as expert opinions. CONCLUSIONS: General measures: Each patient with nephrolithiasis should undertake appropriate evaluation according to the knowledge of the calculus composition. Regardless of the underlying cause of the stone disease, a mainstay of conservative management is the forced increase in fluid intake to achieve a daily urine output of 2 liters. HYPERCALCIURIA: Dietary calcium restriction is not recommended for stone formers with nephrolithiasis. Diets with a calcium content 65 1 g/day (and low protein-low sodium) could be protective against the risk of stone formation in hypercalciuric stone forming adults. Moderate dietary salt restriction is useful in limiting urinary calcium excretion and thus may be helpful for primary and secondary prevention of nephrolithiasis. A low-normal protein intake decrease calciuria and could be useful in stone prevention and preservation of bone mass. Omega-3 fatty acids and bran of different origin decreases calciuria, but their impact on the urinary stone risk profile is uncertain. Sports beverage do not affect the urinary stone risk profile. HYPEROXALURIA: A diet low in oxalate and/or a calcium intake normal to high (800-1200 mg/day for adults) reduce the urinary excretion of oxalate, conversely a diet rich in oxalates and/or a diet low in calcium increase urinary oxalate. A restriction in protein intake may reduce the urinary excretion of oxalate although a vegetarian diet may lead to an increase in urinary oxalate. Adding bran to a diet low in oxalate cancels its effect of reducing urinary oxalate. Conversely, the addition of supplements of fruit and vegetables to a mixed diet does not involve an increased excretion of oxalate in the urine. The intake of pyridoxine reduces the excretion of oxalate. HYPERURICOSURIA: In patients with renal calcium stones the decrease of the urinary excretion of uric acid after restriction of dietary protein and purine is suggested although not clearly demonstrated. HYPOCITRATURIA: The administration of alkaline-citrates salts is recommended for the medical treatment of renal stone-formers with hypocitraturia, although compliance to this treatment is limited by gastrointestinal side effects and costs. Increased intake of fruit and vegetables (excluding those with high oxalate content) increases citrate excretion and involves a significant protection against the risk of stone formation. Citrus (lemons, oranges, grapefruit, and lime) and non citrus fruits (melon) are natural sources of dietary citrate, and several studies have shown the potential of these fruits and/or their juices in raising urine citrate levels. CHILDREN: There are enought basis to advice an adequate fluid intake also in children. Moderate dietary salt restriction and implementation of potassium intake are useful in limiting urinary calcium excretion whereas dietary calcium restriction is not recommended for children with nephrolithiasis. It seems reasonable to advice a balanced consumption of fruit and vegetables and a low consumption of chocolate and cola according to general nutritional guidelines, although no studies have assessed in pediatric stone formers the effect of fruit and vegetables supplementation on urinary citrate and the effects of chocolate and cola restriction on urinary oxalate in pediatric stone formers. Despite the low level of scientific evidence, a low-protein ( 3 liters/day) is strongly advised in children with cystinuria. ELDERLY: In older patients dietary counseling for renal stone prevention has to consider some particular aspects of aging. A restriction of sodium intake in association with a higher intake of potassium, magnesium and citrate is advisable in order to reduce urinary risk factors for stone formation but also to prevent the loss of bone mass and the incidence of hypertension, although more hemodynamic sensitivity to sodium intake and decreased renal function of the elderly have to be considered. A diet rich in calcium (1200 mg/day) is useful to maintain skeletal wellness and to prevent kidney stones although an higher supplementation could involve an increase of risk for both the formation of kidney stones and cardiovascular diseases. A lower content of animal protein in association to an higher intake of plant products decrease the acid load and the excretion of uric acid has no particular contraindications in the elderly patients, although overall nutritional status has to be preserved

    Influence of LV Neutral Grounding on Global Earthing Systems

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    International Standards define a Global Earthing System as an earthing net created interconnecting local Earthing Systems (generally through the shield of MV cables and/or bare buried conductors). In Italy the Regulatory Authority for Electricity and Gas requires Distributors to guarantee the electrical continuity of LV neutral conductor. This requirement has led to the standard practice of realizing “reinforcement groundings” along the LV neutral conductor path and at users’ delivery cabinet. Moreover, in urban high load scenarios (prime candidates to be part of a Global Earthing System), it is common that LV distribution scheme creates, trough neutral conductors, an effective connection between grounding systems of MV/LV substations, modifying Global Earthing System consistency. Aim of this paper is to evaluate the effect, in terms of electrical safety, of the above mentioned LV neutral distribution scheme when an MV-side fault to ground occurs. At this purpose simulations are carried out on a realistic urban test case and suitable evaluation indexes are proposed
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