253 research outputs found

    Wavelet-Fourier CORSING techniques for multi-dimensional advection-diffusion-reaction equations

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    We present and analyze a novel wavelet-Fourier technique for the numerical treatment of multidimensional advection-diffusion-reaction equations based on the CORSING (COmpRessed SolvING) paradigm. Combining the Petrov-Galerkin technique with the compressed sensing approach, the proposed method is able to approximate the largest coefficients of the solution with respect to a biorthogonal wavelet basis. Namely, we assemble a compressed discretization based on randomized subsampling of the Fourier test space and we employ sparse recovery techniques to approximate the solution to the PDE. In this paper, we provide the first rigorous recovery error bounds and effective recipes for the implementation of the CORSING technique in the multi-dimensional setting. Our theoretical analysis relies on new estimates for the local a-coherence, which measures interferences between wavelet and Fourier basis functions with respect to the metric induced by the PDE operator. The stability and robustness of the proposed scheme is shown by numerical illustrations in the one-, two-, and three-dimensional case

    Can Infant Dyschezia Be a Suspect of Rectosigmoid Redundancy?

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    Infant dyschezia is a functional gastrointestinal disorder that occurs in children less than nine months of age. This disorder causes much anxiety among parents who consult different physicians when suspecting major intestinal problems. The aim of this study is to verify whether infant dyschezia involves an anatomic abnormality (redundancy) of the colon. In this retrospective study (48 months) we analyzed all the children younger than 9 months who came to our attention through the suspicion of gastrointestinal abnormality (Hirschsprung’s disease, anorectal malformations, colonic disorders or constipation). They all had a complete medical history, clinical examination and diagnostic tests, such as blood samples, suction rectal biopsy, a study of stool characteristics and, finally, a contrast enema. In cases with infant dyschezia, different colonic sizes and rectosigmoid length were measured, which created a ratio with the diameter of the second lumbar vertebra. These values were compared with those reported in the literature as normal for the age of one year. Of the 24 patients evaluated (mean age 4 months), 9 were excluded for different diagnoses (aganglionic megacolon, hypothyroidism, constipation). The comparison of the ratios obtained in the remaining 15 cases showed a significantly higher rectosigmoid length (redundancy) in children with dyschezia, 18.47 vs. 9.75 (p < 0.001). The rectosigmoid redundancy, a congenital anomaly already reported as a cause of refractory constipation, may be present in children with infant dyschezia

    What Is the Correct Way to Manage Children Requiring Gastrostomy? Single Center Experience

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    Children with complex medical issues often present different comorbidities that cause feeding difficulties. Gastrostomy is often helpful, and should be performed when nutritional supplementation is necessary for longer than 6 weeks. Recently, different techniques have been used for gastrostomy in children. The authors report on their experiences regarding the diagnostic and therapeutic management of children requiring gastrostomy. All patients managed in the last 10 years were reviewed, retrospectively. Everyone underwent investigation to exclude gastroesophageal reflux disease (GERD). A total of 148 patients: 111 cases (75%) were neurologically impaired patients, 18 (12%) had complex heart disease, 10 (6%) had metabolic diseases, 4 (3%) had fibrosis cystic, 4 (3%) had muscle disease, and one had chromosomopathy. After investigation, 49 patients had GERD. PEG was performed in 101 cases (68%), laparo-assisted gastrostomy was performed in 44 cases (29.7%), open gastrostomy was performed in three cases. At follow-up, all patients reported weight gain, but 13 cases had major complications. Currently, the surgeon has the possibility of choosing between several safe techniques for gastrostomy. In our experience, PEG is the most useful technique for patients without GERD, while a laparo-assisted technique is better for patients who require laparoscopic fundoplicatio

    Control Strategy Influence on the Efficiency of a Hybrid Photovoltaic-Battery-Fuel Cell System Distributed Generation System for Domestic Applications☆

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    AbstractThe full exploitation of locally available renewable resources together with the reduction of system installation and management costs are key issues of diffused Distributed Generation (DG). In the given context, hybrid systems are already at an advanced stage of development which typically integrate several sub-systems. In such hybrid systems, Renewable Energy Sources generation systems (e.g. photovoltaic panels) are coupled to energy storage devices (electric batteries) and with programmable generators (a diesel generator or, more recently, with a sub-system based on fuel cells) allowing stable operations under a wide range of conditions. In this paper a solution which uses hydrogen and fuel cells as a programmable source is presented and is studied by means of a mixed experimental and numerical: a Hardware-In-Loop test bench designed and realized at the Department lab, able to reproduce the behavior of a hybrid system for domestic applications. The system is controlled by means of a rule-based control strategy acting on the common DC-bus whose optimization has a significant influence both on system design and on its overall system energy performances. Results show that Rule-Based strategy have a great potential towards cost reduction and components lifetime increase, while energy efficiency mainly depends on correct system sizing

    Lentil fortified spaghetti: Technological properties and nutritional characterization

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    Lentil (Lens culinaris), consumed as a part of the diet worldwide, is a functional dietary ingredient that plays a function in human nutrition as a rich source of bioactive nutrients (low quantities of fat, sodium, and vitamin K; high content of potassium, essential amino acids, insoluble dietary fiber, and polyphenols). In this study spaghetti fortified with lentil flours (40% w/w) were developed and characterized. The addition of two different lentil flours significantly affected the sensory attributes and cooking properties of dry spaghetti. Therefore, the addition of carboxymethyl cellulose was adopted as technological option to improve the quality of fortified pasta; specifically, sensory acceptability, cooking loss, swelling index, and water absorption were studied. Chemical results highlighted that the addition of lentil to semolina significantly increased the content of lysine and threonine. It was observed an increase in essential and branched-chain amino acids. Contrary to what was expected, no increase in mono and polyunsaturated fatty acids was observed in fortified spaghetti, due to their loss during cooking, even after the addition of carboxymethyl cellulose

    Advantages of GPU-accelerated approach for solving the Parker equation in the heliosphere

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    The increasing of experimental observations' accuracy and model complexity requires the development of a new class of numerical solvers. In this work, we present a GPU-accelerated approach for solving the Parker equation in the heliosphere using a stochastic differential equation (SDE) approach. The presented method was applied to a generic system of SDE using the CUDA programming language. Our approach achieves significant speedup compared to a CPU implementation, allowing us to efficiently solve for the modulated spectra of charged particles in the heliosphere. We demonstrate the accuracy and efficiency of our method through numerical experiments on a realistic model of the heliosphere

    Control of colloidal CaCO3 suspension by using biodegradable polymers during fabrication

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    Fabrication of homogenous CaCO3 particles is a significant step in assembling polyelectrolyte capsules. It is crucial to control the dimensions, the shape and the charge of the calcium carbonate particles in order to have homogenously separated and charged templates as final result. For this reason, previously. hey have been deeply investigated. Recently, crystallization of CaCO3 was done by adding poly (sodium 4-styrenesulfonate) (PSS) as negatively charged polymer and poly (allylamine hydrochloride) (PAH) as positively charged polymer and the results were surprising. The homogenous particles were separated and they carried the same charge of the used polymer. The aim of this work was to investigate the synthesis process of CaCO3 particles in different experimental conditions: calcium carbonate was produced in presence and in absence of water and with addition of appropriate polymers. In particular, chitosan (CHI) and poly acrylic acid (PAA) were chosen as biodegradable polymers whereas PSS and PAH were chosen as non-biodegradable polymers. Shape and diameter of particles were investigated by using transmission and scanning electron microscopy, elemental composition was inferred by energy dispersive X-ray analyses whereas their charges were explored by using zeta potential

    Rifaximin improves Clostridium difficile toxin A-induced toxicity in Caco-2 cells by the PXR-dependent TLR4/MyD88 /NF-?B pathway

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    Background: Clostridium difficile infections (CDIs) caused by Clostridium difficile toxin A (TcdA) lead to severe ulceration, inflammation and bleeding of the colon, and are difficult to treat. Aim: The study aimed to evaluate the effect of rifaximin on TcdA-induced apoptosis in intestinal epithelial cells and investigate the role of PXR in its mechanism of action. Methods: Caco‐2 cells were incubated with TcdA and treated with rifaximin (0.1−10 ÎŒM) with or without ketoconazole (10 ÎŒM). The transepithelial electrical resistance (TEER) and viability of the treated cells was determined. Also, the expression of zona occludens‐1 (ZO‐1), toll‐like receptor 4 (TLR4), Bcl‐2‐associated X protein (Bax), transforming growth factor‐ÎČ‐activated kinase‐1 (TAK1), myeloid differentiation factor 88 (MyD88) and nuclear factor‐kappaB (NF‐ÎșB) was determined. Results Rifaximin treatment (0.1, 1.0 and 10 ÎŒM) caused a significant and concentration-dependent increase in the TEER of Caco-2 cells (360%, 480% and 680% vs TcdA treatment) 24 hours after the treatment and improved their viability (61%, 79% and 105%). Treatment also concentration-dependently decreased the expression of Bax protein (–29%, –65% and –77%) and increased the expression of ZO-1 (25%, 54% and 87%) and occludin (71%, 114% and 262%) versus TcdA treatment. The expression of TLR4 (–33%, –50% and –75%), MyD88 (–29%, –60% and –81%) and TAK1 (–37%, –63% and –79%) were also reduced with rifaximin versus TcdA treatment. Ketoconazole treatment inhibited these effects. Conclusions: Rifaximin improved TcdA‐induced toxicity in Caco‐2 cells by the PXR‐dependent TLR4/MyD88/NF‐ÎșB pathway mechanism, and may be useful in the treatment of CDIs

    Effects of Cultivar and Process Variables on Dynamic-Mechanical and Sensorial Behavior of Value-Added Grape-Based Smoothies

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    The effects of either cooking temperature (45, 80, and 100 °C) or inclusion of seed particles on the dynamic-mechanical and sensorial properties of value-added Crimson seedless, Black Pearl, or Baresana grape-based smoothies were studied. The inclusion of seed particles resulted in significant increases of the phenolic content, both in Black Pearl and Baresana, but it did not affect in a negative way the sensorial characteristics of smoothies whereas it caused an increase of the viscoelastic behavior of Black Pearl and a slight decrease in Baresana grape-based smoothies. In particular, the investigated rheological parameters were the loss and storage modulus. Moreover, the loss tangent value (the ratio between loss and storage modulus) remained unchanged, indicating a pseudoplastic behavior of all samples, independent on the process conditions. The smoothies produced from Crimson grapes at the intermediate temperature (80 °C) showed sensorial and rheological characteristics similar to those manufactured at 45 °C and better than those manufactured at 100 °C
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