In this study, we present the results of investigation of plasma electrolytic anodization of aluminum by means of different experimental techniques, in few first minutes of the process. Scanning ...electron microscopy equipped with X-ray energy dispersive spectroscopy was used to study the aluminum oxide coating morphology, microstructure and composition as well as cross-sections of the obtained coating. The mechanism of evolution of microdischarges at the beginning of the plasma electrolytic anodization process is proposed. Our results indicate that during a single discharge event, new inner oxide layer is formed at the bottom of discharge channel, between the metal substrate and the Al2O3 layer. That new oxide layer and the gas that remains in the channel seem to present a higher barrier for dielectric breakdown then the original coating layer.
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We present certain novel insights into the processes that occur during the prolonged (several hours) plasma electrolytic oxidation (PEO) of aluminum. Scanning electron microscopy (SEM) equipped with ...the energy-dispersive spectroscopy option (EDS) was used to study morphologies of the PEO-formed ceramic coating/substrate (C/S) surfaces on aluminum. The morphologies of the oxide layers' cross-sections have also been examined. The plasma electron temperature was calculated from the spectral lines measured by the optical emission spectroscopy (OES). The obtained results demonstrate that during the one single discharge event, a completely new inner oxide layer is being formed at the bottom of the discharge channel. This layer is positioned between the metal substrate and the previous Al2O3 layers. It appears that this new oxide layer, together with the gas trapped in the channel becomes a barrier for the dielectric breakdown that is higher than the original coating layer itself.
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The catalytic degradation of hazardous organic contaminants in industrial wastewater is a promising technology. Reactions of tartrazine, the synthetic yellow azo dye, with Oxone® in the presence of ...catalyst in strong acidic condition (pH 2), were detected by using UV–Vis spectroscopy. In order to extend the applicability profile of Co-supported Al-pillared montmorillonite catalyst an investigation of Oxone® induced reactions were performed in extreme acidic environment. The products of the reactions were identified by liquid chromatography–mass spectrometry (LC-MS). Along with the catalytic decomposition of tartrazine induced by radical attack (confirmed as unique reaction path under neutral and alkaline conditions), the formation of tartrazine derivatives by reaction of nucleophilic addition was also detected. The presence of derivatives under acidic conditions slowed down the hydrolysis of tartrazine diazo bond in comparison to the reactions in neutral environment. Nevertheless, the reaction in acidic conditions (pH 2) is faster than the one conducted in alkaline conditions (pH 11). Theoretical calculations were used to complete and clarify the mechanisms of tartrazine derivatization and degradation, as well as to predict the UV–Vis spectra of compounds which could serve as predictors of certain reaction phases. ECOSAR program, used to estimate toxicological profile of compounds to aquatic animals, indicated an increase in the harmfulness of the compounds identified by LC-MS as degradation products from the reaction conducted for 240min. It could be concluded that an intensification of the process parameters (higher concentration of Oxone®, higher catalyst loading, increased reaction time, etc.) is needed in order to obtain only biodegradable products.
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•Degradation of tartrazine was investigated in the presence of Oxone®.•Co2+ impregnated pillared clay was tested as catalyst for degradation of tartrazine.•Mechanism of the reaction in an extremely acidic environment was clarified.•Toxicological profile of products to aquatic organisms was evaluated.•Degradation capacity and exquisite applicability in wide range of pH was proven.
Coordination effects have been considered through the most common interactions in the crystal structures of fluoro compounds (C–H/F and F/F interactions). The supramolecular profile of these effects ...is based on quantum-chemical calculations for the assessment of the interaction strength and electrostatic potential maps, which provide a qualitative insight into the examined effect. Coordination of aliphatic fluorides leads to an increase of the negative potential of the F atoms, and, hence, an increase in the hydrogen-bonding acceptor ability (strengthening of C–H/F interactions) and a weakening of the F/F interactions, due to an increase in repulsive interactions between the F atoms. There is no significant change in the potential of the F atoms due to coordination of C6-aromatic fluorides, as in the case of aliphatic ones. This results in slight changes in the strengths of the C–H/F and F/F interactions (coupled with parallel interaction at large offsets, PILO), in a noticeable enhancement of stacking interactions, as well as in a significant enhancement of interactions involving the π-system (F/π and C–H/π interactions). It has also been shown that a decrease in the charge of the metal ions leads to a decrease in the negative potential of the F atom and also that the nature of the metal ion has a significant influence on the value of the potential of the F atoms.
Objective: This article reviews the empirical findings directly or indirectly linking Entrepreneurial Orientation to Innovation Intensity in the period 2008-2018. It also investigates the fuzzy ...concept of Innovation Intensity and suggests some research avenues in the future. Research Design & Methods: The research method is based on critical and synthetic literature review. In a three-steps process, relevant papers were identified and classified. These samples were then analyzed and put into a perspective of the explaining then linking the concepts of Entrepreneurial Orientation and Innovation Intensity. Based on that, recommendations for future research are presented. Findings: Although many studies insinuate a positive relationship between Entrepreneurial Orientation and Innovation Intensity, there is no empirical research specifically targeting this link. The main reason seems to be a lack of clarity around the concept of “Intensity” itself. Contribution & Value Added: This study introduces a conceptualization of Innovation Intensity based studying the extant literature. Furthermore, it is good starting point for scholars interested in clarifying the concept of Innovation Intensity or/and determining the nature of relationship linking this latter and Entrepreneurial Orientation.
Résumé
La maladie coeliaque et la maladie de Crohn sont deux maladies digestives chroniques d’étiopathogénie complexe, leur association chez un même malade est rare, posant un problème diagnostique ...et étiopathogénique. Nous rapportons l’observation d’une jeune patiente présentant une diarrhée chronique chez qui les bilans biologique, immunologique, endoscopique et histologique ont conclu à une maladie coeliaque associée à une maladie de Crohn colique droite et duodénale. La patiente a été mise sous régime sans gluten, inhibiteurs de la pompe à protons et corticothérapie orale puis un traitement par azathioprine. Après un recul d’un an, l’évolution a été marquée par une rémission clinique, biologique, endoscopique et histologique. À travers cette observation, nous soulignons la rareté de cette association et nous insistons sur l’étiopathogénie complexe de la maladie coeliaque qui pourrait avoir des points communs avec celle de la maladie de Crohn.
•Multiple Antigenic Peptides advantages justify the interest shown in them as potential vaccines.•The developed immunogen generated antibodies that cross-reacted with Aah II scorpion toxin.•Immunized ...mice showed partial protection against mortality caused by toxin challenge doses.•Mice immune sera had neutralizing properties against the Aah II toxin.•This concept could be used for various applications in scorpion, snake and spider envenomation.
Scorpion envenoming (SE) is a public health problem in developing countries. In Algeria, the population exposed to the risk of SE was estimated at 86.45% in 2019. Thus, the development of a vaccine to protect the exposed population against scorpion toxins would be a major advance in the fight against this disease.
This work aimed to evaluate the immunoprotective effect of a Multiple Antigenic Peptide against the Aah II toxin of Androctonus australis hector scorpion, the most dangerous scorpion species in Algeria. The immunogen MAP1Aah2 was designed and tested accordingly. This molecule contains a B epitope, derived from Aah II toxin, linked by a spacer to a universal T epitope, derived from the tetanus toxin.
The results showed that MAP1Aah2 was non-toxic despite the fact that its sequence was derived from Aah II toxin. The immunoenzymatic assay revealed that the 3 immunization regimens tested generated specific anti-MAP1Aah2 antibodies and cross-reacted with the toxin. Mice immunized with this immunogen were partially protected against mortality caused by challenge doses of 2 and 3 LD50 of the toxin. The survival rate and developed symptoms varied depending on the adjuvant and the challenge dose used. In the in vitro neutralization test, the immune sera of mice having received the immunogen with incomplete Freund’s adjuvant neutralized a challenge dose of 2 LD50.
Hence, the concept of using peptide dendrimers, based on linear epitopes of scorpion toxins, as immunogens against the parent toxin was established. However, the protective properties of the tested immunogen require further optimizations.
In vivo measurements of the optical properties of plant leaves, by spectrophotometric methods, could potentially provide very useful information for the assessment of the plant's health. This paper ...describes a novel experimental set-up that enables continuous measurements of the optical reflection and transmission coefficients of broad-leaved plants. The optical spectral characteristics of leaves, in the broad wavelength range, are often a discussed topic in the scientific literature. Nevertheless, to the best of our knowledge, the real-time spectral analyses of the leaf haven't been reported so far. Monitoring the evolution of the plant activity in real-time has resulted in the graph of the spectral Circadian rhythm as a function of time. The set-up was tested on Phaseolus vulgaris and the results of the measurements are presented and discussed.
Well-balanced nutrition is important for the successful cultivation of healthy plants. In this paper, we demonstrate a nondestructive optical method that can sense a deficiency of certain nutrients. ...The setup was tested on hydroponically grown Ocimum basilicum. The plants were subjected to nutrient deficiency by the exclusion of one of the essential elements (Fe, Mg, P, N) from the hydroponic solution. A control group of plants, fed by the balanced hydroponic solution, was also grown under the same conditions. The proposed method tracks and records the optical transmittance of the plants' leaves. All groups exhibit clearly defined day-night Circadian rhythms. When compared to the control group, the treated plants exhibited modified circadian rhythms of the optical transmission, suggesting an early indicator of the plants' stress. The condition of the plants under test was also assessed by the more common (destructive) methods such as: measurements of the determination of the photosynthetic pigment content, dray weight determination and the efficiency of PSII. Several biological parameters were observed, calculated and compared to the graphs of optical transmission dependence in real time. Presented results have demonstrated a significant potential of the proposed optical method for the early detection of plants' stress in hydroponic cultivation.
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