Derivative FTIR spectroscopy for cluster analysis and classification of morocco olive oils

Fourier transform infrared (FTIR) spectra were employed for differentiation and classification of olive oils from several producing regions of Morocco. A preliminary treatment of the FTIR data was done by a derivative elaboration based on the Savitzky–Golay algorithm to reduce the noise and extract a largest number of analytical information from the spectra. A multivariate statistical procedure based on cluster analysis (CA) coupled to partial least squares-discriminant analysis (PLS-DA), was elaborated, providing an effective classification method. On the basis of a hierarchical agglomerative CA and principal component analysis (PCA), four distinctive clusters were recognised. The PLS-DA procedure was then applied to classify samples from the same regions, picked in different times, or unknown olive oil samples. The model was optimised by applying the Martens’ Uncertainty Test that provided to select the wavelength zones giving the most useful analytical information. The proposed method furnished results reliable in classifying olive oils from different lands with the advantages of being rapid, inexpensive and requiring no prior separation procedure.     

Inactivation of Escherichia coli O157:H7 in fruit juices by combined treatments of citrus fruit essential oils and heat

This work approaches the possibility of combining mild heat treatments with citrus fruit essential oils (EOs) to improve the effectiveness of heat treatments and thus to reduce treatment intensity. Concentrations between 10 and 200μL/L of lemon, mandarin, or orange EO were tested at 54°C for 10min in laboratory media, determining that 200μL/L of each EO was necessary to achieve a 5 log(10) reduction of the initial Escherichia coli O157:H7 concentration. A relationship could be established between sublethally injured cells after the heat treatment and inactivated cells after the combined process. In apple juice, the synergism in the inactivation of E. coli O157:H7 when adding 200μL/L of lemon EO might suppose a reduction in the treatment temperature (of 4.5°C) or in the treatment time (by 5.7 times) within the range of temperature assayed (54-60°C). Addition of 75μL/L of lemon EO was determined to achieve the same synergistic effect of the combined treatment when the initial inoculum was reduced from 3×10(7) to 3×10(4)CFU/mL. Since the addition of lemon EO did not decrease the hedonic acceptability of apple juice, the proposed combined treatment could be further studied and optimized for the production of new minimally processed juices.     

Economic growth and pollutant emissions in Tunisia: An empirical analysis of the environmental Kuznets curve

This paper investigates the relationship between economic growth and pollutant emissions for a small and open developing country, Tunisia, during the period 1961–2004. The investigation is made on the basis of the environmental Kuznets curve hypothesis, using time series data and cointegration analysis. Carbon dioxide (CO₂) and sulfur dioxide (SO₂) are used as the environmental indicators, and GDP as the economic indicator. Our results show that there is a long-run cointegrating relationship between the per capita emissions of two pollutants and the per capita GDP. An inverted U relationship between SO₂ emissions and GDP has been found, with income turning point approximately equals to $1200 (constant 2000 prices) or to $3700 (in PPP, constant 2000 prices). However, a monotonically increasing relationship with GDP is found more appropriate for CO₂ emissions. Furthermore, the causality results show that the relationship between income and pollution in Tunisia is one of unidirectional causality with income causing environmental changes and not vice versa, both in the short-run and long-run. This implies that an emission reduction policies and more investment in pollution abatement expense will not hurt economic growth. It could be a feasible policy tool for Tunisia to achieve its sustainable growth in the long-run.     

Design of a secondary standard for measuring arterial blood pressure

The measurement of blood pressure by mercury sphygmomanometer and auscultation is one of the oldest methods, and it is still widely used in health services. Nowadays, the usage of inexpensive electronic oscillometric devices for home and clinical use has increased dramatically. The purpose of this paper is to verify the reliability of such devices.     

Design and development of a data acquisition system for photovoltaic modules characterization

Testing photovoltaic generators performance is complicated. This is due to the influence of a variety of interactive parameters related to the environment such as solar irradiation and temperature in addition to solar cell material (mono-crystalline, poly-crystalline, amorphous and thin films). This paper presents a computer-based instrumentation system for the characterization of the photovoltaic (PV) conversion. It based on a design of a data acquisition system (DAQS) allowing the acquisition and the drawing of the characterization measure of PV modules in real meteorological test conditions.     

A systematic literature review for network intrusion detection system (IDS)

International Journal of Information Security - With the recent increase in internet usage, the number of important, sensitive, confidential individual and corporate data passing through internet...     

Design,Synthesis, in vitro and in silico Characterization of 2-Quinolone-L-alaninate-1,2,3-triazoles as Antimicrobial Agents

Due to the ever-increasing antimicrobial resistance there is an urgent need to continuously design and develop novel antimicrobial agents. Inspired by the broad antibacterial activities of various heterocyclic compounds such as 2-quinolone derivatives, we designed and synthesized new methyl-(2-oxo-1,2-dihydroquinolin-4-yl)-L-alaninate-1,2,3-triazole derivatives via 1,3-dipolar cycloaddition reaction of 1-propargyl-2-quinolone-L-alaninate with appropriate azide groups. The synthesized compounds were obtained in good yield ranging from 75 to 80 %. The chemical structures of these novel hybrid molecules were determined by spectroscopic methods and the antimicrobial activity of the compounds was investigated against both bacterial and fungal strains. The tested compounds showed significant antimicrobial activity and weak to moderate antifungal activity. Despite the evident similarity of the quinolone moiety of our compounds with fluoroquinolones, our compounds do not function by inhibiting DNA gyrase. Computational characterization of the compounds shows that they have attractive physicochemical and pharmacokinetic properties and could serve as templates for developing potential antimicrobial agents for clinical use.     

Chemical Synthesis of Organo-siloxene 2D Materials from Calcium Di-Silicide: Characterization,Dielectric and Electrochemical Studies

Silicon - Silicon is one of the most used materials in semiconductors and electronic devices. Its miniaturization in two-dimensional (2D) scale is now a great challenge to improve and/or extend its...     

First-principles investigations of structural,electronic and thermoelectric properties of β-Sb/GeI2 van der Waals heterostructures

Journal of Computational Electronics - Two-dimensional materials offer the potential to attain nanoscale optoelectronic and thermoelectric devices. In this paper, the electronic structure and...