First report on the presence of emerging Fusarium mycotoxins enniatins (A,A1, B,B1), beauvericin and fusaproliferin in rice on the Moroccan retail markets

Seventy samples of rice purchased from local markets in six cities from Morocco (Rabat, Casablanca, Kénitra, Mohammadia, Tanger and Errachidia) were analyzed for the presence of six emerging mycotoxins: four enniatins ENs (ENA, ENA₁, ENB and ENB₁), beauvericin (BEA) and fusaproliferin (FUS). Samples were extracted with a mixture of acetonitrile/water (85/15, v/v) by using an ultra-turrax homogenizer. Mycotoxins were then identified and quantified with liquid chromatography (LC) coupled to diode array detector (DAD). Positive samples were confirmed with an LC-MS/MS. Analytical results showed that BEA was present in 75.7% of total analyzed samples. BEA levels varied between 3.8 and 26.3 mg/kg. The frequencies of contamination of samples with total ENs and FUS were 50% and 4.3%, respectively. Among the ENs, ENB was the mycotoxin much more found (30% of total samples), while ENB₁, ENA and ENA₁ were found in 24.6%, 22.8% and 5.7% of total samples, respectively. The high ENs value was registered in a rice sample from kénitra (448.7 mg/kg of ENA₁). This is the first study that describes the presence of emerging Fusarium mycotoxins in rice available in Morocco.     

The dynamics of avalanches of granular materials from initiation to runout. Part II. Experiments

Summary This paper describes a model to predict the flow of an initially stationary mass of cohesionsless granular material down a rough curved bed and checks it against laboratory experiments that were conducted with two different kinds of granular materials that are released from rest and travel in a chute consisting of a straight inclined section, a curved segment that is followed by a straight horizontal segment. This work is of interest in connection with the motion of landslides, rockfalls and ice and dense flow snow avalanches. Experiments were performed with two different granular materials, nearly spherical glass beads of 3 mm nominal diameter, Vestolen particles (a light plastic material) of lense type shape and 4 mm nominal diameter and 2,5 mm height. Piles of finite masses of these granular materials with various initial shapes and weight were released from rest in a 100 mm wide chute with the mentioned bent profile. The basal surface consisted of smooth PVC, but was in other experiments also coated with drawing paper and with sandpaper. The granular masses under motion were photographed and partly video filmed and thus the geometry of the avalanche was recorded as a function of position and time. For the two granular materials and for the three bed linings the angle of repose and the bed friction angle were determined. The experimental technique with which the laboratory avalanches were run are described in detail as is the reliability of the generated data. We present and use the depth-averaged field equations of balance of mass and linear momentum as presented by Savage and Hutter [28]. These are partial differential equations for the depth averaged streamwise velocity and the distribution of the avalanche depth and involve two phenomenological parameters, the internal angle of friction, ø, and a bed friction angle, , both as constitutive properties of Coulomb-type behaviour. We present the model but do not derive its equations. The numerical integration scheme for these equations is a Lagrangian finite difference scheme used earlier by Savage and Hutter [27],[28]. We present this scheme for completeness but do not discuss its peculiarities. Comparison of the theoretical results with experiments is commenced by discussing the implementation of the initial conditions. Observations indicate that with the onset of the motion a dilatation is involved that should be accomodated for in the definition of the initial conditions. Early studies of the temporal evolution of the trailing and leading edges of the granular avalanche indicate that their computed counterparts react sensitively to variations in the bed friction angle but not to those of the internal angle of friction. Furthermore, a weak velocity dependence of the bed friction angle, , is also scen to have a small, but negligible influence on these variables. We finally compare the experimental results with computational findings for many combinations of the masses of the granular materials and bed linings. It is found that the experimental results and the theoretical predictions agree satisfactorily. They thus validate the simple model equations that were proposed in Savage and Hutter [28].     

Plane steady shear flow of a cohesionless granular material down an inclined plane. A model for flow avalanches Part II: numerical results

Summary The granular flow model proposed by Jenkins and Savage., [2], and extended by us [1] is used here to construct numerical solutions of steady chute flows thought to be typical of such flows.We briefly state the equations and boundary conditions and present numerical solutions when the following model parameters of the Senkins and Savage model are varied: (a) the coefficient of restitution of the particles under binary collision, (b) the number of particles per layer, (c) the inclination angle of the chute, and (d) the basal and free surface boundary conditions. We demonstrate that the Jenkins and Savage model may yield physically questionable results, that those of its extension differ markedly from them and are physically more reasonable in certain cases, but yield equally questionable results in others. The results are apt to redefine research directions which granular flow modellers might want to pursue in the near future.With 18 Figures     

Evolution of weakly non-linear shallow water waves generated by a moving boundary

Summary In this study we describe the evolution of weakly non-linear shallow water waves in a rectangular channel of 16 m length which aregenerated by a moving boundary. We present a detailed comparison of computaticnal and observational waveheight-time series and thus verify the theoretical model as presented by Villeneuve and Savage [27].Three different types of wave generating devices were used: pistons with vertical and inclined frontal faces, submerged boxes and a rotating plate. Waveheight-time series are recorded at eight different positions along the channel by electrical resistivity gauges, and velocity profiles are determined at certain selective cross sections. Data of many wave experiments are presented in nondimensional form. This representation reveals that the initial wave forms depend upon a Froude number of the motion of the wave generator, the slope angle of the wedge-type pistons and on the dimensionless displaced volume. Evolving waveheight-time series that are recorded at the various gauges are compared with those obtained from computations by use of equations which generalize the Boussinesq equations to include time variations of the boundaries.The method of inverse scattering is applied both, experimental and numerical waveheight-time series are prescribed as initial data. Results are tested relative to two different observers one fixed in time the other fixed in space. Deviations are shown to be small in all cases.     

Characterization of the Absorption of Theophylline From Immediate- and Controlled-Release Dosage Forms With a Numerical Approach Using the In Vitro Dissolution-Permeation Process Using Caco-2 Cells

After oral administration, drug absorption rate is recognized to be dependent on two major factors: dissolution and intestinal cells permeability. Caco-2 monolayer cells have been largely used as a permeation study model. In this study, a numerical approach funded on an exponential first-order time relationship was tested to compare immediate- and controlled-release tablets of theophylline using a dissolution-permeation system. The dissolution performance using USP II paddle apparatus was coupled to the permeability studies investigated in Caco-2 cell monolayers. The dissolved samples were taken at different times; their pH and osmolarity were adjusted to render them suitable to Caco-2 permeability studies (osmolarity = 300 mosm, pH = 7.4). The experimental data show that the dissolution fits the exponential first-order relationship rate. The permeability values were in a range of 4.45 10^- 6-5.28 10^- 6 cm/s, and percentages of absorbed drug dose were dependent on the fraction initially present in the donor compartment, indicating that absorption of theophylline was dissolution rate limited. Plotting experimental absorbed fractions (F_a) against experimental dissolved fractions (F_d) show that permeation is the rate-limiting step in drug absorption process in the extended release form of theophylline. Our results demonstrate a general agreement between observed F_a/F_d relationships and theoretical F_a/F_d relationships obtained with our approach funded on dissolution and permeation behavior. We concluded that the couple dissolution-caco-2 system could be a useful tool to characterize intestinal permeation for a new formulation of a drug compared with the conventional one.     

Managing Structural Information by Higher-Order Colored Unification

Coloring terms (rippling) is a technique developed for inductive theorem proving that uses syntactic differences of terms to guide the proof search. Annotations (colors) to symbol occurrences in terms are used to maintain this information. This technique has several advantages; for example, it is highly goal oriented and involves little search. In this paper we give a general formalization of coloring terms in a higher-order setting. We introduce a simply typed calculus with color annotations and present appropriate algorithms for the general, pre-, and pattern unification problems. Our work is a formal basis to the implementation of rippling in a higher-order setting, which is required, for example, in the case of middle-out reasoning. Another application is in the construction of natural the language semantics, where the color annotations rule out linguistically invalid readings that are possible using standard higher-order unification.     

Coloring Terms to Control Equational Reasoning

In this article we present an approach to prove the equality between terms in a goal-directed way developed in the field of inductive theorem proving. The two terms to be equated are syntactically split into expressions that are common to both and those that occur only in one term. According to the computed differences we apply appropriate equations to the terms in order to reduce the differences in a goal-directed way. Although this approach was developed for purposes of inductive theorem proving – we use this technique to manipulate the conclusion of an induction step to enable the use of the hypothesis – it is also a powerful method for the control of equational reasoning in general.     

Unraveling robustness of deep face anti-spoofing models against pixel attacks

Multimedia Tools and Applications - In the last few decades, deep-learning-based face verification and recognition systems have had enormous success in solving complex security problems. However,...