88 research outputs found
An simple technique for synthesis of carbon nanotubes by underwater arc plasma
Applicable, low cost technique for the production of carbon nanotubes by underwater (or solution) AC arc plasma discharge is described. The growth takes place in an AC arc in water solution between graphite electrodes.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200
MODELING, SIMULATION AND ENERGY EFFICIENCY DETERMINATION OF A PNEUMATIC PRESSURE AMPLIFIER
In order to increase energy efficiency of a pneumatic system the compressed air discharged from pneumatic actuator is being collected. In those conditions, the air contains a certain amount of energy and can be used at the points Ā that require a lower level of pressure for their operations. If the collected air can not be directly returned and used in a pneumatic system, then the air pressure is increased by using pressure intensifier which is known in the commercial use as pneumatic booster. For that operation, the booster usesĀ and consumes a part of the collected air. In this paper we analyze the dynamic behavior of a pressure boosterĀ and calculate its energy efficiency by using mathematical modeling and simulation in Simulink. The model of one pneumatic booster and its energy efficiency is verified by conducted experimental testing
Hemijski sastav i antifungalna aktivnost etarskog ulja daglasove jele (Pseudosuga menziesii mirb. Franco) iz Srbije
The chemical composition of the essential oil of fresh young needles with twigs of Douglas fir (Pseudosuga menziesii Mirb. Franco) obtained by hydrodistillation were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Ten compounds, accounting for 94.26 % of the oil, were identified. The main compounds found were bornyl acetate (34.65 %), camphene (29.82 %), alpha-pinene (11.65 %) and santene (5.45 %). The antifiangal activity of the essential oil was tested against various fungal species. The minimum inhibitory concentration of Douglas fir essential oil ranged from 1.5 to 4 mu g mL(-1). The fungi most sensitive to the tested oil were Phomopsis helianthi, while Penicillium species, along with Microsporum canis, were the most resistant. Compared to the commercial fungicidal agent bifonazole, the studied essential oil demonstrated higher antifungal activity.Hemijski sastav etarskog ulja mladih iglica sa granÄicama duglazije (Pseudosuga menziesii Mirb. Franco) dobijenog destilacijom vodenom parom, analiziran je gasnom hromatografijom (GC) i kombinacijom gasne hromatografije i masene spektrometrije (GC/MS). Identifikovano je deset jedinjenja ukupne zastupljenosti 94,26 %. Kao glavne komponente su naÄeni: bornil-acetat (34,65 %), kamfen (29,82 %), Ī±-pinen (11,65 %) i santen (5,45 %). Pored toga, etarsko ulje je testirano na antifungalnu aktivnost. Etarsko ulje pokazuje mnogo bolju antifugalnu akivnost od komercijalnog fungicidnog agensa bifonazola. Minimalna inhibitorna koncentracija etarskog ulja duglazije je u opsegu od 0,6 do 1,4 Ī¼L mL-1. Najosetljiviji na testirano ulje je bio soj Phomopsis helianthi, dok sojevi Penicillium i Microsporum canis pokazuju najveÄu rezistentnost
Supplementary data for article: Novakovic, M.; Nikodinovic-Runic, J.; Veselinovic, J.; Ilic-Tomic, T.; Vidakovic, V.; Tesevic, V.; Milosavljevic, S. Bioactive Pentacyclic Triterpene Ester Derivatives from Alnus Viridis Ssp. Viridis Bark. Journal of Natural Products 2017, 80 (5), 1255ā1263. https://doi.org/10.1021/acs.jnatprod.6b00805
Supporting information for: [https://doi.org/10.1021/acs.jnatprod.6b00805]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2466
Supplementary data for article: Novakovic, M.; Bukvicki, D.; Andjelkovic, B.; Ilic-Tomic, T.; Veljic, M.; Tesevic, V.; Asakawa, Y. Cytotoxic Activity of Riccardin and Perrottetin Derivatives from the Liverwort Lunularia Cruciata. Journal of Natural Products 2019, 82 (4), 694ā701. https://doi.org/10.1021/acs.jnatprod.8b00390
Supporting information for: [https://doi.org/10.1021/acs.jnatprod.8b00390]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/3096
Supplementary data for article: NovakoviÄ, M. M.; StankoviÄ, M.; VuÄkoviÄ, I. M.; TodoroviÄ, N.; TrifunoviÄ, S. S.; TeÅ”eviÄ, V.; Vajs, V.; MilosavljeviÄ, S. M. Diarylheptanoids from Alnus Glutinosa Bark and Their Chemoprotective Effect on Human Lymphocytes DNA. Planta Medica 2013, 79 (6), 499ā505. https://doi.org/10.1055/s-0032-1328301
Supporting information for: [https://doi.org/10.1055/s-0032-1328301]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1630
Chemical Composition, Total Phenols and Flavonoids Contents and Antioxidant Activity as Nutritive Potential of Roasted Hazelnut Skins (Corylus avellana L.)
The present study evaluates natural composition of Serbian roasted hazelnut skins (HS) with potential role in application as functional nutrient of various food products. Total phenols (TPC) and flavonoids contents (TFC) in HS extracts obtained with dierent ethanol concentrations (10%āI, 50%āII and 96%āIII) and their antioxidant activities were investigated. The highest total phenols content (706.0 9.7 mgGAE/gextract) was observed in 96% ethanol HS extract. Ethanol HS extracts showed very high antioxidant activity with eective concentrations (EC50) ranged between 0.052 and 0.066 mg/mL. The phenol and flavonoid content of roasted HS extracts IāIII was determined by HPLC-ESI-MS/MS analyses. Contents of lipids, proteins, carbohydrates, metals, and C, H, N, S elements in roasted HS were also determined. Relatively high C/N, C/P and C/N/P ratios, rich metal contents and fatty acids composition indicated that hazelnut skin might be a good candidate for use as either human or fungal functional nutrient. In addition, possible application of phenolic HS extracts as UV booster was studied by recording UV spectra (220ā440 nm) of 10 mg/L of HS extracts IāIII combined with 10 mg/L of chemical sunscreen agent benzophenone-3 and in vitro sun protection factor (SPF) was calculated
Supplementary data for article: ÄorÄevic, N. O.; NovakoviÄ, M. M.; Pejin, B.; MutiÄ, J.; Vajs, V.; Pajovic, S. B.; TeÅ”eviÄ, V. Comparative Analytical Study of the Selected Wine Varieties Grown in Montenegro. Natural Product Research 2017, 31 (15), 1825ā1830. https://doi.org/10.1080/14786419.2017.1289209
Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2481]Supplementary material for: [https://doi.org/10.1080/14786419.2017.1289209
Supplementary data for article: Ilic-Tomic, T.; Sokovic, M.; Vojnovic, S.; Ciric, A.; Veljic, M.; Nikodinovic-Runic, J.; Novakovic, M. Diarylheptanoids from Alnus Viridis Ssp Viridis and Alnus Glutinosa: Modulation of Quorum Sensing Activity in Pseudomonas Aeruginosa. Planta Medica 2017, 83 (1ā2), 117ā125. https://doi.org/10.1055/s-0042-107674
Supplementary material for: [https://doi.org/10.1055/s-0042-107674]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2395
Diarylheptanoids from Alnus viridis ssp viridis and Alnus glutinosa: Modulation of Quorum Sensing Activity in Pseudomonas aeruginosa
Diarylheptanoids from the barks of Alnus viridis ssp. viridis (green alder) and Alnus glutinosa (black alder) were explored for anti-quorum sensing activity. Chemicals with anti-quorum sensing activity have recently been examined for antimicrobial applications. The anti-quorum sensing activity of the selected diarylheptanoids was determined using two biosensors, namely Pseudomonas aeruginosa PAO1 and Chromobacterium violaceum CV026. Although all of the investigated compounds negatively influenced the motility of P. aeruginosa PAO1, four were able to inhibit biofilm formation of this human opportunistic pathogen for 40-70%. Three of the diarylheptanoids (3, 4, and 5) negatively influenced the biosynthesis of pyocyanin, which is under the control of quorum sensing. Platyphyllenone (7) and hirsutenone (5) were able to inhibit the biosynthesis of violacein in C. violaceum CV026, with 5 being able to inhibit the synthesis of both biopigments. Only one of the tested diarylheptanoids (1) was shown to significantly decrease the production of acyl homoserine lactones (AHL) in P. aeruginosa PAO1, more specifically, production of the long chain N-(3-oxododecanoyl)- l-HSL. On the other side, four diarylheptanoids (2-5) significantly reduced the synthesis of 2-alkyl-4-quinolones, part of the P. aeruginosa quinolone-mediated signaling system. To properly assess therapeutic potential of these compounds, their in vitro antiproliferative effect on normal human lung fibroblasts was determined, with doses affecting cell proliferation between 10 and 100 mu g/mL. This study confirms that the barks of green and black alders are rich source of phytochemicals with a wide range of biological activities that could further be exploited as natural agents against bacterial contaminations and infections.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3034
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