Food Quality And Authenticity Screening Via Easy Ambient Sonic-spray Ionization Mass Spectrometry.

This review is the first to summarize a decade of studies testing the use of easy ambient sonic-spray ionization mass spectrometry (EASI-MS) and its several sister techniques, Venturi (V-EASI), thermal imprinting (TI-EASI) and Spartan (S-EASI) mass spectrometry in food quality control and authentication. Since minimal or no sample preparation is required, such ambient desorption/ionization techniques have been shown to provide direct, fast and selective fingerprinting characterization at the molecular level based on the pools of the most typical components. They have also been found to be applicable on intact, undisturbed samples or on simple solvent extracts. Fundamentals of EASI-MS and its sister techniques, including mechanisms, devices, parameters and strategies, as well as the many applications reported for food analysis, are summarized and discussed.1411172-118

Blumgart Anastomosis After Pancreaticoduodenectomy. A Comprehensive Systematic Review, Meta-Analysis, and Meta-Regression

Background: The superiority of Blumgart anastomosis (BA) over non-BA duct to mucosa (non-BA DtoM) still remains under debate. Methods: We performed a systematic search of studies comparing BA to non-BA DtoM. The primary endpoint was CR-POPF. Postoperative morbidity and mortality, post-pancreatectomy hemorrhage (PPH), delayed gastric emptying (DGE), reoperation rate, and length of stay (LOS) were evaluated as secondary endpoints. The meta-analysis was carried out using random effect. The results were reported as odds ratio (OR), risk difference (RD), weighted mean difference (WMD), and number needed to treat (NNT). Results: Twelve papers involving 2368 patients: 1075 BA and 1193 non-BA DtoM were included. Regarding the primary endpoint, BA was superior to non-BA DtoM (RD = 0.10; 95% CI: −0.16 to −0.04; NNT = 9). The multivariate ORs' meta-analysis confirmed BA's protective role (OR 0.26; 95% CI: 0.09 to 0.79). BA was superior to DtoM regarding overall morbidity (RD = −0.10; 95% CI: −0.18 to −0.02; NNT = 25), PPH (RD = −0.03; 95% CI −0.06 to −0.01; NNT = 33), and LOS (− 4.2 days; −7.1 to −1.2 95% CI). Conclusion: BA seems to be superior to non-BA DtoM in avoiding CR-POPF

Aging and memory effects in beta-hydrochinone-clathrate

The out-of-equilibrium low-frequency complex susceptibility of the orientational glass methanol(73%)-beta-hydrochinone-clathrate is studied using temperature-stop protocols in aging experiments . Although the material does not have a sharp glass transition aging effects including rejuvenation and memory are found at low temperatures. However, they turn out to be much weaker, however, than in conventional magnetic spin glasses.Comment: 5 pages RevTeX, 6 eps-figures include

Wood chemotaxonomy via ESI-MS profiles of phytochemical markers: the challenging case of african versus brazilian mahogany woods

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The harvesting of Brazilian mahogany (Swietenia macrophylla) is a main cause of the Brazilian Amazon deforestation and has been therefore prohibited. African mahogany (Khaya ivorensis) was then introduced for Amazon reforestation and the commercialization of such wood is legal, thus creating a challenging problem for wood certification. Herein we report that a wood chemotaxonomic method based on distinct profiles of phytochemical markers is able to promptly characterize both the native and foreign mahogany species. This challenging task has been performed via a simple, fast and unambiguous methodology using direct electrospray ionization mass spectrometry (ESI-MS) analysis of a simple methanolic extract of a tiny wood chip. Typical limonoids such as khivorin, khayanolide A and mexicanolide for African mahogany and phragmalin-type limonoids for the native Brazilian species, as well as distinct polyphenols such as catechin derivatives and cinchonain, form the characteristic phytochemical marker pools for both species. This rapid methodology could therefore be used to monitor legal and illegal mahogany tree harvesting, and hence to control Amazon deforestation. It could also be applied to create a wood certification program for African and Brazilian mahogany trees, as well as for wood certification in general.The harvesting of Brazilian mahogany (Swietenia macrophylla) is a main cause of the Brazilian Amazon deforestation and has been therefore prohibited. African mahogany (Khaya ivorensis) was then introduced for Amazon reforestation and the commercialization72085768583FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)sem informaçãosem informaçãosem informaçã

Enzymatic pre-treatment of fruit pomace for fibre hydrolysis and antioxidants release

Processing of grapes and other fruits in the wine and fruit juice industry generates huge amounts of solid residues (pomace) which, if not properly disposed of, can represent an environmental concern due to their high organic load. To avoid landfill and incineration, different alternative uses are available and commonly applied. Among these, the most common are for feeding, composting and biogas production which are, anyway, not proper valorisation strategies. On the other hand, fruit pomaces are by-products still rich in bioactive components, such as dietary fibre and phenolic/antioxidant compounds. Considering the positive health potentials of such components, together with their potential technological role (as texturing and antioxidant ingredients), fruit pomaces may then be simply dried and milled to get functional food ingredients. It is known however, that incorporation of high levels of raw fibres into food products often causes unpleasant textures and colours. Furthermore, phenolic compounds only partially occur in fruit pomace as free compounds, while they are bound to cell wall (fibre) fractions. Enzymatic hydrolysis processes could be applied as a pre-drying treatment of fruit pomace to improve the functional properties of the final powders in terms of fibre composition and antioxidants release. In this study different fruit skins separated from different pomaces (grape, apple and blackcurrant) were submitted to an enzymatic treatment before drying. Two different commercial pectinase preparations were used: One already used in the apple juice processing for the treatment of apple and blackcurrant skins, the other currently used in the winemaking process for the treatment of grape skins. Untreated and treated dried skins were analysed for structural carbohydrates, soluble and insoluble dietary fibre, free glucose and xylose, water holding capacity, water solubility and total phenolics and antioxidants release. The results were highly variable depending on the fruit type, probably due to a different cell wall composition which requires targeted enzyme selection. In general, the enzyme treatment led to an increase in water solubility, water and oil holding capacity and free monosaccharides. Release of antioxidant compounds was observed only for apple peels

Mean-field theory of temperature cycling experiments in spin-glasses

We study analytically the effect of temperature cyclings in mean-field spin-glasses. In accordance with real experiments, we obtain a strong reinitialization of the dynamics on decreasing the temperature combined with memory effects when the original high temperature is restored. The same calculation applied to mean-field models of structural glasses shows no such reinitialization, again in accordance with experiments. In this context, we derive some relations between experimentally accessible quantities and propose new experimental protocols. Finally, we briefly discuss the effect of field cyclings during isothermal aging.Comment: Some misprints corrected, references updated, final version to apper in PR

Chaotic, memory and cooling rate effects in spin glasses: Is the Edwards-Anderson model a good spin glass?

We investigate chaotic, memory and cooling rate effects in the three dimensional Edwards-Anderson model by doing thermoremanent (TRM) and AC susceptibility numerical experiments and making a detailed comparison with laboratory experiments on spin glasses. In contrast to the experiments, the Edwards-Anderson model does not show any trace of re-initialization processes in temperature change experiments (TRM or AC). A detailed comparison with AC relaxation experiments in the presence of DC magnetic field or coupling distribution perturbations reveals that the absence of chaotic effects in the Edwards-Anderson model is a consequence of the presence of strong cooling rate effects. We discuss possible solutions to this discrepancy, in particular the smallness of the time scales reached in numerical experiments, but we also question the validity of the Edwards-Anderson model to reproduce the experimental results.Comment: 17 pages, 10 figures. The original version of the paper has been split in two parts. The second part is now available as cond-mat/010224

Computer Simulations of Supercooled Liquids and Glasses

After a brief introduction to the dynamics of supercooled liquids, we discuss some of the advantages and drawbacks of computer simulations of such systems. Subsequently we present the results of computer simulations in which the dynamics of a fragile glass former, a binary Lennard-Jones system, is compared to the one of a strong glass former, SiO_2. This comparison gives evidence that the reason for the different temperature dependence of these two types of glass formers lies in the transport mechanism for the particles in the vicinity of T_c, the critical temperature of mode-coupling theory. Whereas the one of the fragile glass former is described very well by the ideal version of mode-coupling theory, the one for the strong glass former is dominated by activated processes. In the last part of the article we review some simulations of glass formers in which the dynamics below the glass transition temperature was investigated. We show that such simulations might help to establish a connection between systems with self generated disorder (e.g. structural glasses) and quenched disorder (e.g. spin glasses).Comment: 37 pages of Latex, 11 figures, to appear as a Topical Review article in J. Phys.: Condens. Matte

Real-time non-equilibrium dynamics of quantum glassy systems

We develop a systematic analytic approach to aging effects in quantum disordered systems in contact with an environment. Within the closed-time path-integral formalism we include dissipation by coupling the system to a set of independent harmonic oscillators that mimic a quantum thermal bath. After integrating over the bath variables and averaging over disorder we obtain an effective action that determines the real-time dynamics of the system. The classical limit yields the Martin-Siggia-Rose generating functional associated to a colored noise. We apply this general formalism to a prototype model related to the $p$ spin-glass. We show that the model has a dynamic phase transition separating the paramagnetic from the spin-glass phase and that quantum fluctuations depress the transition temperature until a quantum critical point is reached. We show that the dynamics in the paramagnetic phase is stationary but presents an interesting crossover from a region controlled by the classical critical point to another one controlled by the quantum critical point. The most characteristic property of the dynamics in a glassy phase, namely aging, survives the quantum fluctuations. In the sub-critical region the quantum fluctuation-dissipation theorem is modified in a way that is consistent with the notion of effective temperatures introduced for the classical case. We discuss these results in connection with recent experiments in dipolar quantum spin-glasses and the relevance of the effective temperatures with respect to the understanding of the low temperature dynamics.Comment: 56 pages, Revtex, 17 figures include