Ultrasonic processes for the advanced remediation of contaminated sediments.

Sediments play a fundamental role in the aquatic environment, so that the presence of contaminants poses severe concern for the possible negative effects on both environmental and human health. Sediment remediation is thus necessary to reduce pollutant concentrations and several techniques have been studied so far. A novel approach for sediment remediation is the use of Advanced Oxidation Processes, which include ultrasound (US). This paper focuses on the study of the ultrasonic effects for the simultaneous reduction of both organic and inorganic contaminants from sediments. To this end, the US technology was investigated as a stand-alone treatment as well as in combination with an electro-kinetic (EK) process, known to be effective in the removal of heavy metals from soil and sediments. The US remediation resulted in higher organic compound degradation, with an average 88% removal, but promising desorption yields (47-84%) were achieved for heavy metals as well. The combined EK/US process was found to be particularly effective for lead. Experimental outcomes highlighted the potential of the ultrasonic technology for the remediation of contaminated sediments and addressed some considerations for the possible scale-up.

Nuclear magnetic resonance studies of DNP-ready trehalose obtained by solid state mechanochemical amorphization.

(1)H nuclear spin-lattice relaxation and Dynamic Nuclear Polarization (DNP) have been studied in amorphous samples of trehalose sugar doped with TEMPO radicals by means of mechanical milling, in the 1.6-4.2 K temperature range. The radical concentration was varied between 0.34 and 0.81%. The highest polarization of 15% at 1.6 K, observed in the sample with concentration 0.50%, is of the same order of magnitude of that reported in standard frozen solutions with TEMPO. The temperature and concentration dependence of the spin-lattice relaxation rate 1/T1, dominated by the coupling with the electron spins, were found to follow power laws with an exponent close to 3 in all samples. The observed proportionality between 1/T1 and the polarization rate 1/Tpol, with a coefficient related to the electron polarization, is consistent with the presence of Thermal Mixing (TM) and a good contact between the nuclear and the electron spins. At high electron concentration additional relaxation channels causing a decrease in the nuclear polarization must be considered. These results provide further support for a more extensive use of amorphous DNP-ready samples, obtained by means of comilling, in dissolution DNP experiments and possibly for in vivo metabolic imaging.

Stacking of purines in water: the role of dipolar interactions in caffeine.

During the last few decades it has been ascertained that base stacking is one of the major contributions stabilizing nucleic acid conformations. However, the understanding of the nature of the interactions involved in the stacking process remains under debate and it is a subject of theoretical and experimental studies. Structural similarity between purine bases (guanine and adenine) in DNA and the caffeine molecule makes caffeine an excellent model for the purine bases. The present study clearly shows that dipolar interactions play a fundamental role in determining stacking of purine molecules in solution. In order to reach this achievement, polarized ultraviolet Raman resonant scattering experiments have been carried out on caffeine aqueous solutions as a function of concentration and temperature. The investigation pointed out at the aggregation and solvation properties, particularly at elevated temperatures. Kubo-Anderson theory was used as a framework to investigate the non-coincidence effect (NCE) occurring in the totally symmetric breathing modes of the purine rings, and in the bending modes of the methyl groups of caffeine. The NCE concentration dependence shows that caffeine aggregation at 80 °C occurs by planar stacking of the hydrophobic faces. The data clearly indicate that dipolar interactions determine the reorientational motion of the molecules in solution and are the driving force for the stacking of caffeine. In parallel, the observed dephasing times imply a change in caffeine interactions as a function of temperature and concentration. A decrease, at low water content, of the dephasing time for the ring breathing vibration mode indicates that self-association alters the solvation structure that is detectable at low concentration. These results are in agreement with simulation predictions and serve as an important validation of the models used in those calculations.

Chitosan-pectin hybrid nanoparticles prepared by coating and blending techniques.

The preparation of chitosan nanoparticles in combination with pectins, as additional mucoadhesive biopolymers, was investigated. Pectins from apple and from citrus fruit were considered; polygalacturonic acid was taken as a reference. Tripolyphosphate was used as an anionic cross-linker. Two different techniques were compared, namely the coating and the blending. Coated nanoparticles (NPs) in the ratio pectin:NPs from 2:1 to 5:1 evidenced that the size of NPs increased as the amount of pectin (both from apple and citrus fruit) was increased. In particular, for NPs coated with pectin from citrus fruit the size ranges from 200 to 260nm; while for NPs coated with pectin from apple the size ranges from 330 to 450nm. A minimum value of Z-potential around -35mV was obtained for the ratio pectin:NPs 4:1, while further addition of pectin did not decrease the Z-potential. Also blended NPs showed a dependence of the size on the ratio of the components: for a given ratio pectin:tripolyphosphate the size increases as the fraction of chitosan increases; for a low ratio chitosan:pectin a high amount of tripolyphosphate was needed to obtain a compact structure. The effect of the additional presence of loaded proteins in chitosan-pectin nanoparticles was also investigated, since proteins contribute to alter the electrostatic interactions among charged species. FT-IR and DSC characterization are presented to confirm the interactions between biopolymers. Finally, the biocompatibility of the used materials was assessed by the chorioallantoic membrane assay, confirming the safety of the materials.

Hydration of Caffeine at High Temperature by Neutron Scattering and Simulation Studies.

The solvation of caffeine in water is examined with neutron diffraction experiments at 353 K. The experimental data, obtained by taking advantage of isotopic H/D substitution in water, were analyzed by empirical potential structure refinement (EPSR) in order to extract partial structure factors and site-site radial distribution functions. In parallel, molecular dynamics (MD) simulations were carried out to interpret the data and gain insight into the intermolecular interactions in the solutions and the solvation process. The results obtained with the two approaches evidence differences in the individual radial distribution functions, although both confirm the presence of caffeine stacks at this temperature. The two approaches point to different accessibility of water to the caffeine sites due to different stacking configurations.

Dynamic nuclear polarization of a glassy matrix prepared by solid state mechanochemical amorphization of crystalline substances.

A mechanochemical "solvent-free" route is presented for the preparation of solid samples ready to be employed in the Dynamic Nuclear Polarization (DNP). (1)H-DNP build-up curves at 3.46 T as a function of temperature and radical concentration show steady state nuclear polarization of 10% (0.5% TEMPO concentration at 1.75 K).

Isothermal dehydration of thin films of water and sugar solutions.

The process of quasi-isothermal dehydration of thin films of pure water and aqueous sugar solutions is investigated with a dual experimental and theoretical approach. A nanoporous paper disk with a homogeneous internal structure was used as a substrate. This experimental set-up makes it possible to gather thermodynamic data under well-defined conditions, develop a numerical model, and extract needed information about the dehydration process, in particular the water activity. It is found that the temperature evolution of the pure water film is not strictly isothermal during the drying process, possibly due to the influence of water diffusion through the cellulose web of the substrate. The role of sugar is clearly detectable and its influence on the dehydration process can be identified. At the end of the drying process, trehalose molecules slow down the diffusion of water molecules through the substrate in a more pronounced way than do the glucose molecules.

Autophagy and Crohn's disease: at the crossroads of infection, inflammation, immunity, and cancer.

Inflammatory bowel diseases (IBD) are common inflammatory disorders of the gastrointestinal tract that include ulcerative colitis (UC) and Crohn's disease (CD). The incidences of IBD are high in North America and Europe, affecting as many as one in 500 people. These diseases are associated with high morbidity and mortality. Colorectal cancer risk is also increased in IBD, correlating with inflammation severity and duration. IBD are now recognized as complex multigenetic disorders involving at least 32 different risk loci. In 2007, two different autophagy-related genes, ATG16L1 (autophagy-related gene 16-like 1) and IRGM (immunity-related GTPase M) were shown to be specifically involved in CD susceptibility by three independent genome-wide association studies. Soon afterwards, more than forty studies confirmed the involvement of ATG16L1 and IRGM variants in CD susceptibility and gave new information on the importance of macroautophagy (hereafter referred to as autophagy) in the control of infection, inflammation, immunity and cancer. In this review, we discuss how such findings have undoubtedly changed our understanding of CD pathogenesis. A unifying autophagy model then emerges that may help in understanding the development of CD from bacterial infection, to inflammation and finally cancer. The Pandora's box is now open, releasing a wave of hope for new therapeutic strategies in treating Crohn's disease.

Molecular dynamics studies of the conformation of sorbitol.

Molecular dynamics simulations of a 3 molal aqueous solution of D-sorbitol (also called D-glucitol) have been performed at 300 K, as well as at two elevated temperatures to promote conformational transitions. In principle, sorbitol is more flexible than glucose since it does not contain a constraining ring. However, a conformational analysis revealed that the sorbitol chain remains extended in solution, in contrast to the bent conformation found experimentally in the crystalline form. While there are 243 staggered conformations of the backbone possible for this open-chain polyol, only a very limited number were found to be stable in the simulations. Although many conformers were briefly sampled, only eight were significantly populated in the simulation. The carbon backbones of all but two of these eight conformers were completely extended, unlike the bent crystal conformation. These extended conformers were stabilized by a quite persistent intramolecular hydrogen bond between the hydroxyl groups of carbon C-2 and C-4. The conformational populations were found to be in good agreement with the limited available NMR data except for the C-2-C-3 torsion (spanned by the O-2-O-4 hydrogen bond), where the NMR data support a more bent structure.

Concentration-temperature dependencies of structural relaxation time in trehalose-water solutions by brillouin inelastic UV scattering.

A Brillouin scattering investigation has been carried out on trehalose-water solutions in a wide range of concentrations (0

Upper airway obstructive disease in mucopolysaccharidoses: polysomnography, computed tomography and nasal endoscopy findings.

In mucopolysaccharidoses, upper airway obstruction has multiple causative factors and progressive respiratory disease may severely affect morbidity and mortality. In a cross-sectional study over 2 years we evaluated upper airway obstructive disease through overnight polysomnography, upper airway computed tomography and nasal endoscopy in 5 children and 6 adults with mucopolysaccharidoses of various types. Measurements of apnoea and apnoea-hypopnoea index, arousal index, and sleep efficiency were obtained through polysomnography. Retropalatal and retroglossal spaces were calculated through computed tomography, and the degree of adenoid hypertrophy was assessed through endoscopy. Apnoea index and apnoea-hypopnoea index were significantly higher in children than in adults with mucopolysaccharidoses (p = 0.03 and p = 0.03, respectively). Compared to healthy controls, retropalatal and retroglossal spaces were significantly smaller in children (p = 0.03 and p = 0.004, respectively) or adults with mucopolysaccharidoses (p = 0.004 and p = 0.004, respectively). All subjects had adenoid hypertrophy causing first-degree (36%) or second-degree (64%) obstruction at endoscopy. Overnight polysomnography, upper airway computed tomography and nasal endoscopy are useful tools for diagnosing obstructive sleep apnoea syndrome in mucopolysaccharidoses, and identifying the site and severity of airway obstruction.

Inhibition of p38 mitogen activated protein kinase controls airway inflammation in cystic fibrosis.

BACKGROUND: Cystic fibrosis (CF) airways are characterised by chronic inflammation, increased interleukin (IL)-8 secretion, and neutrophil activation which are considered the principal factors of morbidity and mortality in CF patients. Optimising management of this chronic inflammatory response is therefore a key issue of basic and clinical CF research. Several reports have addressed ways to manage CF airways inflammation, and an attractive therapeutic strategy may be the inhibition of the p38-mitogen activated protein kinase (p38-MAP-k) pathway. METHODS: A new ex vivo model was used to study the mucosal inflammatory response to environmental airways stimuli. Nasal biopsy tissues from CF patients and controls were cultured ex vivo for 20 minutes, 4 hours, and 24 hours in the presence of lipopolysaccharide (LPS) from Pseudomonas aeruginosa (PA) with and without the p38-MAP-k inhibitor SB203580. Quantitative mRNA assessment, immunohistochemistry, and Western blots were used to detect the expression and modulation of inflammatory markers. RESULTS: PA-LPS challenge induced a time dependent mucosal inflammation indicated by rapid epithelial activation, IL-8 release, COX-2 upregulation, and neutrophil migration to the upper mucosal layers. Some of these LPS induced changes (IL-8 release and neutrophil migration) were specific to CF tissues. SB203580 significantly controlled all LPS induced mucosal changes in CF tissues. CONCLUSION: These findings provide a rationale and proof of principle for the potential use of p38-MAP-k inhibitors to control inflammation in patients with CF.

An experimental evaluation of self-interference in Narcissus assoanus: functional and evolutionary implications.

Floral traits that reduce self-pollination in hermaphroditic plants have usually been interpreted as mechanisms that limit the genetic consequences of self-fertilization. However, the avoidance of sexual conflict between female and male function (self-interference) may also represent an important selection pressure for the evolution of floral traits, particularly in self-incompatible species. Here, we use experimental manipulations to investigate self-interference in Narcissus assoanus, a self-incompatible species with a stigma-height dimorphism in which the degree of spatial separation between sex organs (herkogamy) differs strikingly between the long- and short-styled morphs (hereafter L- and S-morphs). We predicted that weak herkogamy in the L-morph would cause greater self-pollination and hence self-interference. Experimental self-pollination reduced seed set when it occurred prior to, or simultaneously with, cross-pollination in the L-morph, but only if it occurred prior to cross-pollination in the S-morph. In the field, autonomous self-pollination was greater in the L-morph than the S-morph, but we found no evidence that self-interference reduced maternal or paternal fitness in either morph. One-day-old flowers of the L-morph have reduced stigma receptivity and hence exhibit protandry, whereas stigma receptivity and anther dehiscence are concurrent in the S-morph. This suggests that the two style morphs have alternative strategies for reducing self-interference: dichogamy in the L-morph and herkogamy in the S-morph. These results provide insight into the mechanisms that reduce sexual conflict in hermaphrodite plants and are of significance for understanding the evolution and maintenance of sexual polymorphisms.

[Effects of atorvastatin on ischemic acute renal failure in aging rats]. / Effetti della atorvastatina nell'insufficienza renale acuta ischemica del ratto anziano.

BACKGROUND: Aging (O) rats have a greater susceptibility to renal ischemia than young (Y) rats due to an endothelial dysfunction partially reversed by exogenous administration of L-Arginine. Since statins are able to increase nitric oxide (NO) production, aim of the study was to evaluate whether pre-treatment with atorvastatin (ATO, 10 mg/kg/day for 12 days), had positive effects on ischemic acute renal failure (ARF) of aging rats. METHODS: Renal clearance studies (inulin) were performed 24 hours after ischemia in 6 Groups (n=6 in each Group) of both Y- and O-rats: control rats (CON), untreated rats with ARF (Groups IRA), and rats with ARF but pretreated with ATO (Groups ATO+IRA). RESULTS: Renal ischemia determined a sharper decrease in GFR of Group O-IRA than Y-IRA (-80% and -63% vs respective CON, both p<0.001). In both Groups the fall in GFR was secondary to renal vasoconstriction and the consequent reduction in renal plasma flow. Pre-treatment with ATO did not modify GFR in Group Y-ATO+IRA, but was able to determine a marked rise in GFR of rats of O-ATO+IRA Group (+100% vs O-IRA), through a reduction in renal vascular resistances. Induction of ARF greatly enhanced nitrate excretion in Group Y-IRA, but slightly affected Group O-ARF. Administration of ATO did not modify nitrite excretion in Y rats, whereas it was able to increase nitrate excretion in O-ATO+ARF rats (+111% vs O-IRA). CONCLUSIONS: Pre-treatment with ATO is able to improve the renal response to ischemia in aging rats, through a mechanism which likely is NO-dependent.

[Progression of chronic renal failure in remnant rats: role of arginase inhibition]. / Progressione dell'insufficienza renale cronica nel ratto remnant: ruolo della inibizione dell'arginasi.

BACKGROUND: Oral administration of arginine to remnant (REM) rats (5/6 nx) slows the progression of chronic renal failure through a nitric-oxide(NO)-dependent mechanism. We have recently shown that inhibition of arginase, the main metabolic pathway of arginine, was able to induce similar results on renal dynamics (GIN: 2001, 18:285-290). Aim of the present study was to test whether these changes were mediated by increased availability of arginine-derived NO. Methods. Three Groups of REM rats were studied for 8 weeks after surgery: 1) untreated REM (Group REM); 2) REM rats treated with arginine (1%) in tap water (Group ARG); 3) REM rats administered a Mn++-free diet, to induce partial inhibition of arginase (Group MNF). Normal unmanipulated rats were used as controls (Group NOR). RESULTS: Liver arginase activity was significantly depressed only in MNF-rats (-35% vs. REM, p < 0.01). Blood pressure was significantly lower in Group MNF vs. ARG and REM after 6 weeks (p < 0.05). Proteinuria was significantly decreased in Group ARG (-42%, p < 0.05 vs. REM) and even more in Group MNF (-57%, p < 0.01). ARG plasma levels, decreased in REM rats (-41% vs. Group CON), were normalized in Group ARG (p < 0.01 vs. Group REM); arginase inhibition was able to increase such levels in Group MNF (+38% vs. REM) and this resulted in a proportional rise in urinary nitrite excretion (+33% vs. REM), grossly depressed in REM rats. Renal arginase activity was lower in all the Groups of remnant rats vs. Group NOR, but intrarenal concentrations of ARG were significantly lower only in rats of Group MNF (p < 0.05 vs. all the other Groups). Histological examination showed that MNF-rats had a glomerular sclerosis index lower than in the other Groups (p < 0.05 vs. Group REM and ARG). CONCLUSIONS: In conclusion, inhibition of arginase in remnant rats slows the progression of CRF and preserves renal histology through a direct and/or indirect NO-dependent mechanism.

Cardiac performance in Turner's syndrome patients on growth hormone therapy.

OBJECTIVES: To investigate possible cardiac morphofunctional alterations observed in 26 Turner's syndrome (TS) patients on prolonged high-dose growth hormone (GH) therapy. STUDY DESIGN: We examined 26 TS subjects treated with rhGH (1 U/kg/week) for a mean period of 4.9 years (range 1-7.8) and 37 age-, weight- and height-matched healthy girls. Left ventricular volume, mass, systolic function, cardiac index, systemic vascular resistance and diastolic function were evaluated by two-dimensional and Doppler echocardiography. RESULTS: Heart rate and systolic blood pressure (BP) were higher in TS patients than in controls, while diastolic BP was lower. Left ventricular volumes, ejection fraction, mass index, M/V ratio and cardiac index did not differ significantly; systemic vascular resistance was slightly decreased. Left ventricular fractional shortening and mean velocity of circumferential shortening were slightly increased while end-systolic meridional stress was decreased in TS. Contractile state was normal in TS. Diastolic function assessment showed a shortening of isovolumetric relaxation and diastolic filling times with an increased atrial contribution and a normal pulmonary venous flow. CONCLUSION: Cardiac morphology in TS patients on GH therapy is similar to controls. The observed changes in left ventricular systolic and diastolic function should be interpreted as an adaptation to the higher heart rate and reduced peripheral vascular resistance induced by GH therapy.

Reversible dehydration of trehalose and anhydrobiosis: from solution state to an exotic crystal?

Physico-chemical properties of the trehalose-water system are reviewed with special reference to the transformations that may shed light on the mechanism of trehalose bio-protection. Critical analysis of solution thermodynamics is made in order to scrutinize trehalose properties often called 'anomalous' and to check the consistency of literature results. Discussion on the conversion between the solid state polymorphic forms is given, with a special emphasis of the transformations involving the newly identified anhydrous crystalline form of alpha,alpha-trehalose, TRE(alpha). This exotic crystal is almost 'isomorphous' with the dihydrate crystal structure, and possesses the unique feature of reversibly absorbing water to produce the dihydrate, without changing the main structural features. The reversible process could play a functional role in the well-known ability of this sugar to protect biological structures from damage during desiccation. The final aim of the paper is to add some new insights into and to reconcile previous hypotheses for the peculiar 'in vivo' action of trehalose.

Kinetics of gelatin transitions with phase separation: T-jump and step-wise DSC study.

The isothermal gelation (or melting) of gelatin after fast cooling (or heating) steps is studied by using high sensitivity differential scanning micro-calorimetry, in order to determine the dependence of the kinetic and thermodynamic parameters upon changes in composition and in temperature. The calorimetric heat flow curves, obtained according to defined temperature profiles, have been fitted with exponential functions (simple exponentials or stretched exponentials for the step-wise and for T-jump experiments, respectively). The gelation process of gelatin alone for t<300 min shows that the characteristic time tau and the fractional exponent are beta very sensitive to the concentration of gelatin chains and to the microscopic phase segregation due to the presence of another polymeric component.

The kinetics of periodate oxidation of carbohydrates: a calorimetric approach.

A calorimetric approach is described for analysing the kinetics of periodate oxidation on a series of monosaccharidic substrates. Rate constants at several temperatures were calculated from the calorimetric decay curves that are proportional to the rate of conversion. Arrhenius plots provided the activation parameters for the various carbohydrates and a linear correlation was found between the values of enthalpy and entropy of activation. The dependence of the values of kinetic rates on stereochemistry is interpreted in terms of conformational probability of the reactive state. The suitability of the calorimetric method to track the kinetic process of slow reactions is emphasised, in particular its ability to monitor, directly and continuously, the course of the reaction.

The trajectory of a dot crossing a pattern of tilted lines is misperceived.

The straight trajectory of a dot crossing a pattern of tilted lines is perceived as being sinusoidal. Manipulation of the size of the angle between the trajectory and the tilted lines, the velocity of the dot, and the distance between the tilted lines shows that the magnitude of the illusion is inversely proportional to the size of the incidence angle, to velocity, and to the distance between the lines. The illusion is interpreted as being the result of an integration process of local distortions occurring at the intersections with the tilted lines.