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This work investigates the relationship between the structure and physicochemical properties of three different starches in starch/polyvinyl alcohol aqueous solutions. For this purpose, accurate nuclear magnetic resonance (NMR) analyses were performed to determine the role that the starch structure plays in the formation of binder solutions. Moreover, a dynamic shear rheometer (DSR) was used to investigate the mechanical properties of the solutions and correlate them with the structure of each starch. Complete characterization of the analysed starches and the starch/PVOH solutions was also carried out through light scattering measurements. Furthermore, by crossing the data coming from NMR and light scattering with those coming from rheology, the best solution was identified. Finally, to confirm the interaction mechanism between starch and PVOH, thermogravimetric analysis and an NMR study, using 1H and 13C NMR spectra, were carried out on the film obtained from the best solution. The analyses carried out showed that PVOH has a stabilizing effect on starch/PVOH solutions, and the starch with the greatest branching degree is the one that forms a more structured network.
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In recent years, the food industry has become increasingly involved in researching vegetable fats and oils with appropriate mechanical properties (ease of transport, processing, and storage) and a specific lipidic composition to ensure healthy products for consumers. The chemical-physical behavior of these matrices depends on their composition in terms of single fatty acids (FA). However, as we demonstrate in this work, these properties, as well as the absorption, digestion and uptake in humans of specific FAs, are also largely determined by their regiosomerism within the TriAcylGlycerols (TAG) moieties (sn-1,2,3 positions). The goal of this work is to study for the first time vegetable fats obtained directly from a sample of natural cocoa butter (CB) through a process that manipulates the distribution of FAs but not their nature. Even if the initial percentage of each FA in the mixture remains the same, CB derivatives seem to show improved chemical-physical features. In order to understand which factors account for their physical and chemical characteristics, and to check whether or not the obtained new matrices could be considered as valid alternatives to other vegetable fats (e.g., palm oil (PO)), we carried out an experimental investigation at both the macroscopic and molecular level including: (i) Differential Scanning Calorimetry (DSC) analyses to examine thermal features; (ii) rheological testing to explore mechanical properties; (iii) powder X-ray diffraction (PXRD) to evaluate the solid-state phases of the obtained fats; and (iv) 1H and 13C Nuclear Magnetic Resonance (NMR, 1D and 2D) spectroscopy to rapidly analyze fatty acid composition including regioisomeric distribution on the glycerol backbone. These last results open up the possibility of using NMR spectroscopy as an alternative to the chromatographic techniques routinely employed for the investigation of similar matrices.
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Grasas de la Dieta , Ácidos Grasos , Humanos , Triglicéridos/química , Rayos X , Rastreo Diferencial de Calorimetría , Grasas de la Dieta/análisis , Ácidos Grasos/química , Grasas , Espectroscopía de Resonancia MagnéticaRESUMEN
In this work, a sample of pure and certified bergamot essential oil (BEO) was extensively studied for the first time directly by NMR spectroscopy with the aim of investigating its metabolic composition, quantifying the main components of this complex natural matrix and simultaneously assessing whether the NMR technique is able to highlight possible frauds to which this high-cost product may be subjected. Eleven low molecular weight compounds have been identified by using 1D 1H and 13C-{1H} NMR experiments, 2D homo- and heteronuclear correlation NMR spectra, and 2D 1H DOSY experiments; the most abundant of them, i.e., about 90% of the sample analyzed, has been quantified by employing benzoic acid as an internal standard by 1H NMR spectrum. Moreover, since the commercial fraud of this precious oil is often due to the addition of less expensive oils, we have simulated a possible adulteration through the preparation of BEO samples to which different percentages of orange essential oil (OEO) were added. The results, obtained by combining the 1H NMR spectra collected on the adulterated samples and on pure BEO, with chemometric analysis, principal component analysis (PCA), indicate that it is possible to distinguish the sample of pure BEO from the adulterated ones and also, among them, to differentiate between the degrees of adulteration.
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Aceites Volátiles , Contaminación de Medicamentos , Contaminación de Alimentos/análisis , Imagen por Resonancia Magnética , Espectroscopía de Resonancia Magnética/métodos , Aceites Volátiles/análisis , Aceites de Plantas/química , Análisis de Componente PrincipalRESUMEN
Cannabis sativa is a herbaceous multiple-use species commonly employed to produce fiber, oil, and medicine. It is now becoming popular for the high nutritional properties of its seed oil and for the pharmacological activity of its cannabinoid fraction in inflorescences. The present study aims to apply nuclear magnetic resonance (NMR) spectroscopy to provide useful qualitative and quantitative information on the chemical composition of seed and flower Cannabis extracts obtained by ultra-sound-assisted extraction, and to evaluate NMR as an alternative to the official procedure for the quantification of cannabinoids. The estimation of the optimal ω-6/ω-3 ratio from the 1H NMR spectrum for the seed extracts of the Futura 75 variety and the quantitative results from the 1H and 13C NMR spectra for the inflorescence extracts of the Tiborszallasi and Kompolti varieties demonstrate that NMR technology represents a good alternative to classical chromatography, supplying sufficiently precise, sensitive, rapid, and informative data without any sample pre-treatment. In addition, different extraction procedures were tested and evaluated to compare the elaboration of spectral data with the principal component analysis (PCA) statistical method and the quantitative NMR results: the extracts obtained with higher polarity solvents (acetone or ethanol) were poor in psychotropic agents (THC < LOD) but had an appreciable percentage of both cannabinoids and triacylgliceroles (TAGs). These bioactive-rich extracts could be used in the food and pharmaceutical industries, opening new pathways for the production of functional foods and supplements.
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Cannabinoides , Cannabis , Cannabinoides/química , Cannabis/química , Inflorescencia/química , Espectroscopía de Resonancia Magnética , Extractos Vegetales/químicaRESUMEN
The reaction of PMe3 or PPh3 with PF5 in anhydrous CH2Cl2 or hexane forms the white, moisture-sensitive complexes [PF5(PR3)] (R = Me, Ph). Similar reactions involving the diphosphines o-C6H4(PR2)2 afford the complexes [PF4{o-C6H4(PR2)2}][PF6]. The X-ray structures of [PF5(PR3)] and [PF4{o-C6H4(PMe2)2}][PF6] show pseudo-octahedral fluorophosphorus centers. Multinuclear NMR spectra (1H, 19F{1H}, 31P{1H}) show that in solution in CH2Cl2/CD2Cl2 the structures determined crystallographically are the only species present for [PF5(PMe3)] and [PF4{o-C6H4(PMe2)2}][PF6] but that [PF5(PPh3)] and [PF4{o-C6H4(PPh2)2}][PF6] exhibit reversible dissociation of the phosphine at ambient temperatures, although exchange slows at low temperatures. The complex 19F{1H} and 31P{1H} NMR spectra have been analyzed, including those of the cation [PF4{o-C6H4(PMe2)2}]+, which is a second-order AA'XX'B2M spin system. The unstable [PF5(AsMe3)], which decomposes in a few hours at ambient temperatures, has also been isolated and spectroscopically characterized; neither AsPh3 nor SbEt3 forms similar complexes. The electronic structures of the PF5 complexes have been explored by DFT calculations. The DFT optimized geometries for [PF5(PMe3)], [PF5(PPh3)], and [PF4{o-C6H4(PMe2)2}]+ are in good agreement with their respective crystal structure geometries. DFT calculations on the PF5-L complexes reveal the P-L bond strength falls with L in the order PMe3 > PPh3 > AsMe3, consistent with the experimentally observed stabilities, and in the PF5-L complexes, electron transfer from L to PF5 on forming these complexes also follows the order PMe3 > PPh3 ≈ AsMe3.
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INTRODUCTION: Renal dysfunction is a frequent complication in patients suffering from ß-thalassemia major (ß-TM). The aim of this study was to analyze the renal function and urine metabolomic profile of ß-TM patients undergoing transfusions and deferasirox (DFX) therapy, in order to better characterize and shed light on the pathogenesis of renal disease in this setting. METHODS AND SUBJECTS: 40 patients affected by ß-TM treated with DFX and 35 age- and gender-matched healthy controls were enrolled in the study. Renal function was assessed. Glomerular filtration rate (GFR) was estimated with CKD-EPI and Schwartz formula for adults and children, respectively. Renal tubular function and maximal urine concentration ability were tested. Urine specimens were analyzed by nuclear magnetic resonance spectroscopy to identify the urinary metabolite profiles. RESULTS: The study of renal function in ß-TM patients revealed normal estimated (e)GFR mean values and the albumin-to-creatinine ratio was <30 mg/g. The analysis of tubular function showed normal basal plasma electrolyte levels; 60% of patients presented hypercalciuria and many subjects showed defective urine concentration. Several amino acids, N-methyl compounds, and organic acids were overexcreted in the urine of thalassemic patients compared with controls. DISCUSSION: The major finding of this work is that ß-TM patients and controls exhibit different concentrations of some metabolites in the urine. Early recognition of urinary abnormalities may be useful to detect and prevent kidney damage.
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Deferasirox/uso terapéutico , Urinálisis/métodos , Talasemia beta/tratamiento farmacológico , Talasemia beta/orina , Adulto , Deferasirox/farmacología , Femenino , Humanos , MasculinoRESUMEN
The unique power of NMR spectroscopy in anisotropic media (LX-NMR) as a tool to obtain local and bulk structural information, combined with the effectiveness of molecular dynamics simulations at the atomistic level, shows very attractive potentialities for the study of interesting, even though still poorly understood, materials such as Ionic Liquid Crystals (ILCs). In this work, we focused our attention, in particular, on the orientational ordering of two mesophases: 1-dodecyl-3-methylimidazolium chloride, [C12C1im]Cl, and 1-dodecyl-3-methylimidazolium tetrafluoroborate, [C12C1im][BF4]. Both ILCs were studied by a 2H NMR direct investigation of the molecules forming the phases, suitably deuterated, and by 1H NMR spectroscopy, using the small rigid probe-solutes 1,4-dichlorobenzene (DCB), dissolved in [C12C1im][BF4] and [C12C1im]Cl, and 1,4-dibromobenzene (DBB) dissolved in [C12C1im][BF4], to probe the local, internal structure and organization of the mesophases. The experimental results were then compared with the predictions, by atomistic MD simulations, of the structure of the smectic phase of the two salts, at two selected temperatures, containing a single DCB molecule as a probe. The MD simulations show that the DCB solute is distributed only within the hydrophobic layers of the ILC. Orientational order parameters of the imidazolium cations and of the DCB molecule were obtained and compared with the experiments, showing a general good agreement and allowing a deeper understanding of the microscopic structure of the systems.
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Forecasting user flows on transportation networks is a fundamental task for Intelligent Transport Systems (ITSs). Indeed, most control and management strategies on transportation systems are based on the knowledge of user flows. For implementing ITS strategies, the forecast of user flows on some network links obtained as a function of user flows on other links (for instance, where data are available in real time with sensors) may provide a significant contribution. In this paper, we propose the use of Artificial Neural Networks (ANNs) for forecasting metro onboard passenger flows as a function of passenger counts at station turnstiles. We assume that metro station turnstiles record the number of passengers entering by means of an automatic counting system and that these data are available every few minutes (temporal aggregation); the objective is to estimate onboard passengers on each track section of the line (i.e., between two successive stations) as a function of turnstile data collected in the previous periods. The choice of the period length may depend on service schedules. Artificial Neural Networks are trained by using simulation data obtained with a dynamic loading procedure of the rail line. The proposed approach is tested on a real-scale case: Line 1 of the Naples metro system (Italy). Numerical results show that the proposed approach is able to forecast the flows on metro sections with satisfactory precision.
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This paper proposes a method for estimating traffic flows on some links of a road network knowing the data on other links that are monitored with sensors. In this way, it is possible to obtain more information on traffic conditions without increasing the number of monitored links. The proposed method is based on artificial neural networks (ANNs), wherein the input data are the traffic flows on some monitored road links and the output data are the traffic flows on some unmonitored links. We have implemented and tested several single-layer feed-forward ANNs that differ in the number of neurons and the method of generating datasets for training. The proposed ANNs were trained with a supervised learning approach where input and output example datasets were generated through traffic simulation techniques. The proposed method was tested on a real-scale network and gave very good results if the travel demand patterns were known and used for generating example datasets, and promising results if the demand patterns were not considered in the procedure. Numerical results have underlined that the ANNs with few neurons were more effective than the ones with many neurons in this specific problem.
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Despite the potential versatility of Vitamin C as a ligand, only for few metal complexes does full characterization exist. Vitamin C metal complexes, indeed, are difficult to study experimentally because the ligand has multiple protonation and oxidation states, and the metal-ligand complexes are in general not as tight as one might expect and frequently resistant to crystallographic characterization. In most cases, coordination via one of the hypothesized modes is invoked, characterized by monodentate or bidentate coordination via the most acidic oxygen atoms, with the ligand singly or doubly deprotonated. In this study the ability of l-ascorbic acid to form complexes with Al3+ and Ni2+ ions under physiological conditions was investigated by using a combination of potentiometric measurements, 1H NMR spectroscopy, and DFT computations in order to recognize the structural properties of the resulting complexes in aqueous solution. The comparison between the values of the free energies of complexation obtained by using DFT quantum chemical calculations and estimated from experimental stability constants according to the mass action law and by considering the involved equilibria allows to select structure and preferred coordination modes of formed complexes. The protonation constant of the free ligand was also determined using potentiometric data and its reproduction by using computational approaches was critically commented.
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Aluminio/química , Ácido Ascórbico/química , Níquel/química , Compuestos Organometálicos/química , Teoría Cuántica , Cristalografía por Rayos X , Modelos Moleculares , Estructura Molecular , Compuestos Organometálicos/síntesis química , Potenciometría , Espectroscopía de Protones por Resonancia MagnéticaRESUMEN
The conformational equilibrium of methyl 4-nitrophenyl sulfoxide (MNPSO) was experimentally investigated in the gas phase by using microwave spectroscopy and in isotropic and nematic liquid-crystal solutions, in which the solvents are nonaqueous and aprotic, by using NMR spectroscopy; moreover, it was theoretically studied in vacuo and in solution at different levels of theory. The overall set of results indicates a significant dependence of the solute conformational distribution on the solvent dielectric permittivity constant: when dissolved in low-polarity media, the most stable conformation of MNPSO proved to be strongly twisted with respect to that in more polar solvents, in which the conformational distribution maximum essentially coincides with that obtained in the gas phase. We discuss a possible explanation of this behavior, which rests on electrostatic solute-solvent interactions and is supported by calculations of the solute electric dipole moment as a function of the torsional angle. This function shows that the least polar conformation of MNPSO is located at a twist angle close to that of the conformational distribution maximum found in less-polar solvents. This fact, associated with a relatively flat torsional potential, can justify the stabilization of the twisted conformation by the less-polar solvents.
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The alignment of biphenyl (2P) in the liquid-crystal phases of 4-n-pentyl-4'-cyanobiphenyl (5CB) and 4-n-octyl-4'-cyanobiphenyl (8CB) is investigated by using a combination of predictive atomistic molecular dynamics (MD) simulations and (1)H liquid-crystal nuclear magnetic resonance (LXNMR) residual dipolar coupling measurements. A detailed comparison and validation of the MD results with LXNMR is provided, showing a good agreement between the simulated and experimental dipolar couplings at the same reduced temperature. MD is then used to examine the location of 2P in the smectic phase, which is unavailable to LXNMR, and 2P is found to be rather uniformly distributed. The combination of MD and NMR spectroscopy provides detailed information about the order, interconnection between orientation and conformation, local positional order, and interactions with the liquid-crystalline solvent.
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Heterogeneous bifuctional catalysts are multifunctional synthetic catalysts enabling efficient organic transformations by exploiting two opposite functionalities without mutual destruction. In this paper we report the first Er(III)-based metallorganic heterogeneous catalyst, synthesized by post-calcination MW-assisted grafting and modification of the natural aminoacid L-cysteine. The natural acid-base distance between sites was maintained to assure the cooperation. The applicability of this new bifunctional heterogeneous catalyst to C-C bond formation and the supposed mechanisms of action are discussed as well.
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Erbio/química , Carbono/química , CatálisisRESUMEN
Several patients with partial trisomy 6p resulting from parental balanced translocations or from a de novo duplication or insertion have already been described. Here, we report on the first case of familial pure trisomy 6p as a result of interstitial tandem duplication. The patient, an 11-year-old female, presented with mild dysmorphic features, moderate intellectual disability with behavioral disturbances, immunodeficiency, and epilepsy. Conventional cytogenetic analysis showed a duplication of the 6p region in the patient and in her mother presenting with a partially overlapping phenotype. The rearrangement was confirmed and defined by molecular cytogenetic analysis, including FISH and array CGH analysis showing a gain of ~13.8 Mb from 6p12.3 to 6p21.31. The phenotype of a pure partial trisomy 6p is extremely heterogeneous depending on the gene contents of the duplicated region. The clinical features of our patients have been compared with overlapping cases from the literature.
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Trisomía/genética , Estatura/genética , Niño , Cromosomas Humanos Par 6/genética , Epilepsia/genética , Cara/anomalías , Femenino , Humanos , Hibridación Fluorescente in Situ , Discapacidad Intelectual/genética , Madres , Núcleo Familiar , Fenotipo , Trisomía/fisiopatologíaRESUMEN
Solute molecules were dissolved in the liquid crystal 4-cyano-4'-n-octyloxybiphenyl (8OCB), known to form a partial bilayer smectic-A phase. Through measurement of solutes' and solvent's orientational order parameters via nuclear magnetic resonance spectroscopy, and their analysis via a statistical thermodynamic density functional theory, values of the solvent's positional order parameters and solutes' positional-orientational distribution functions were obtained. Near to the transition to the nematic phase, the main positional order parameter of the smectic liquid crystal turned out to be comprised in the interval 0.4-0.6, though the quality of the fittings assuming the phase as nematic all across the temperature range investigated was only slightly worse. This may be ascribed to the looseness of the partial bilayer smectic structure. Solutes were found to preferentially lie in those regions where liquid crystal molecule terminal chains are located.
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Tacle is a citrus variety which recently gained further interest due to its antioxidant and biological properties. This study suggests using Nuclear Magnetic Resonance (NMR) imaging to characterize Tacle juice's metabolic composition as it is intimately linked to its quality. First, polar and apolar solvent systems were used to identify a significant fraction of the Tacle metabolome. Furthermore, the antioxidant capacity and the total content of flavonoids, polyphenols and ß-carotene in the juice were investigated with UV-Visible spectroscopy. Tacle juice was clarified and fractionated by ultrafiltration (UF) and nanofiltration (NF) membranes in order to recover and purify its bioactive principles. Finally, the second part of this work sheds light on the spectrophotometric assays and 1H-NMR spectra of fractions coming from membrane operations coupled with a multivariate data analysis technique, PCA, to explore the impact of UF and NF processes on the metabolic profile of the juice.
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Partial removal of sugars in fruit juices without compromising their biofunctional properties represents a significant technological challenge. The current study was aimed at evaluating the separation of sugars from phenolic compounds in apple juice by using three different spiral-wound nanofiltration (NF) membranes with a molecular weight cut-off (MWCO) in the range of 200-500 Da. A combination of diafiltration and batch concentration processes was investigated to produce apple juice with reduced sugar content and improved health properties thanks to the preservation and concentration of phenolic compounds. For all selected membranes, permeate flux and recovery rate of glucose, fructose, and phenolic compounds, in both diafiltration and concentration processes, were evaluated. The concentration factor of target compounds as a function of the volume reduction factor (VRF) as well as the amount of adsorbed compound on the membrane surface from mass balance analysis were also evaluated. Among the investigated membranes a thin-film composite membrane with an MWCO of 200-300 Da provided the best results in terms of the preservation of phenolic compounds in the selected operating conditions. More than 70% of phenolic compounds were recovered in the retentate stream while the content of sugars was reduced by about 60%.
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The structural characterization of a new flavonoid from bergamot fruit (Citrus bergamia Risso) carrying the 3-hydroxy-3-methyl glutaryl (HMG) ester moiety has been accomplished, and its antioxidant ability was tested from a chemical point of view. The peculiarity of the new molecule, named peripolin, relies on the presence of the HMG chemical group linked to the sugar portion of neoeriocitrin; the structure was elucidated using both high-resolution mass spectrometry and nuclear magnetic resonance experiments performed on the purified molecule extracted from the fruit. The antioxidant ability of the new molecule was tested by classical chemical approaches, such as DPPH, ABTS and FRAP assays, and from a theoretical point of view. 1H and 13C NMR experiments and HR-ESI-MS/MS experiments show unequivocally that the HMG moiety is linked to the primary position of the glucose unit of neohesperidose, while the chemical tests and the computational results show that peripolin possesses strong antioxidant behavior, similar to that of neoeriocitrin and remarkably higher respect to the other flavonoids present in the fruit. Furthermore, the quantitative assays carried out by UPLC-MS/MS showed that its amount in the fruit is similar to that of the other main flavonoids. Furthermore, molecular dynamics simulations allowed us to investigate the possible conformations adopted by the antioxidants in the presence of water molecules. In particular, the switch of open-closed conformations of HMG-containing species was evidenced. As far as the reaction with DPPH, the calculation of ΔGrea supported the experimental outcomes regarding the peripolin and neoeriocitrin activity. In conclusion, bergamot fruit, already known for its potential to lower the level of blood cholesterol, has been proven to contain molecules such as neoeriocitrin and the newly characterized peripolin, which could have important in-vivo antioxidant characteristics.
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It is well-accepted that the endogenous antioxidant protection system progressively decays in elderly people, and that the oxidative stress contributes to different neurodegenerative disorders such as Alzheimer's Diseases (AD). The lower incidence of AD in countries which feature the Mediterranean Diet was associated to the high consumption of extra virgin olive oil and its polyphenolic fraction, in particular hydroxytyrosol. The protective role of these bio-phenols against oxidative stress, suggested that we combine their antioxidant/free radical scavenging activity with donepezil, an active ingredient which has just been approved for the treatment of AD. Different synthetic strategies were tested to conjugate the two different synthons in good yields. Additionally, a nitro-hydroxytyrosol derivative was synthesized to extend the application to other neurodegeneration inflammatory models. Then, their bioactivity was measured in different chemical and biological tests on a human neuroblastoma cell line (SHSY-5Y). Remarkable results on cell viability and the regulation of the redox state of cells were obtained. All hybrids showed negligible cell death under 1 µM and are stable and non toxic. Reactive oxygen species (ROS) measurements showed that the nitro-hybrid was the more effective one at reducing the ROS amount to physiological values. Then, in light of the bio-metal hypothesis of diverse neurodegenerative disorders, we tested these new compounds on the chelation properties of redox-active metals. The nitro-hybrid was able to chelate all of the tested metal cations, suggesting that we propose it as potential lead compound for a new class of neuroprotective antioxidant agents.
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A two-dimensional Fluorine Detected Local Field (FDLF) NMR experiment is demonstrated on a sample of perfluoropropyl iodide dissolved in the nematic solvent ZLI1132. In analogy to the proton detected local field (PDLF) technique, for each resolved site of the carbon spectrum, a simple map of the heteronuclear coupling network is obtained in the indirect dimension. A full analysis of the FDLF spectrum was achieved with the aid of two-dimensional (19)F-(13)C HETCOR and (13)C, D-resolved spectra (with D representing the anisotropic spin-spin coupling). A one-dimensional (19)F spectrum was recorded on the same sample at intermediate resolution, and values of the residual spin-spin couplings T(CF) and T(FF) obtained from both experiments were combined and used to provide starting parameters for the analysis of a very high resolution (19)F spectrum, including the weak satellite lines from single-(13)C isotopomers. The high-precision, residual, anisotropic couplings were used to explore whether they have an appreciable contribution from the anisotropic electron-mediated spin-spin couplings.