25 research outputs found

    Assessment of Antioxidant and Antibacterial Activities of Cystoseira mediterranea and Padina pavonica from Algerian North-East for a Potential Use as a Food Preservative

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    The aim of this work was to evaluate the antioxidant and antibacterial activities of two marine algae, Cystoseira mediterranea and Padina pavonica, extracts. Total phenols (TPC), carotenoids, and phlorotannins contents of the extracts obtained by four extraction solvents were determined and compared. The highest TPC content was observed for aqueous extract of C. mediterranea with 37.09±0.46 mg GAE/g DE followed by ethanol extract of P. pavonica (24.28±0.99 mg GAE/g DE), which showed the highest phlorotannins content (1.18±0.18 mg PE/g DE), while its methanol extract held carotenoids content of 66.96±4.78 μg g–1 DE. Ethanol extract of C. mediterranea exhibited the best antioxidant activity with an EC50 of 58.3±1.16 μg ml–1. The antibacterial activity screening against MRSA and E. coli showed that ethanol extract of C. mediterranea towards a Methicillin resistant Staphyloccocus aureus (20.33±0.28 mm) and E. coli (15.66±0.57 mm) was more efficient with MICs about 80 mg ml–1 and 20 mg ml–1, respectively. Ethanol extract of C. mediterranea seems to have the highest potential for use in food industries

    Symphony on strong field approximation

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    This paper has been prepared by the Symphony collaboration (University of Warsaw, Uniwersytet Jagiellonski, DESY/CNR and ICFO) on the occasion of the 25th anniversary of the 'simple man's models' which underlie most of the phenomena that occur when intense ultrashort laser pulses interact with matter. The phenomena in question include high-harmonic generation (HHG), above-threshold ionization (ATI), and non-sequential multielectron ionization (NSMI). 'Simple man's models' provide both an intuitive basis for understanding the numerical solutions of the time-dependent Schrodinger equation and the motivation for the powerful analytic approximations generally known as the strong field approximation (SFA). In this paper we first review the SFA in the form developed by us in the last 25 years. In this approach the SFA is a method to solve the TDSE, in which the non-perturbative interactions are described by including continuum-continuum interactions in a systematic perturbation-like theory. In this review we focus on recent applications of the SFA to HHG, ATI and NSMI from multi-electron atoms and from multi-atom molecules. The main novel part of the presented theory concerns generalizations of the SFA to: (i) time-dependent treatment of two-electron atoms, allowing for studies of an interplay between electron impact ionization and resonant excitation with subsequent ionization; (ii) time-dependent treatment in the single active electron approximation of 'large' molecules and targets which are themselves undergoing dynamics during the HHG or ATI processes. In particular, we formulate the general expressions for the case of arbitrary molecules, combining input from quantum chemistry and quantum dynamics. We formulate also theory of time-dependent separable molecular potentials to model analytically the dynamics of realistic electronic wave packets for molecules in strong laser fields. We dedicate this work to the memory of Bertrand Carre, who passed away in March 2018 at the age of 60

    Particularities of multi-cutter cutting dynamics

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    Certain particularities of steady continuous cutting dynamics for multi-cutter turning and the results of mathematical modeling are discussed in the paper. The effect of processing parameters on the excitation of vibration in the case of multi-cutter turning of a long cylindrical part with finite flexibility is studied. Depending on the fixing rigidity of the cutters and their relative positioning, different forms of the tool oscillation and formed chips are analyzed. The model is based on equations of motion and the cutting law in the form of a fractional function together with the equation for new surfaces formation which are represented as a system of differential-algebraic equations with several delays describing the dynamics of multi-cutter turning. These equations allow consider the regenerative mechanism of oscillations excitation in the system. The evolution of the cutter’s oscillations to steady regime in the case of an angular shift of the cutters, as well as the evolution of chips are shown in the work. An example of the operation of cutters, which angular shift allows to control the work of the cutting edges is given. The reasons for the stability loss and the self-oscillations excitation are noticed. The procedure for integrating systems of differentialalgebraic equations with retarded argument and the model of two-cutter turning taking into account the compliance of the cutting tool fixation is considered. Influence of the technological system parameters on the stability of continuous cutting regime is analyzed

    New readings of the multilingual Petelia curse tablet

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    Petelia 2 is a curse text written on a leaf-shaped lead tablet, 0.028m high and 0.184m wide.1 It was found on the surface at loc. Cassana, north of modern Strongoli, by Luigi Mazza. The inscription was fi rst published by Lazzarini (2004), with a small amount of further discussion in Lazzarini (2009);2 it was subsequently re-edited by Crawford (2011: 1475–77) without autopsy. Lazzarini dates the tablet to the fourth or early third century BC (Lazzarini 2004: 674), while Crawford dates it to c.300 BC (Crawford 2011: 1475). The tablet is now in the deposit of the Museo Nazionale Archeologico di Crotone (inventory no. 4016/M), where the members of the ‘Greek in Italy’ project examined it on the 16th September 2014.3 As a result of our autopsy we propose a different reading in column 4 and several possible reinterpretations of this section of the text [...

    Ocena podatności wód gruntowych na zanieczyszczenia przy użyciu metody Kherici w regionie Collo na równinie Talezza (NE Algieria)

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    The intrinsic vulnerability of groundwater aquifers refers to their sensitivity to all contamination coming from soil surface irrespective of the nature of the polluting. In order to improve the protection of groundwater, there must be a reduction in the infiltration of contaminants towards the reservoir through the impacting factors determination of this phenomenon by means of research. There are collected models that include particular number of factors which allow the determination of a sign of groundwater vulnerability of all superficial pollutions. The goal of the study centers on ascertaining the state of vulnerability and the risk of groundwater pollution of the Collo region with a new proposed method by Kherici. Generally, assessment methods of vulnerability and the danger of groundwater pollution employ parametric systems with numerical quotation, cartographic superposition where the analytical methods are based on equations. In this study, we consider the combination of criteria dependent on natural factors (thickness of the unsaturated zone, geologic facies, degree of auto-purification) and the causes of groundwater vulnerability to man-made pollution (anthropogenic factors).Podatność podziemnych poziomów wodonośnych odnosi się do ich wrażliwości na zanieczyszczenia pochodzące z powierzchni gleby, niezależnie od ich charakteru. Dla ochrony wód gruntowych konieczne jest ograniczenie infiltracji zanieczyszczeń po ustaleniu czynników wpływu metodami badawczymi. Istnieją modele obejmujące szereg czynników, które umożliwiają określenie podatności wód gruntowych na zanieczyszczenia powierzchniowe. Celem badań było określenie stanu podatności i ryzyka zanieczyszczenia wód gruntowych w regionie Collo za pomocą nowej metody zaproponowanej przez Kherici. W metodach oceny podatności i zagrożenia zanieczyszczeniem wód gruntowych stosowane są zwykle parametryczny system numeryczny i kartograficzne nałożenia, w których metody analityczne bazują na równaniach. W pracy rozważano kombinację kryteriów zależnych od czynników naturalnych (miąższość strefy nienasyconej, facje geologiczne i stopień samooczyszczenia) oraz przyczyny podatności wód gruntowych na zanieczyszczenia antropogeniczne

    Metabolic syndrome is associated with prostate enlargement: a systematic review, meta-analysis, and meta-regression on patients with lower urinary tract symptom factors

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    Background: Metabolic syndrome (MetS) is defined by at least three of the following five criteria: blood pressure ⩾130/85 mmHg, fasting blood glucose ⩾5.6 mmol/l, triglycerides concentration ⩾1.7 mmol/l, waist circumference ⩾102 cm (for men), and high-density lipoprotein cholesterol concentration <1.03 mmol/l (for men). MetS has been associated with worse lower urinary tract symptoms (LUTS) and higher International Prostate Symptom questionnaire scores. Materials and Methods: MEDLINE, Cochrane, ClinicalTrials.gov, and SCOPUS were critically appraised for all peer-reviewed manuscripts that suitably fulfilled our protocol’s inclusion criteria established a priori. Meta-analytical and meta-regression calculations were performed in R using the Sidik–Jonkman and Hartung–Knapp random effects model and predefined covariates. Results: A total of 70 studies (n = 90,206) were included in qualitative synthesis. From these, 60 studies focused on MetS and LUTS: 44 reported positive correlations, 5 reported negative correlations, 11 reported no association, and 10 studies focused on MetS and total prostate volume (TPV). MetS positively correlated with moderate LUTS [odds ratio (OR)  = 1.56, 95% confidence interval (CI) = 1.35–1.80], severe LUTS (OR = 2.35, 95% CI = 1.82–3.03), overactive bladder (OAB; OR = 3.2, 95% CI = 1.6–5.8), and nocturia severity (OR = 2.509, 95% CI = 1.571–4.007) at multivariate analysis. A total of 30 studies (n = 22,206) were included in meta-analysis; MetS was significantly associated with higher TPV (mean differences = 4.4450 ml, 95% CI = 2.0177–6.8723), but no significant predictive factors for effect sizes were discovered. Conclusion: Our meta-analysis demonstrates a significant association between the aggravating effects of MetS, which commonly coexists with obesity and benign prostate enlargement

    Near infrared few-cycle pulses for high harmonic generation

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    We report on the development of tunable few-cycle pulses with central wavelengths from 1.6 μm to 2 μm. Theses pulses were used as a proof of principle for high harmonic generation in atomic and molecular targets. In order to generate such pulses we produced a filament in a 4 bar krypton cell. Spectral broadening by a factor of 2 - 3 of a 40 fs near infrared input pulse was achieved. The spectrally broadened output pulses were then compressed by fused silica plates down to the few-cycle regime close to the Fourier limit. The auto-correlation of these pulses revealed durations of ∼ 3 cycles for all investigated central wavelengths. Pulses with a central wavelength of 1.7 μm and up to 430 μJ energy per pulse were employed to generate high order harmonics in Xe, Ar and N2. Moving to near infrared few-cycle pulses opens the possibility to operate deeply in the non-perturbative regime with a Keldysh parameter γ << 1. Hence, this source is suitable for the study of the non-adiabatic tunneling regime in most generating systems used for high order harmonic generation and attoscience
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