MEMS Devices for Miniaturized Gas Chromatography

In the era of the Internet of Things, the need for mobile devices able to analyze accurately real samples with sometimes very small volumes is a must. Gas chromatography (GC) is a common laboratory technique widely used for analyzing semi-volatile and volatile compounds. However, this technique is not suitable to be used outside labs. The development of micro-machined processes encouraged the development of miniaturized gas chromatographs. This chapter focuses on the recent development in the field of miniaturized gas chromatography and its component up to the present in various fields of analyses

COMPARATIVE COMPOSITIONS AND ANTIBACTERIAL ACTIVITY OF THE ESSENTIAL OILS OF ANTHEMIS NOBILIS L. AND ANTHEMIS MIXTA L. (ASTERACEAE)

Objective: To evaluate the chemical composition of essential oils from aerial parts of Anthemis nobilis (An) and Anthemis mixta L (Am). and investigate their antibacterial property.Methods: The essential oils were isolated by hydro distillation and analyzed by GC and GC-MS. The disc diffusion and Agar dilution methods were used to screen the antibacterial activity against referenced and/or clinically isolated (HS) strains of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica, Klebsiella pneumonia and Shighuelle sonnei.Results: The main constituents of An essential oil were 3-methyl-2-buten-1-yl cyclopropane carboxylate (29.3%), vinyl-2,2-dimethylbutanoate (24.2%), glycidyl methacrylate (9.9%), 2-methylbutyl-2-mehylbutyrate (9.1%), isobutyl isobutyrate (7.8%) and 3,3,4-trimethylhexane (6.2%), while Am essential oil was mainly characterized by α-thujone (51.8%), β-thujone (14.6%), borneol (7.3%) and 3-hexen-1-ol (4.9%). An and Am essential oils exhibited the best antibacterial activity against the following strains of Escherichia coli ATCC 25922 (25±1.20, 32±1.00 mm), Pseudomonas aeruginosa ATCC 27853 (23±0.87, 32±0.76 mm) and Staphylococcus aureus ATCC 43300 (21±1.44, 25±1.24 mm inhibition zone diameters, respectively). Minimum inhibitory concentration (MICs) values of these oils were ranged from 32-128µg/ml.Conclusion: From this study, it can be concluded that the chemical composition of the essential oils was related to their antibacterial activity.Keywords: Anthemis nobilis L., Anthemis mixta L., Chemical composition, Antibacterial activit

Potentiel des composés bioactifs: étude des extraits de quelques plants steppiques de la flore Algérienne

La flore algérienne contient une grande variété d'espèces végétales présentant un potentiel pour être utilisé dans les réalisations médicinales. Lors de cette étude, les propriétés bioactives des plantes médicinales en provenance d'Algérie ont été évaluées pour sélectionner les espèces avec la plus grande aptitude à être utilisé dans des buts spécifiques, tout en validant scientifiquement leurs revendications médicales. L'activité antioxydante a été évaluée à l'aide de plusieurs essais de même les tests de cytotoxicité contre des lignées cellulaires tumorales humaines (pareille pour les cellules non tumorales) ont été effectué. Les composés bioactifs ont également été quantifiés par plusieurs méthodes. Les résultats ont été analysés en considérant les variations individuelles de chaque paramètre, mais aussi dans une approche agrégée en appliquant l'analyse en composante principale afin d'acquérir une connaissance approfondie sur le potentiel bioactif globale des espèces étudiés.En effet, T. pallescens a montré la plus forte activité antioxydante (54 à 240μg/ml), tandis que A. graveolens a donné la meilleure cytotoxicité contre des lignées cellulaires tumorales humaines (valeurs d’GI50 allant de 11 au 29μg). T. pallescens ressortaient comme espèces avec des composés teneurs les plus élevées de bioactive (phénols: 463 mg GAE, flavonoïdes: 194 mg CE, esters; 186 mg CAE; flavonols: 85 mg QE, dans l’extrait hydrique). D'un point de vue global, les espèces appartenant à la famille des lamiacées se sont avérés être les choix préférables comme source de composés bioactifs à haut potentiel, ces espèces seraient les matrices les plus appropriées compte tenu de leur bioactivité (en particulier la cytotoxicité) critère déduit à partir des données de l'ACPinfo:eu-repo/semantics/publishedVersio

Recent Advances in Targeting Clinical Volatile Organic Compounds (VOC)

This chapter introduces the significance of exploring volatile organic compounds (VOC) in clinical samples. Because exhaled-breath is easy to collect, unlimited, and instruments are already commercially available, VOC analysis in exhaled breath seems to be a promising tool for non-invasive detection of many diseases including infections, respiratory diseases, and cancers. Here, we have focused on some appropriate technologies to extract, pre-concentrate, and evaluate VOC biomarkers in exhaled breath. The second part of this chapter discusses the comprehensive GC × GC in bio-VOCs analysis and illustrates the potential of using this analytical technique

Enhanced Long-term Stability and Carbon Resistance of Ni/MnxOy-Al2O3 Catalyst in Near-equilibrium CO2 Reforming of Methane for Syngas Production

Herein we study the catalytic activity/stability of a new generation of cheap and readily available Ni and Al-based catalysts using two Mn precursors, namely Mn(NO3)2 and Mn(EDTA)2- complex in the reaction of CO2 reforming of methane. In this respect, Ni/Al2O3 and two types of Ni/MnxOy-Al2O3 catalysts were successfully synthesized and characterized using various analytical techniques: TGA, ICP, XRD, BET, FTIR, TPR-H2, SEM-EDX, TEM, XPS and TPO-O2. Utilization of Mn(EDTA)2- as synthetic precursor successfully furnished Ni/Al2O3-MnxOyY (Y = EDTA) catalyst which was more active during CO2 reforming of methane when compared to Ni/MnxOy-Al2O3 catalyst, synthesized using Mn(NO3)2 precursor. Compared to Ni/MnxOy-Al2O3, Ni/Al2O3-MnxOyY catalyst afforded near-equilibrium conversion values at 700 °C (ca. 95% conversion for CH4 and CO2, and H2/CO = 0.99 over 50 h reaction time). Also, Ni/Al2O3-MnxOyY showed more resistance to carbon formation and sintering; interestingly, after 50 h reaction time, the size of Ni0 particles in Ni/MnxOy-Al2O3 almost doubled while that of Ni/Al2O3-MnxOyY remained unchanged. The elevated conversion of CO2 and CH4 in conjunction with the observed low carbon deposition on the surface of our best catalyst (Ni/Al2O3-MnxOyY) indicated the presence of MnxOy oxide positioning mediated simultaneous in-situ carbon elimination with subsequent generation of oxygen vacant sites on the surface for more CO2 adsorption. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).Corrigendum to this article is here: https://doi.org/10.9767/bcrec.15.3.9855.907-907

Ultrasound Assisted Synthesis of Polylimonene and Organomodified-clay Nanocomposites: A Structural, Morphological and Thermal Properties

Polylimonene-clay nanocomposites (PLM-Mag 2, 3, 6 and 10% by weight of clay) were prepared by mixing Maghnite-CTA+ (Mag-CTA+) and polylimonene (PLM) in solution using ultrasonic irradiation. The catalyst preparation method were studied in order to determine and evaluate their structural, morphological and thermal properties. The Mag-CTA+ is an organophylic montmorillonite silicate clay prepared through a direct exchange process, using green natural clay of Maghnia (west of Algeria) called Maghnite. The Algerian clay was modified by ultrasonic-assisted method using cetyltrimethylammonuim bromide (CTAB) in which they used as green nano-reinforcing filler. Polylimonene was obtained by the polymerization of limonene, using Mag-H+ as a catalyst. The morphology of the obtained nanocomposites was studied by X-ray diffraction (XRD), scanning electronic microscopy (SEM), transmission electronic microscopy (TEM) and infrared spectroscopy (FT-IR). Thermogravimetric analysis (TGA) shows that the nanocomposites have a high degradation temperature (200−250 °C) compared with the pure polylimonene (140 °C). The analyses confirmed the chemical modification of montmorillonite layers and their uniformly dispersion in the polylimonene matrix. Exfoliated structures were obtained for low amounts of clay (2 and 3% by weight), while intercalated structures and immiscible regions were detected for high amounts of clay (6 and 10% by weight). Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

Synthesis and Characterization of PANI and Block Copolymer PANI-b-PEO Catalyzed by Maghnite (AlgerianMMT): Electrical and Electronic Domain

Polyaniline (PANI) and its block copolymer (PANI-PEO2000) has been prepared under effect of Maghnite-H+ (Algerian MMT) in different weight percentage (wt %) by cationic polymerization method. The structure of PANI and PANI-PEO2000 is predicted by the FT-IR and 1HNMR spectra. The thermal stability of homopolymer and block copolymer is confirmed by difference scanning calorimetry and analysis thermogravimetry. So after this results we can suggest that our heterogeneous catalyst called maghnite (Algerian MMT) can modified the morphology and the physical chemical properties of polyaniline (PANI) and its homolog block polyaniline-b-poly ethylene oxide (PANI-b-PEO2000) in the mild conditions under microwave irradiation

Green nanocomposites from rosin-limonene copolymer and algerian clay

Green nanocomposites from rosin-limonene (Ros-Lim) copolymers based on Algerian organophilic-clay named Maghnite-CTA+ (Mag-CTA+) were prepared by in-situ polymerization using di erent amounts (1, 5 and 10% by weight) of Mag-CTA+ and azobisisobutyronitrile as a catalyst. The Mag-CTA+ is an organophilic montmorillonite silicate clay prepared through a direct exchange process; the clay was modified by ultrasonic-assisted method using cetyltrimethylammonuim bromide in which it used as green nano-filler.The preparation method of nanocomposites was studied in order to determine and improve structural, morphological, mechanical and thermal properties ofsin.The structure and morphology of the obtained nanocomposites(Ros-Lim/Mag-CTA+) were determined using Fourier transform infrared spectroscopy, X-ray di raction, scanning electronic microscopy and transmission electronic microscopy. The analyses confirmed the chemical modification of clay layers and the intercalation of rosin-limonene copolymer within the organophilic-clay sheets. An exfoliated structure was obtained for the lower amount of clay (1% wt of Mag-CTA+), while intercalated structures were detected for high amounts of clay (5 and 10% wt of Mag-CTA+). The thermal properties of the nanocomposites were studied by thermogravimetric analysis (TGA) and show a significant improvement inthe thermal stability of the obtained nanocomposites compared to the purerosin-limonene copolymer (a degradation temperature up to 280ºC).info:eu-repo/semantics/publishedVersio

Detailed chemical composition and functional properties of Ammodaucus leucotrichus Cross. & Dur. and Moringa oleifera Lamarck

Edible Ammodaucus leucotrichus Cross. & Dur. and Moringa oleifera Lamarck are largely used in the Algerian Sahara. In this context, soluble sugars, fatty acids, organic acids, and tocopherols were characterized. Decoctions and hydroethanolic extracts were studied regarding their phenolic compounds by HPLC-DAD-ESI/MSn, and in-vitro cytotoxic, anti-inflammatory, and antibacterial activities were evaluated. Results indicate high contents of carbohydrates (glucose and sucrose) and significant levels of protein and mineral were recorded for both plants. Malic acid was the major organic acid alongside with α-tocopherol, while PUFA was predominant in M. oleifera and MUFA in A. leucotrichus. Flavonoid derivatives were the most abundant group, being luteolin-O-(malonyl-glucoside) the main compound in A. leucotrichus and quercetin-3-O-(6″-malonyl-glucoside) and 3-O-caffeoylquininc acid the major molecules in M. oleifera. Extracts exhibited significant cytotoxicity on Hela and MCF-7 cell lines. The anti-inflammatory activity was also higher in the hydroethanolic extracts, which also revealed the highest antibacterial effects, especially for Gram-positive bacteria.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013), L. Barros and R.M. Calhelha contract. The authors are also grateful to the Interreg España-Portugal for financial support through the project 0377_Iberphenol_6_E.info:eu-repo/semantics/publishedVersio