Studio NMR di molecole biologicamente attive nell'olio di oliva

Il crescente interesse a livello chimico e biochimico verso i composti biofenolici minori polari degli oli di oliva ci ha indotto alla applicazione di moderne tecniche NMR come la DOSY (Diffusion Ordered Spectroscopy). L'utilizzo di specifiche sequenze NMR con gradienti consente di determinare il coefficiente di diffusione delle molecole in soluzione. Recentemente queste sequenze sono state applicate allo scopo di separare le componenti di miscele che si differenziano per la diversa velocità  di diffusione

Studio 13-C NMR di oli essenziali di <i>Helicrysum Italicum</i> sub. <i>Microphyllum</i>

In questo lavoro mostriamo l'assegnazione dei componenti maggiori dell'olio essenziale di Elicriso provenienti da varie zone della Sardegna. Per l'esatta determinazione di alcuni componenti si è resa necessaria una separazione cromatografica

Bag of Peaks

Abstract Motivation: The analysis of high-resolution proton nuclear magnetic resonance (NMR) spectrometry can assist human experts to implicate metabolites expressed by diseased biofluids. Here, we explore an intermediate representation, between spectral trace and classifier, able to furnish a communicative interface between expert and machine. This representation permits equivalent, or better, classification accuracies than either principal component analysis (PCA) or multi-dimensional scaling (MDS). In the training phase, the peaks in each trace are detected and clustered in order to compile a common dictionary, which could be visualized and adjusted by an expert. The dictionary is used to characterize each trace with a fixed-length feature vector, termed Bag of Peaks, ready to be classified with classical supervised methods. Results: Our small-scale study, concerning Type I diabetes in Sardinian children, provides a preliminary indication of the effectiveness of the Bag of Peaks approach over standard PCA and MDS. Consistently, higher classification accuracies are obtained once a sufficient number of peaks (&gt;10) are included in the dictionary. A large-scale simulation of noisy spectra further confirms this advantage. Finally, suggestions for metabolite-peak loci that may be implicated in the disease are obtained by applying standard feature selection techniques. Availability: Matlab code to compute the Bag of Peaks representation may be found at http://economia.uniss.it/docenti/bicego/BagOfPeaks/BagOfPeaks.zip Contact: [email protected]

Applicazione dell'MRI ai prodotti agroalimentari: analisi del profilo dell'acqua durante la conservazione

In questo lavoro, un modello di diffusione basato su legge del Fick secondo è stato usato per simulare il trasporto dell'acqua in pere in varie condizioni (20° C e RH di 75%; 1°C e RH di 60%). Il metodo degli elementi finiti è stato usato per la definizione delle equazioni differenziali che modellano il comportamento dell’acqua applicato alla geometria 3D della pera. Per la prima volta, il trasporto dell'acqua nella pera di cultivar Conference è stato descritto al livello della mesoscala incorporando i differenti tessuti ( corteccia, interna ed esterna, e cuticola) con differenti proprietà di diffusione

Functionalization of Screen-Printed Sensors with a High Reactivity Carbonaceous Material for Ascorbic Acid Detection in Fresh-Cut Fruit with Low Vitamin C Content

In this study, carbon screen-printed sensors (C-SPEs) were functionalized with a high reactivity carbonaceous material (HRCM) to measure the ascorbic acid (AA) concentration in fresh-cut fruit (i.e., watermelon and apple) with a low content of vitamin C. HRCM and the functionalized working electrodes (WEs) were characterized by SEM and TEM. The increases in the electroactive area and in the diffusion of AA molecules towards the WE surface were evaluated by cyclic voltammetry (CV) and chronoamperometry. The performance of HRCM-SPEs were evaluated by CV and constant potential amperometry compared with the non-functionalized C-SPEs and MW-SPEs nanostructured with multi-walled carbon nanotubes. The results indicated that SPEs functionalized with 5 mg/mL of HRCM and 10 mg/mL of MWCNTs had the best performances. HRCM and MWCNTs increased the electroactive area by 1.2 and 1.4 times, respectively, whereas, after functionalization, the AA diffusion rate towards the electrode surface increased by an order of 10. The calibration slopes of HRCM and MWCNTs improved from 1.9 to 3.7 times, thus reducing the LOD of C-SPE from 0.55 to 0.15 and 0.28 μM, respectively. Finally, the functionalization of the SPEs proved to be indispensable for determining the AA concentration in the watermelon and apple samples

Mycophenolate Mofetil Versus Cyclophosphamide for Remission Induction in Childhood Polyarteritis Nodosa: An Open‐Label, Randomized, Bayesian Noninferiority Trial

Funder: Lauren Currie Twilight FoundationFunder: Great Ormond Street Hospital Charity; Id: http://dx.doi.org/10.13039/501100001279Funder: Vasculitis UK; Id: http://dx.doi.org/10.13039/100010876Objective: Cyclophosphamide (CYC) is used in clinical practice off‐label for the induction of remission in childhood polyarteritis nodosa (PAN). Mycophenolate mofetil (MMF) might offer a less toxic alternative. This study was undertaken to explore the relative effectiveness of CYC and MMF treatment in a randomized controlled trial (RCT). Methods: This was an international, open‐label, Bayesian RCT to investigate the relative effectiveness of CYC and MMF for remission induction in childhood PAN. Eleven patients with newly diagnosed childhood PAN were randomized (1:1) to receive MMF or intravenous CYC; all patients received the same glucocorticoid regimen. The primary end point was remission within 6 months while compliant with glucocorticoid taper. Bayesian distributions for remission rates were established a priori for MMF and CYC by experienced clinicians and updated to posterior distributions on trial completion. Results: Baseline disease activity and features were similar between the 2 treatment groups. The primary end point was met in 4 of 6 patients (67%) in the MMF group and 4 of 5 patients (80%) in the CYC group. Time to remission was shorter in the MMF group compared to the CYC group (median 7.1 weeks versus 17.6 weeks). No relapses occurred in either group within 18 months. Two serious infections were found to be likely linked to MMF treatment. Physical and psychosocial quality‐of‐life scores were superior in the MMF group compared to the CYC group at 6 months and 18 months. Combining the prior expert opinion with results from the present study provided posterior estimates of remission of 71% for MMF (90% credibility interval [90% CrI] 51, 83) and 75% for CYC (90% CrI 57, 86). Conclusion: The present results, taken together with prior opinion, indicate that rates of remission induction in childhood PAN are similar with MMF treatment and CYC treatment, and MMF treatment might be associated with better health‐related quality of life than CYC treatment

A Concise highly enantioselective cascade synthesis of indolizidine alkaloids with a quaternary stereocenter

Enantiomerically pure indolizidinones bearing a quaternary stereocenter were obtained by Rh(II)-catalyzed decomposition of α-diazo ketodiesters through a carbenoid/spiro[5,5]ammonium ylide/Stevens [1,2]-shift with a ring-expansion cascade process. The isolation of stable chiral ammonium ylides, namely the key intermediates of the process, unambiguously confirmed the stereochemistryof the total process

Chemical Composition of Myrtle (Myrtus communis L.) Berries Essential Oils as Observed in a Collection of Genotypes

Myrtle (Myrtus communis L.) is a shrub spontaneously growing in the Mediterranean area. The leaf and fruit content of essential oils and phenolic compounds justify the wide use of the plant as medicinal and aromatic. Because of overexploitation of wild plants, a domestication process is in progress in different regions and the influence of the genotype variability on the chemical composition of fruit essential oils may be useful to breeding programs. Consequently, the analysis performed on a selected group of candidate clones growing in the same field collection in Sardinia is the object of this report. Forty-seven selections provided fully ripe fruits for essential oil extraction by hydrodistillation and Gas Chromatography-Mass Spectrometry (GC-MS) analysis. Only five candidate clones showed white fruits. The highest yield of essential oil was observed in the LAC31 genotype with 0.55 g&middot;kg&minus;1, while the samples BOS1, MON5, RUM4, RUM10, V4 and V8 showed values above 0.20 g&middot;kg&minus;1 and most of the genotypes under 0.10 g&middot;kg&minus;1. Geranyl acetate was the compound with the highest relative abundance. The second compound for relative abundance was the 1,8-cineole. Other compounds with high relative abundance were &alpha;-terpinyl acetate, methyleugenol, linalool, &alpha;-terpineol, &beta;-caryophyllene, &alpha;-humulene, Trans-caryophyllene oxide, and humulene epoxide II

Bag of Peaks: interpretation of NMR spectrometry

Motivation: The analysis of high-resolution proton nuclear magnetic resonance (NMR) spectrometry can assist human experts to implicate metabolites expressed by diseased biofluids. Here, we explore an intermediate representation, between spectral trace and classifier, able to furnish a communicative interface between expert and machine. This representation permits equivalent, or better, classification accuracies than either principal component analysis (PCA) or multi-dimensional scaling (MDS). In the training phase, the peaks in each trace are detected and clustered in order to compile a common dictionary, which could be visualized and adjusted by an expert. The dictionary is used to characterize each trace with a fixedlength feature vector, termed Bag of Peaks, ready to be classified with classical supervised methods. Results: Our small-scale study, concerning Type I diabetes in Sardinian children, provides a preliminary indication of the effectiveness of the Bag of Peaks approach over standard PCA and MDS. Consistently, higher classification accuracies are obtained once a sufficient number of peaks (>10) are included in the dictionary. A large-scale simulation of noisy spectra further confirms this advantage. Finally, suggestions for metabolite-peak loci that may be implicated in the disease are obtained by applying standard feature selection techniques

NMR investigations for a quality assessment of Italian PDO saffron (<i>Crocus sativus</i> L.)

High-resolution NMR spectroscopy was employed to analyze Italian Protected Designation of Origin (PDO) saffron from L'Aquila, S. Gimignano and Sardinia and commercial saffron samples available on the Italian market. An extensive resonance assignment of DMSO saffron extract was reported, including glucose and gentiobiose in bound and unbound form for the first time. A multivariate statistical analysis of NMR data led to a clustering of samples by performing unsupervised PCA. OPLS-DA model was successively performed to highlight the markers responsible for this discrimination. An analysis of the corresponding S-plot indicated that picrocrocin and crocins were the most relevant compounds for characterizing Italian PDO saffron. By contrast, commercial saffron barely contained these characteristic compounds, and they were primarily enriched in fatty acids