394 research outputs found
Chemical composition and antiradical capacity of essential oils from Lebanese medicinal plants
No full textEssential oils from five wild species growing in Lebanon and used in traditional medicine were obtained by hydrodistillation. Their chemical composition was determined by gas chromatography (GC) and GC-mass spectrometry (GC-MS), and the major constituents were α-pinene in Juniperus excelsa M. Bieb. (68.8-86.8%, according to different organs), carvacrol in Thymbra spicata L. (65.8%) and Coridothymus capitatus (L.) Rchb. f. (47%), pulegone in Mentha spicata L. subsp. condensata (Briq.) Greuter & Burdet (32.8%) and 1,8-cineole in Salvia fruticosa (Mill.) K. Schum. (48.7%). Antiradical capacity of the essential oils was measured in vitro by the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTSs+) radical cation and 2,2-diphenyl-picryl hydrazyl (DPPHs) radical assays. A good agreement between the two tests was recorded: C. capitatus and T. spicata oils showed the highest ABTSs+ and DPPHs radical-scavenging activity, possibly due to their high levels of carvacrol, whereas the lowest antiradical capacity was reported for J. excelsa oils
Chemical composition and antimicrobial activity against food-related microorganisms of different essential oils from Lebanon
No full textEssential oils (EOs) have long been recognized for their medicinal properties. Application of EOs in food preservation has gained recent interest as natural alternatives to conventional chemicals. Even though the properties of EOs are extensively documented, their effect on several food-related microorganisms is yet to be explored. In this study, six EOs were extracted by hydrodistillation and analyzed using GC/MS techniques, and then antimicrobial activity was tested against microorganisms of food interests through minimal inhibitory concentration (MIC) techniques. Both Coridothymus capitatus and Origanum syriacum EOs showed an antifungal activity (MIC ≤ 0.625 μL/mL). Interestingly all foodborne pathogens tested were sensitive to C. capitatus EO and two of them, Staphylococcus aureus and Listeria monocytogenes, to O. syriacum EO (MIC ≤ 1.25 μL/mL) while the beneficial food-related bacteria (Lactobacillus sp.) were not affected (MIC ± 10 μL/mL). Finally, Cinnamomum zeylanicum EO showed a broader antimicrobial activity on all microorganisms analyzed. Practical Applications: Essential oils from Lebanese plants could be used to selectively control foodborne pathogens, including fungi and bacteria. These essential oils could represents an alternative to conventional anti microbials as they did not affect benefiacial food-related bacteria
Antimicrobial activity of essential oils from three wild Lamiaceae species in Lebanon - an in vitro and in vivo studies
No full textEssential Oil from Berries of Lebanese Juniperus excelsa M. Bieb Displays Similar Antibacterial Activity to Chlorhexidine but Higher Cytocompatibility with Human Oral Primary Cells
No full textChlorhexidine (CHX), one of the most effective drugs administered for periodontal treatment, presents collateral effects including toxicity when used for prolonged periods; here, we have evaluated the bactericidal potency and the cytocompatibility of Juniperus excelsa M. Bieb essential oil (EO) in comparison with 0.05% CHX. The EO was extracted from berries by hydrodistillation and components identified by gas chromatography and mass spectrometry. Bacterial inhibition halo analysis, quantitative cell viability 2,3-bis(2-methoxy-4-nitro-5-sulphophenyl)-5-[(phenyl amino) carbonyl]-2H-tetrazolium hydroxide assay (XTT), and colony forming unit (CFU) count were evaluated against the two biofilm formers Aggregatibacter actinomycetemcomitans and Streptococcus mutans. Finally, cytocompatibility was assessed with human primary gingival fibroblasts (HGF) and mucosal keratinocytes (HK). The resulting EO was mainly composed of monoterpene hydrocarbons and oxygenated monoterpenes. An inhibition halo test demonstrated that both bacteria were sensitive to the EO; XTT analysis and CFU counts confirmed that 10-fold-diluted EO determined a statistically significant (p < 0.05) reduction in bacteria count and viability towards both biofilm and planktonic forms in a comparable manner to those obtained with CHX. Moreover, EO displayed higher cytocompatibility than CHX (p < 0.05). In conclusion, EO exhibited bactericidal activity similar to CHX, but a superior cytocompatibility, making it a promising antiseptic alternative to CHX
Complete Catheter Disconnection and Migration of an Implantable Venous Access Device: The Disconnected Cap Sign
No full textThe use of totally implantable venous access device has provided a solution to difficult venous access. Early reports have, however, recognized several complications with their use. Catheter disruption is a rare but important complication of these devices; it may be asymptomatic but can be fatal in some cases. We present a case of a patient who had a rare and serious complication secondary to catheter disconnection from its chamber. © 2010 Annals of Vascular Surgery Inc.AITKEN DR, 1984, AM J SURG, V148, P633, DOI 10.1016-0002-9610(84)90340-4; ANDRIS DA, 1994, JPEN-PARENTER ENTER, V18, P531, DOI 10.1177-0148607194018006531; Ballarini C, 1999, ONCOLOGY-BASEL, V56, P97, DOI 10.1159-000011947; BARRIOS CH, 1992, ONCOLOGY, V49, P474; Behrend M, 2002, SURG TODAY, V32, P724; Biffi R, 1998, ANN ONCOL, V9, P767, DOI 10.1023-A:1008392423469; Biffi R, 1997, EUR J CANCER, V33, P1190, DOI 10.1016-S0959-8049(97)00039-7; Bodner LJ, 2000, CARDIOVASC INTER RAD, V23, P187, DOI 10.1007-s002700010041; Di Carlo I, 2000, J SURG ONCOL, V73, P172, DOI 10.1002-(SICI)1096-9098(200003)73:3172::AID-JSO113.0.CO;2-Z; Filippou Dimitrios K, 2004, World J Surg Oncol, V2, P36, DOI 10.1186-1477-7819-2-36; Gowda MR, 2004, ANGIOLOGY, V55, P557, DOI 10.1177-000331970405500512; GREENE FL, 1988, SOUTHERN MED J, V81, P580; HINKE DH, 1990, RADIOLOGY, V177, P353; Iannelli A, 2001, Minerva Chir, V56, P303; Karam AR, 2009, CLIN IMAG, V33, P140, DOI 10.1016-j.clinimag.2008.10.001; Kock HJ, 1998, WORLD J SURG, V22, P12; Koller M, 1998, J SURG ONCOL, V68, P166, DOI 10.1002-(SICI)1096-9098(199807)68:3166::AID-JSO63.0.CO;2-3; KOONINGS PP, 1994, J AM COLL SURGEONS, V178, P164; Lam AWC, 1999, JPN J CLIN ONCOL, V29, P643, DOI 10.1093-jjco-29.12.643; Liu JC, 2004, CLIN IMAG, V28, P223, DOI 10.1016-S0899-7071(03)00119-0; LOKICH JJ, 1985, J CLIN ONCOL, V3, P710; Maisey NR, 2003, BREAST, V12, P287, DOI 10.1016-S0960-9776(03)00060-2; Ouaknine-Orlando B, 1999, ANN FR ANESTH, V18, P949, DOI 10.1016-S0750-7658(00)87944-7; ROGGLA G, 1993, INT J SPORTS MED, V14, P345, DOI 10.1055-s-2007-1021190; Sattari Maryam, 2003, Interact Cardiovasc Thorac Surg, V2, P532, DOI 10.1016-S1569-9293(03)00137-3; SUAREZPENARANDA JM, 1995, AM J FOREN MED PATH, V16, P124; Surov A, 2008, ANGIOLOGY, V59, P90, DOI 10.1177-000331970730388312
Caractérisation et modélisation du bruit de basse fréquence dans les transistors bipolaires développés en technologie BiCMOS (nœud 55 nm) pour des applications RF et THz.
No full textIn this thesis, Si/SiGe:C heterojunction bipolar transistors (HBTs) issued from BiCMOS technologies developed for RF, THz and mm-wave applications are investigated. The BiCMOS technology (B55) studied in this work is based on a 55 nm CMOS node and is compared to a previous mature generation (BiCMOS9MW) developed on a 130 nm CMOS node. The main objective of this work is to investigate the impact of X-ray and Gamma-ray irradiations on these devices through Low Frequency Noise measurements. LFN study is considered as a high sensitive and non-destructive measurement technique to investigate the technological development from a generation to another. Technological developments of the B55 technology, collector structures and Emitter-Base dopant activation techniques, are investigated on both DC and excess noises: forward Gummel plots, 1/f noise and Generation-Recombination components respectively. Compact models are extracted for the two excess noise components, the suspected areas of the associated noise sources are located at the E-B surface and periphery. The degradations induced by X-ray and Gamma-ray on both DC measurements (excess Base current) and LFN ones (1/f noise and G-R components) are examined in function of the Total Ionizing Dose (TID). The main result is the higher tolerance of the B55 technology. Moreover, by studying the effects versus base current and geometrical parameters, compact models are developed classically for 1/f noise and, in more innovative ways, for G-R component. The induced LFN sources are suggested to be located in the vicinity of the spacer and STI oxides. A healing effect after annealing processes is also brought to the fore.Durant cette thèse, des transistors bipolaires à hétérojonction Si/SiGe:C (HBTs) issus de technologies BiCMOS développées pour des applications RF, THz et mm-wave sont étudiés. La principale technologie étudiée dans ce travail, BiCMOS B55, est basée sur un nœud CMOS 55 nm et elle est comparée à une génération plus mature BiCMOS9MW développée sur un nœud CMOS 130 nm. L’objectif principal de ces travaux est d’analyser l’impact des rayonnements X et Gamma sur ces composants par des mesures de bruit basse fréquence. Le bruit basse fréquence est une technique de mesure très sensible et non destructive utilisée comme indicateur de qualité et de performance durant le développement technologique. Les effets de certains paramètres technologiques de la filière B55, comme différentes structures de Collecteur et deux techniques d’activation des dopants de la jonction Emetteur-Base, sont étudiés à la fois sur les mesures DC et sur les composantes de bruit en excès : courbes de Gummel, bruit en 1/f et composantes de Génération-Recombination. A partir de la modélisation compacte du bruit basse fréquence, les sources de bruits associées sont localisées à la surface et à la périphérie de la jonction E-B. Ensuite, les effets induits par les rayonnements X et Gamma sur les mesures DC (courant de base excédentaire) et LFN (bruit en 1/f et composantes G-R) sont étudiés en fonction de la dose ionisante cumulée (TID). Le principal résultat est la tolérance aux irradiations plus élevée de la technologie B55. De plus, l’analyse de ces effets par rapport au courant de base et aux paramètres géométriques a permis de développer des modèles compacts, de manière classique pour le bruit en 1/f et de manière plus innovante pour les composantes G-R. Il est suggéré que les sources de bruit induites par les irradiations soient situées à proximité des oxydes spacer et STI. Enfin, un effet de guérison par recuit thermique des défauts générés est également mis en évidence
Plant-derived bioactives and oxidative stress-related disorders: a key trend towards health and longevity promotion
No full textChemical composition and antimicrobial activity of the essential oil of Juniperus excelsa M.Bieb. growing wild in Lebanon
No full textThe essential oils (EOs) isolated from the leaves and twigs of Juniperus excelsa M.Bieb. growing wild in Lebanon were characterized, and their antimicrobial activity and antiradical capacity were evaluated. The EOs were obtained by hydrodistillation using a Clevenger-type apparatus and characterized by GC and GC/MS analyses. The antimicrobial activity was evaluated by determining minimal inhibitory concentrations (MICs) against a Gram-positive and a Gram-negative bacterium, a yeast, and a dermatophyte with the broth microdilution technique. A total of 28 constituents was identified and accounted for 90.1 and 95.6% of the twig and leaf EO composition, respectively. Both EOs were essentially composed of monoterpene hydrocarbons (46.7 and 59.6% for twig and leaf EOs, resp.) and sesquiterpenes (39.4 and 32.1%, resp.). The main components were α-pinene, α-cedrol, and δ-car-3-ene. The J. excelsa EOs did not show any antiradical potential, but revealed interesting in vitro antimicrobial activities against Staphylococcus aureus and Trichophyton rubrum (MICs of 64 and 128 μg/ml, resp.). The three major compounds were tested separately and in combination according to their respective amounts in the oil. δ-Car-3-ene was the most active component and is undoubtedly one of the constituents driving the antifungal activity of J. excelsa essential oil, even though synergies are probably involved
Chemical Variability of the Essential Oil of Origanum ehrenbergii Boiss. from Lebanon, Assessed by Independent Component Analysis (ICA) and Common Component and Specific Weight Analysis (CCSWA)
No full textInternational audienceOriganum ehrenbergii Boiss., an endemic plant to Lebanon, is widely acknowledged in Lebanese traditional medicine. The aim of the present study was to evaluate the influence of the drying method, region, and time of harvest on yield and chemical composition of O. ehrenbergii essential oils (EOs). Plants were harvested monthly throughout 2013 and 2014, from two different regions, Aabadiye and Qartaba, then dried using two drying methods: lyophilization and shade-drying at 4 • C. EO was extracted by hydrodistillation and analyzed by GC/MS. GC-MS data, combined with independent component analysis (ICA) and common component and specific weight analysis (CCSWA), showed that drying techniques, region of harvest, and soil composition have no effect on the chemical composition of O. ehrenbergii EOs. Of the factors analyzed, only harvesting time affected the EO composition of this species. High and stable amounts of carvacrol, associated with reliable antimicrobial activities, were detected in material harvested between March and October. EOs obtained from plants harvested in Aabadiye in January and February showed high amounts of thymoquinone, related to anti-inflammatory and cytotoxic effects. The use of ICA and CCSWA was proven to be efficient, and allowed the development of a discriminant model for the classification of O. ehrenbergii chemotype and the determination of the best harvesting time
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