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1
Serbout, Sanae, Laurent Maxit e Frédéric Michel. "Vibration of a stiffened pipe filled with a bubbly liquid: analysis of resonance frequencies in function of bubble fraction". INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, n. 5 (1 agosto 2021): 1008–18. http://dx.doi.org/10.3397/in-2021-1730.
Abstract (sommario):
The characterization of the presence of bubbles in industrial fluid circuits may be extremely important for many safety issuses. It is well known that the acoustic properties of liquids can be drastically modified by a small amount of gaz content in the liquid. At sufficiently low frequencies, the speed of sound depends primarily on the gas volume fraction. The variation of the gas fraction may then induce some variations in the vibroacoustic behavior of the pipe transporting the liquid. Analysis of the pipe vibrations can then help in the monitoring of the bubble presence. In such a context, the aim of this study is to show how the the presence of bubbles in the liquid could affect the resonance frequencies of the pipe. A numerical vibroacoustical model has been developed to predict the vibroacoustical behavior of a stiffened cylindrical shell filled with a bubbly liquid exhibiting low frequency resonances. The model, experimentally verified with a well-characterized bubbly liquid, is then used to analyse the frequency shifts of the shell resonances in function of the bubble. Keywords : pipe, heavy fluid, numerical modelling, circumferential admittance approach, cylindrical shell, resonance frequency, void fraction
2
Quénet, E., G. Weil e V. Billard. "Optimisation de l’administration des agents anesthésiques inhalés : débit de gaz frais ou fraction délivrée ?" Annales Françaises d'Anesthésie et de Réanimation 27, n. 11 (novembre 2008): 900–908. http://dx.doi.org/10.1016/j.annfar.2008.07.097.
3
Jaussaud, Jérémie, Pierre Blanc, Pierre Bordachar, Raymond Roudaut e Hervé Douard. "Response to Cardiac Resynchronization Therapy: The Muscular Metabolic Pathway". Cardiology Research and Practice 2011 (2011): 1–5. http://dx.doi.org/10.4061/2011/830279.
Abstract (sommario):
Background. Changes in peripheral muscle in heart failure lead to a shift from aerobic to early anaerobic metabolism during exercise leading to ergoreflex overactivation and exaggerated hyperventilation evaluated by the VE/VCO2slope.Methods. 50 patients (38 males, years) performed cardio-pulmonary exercise test with gaz exchange measurement and echocardiographic evaluation before and 6 months after CRT.Results. The peak respiratory exchange (VCO2/ VO2) ratio was significantly reduced from to () and the time to the anaerobic threshold was increased from to seconds (). Peak VO2, VE/VCO2, peak circulatory power and NYHA were improved after CRT ( to ml/kg/min (), to (), to mmHg.ml/kg/min () and to ()). In addition, left ventricular ejection fraction and end-systolic volumes were improved from to % () and from to ml ().Conclusion. We suggest that CRT leads to an increase in oxidative muscular metabolism and postponed anaerobic threshold reducing exaggerated hyperventilation during exercise.
4
Traore, S., S. Ouedraogo-Kone, A. Samake, M. D. Traore e K. Bengaly. "Effet de l’association entre le tourteau de coton et les gousses de Piliostigma reticulatum (dc) Hochst sur l’ingestion et la digestibilité de la paille de riz". International Journal of Biological and Chemical Sciences 16, n. 3 (27 agosto 2022): 1071–83. http://dx.doi.org/10.4314/ijbcs.v16i3.14.
Abstract (sommario):
L’effet associatif entre les constituants d’une ration peut induire un effet positif ou negative sur les performances de production des ruminants,en function de la nature des constituants de la ration. De plus, La prediction de la valeur alimentaire de la ration sur la base de la somme des valeurs des constituants comporte beaucoup de limites. Deux essais ont été conduits pour évaluer l’effet associatif entre du tourteau de graine de coton non décortiquée (TBM) et les gousses de Piliostigma reticulatum (GP) sur l’ingestion volontaire (essai 1) et la fermentation in vitro à l’aide de la technique du gaz test (essai 2) de la paille de riz seule (PS) ou avec la mélasse et l’urée (PMU). Le TBM a été ajouté à PS ou à PMU dans la proportion: 70 / 30 (PS/TBM ou PMU / TBM). Les GP ont été ensuite substituées au TBM dans la proportion de 15%. Quatre rations ont été formulées pour l’essai 1: R1 (70% PS + 30% TBM), R2 (70% PMU + 30% TBM), R3 (70% PMU + 15% TBM + 15% GP) et R4 = R3 mais TBM et GP ont été distribués de façon séquentielle. Deux autres rations: 100% PS et 100% PMU en plus des rations précédentes, ont servi de substrats pour le gaz test. La ration R2 comparée à R1 a significativement (p < 0.05) amélioré les performances de croissance des taurillons. Par contre, l’apport de GP n’a pas eu d’effet car les GP n’ont pas été consommées tout au long de l’essai. Contrairement aux traitements PS et TBM (essai 2), les traitements PMU et TBM ont engendré une augmentation significative (p < 0.05) du taux horaire (c) de fermentation de la fraction insoluble (b), la concentration des acides gras volatiles (AGV) et la production de gaz à 12, 24, 36 et 48 h. L’interaction entre PMU, TBM et GP a été positive et significative. L’apport de la mélasse-urée en plus du tourteau et les gousses de Piliostigma a permis d’améliorer la valeur nutritive de la paille de riz.
The associative effect between the constituents of a ration can positively or negatively affect ruminant animals ‘performances, depending on the nature of the constituents of the ration. Moreover, predicting the feeding value of the ration by simply adding the individual feed value of the constituents has some limitations. Two trials were conducted to assess the associative effect between unhulled cottonseed meal (TBM) and Piliostigma reticulatum pods (GP) on voluntary intake (trial 1) and in vitro fermentation using the gas production technique (trial 2) of rice straw alone (PS) or PS with molasses and urea (PMU). TBM was added to PS or PMU in the proportion: 70/30 (PS/TBM or PMU/TBM). The GPs were then substituted for the TBM in the proportion of 15%. Four rations were formulated for trial 1: R1 (70% PS + 30% TBM), R2 (70% PMU + 30% TBM), R3 (70% PMU + 15% TBM + 15% GP) and R4 = R3 but TBM and GP distributed sequentially. Two other rations: 100% PS and 100% PMU in addition to the previous rations, served as substrates for the gas test. The R2 ration compared to R1 significantly (p < 0.05) improved the growth performance of the young bulls. On the other hand, the supply of GP had no effect because the GP were not consumed throughout the trial. Unlike the PS and TBM treatments (trial 2), the PMU and TBM treatments generated a significant increase (p < 0.05) in the hourly rate (c) of fermentation of the insoluble fraction (b), the concentration of volatile fatty acids (VFAs) and gas production at 12, 24, 36 and 48 h. The interaction between PMU, TBM and GP was positive and significant. The supply of molasses and urea in addition to cottonseed cake and Piliostigma pods improved the nutritional value of rice straw.
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Do, Dinh Nhat, Dinh Phuc Nguyen, Viet-Duc Phung, Xuan-Tien Le, Tuan Minh Le, Van Manh Do, Bui Quang Minh e Xuan Cuong Luu. "Fractionating of Lemongrass (Cymbopogon citratus) Essential Oil by Vacuum Fractional Distillation". Processes 9, n. 4 (29 marzo 2021): 593. http://dx.doi.org/10.3390/pr9040593.
Abstract (sommario):
Lemongrass essential oil has many compounds appropriate for application in foods, cosmetics, and pharmaceutical products. Of these, citral is a high-value compound of interest to industry. This work aims to evaluate the use of vacuum fractional distillation to separate lemongrass essential oil compounds, producing essential oil fractions containing high citral content. The effect of process parameters, namely vacuum pressure, type column, and energy input, on the fractionation time, content, and recovery of citral in the fractions, was investigated. The fractionation of lemongrass oils successfully provided five fractions, i.e., fraction 1 (F1), fraction 2 (F2), fraction 3 (F3), fraction 4 (F4), and fraction 5 (F5). GC-MS (Gas Chromatography-Mass Spectrometry) spectra showed that the main compound contained in F1 and F2 fractions was β-myrcene (>70%). Meanwhile, F4 and F5 were the two main fractions for citral recovery. The optimal conditions of the fractional distillation system included a column height of 400 mm, power input of 165 W, and pressure of 15 mmHg. These conditions correspond to the highest total citral content of 95%, with a recovery of 80% at the F4 and F5 fractions. Therefore, fractional vacuum distillation may be an effective method to upgrade lemongrass essential oil.
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Deng, Min, Pavlos Kollias, Zhe Feng, Chidong Zhang, Charles N. Long, Heike Kalesse, Arunchandra Chandra, Vickal V. Kumar e Alain Protat. "Stratiform and Convective Precipitation Observed by Multiple Radars during the DYNAMO/AMIE Experiment". Journal of Applied Meteorology and Climatology 53, n. 11 (novembre 2014): 2503–23. http://dx.doi.org/10.1175/jamc-d-13-0311.1.
Abstract (sommario):
AbstractIn this study, methods of convective/stratiform precipitation classification and surface rain-rate estimation based on the Atmospheric Radiation Measurement Program (ARM) cloud radar measurements were developed and evaluated. Simultaneous and collocated observations of the Ka-band ARM zenith radar (KAZR), two scanning precipitation radars [NCAR S-band/Ka-band Dual Polarization, Dual Wavelength Doppler Radar (S-PolKa) and Texas A&M University Shared Mobile Atmospheric Research and Teaching Radar (SMART-R)], and surface precipitation during the Dynamics of the Madden–Julian Oscillation/ARM MJO Investigation Experiment (DYNAMO/AMIE) field campaign were used. The motivation of this study is to apply the unique long-term ARM cloud radar observations without accompanying precipitation radars to the study of cloud life cycle and precipitation features under different weather and climate regimes. The resulting convective/stratiform classification from KAZR was evaluated against precipitation radars. Precipitation occurrence and classified convective/stratiform rain fractions from KAZR compared favorably to the collocated SMART-R and S-PolKa observations. Both KAZR and S-PolKa radars observed about 5% precipitation occurrence. The convective (stratiform) precipitation fraction is about 18% (82%). Collocated disdrometer observations of two days showed an increased number concentration of small and large raindrops in convective rain relative to dominant small raindrops in stratiform rain. The composite distributions of KAZR reflectivity and Doppler velocity also showed distinct structures for convective and stratiform rain. These evidences indicate that the method produces physically consistent results for the two types of rain. A new KAZR-based, two-parameter [the gradient of accumulative radar reflectivity Ze (GAZ) below 1 km and near-surface Ze] rain-rate estimation procedure was developed for both convective and stratiform rain. This estimate was compared with the exponential Z–R (reflectivity–rain rate) relation. The relative difference between the estimated and surface-measured rainfall rates showed that the two-parameter relation can improve rainfall estimation relative to the Z–R relation.
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Rieger, Tobias, Jessen C. Oey, Volodymyr Palchyk, Alexander Hofmann, Matthias Franke e Andreas Hornung. "Chemical Recycling of WEEE Plastics—Production of High Purity Monocyclic Aromatic Chemicals". Processes 9, n. 3 (16 marzo 2021): 530. http://dx.doi.org/10.3390/pr9030530.
Abstract (sommario):
More than 200 kg real waste electrical and electronic equipment (WEEE) shredder residues from a German dismantling plant were treated at 650 °C in a demonstration scale thermochemical conversion plant. The focus within this work was the generation, purification, and analysis of pyrolysis oil. Subsequent filtration and fractional distillation were combined to yield basic chemicals in high purity. By means of fractional distillation, pure monocyclic aromatic fractions containing benzene, toluene, ethylbenzene, and xylene (BTEX aromatics) as well as styrene and α-methyl styrene were isolated for chemical recycling. Mass balances were determined, and gas chromatography–mass spectrometry (GC-MS) as well as energy dispersive X-ray fluorescence (EDXRF) measurements provided data on the purity and halogen content of each fraction. This work shows that thermochemical conversion and the subsequent refining by fractional distillation is capable of recycling WEEE shredder residues, producing pure BTEX and other monocyclic aromatic fractions. A significant decrease of halogen content (up to 99%) was achieved with the applied methods.
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Krishnamoorthy, Gautham, Rydell Klosterman e Dylan Shallbetter. "A Radiative Transfer Modeling Methodology in Gas-Liquid Multiphase Flow Simulations". Journal of Engineering 2014 (2014): 1–14. http://dx.doi.org/10.1155/2014/793238.
Abstract (sommario):
A methodology for performing radiative transfer calculations in computational fluid dynamic simulations of gas-liquid multiphase flows is presented. By considering an externally irradiated bubble column photoreactor as our model system, the bubble scattering coefficients were determined through add-on functions by employing as inputs the bubble volume fractions, number densities, and the fractional contribution of each bubble size to the bubble volume from four different multiphase modeling options. The scattering coefficient profiles resulting from the models were significantly different from one another and aligned closely with their predicted gas-phase volume fraction distributions. The impacts of the multiphase modeling option, initial bubble diameter, and gas flow rates on the radiation distribution patterns within the reactor were also examined. An increase in air inlet velocities resulted in an increase in the fraction of larger sized bubbles and their contribution to the scattering coefficient. However, the initial bubble sizes were found to have the strongest impact on the radiation field.
9
Yeh, Chun-Lang. "Numerical study of the burner parameters on the thermal field in a sulfur recovery unit thermal reactor". MATEC Web of Conferences 169 (2018): 01013. http://dx.doi.org/10.1051/matecconf/201816901013.
Abstract (sommario):
A sulfur recovery unit (SRU) thermal reactor is the most important equipment in a sulfur plant and is negatively affected by high temperature operations. In this paper, the effect of burner parameters, including the clearance of the acid gas tip and the inlet air swirler angle, on the thermal field in a SRU thermal reactor are investigated numerically, with the aim to reduce the high temperature inside the thermal reactor and to ensure an acceptable sulfur recovery. The simulation results show that the burner with a smaller clearance of the acid gas tip produces a lower temperature, a lower exit SO2 mole fraction and higher exit S2 and H2S mole fractions. Among the clearancs of the acid gas tip investigated, the horizontal clearance of 152.4mm and vertical clearance of 240mm yield the lowest temperature, exit SO2 mole fraction and highest exit S2, H2S mole fractions. The burner with a smaller inlet air swirler angle produces a higher temperature, a higher exit SO2 mole fraction and lower exit S2 and H2S mole fractions. Among the swirler angles investigated, 60° yields the lowest temperature, exit SO2 mole fraction and highest exit S2 , H2S mole fractions.
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Sumi Lestari, Fajar, Ricson Pemimpin Hutagaol e Srikandi Srikandi. "Crystal guava (Psidium guajava L. “Crystal”) treated with gibberelic acid (GA3) : Evaluation of in vitro antioxidant capacities". Jurnal Pendidikan Kimia 15, n. 2 (30 agosto 2023): 82–90. http://dx.doi.org/10.24114/jpkim.v15i2.41780.
Abstract (sommario):
Free radicals can cause many diseases, such as cancer. Antioxidant is a compound that could scavenge free radicals. One of the natural source antioxidants is guava. The application of gibberellic acid (GA3) is known to affect the physicochemical properties and antioxidant content of the fruit. The goals of this research were to investigate the antioxidant activity of skin, flesh and fruit of crystal guava were given additional GA3 treatment with concentration 0; 60; 120; 180; 240; and 300 ppm by determining the value of the Antioxidant Activity Index (AAI) using DPPH; evaluate the total phenolic content (TPC), ferric reducing antioxidant power (FRAP) and physicochemical properties; analyse the correlation between the TPC with AAI DPPH by Pearson’s method. Extraction was performed by the maceration method using acetone 50% mixed with a magnetic stirrer for 1 h. Determination of AAI DPPH, FRAP and the TPC was performed by UV-Visible spectrophotometry. TPC in the flesh and fruit fractions tended to increase and FRAP values in all fractions decreased with GA3 application. The highest TPC and FRAP was given by the G3 treatment on the skin fraction and G0 treatment on the skin fraction. The highest AAI in all fractions was given by the G3 treatment. The TPC was significantly positively correlated with the AAI DPPH of the flesh and fruit fraction extracts (0.250 ≤ r ≤ 0.880), and the skin fraction extracts showed a strong negative correlation between TPC and AAI DPPH (-0.813 < r < -0.973).
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Oyinloye, Oladapo Elijah, A. A. Murtala, F. A. Oladoja, O. L. Okunye, A. A. Aderinola e E. O. Kasumu. "Evaluation of phytochemical constituents, total phenolic contents and in vitro antioxidant activities of Mucuna pruriens fractions leaves". Journal of Phytomedicine and Therapeutics 22, n. 1 (28 giugno 2023): 1017–34. http://dx.doi.org/10.4314/jopat.v22i1.2.
Abstract (sommario):
Mucuna pruriens is a tropical annual climbing legume plant used in traditional medicine systems to treat diabetes, arthritis, dysentery, hematinics, inflammation, and cardiovascular conditions. The present study investigates the phytochemical constituents, phenolic contents and in vitro, antioxidant potentials of M. pruriens leaf fractions using spectrophotometric methods. Phytochemical screening of hexane, chloroform, ethyl acetate, and methanol fractions of M. pruriens was determined using standard methods. The antioxidant activities of the fractions were assessed against total phenolic contents, total antioxidant contents, ferric ion reducing antioxidant power assay, and 1,1-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity using standard protocols. Phytochemical screening showed that only the ethyl acetate fraction of M. pruriens leaves contain all the phytochemical constituents tested for, saponins, tannins, flavonoids, cardiac glycosides, anthraquinones, terpenoids, steroids, alkaloids, phenol. The activities of the fractions against total phenolic contents were high in ethyl acetate fraction (1.958±0.24 mg GAE/g), while chloroform fraction gave the lowest total phenolic contents (1.476±0.19 mg GAE/g). On the contrary, chloroform fraction showed more significant total antioxidant contents (2.078±0.80 mg ASCE/g). The methanol fraction demonstrated higher ferric ion-reducing antioxidant power (4.866±1.19 mg ASCE/g). The methanol fraction scavenging activity against DPPH radical exhibited a lower IC50 value of 404.92 (μg/mL) relative to other fractions. It is concluded that ethyl acetate and methanolic fractions of Mucuna pruriens leaves, which contain large amounts of phenolic compounds, exhibited high antioxidant activities. These in vitro assays indicated that Mucuna pruriens leaves fraction is a significant source of natural antioxidants, which might help prevent the progress of various oxidative stresses.
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Manilal, Aseer, Sugathan Sujith, Balu Sabarathnam, George Kiran, Joseph Selvin, Chippu Shakir e Aaron Lipton. "Biological activity of the red alga Laurencia brandenii". Acta Botanica Croatica 70, n. 1 (1 gennaio 2011): 81–90. http://dx.doi.org/10.2478/v10184-010-0001-x.
Abstract (sommario):
Biological activity of the red algaLaurencia brandeniiThe marine red algaLaurencia brandeniicollected from the southwest coast of India (Indian Ocean) was extracted and fractioned using column chromatography. The individual fractions were evaluatedin vitrovia antimicrobial activity against six species of Microbial Type Culture Collection and three species of clinical human pathogens, antipest activity onSitophilus oryzae, maggoticidal activity against 2ndinstar larvae ofSarcophagasp. and termiticidal activity againstMicrotermes obesi.It was found that the fraction eluted using petroleum ether:chloroform (6:4) exhibited broader biological activities. The phyco-constituents of the active fraction were identified by gas chromatography-mass spectrometry (GC-MS) analysis. The GC-MS profile of the active fraction revealed that the main constituent was octadecadienoic acid (49.75%) followed by n-hexadecanoic acid (14.24%), which might have a functional role in the biological activities. The overall activity profile envisages that these bioactive compounds fromL. brandeniicould be utilized as a renewable natural resource for the development of novel environmental-compatible formulations for the control of human pathogens, pests, termites and maggots.
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Olive, John. "Bridging the Gap: Using Interactive Computer Tools to Build Fraction Schemes". Teaching Children Mathematics 8, n. 6 (febbraio 2002): 356–61. http://dx.doi.org/10.5951/tcm.8.6.0356.
Abstract (sommario):
Teaching fractions has been a complex and largely unsuccessful aspect of mathematics instruction in the elementary grades for many years. Students' understanding of fraction concepts is a big stumbling block in their mathematical development. Some researchers have pointed to children's whole-number knowledge as interfering with, or creating a barrier to, their understanding of fractions (Behr et al. 1984; Streefland 1993; Lamon 1999). This article illustrates an approach to constructing fraction concepts that builds on children's whole-number knowledge using specially designed computer tools. This approach can help children make connections between whole-number multiplication and their notion of a fraction as a part of a whole, thus bridging the gap between whole-number and fraction knowledge.
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Liu, Zhenguo, Kanji Nakatsu, James F. Brien, E. Danielle Beaton, Gerald S. Marks e Donald H. Maurice. "Selective sequestration of nitric oxide by subcellular components of vascular smooth muscle and platelets: relationship to nitric oxide stimulation of the soluble guanylyl cyclase". Canadian Journal of Physiology and Pharmacology 71, n. 12 (1 dicembre 1993): 938–45. http://dx.doi.org/10.1139/y93-142.
Abstract (sommario):
Sequestration of nitric oxide (NO) by subcellular fractions isolated from bovine pulmonary arterial medial layer (BPA) and rabbit platelets (RP) was studied utilizing a novel chemiluminescence – headspace gas technique. Sequestration in all fractions was similarly rapid (5 min) and remained constant for at least 30 min. When incubated with 108 pmol of NO, the BPA mitochondrial, microsomal, and nuclear fractions sequestered 22.8 ± 1.9, 20.5 ± 2.2 and 15.2 ± 3.6% of the NO, respectively (n = 14). However, significantly more of the 108 pmol of NO, 36.8 ± 2.8 and 32.9 ± 3.6%, respectively, was sequestered by the BPA homogenate (about 2 mg protein/mL) and BPA cytosolic fraction (about 1 mg protein/mL) (n = 19). Also, RP cytosolic fraction (about 3 mg protein/mL) sequestered a greater amount of NO than any BPA fraction when incubated with 108 pmol of NO (83.0 ± 1.0%; n = 3). Analysis of the binding data obtained for the BPA homogenate and cytosolic fraction was consistent with the existence of two binding sites, one site with a Kd of approximately 100 nM and another with a Kd of approximately 1 μM. Both the BPA homogenate fraction and the cytosolic fraction as well as the RP cytosolic fraction were shown to have soluble guanylyl cyclase activity. The nitrovasodilator sodium nitroprusside (SNP) caused a concentration-dependent increase in the activity of this enzyme in all these fractions. Maximum stimulations caused by 1 mM SNP in BPA homogenate fraction, BPA cytosolic fraction, and RP cytosolic fraction were equivalent to 2-, 4- and 3-fold increases in catalytic activity, respectively. No effect of SNP was observed in BPA mitochondrial, microsomal, or nuclear fraction. Prior incubation of BPA and RP cytosolic fractions with authentic NO significantly stimulated the soluble guanyiyl cyclase activity. In both the BPA and RP cytosolic fractions, maximal stimulation brought about by prior incubation with authentic NO was equivalent to approximately 60% of that caused by 100 μM SNP. Thus, incubation of subcellular fractions from two nitrovasodilator-sensitive tissues with authentic NO resulted in significant sequestration of the free radical in these fractions and a concentration-dependent activation of the soluble guanylyl cyclase. In conclusion, the chemiluminescence – headspace gas technique is a suitable method for the study of NO sequestration in subcellular fractions of various tissues. Also, this study demonstrates that NO is sequestered preferentially by subcellular fractions of BPA and RP that contain soluble guanylyl cyclase activity, and that the sequestration of NO in these fractions stimulates the catalytic activity of this enzyme.Key words: nitric oxide, vascular smooth muscle, platelets, soluble guanylyl cyclase.
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Cuevas-Rodríguez, Edith Oliva, Liliana León-López, Yudith Escobar-Zúñiga, Jorge Milán-Carrillo, Dulce María Domínguez-Arispuro e Roberto Gutiérrez-Dorado. "Chemical proximate composition, antinutritional factors content, and antioxidant capacity of anatomical seed fractions of Moringa oleifera". Acta Universitaria 30 (4 novembre 2020): 1–11. http://dx.doi.org/10.15174/au.2020.2892.
Abstract (sommario):
For rational use of moringa seeds and its anatomical fractions (kernel, shells, and wings), the objective of the present investigation was to analyze their chemical composition, antinutritional factors content, and antioxidant capacity. The seed kernel fraction represents 71.78% of the whole seed weight and possesses high contents of protein (32.19%) and lipids (38.72%), whereas seed shells and wings fractions are mainly composed of dietary fiber and carbohydrates. Phytate was the most abundant antinutritional factor detected in all fractions (604.0 mg PAE/100 g-1674.9 mg PAE/100 g), followed by total phenolics (218.5 mg GAE/100 g-386.9 mg GAE/100 g) and saponins (130.4 mg DE/100 g-197.4 mg DE/100 g). Moringa seeds fractions showed a high antioxidant capacity. The kernel fraction exerts the highest activity (15 251.90 μmol TE/100g), followed by shells (8 499.50 μmol TE/100g) and wings (5 878.90 μmol TE/100g). Moringa seed kernel fraction seems to be a promising source of protein. All anatomical seed fractions of moringa are a reservoir of dietary fiber and antioxidants.
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Lis, Bernadetta, Dariusz Jedrejek, Joanna Rywaniak, Agata Soluch, Anna Stochmal e Beata Olas. "Flavonoid Preparations from Taraxacum officinale L. Fruits—A Phytochemical, Antioxidant and Hemostasis Studies". Molecules 25, n. 22 (18 novembre 2020): 5402. http://dx.doi.org/10.3390/molecules25225402.
Abstract (sommario):
Dandelion (Taraxacum officinale L.) roots, leaves, and flowers have a long history of use in traditional medicine. Compared to the above organs, dandelion fruits are the least known and used. Hence, the present paper was aimed at the phytochemical analysis of T. officinale fruit extract and estimating its antiradical, antiplatelet, and antioxidant properties related to hemostasis. Methanolic extract of fruits (E1), enriched with polyphenols (188 mg gallic acid equivalents (GAE)/g), was successfully separated into cinnamic acids (E2; 448 mg GAE/g) and flavonoids (E3; 377 mg GAE/g) extracts. Flavonoid extract was further divided into four fractions characterized by individual content: A (luteolin fraction; 880 mg GAE/g), B (philonotisflavone fraction; 516 mg GAE/g), C (flavonolignans fraction; 384 mg GAE/g), and D (flavone aglycones fraction; 632 mg GAE/g). High DPPH radical scavenging activity was evaluated for fractions A and B (A > B > Trolox), medium for extracts (Trolox > E3 > E2 > E1), and low for fractions C and D. No simple correlation between polyphenol content and antiradical activity was observed, indicating a significant influence of qualitative factor, including higher anti-oxidative effect of flavonoids with B-ring catechol system compared to hydroxycinnamic acids. No cytotoxic effect on platelets was observed for any dandelion preparation tested. In experiments on plasma and platelets, using several different parameters (lipid peroxidation, protein carbonylation, oxidation of thiols, and platelet adhesion), the highest antioxidant and antiplatelet potential was demonstrated by three fruit preparations–hydroxycinnamic acids extract (E2), flavonoid extract (E3), and luteolin fraction (A). The results of this paper provide new information on dandelion metabolites, as well as their biological potential and possible use concerning cardiovascular diseases.
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Bronson, R. E., J. A. Treat e C. N. Bertolamp. "Fibroblastic Subpopulations in Uninjured and Wounded Rabbit Oral Mucosa". Journal of Dental Research 68, n. 1 (gennaio 1989): 51–58. http://dx.doi.org/10.1177/00220345890680010801.
Abstract (sommario):
Fibroblast cultures derived from uninjured and reparative rabbit buccal mucosa were compared in terms of extracellular glycosaminoglycan (GAG) content and cellular response to interleukin-1 (IL-1). Under identical growth conditions, proliferation of both cell lines was the same. Both lines incorporated [3H]-glucosamine into GAG in cellular, pericellular, and medium fractions, with the majority of incorporated label residing in the medium. Dermatan sulfate (DS) was the predominant GAG in the medium fraction of both normal and wound fibroblast cultures; however, the two cell lines differed in the identity of the medium fraction's secondary GAG: chondroitin sulfate (CS) for normal fibroblasts and hyaluronic acid (HA) for wound-derived cells. The GAG content of the pericellular matrix for all cultures was the same regardless of the tissue of origin: heparan sulfate (HS) accompanied by a very small amount of CS. Exposure to IL-1 produced limited but highly specific effects: It was not mitogenic for either cell line but did cause a quantitative change (increase) in overall incorporation into GAG for medium and pericellular fractions for both cell lines. Further, IL-1 induced a qualitative change in GAG composition for normal mucosal fibroblastic medium fractions by causing the synthesis/release of heparan sulfate (HS) and a variant form of DS. These data support the hypothesis that different fibroblastic substrains can populate a given oral site as a function of variables such as injury andlor healing status.
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Saleh, Ahmed Taha Abdullah Galeb, Amir T. Gilmutdinov e Igor G. Lapshin. "PHYSICAL AND CHEMICAL PROPERTIES OF OIL FRACTIONS FROM GAS CONDENSATE OF AL-MASILA FIELDS (REPUBLIC OF YEMEN)". Oil and Gas Business, n. 1 (6 marzo 2024): 161–75. http://dx.doi.org/10.17122/ogbus-2024-1-161-175.
Abstract (sommario):
The results of physical and chemical studies of gas condensate fractions, including gasoline, kerosene and diesel, are presented. Experiments were carried out on the separation of gasoline, kerosene and diesel fuel from gas condensate into fractions. The analysis showed that the collected gas condensate contains 38.02 % gasoline with a boiling point of 180 °C, 20.87 % kerosene with a boiling point of 140–240 °C and 43.67 % diesel fuel with a boiling point of 180–360 °C. The 140–240 °C fraction was obtained by secondary distillation of the straight-run fraction. The data obtained confirm that these fractions are high-quality raw materials for the production of motor gasoline, diesel fuel and jet fuel that meet modern standards. As a result of physical and chemical studies, the properties of the above mentioned fractions and their potential in the production of commercial petroleum products were determined.
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EL MDERSSA, Mohamed. "Détermination des paramètres d’évaluation du stock de carbone dans les écosystèmes forestiers (Cedrus atlantica Manetti, cèdre de l’Atlas au Maroc) : méthodes spécifiques et génériques". BOIS & FORETS DES TROPIQUES 351 (28 febbraio 2022): 67–77. http://dx.doi.org/10.19182/bft2022.351.a36330.
Abstract (sommario):
La quantification du carbone emmagasiné dans les écosystèmes forestiers et de son équivalent en CO2 constitue un impératif pour une estimation fiable de la contribution de ce puits de carbone dans la limitation des émissions de gaz à effet de Serre. La présente étude vise dans un premier temps, par une étude de terrain, à évaluer le volume de bois sur pied et à estimer la quantité de carbone contenue dans les parties aériennes et racinaires, tout en déterminant le facteur d’expansion et de conversion de la biomasse (FECB) spécifique du cèdre de l’Atlas (Cedrus atlantica Manetti) situé dans la zone du Moyen Atlas central. D’autre part, les résultats obtenus ont été comparés à ceux provenant de l’utilisation des paramètres génériques du Groupe d’experts Intergouvernemental sur l’évolution du climat (GIEC) en 2006. Le volume de bois sur pied et la biomasse aérienne ont été déterminés en utilisant des tarifs de cubage et des modèles de biomasse développés à partir des mesures directes du poids sec et du volume sur 30 arbres échantillonnés et prélevés dans chaque forêt de la zone d’étude. Le volume et la biomasse aérienne ont été évalués respectivement à 3 321 284 m3 et à 1 521 153 t de matière sèche. Le FECB, déterminé par le rapport entre le volume et la biomasse, est de 0,36 tMS/m3, valeur inférieure à celle estimée par le GIEC (0,55 tMS/m3). La fraction de carbone (FC), issue de la calcination des échantillons de bois prélevés, est de l’ordre de 0,5643 tC/tMS. Elle est supérieure à la valeur donnée par le GIEC (0,51 tC/tMS). Au final, la quantité de carbone contenue dans l’écosystème étudié est de 858 387 t de matière sèche contre 931 620 t estimées à partir des paramètres du GIEC.
20
Kainulainen, T., T. Tuhkanen, T. Vartiainen, H. Heinonen-Tanski e P. Kalliokoski. "The effect of different oxidation and filtration processes on the molecular size distribution of humic material". Water Science and Technology 30, n. 9 (1 novembre 1994): 169–74. http://dx.doi.org/10.2166/wst.1994.0471.
Abstract (sommario):
The effect of different oxidation and filtration processes on the amount and character of organic matter in drinking water was studied. TOC, KMnO4 value, colour and fractions of humic material were analyzed from bank filtrated lake water, chemically coagulated and sand filtrated water, ozonated, O3/H2O2 treated, chlorinated, granular activated carbon (GAC) filtrated and nanofiltrated water. Size exclusion chromatography was used to separate different fractions of humic molecules. Six different fractions were found from bank filtrated lake water and from chemically coagulated and sand filtrated water. The molecular weight of humic fractions ranged from about 1000 (the last fraction) to about 100 000 dalton (the first fraction). Most of the humic molecules of bank filtrated lake water were found in the third and fourth fractions. After the oxidation and filtration processes the first fraction of humic molecules disappeared completely and the fourth and fifth fractions dominated. The total sum of the humic fractions was most effectively reduced after the O3/H2O2 treatment, by about 70%.
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Tans, Pieter P., Andrew M. Crotwell e Kirk W. Thoning. "Abundances of isotopologues and calibration of CO<sub>2</sub> greenhouse gas measurements". Atmospheric Measurement Techniques 10, n. 7 (26 luglio 2017): 2669–85. http://dx.doi.org/10.5194/amt-10-2669-2017.
Abstract (sommario):
Abstract. We have developed a method to calculate the fractional distribution of CO2 across all of its component isotopologues based on measured δ13C and δ18O values. The fractional distribution can be used with known total CO2 to calculate the amount of substance fraction (mole fraction) of each component isotopologue in air individually. The technique is applicable to any molecule where isotopologue-specific values are desired. We used it with a new CO2 calibration system to account for isotopic differences among the primary CO2 standards that define the WMO X2007 CO2-in-air calibration scale and between the primary standards and standards in subsequent levels of the calibration hierarchy. The new calibration system uses multiple laser spectroscopic techniques to measure mole fractions of the three major CO2 isotopologues (16O12C16O, 16O13C16O, and 16O12C18O) individually. The three measured values are then combined into total CO2 (accounting for the rare unmeasured isotopologues), δ13C, and δ18O values. The new calibration system significantly improves our ability to transfer the WMO CO2 calibration scale with low uncertainty through our role as the World Meteorological Organization Global Atmosphere Watch Central Calibration Laboratory for CO2. Our current estimates for reproducibility of the new calibration system are ±0.01 µmol mol−1 CO2, ±0.2 ‰ δ13C, and ±0.2 ‰ δ18O, all at 68 % confidence interval (CI).
22
Taghizadeh, A. T., B. Najafnejad e R. Noori. "Evaluation of nutritive value of tropical clover (Trifolium resupinatum) using gas production technique". Proceedings of the British Society of Animal Science 2007 (aprile 2007): 217. http://dx.doi.org/10.1017/s1752756200021207.
Abstract (sommario):
Gas measurement provides a useful data on digestion kinetics of both soluble and insoluble fractions of feedstuffs (Getachew et al., 1998). Carbohydrate portion of each feed is divided into three digestible fraction: the A fraction, containing sugars, short oligosaccharides, and organic acids; the B1 fraction, containing starch and pectin; and B2, the digestible fibre fraction (Doane et al. 1998). The objective of this study was to measure of fermentation parameters of tropical clover (Trifolium resupinatum) (pre bud, full bud, pre bloom and full bloom) using gas production technique.
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Łokas, Ewa L. "The effect of warm gas on the buckling instability in galactic bars". Astronomy & Astrophysics 634 (febbraio 2020): A122. http://dx.doi.org/10.1051/0004-6361/201937165.
Abstract (sommario):
By using N-body and hydro simulations, we study the formation and evolution of bars in galaxies with significant gas content focusing on the phenomenon of the buckling instability. The galaxies are initially composed of a spherical dark matter halo and only stellar, or stellar and gaseous, disks with parameters that are similar to the Milky Way and are evolved for 10 Gyr. We consider different values of the gas fraction f = 0−0.3 and in order to isolate the effect of the gas, we kept the fraction constant during the evolution by not allowing the gas to cool and form stars. The stellar bars that form in simulations with higher gas fractions are weaker and shorter, and they do not form at all for gas fractions that are higher than 0.3. The bar with a gas fraction of 0.1 forms sooner due to initial perturbations in the gas, but despite the longer evolution, it does not become stronger than the one in the collisionless case at the end of evolution. The bars in the gas component are weaker; they reach their maximum strength around 4 Gyr and later decline to transform into spheroidal shapes. The distortion of the stellar bar during the buckling instability is weaker for higher gas fractions and weakens the bar less significantly, but it has a similar structure both in terms of radial profiles and in face-on projections. For f = 0.2, the first buckling lasts significantly longer and the bar does not undergo the secondary buckling event, while for f = 0.3, the buckling does not occur. Despite these differences, all bars develop boxy/peanut shapes in the stellar and gas component by the end of the evolution, although their thickness is smaller for higher gas fractions.
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Moein, Mahmoodreza R., Kamiar Zomorodian, Keyvan Pakshir, Farnoosh Yavari, Marjan Motamedi e Mohammad M. Zarshenas. "Trachyspermum ammi (L.) Sprague". Journal of Evidence-Based Complementary & Alternative Medicine 20, n. 1 (10 ottobre 2014): 50–56. http://dx.doi.org/10.1177/2156587214553302.
Abstract (sommario):
Resistance to antibacterial agents has become a serious problem for global health. The current study evaluated the antimicrobial activities of essential oil and respective fractions of Trachyspermum ammi (L.) Sprague. Seeds of the essential oil were extracted and fractionated using column chromatography. All fractions were then analyzed by gas chromatography/mass spectrometry. Antifungal and antibacterial activities of the oil and its fractions were assessed using microdilution method. Compounds γ-terpinene (48.07%), ρ-cymene (33.73%), and thymol (17.41%) were determined as major constituents. The effect of fraction II was better than total essential oil, fraction I, and standard thymol. The greater effect of fraction II compared to standard thymol showed the synergistic effects of the ingredients in this fraction. As this fraction and also total oil were effective on the studied microorganism, the combination of these products with current antimicrobial agents could be considered as new antimicrobial compounds in further investigations.
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Hutton, D., J. Callender, N. Hutton, H. Wong e I. Syndikus. "A feasibility study for the introduction of micro-enema to improve organ consistency in patients receiving radiotherapy for urinary bladder cancer". Journal of Radiotherapy in Practice 17, n. 1 (20 giugno 2017): 20–28. http://dx.doi.org/10.1017/s1460396917000413.
Abstract (sommario):
AbstractAimsThe aim of the study was to assess the effect on rectal consistency, of introducing a micro-enema in the preparation of patients receiving radiotherapy treatment of urinary bladder cancer.Materials and methodsThe treatment cone beam computed tomography (CBCT) images from patients receiving radiotherapy for bladder cancer were retrospectively assessed. CBCT datasets from nine patients treated without rectal preparation (97 CBCT), and 13 patients (134 CBCT) treated following micro-enema use before planning and treatment were evaluated. CBCT were compared with the planning computed tomography for rectal status, rectal diameter and presence of gas.ResultsReproducibility of an empty rectum was achieved in 70% of treatment fractions delivered using an enema protocol compared with 33% of fractions delivered without preparation. In total, 10% of fractions were delivered with the presence of faeces or faeces and gas, compared with 46% of fractions for the non-intervention group. Enemas did not affect the proportion of fractions delivered with gas, however, where gas was present, 65% of CBCT fractions had <5% gas for patients using enemas compared with 32% without.FindingsThe use of a micro-enema before planning scan and each fraction was well tolerated and proved effective in managing and reducing inter-fraction variations in rectal volume and contents.
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Zainon, Mohd Zamri, Mohd Ardan Zubir e Rahizar Ramli. "Velocities Effects on the Void Fraction Distribution in a Vertical Gas-Liquid Two-Phase Flow Channel". Advanced Materials Research 889-890 (febbraio 2014): 369–73. http://dx.doi.org/10.4028/www.scientific.net/amr.889-890.369.
Abstract (sommario):
Measurement of void fraction in a vertically arranged gas-liquid two-phase flow channel has been conducted for wide range of flow conditions using a specially developed sensor based on electric conductance method. The effects of velocities of both phases were examined with variety of combinations using an industrial scale two-phase flow loop. The results show that at a constant rate of liquid superficial velocities the void fractions increases with the increasing gas superficial velocities and at higher velocities of liquid phase, the value of void fraction becoming lower. The average void fractions were also compared with other scholars results.
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Zhang, Zhiwen, Xiaosen Li, Zhaoyang Chen, Yu Zhang e Hao Peng. "Investigation of Gas-Water-Sand Fluid Resistivity Property as Potential Application for Marine Gas Hydrate Production". Entropy 24, n. 5 (29 aprile 2022): 624. http://dx.doi.org/10.3390/e24050624.
Abstract (sommario):
The phase fraction measurement of gas-water-sand fluid in downhole is an important premise for safe and stable exploitation of natural gas hydrates, but the existing phase fraction measurement device for oil and natural gas exploitation can’t be directly applied to hydrate exploitation. In this work, the electrical resistivity properties of different gas-water-sand fluid were experimentally investigated using the multiphase flow loop and static solution experiments. The effect of gas phase fraction and gas bubbles distribution, sand fraction and sand particle size on the relative resistivity of the multiphase fluid were systematically studied. The measurement devices and operating parameters were also optimized. A novel combined resistivity method was developed, which demonstrated a good effect for the measurement of phase fractions of gas-water-sand fluid, and will have a good application potential in marine natural gas hydrates exploitation.
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Menkovic, Nebojsa, Jelena Zivkovic, Katarina Savikin, Dejan Godjevac e Gordana Zdunic. "Phenolic composition and free radical scavenging activity of wine produced from Serbian autochtonous grape variety Prokupac: A model approach". Journal of the Serbian Chemical Society 79, n. 1 (2014): 11–24. http://dx.doi.org/10.2298/jsc130511089m.
Abstract (sommario):
Phenolic compounds are very important quality parameters of wine because of their impact on colour, taste and health properties. The present study aimed to evaluate the general phenolic composition and free radical scavenging activity of aqueous and organic fractions obtained using liquid/liquid extractions from red wine produced from Serbian autochtonous grape variety Prokupac. Total phenolic contents in different fractions ranged from 48.22 to 289.12 mg GAE/g dry fraction. Phenolic acids (mainly hydroxycinnamic acids) and quercetin-3-glucuronide were the main components of the EtOAc fraction at pH 2.0; catechins, phenolic acids (mainly hydroxybenzoic acids) and quercetin were found in the EtOAc fraction at pH 7.0, while anthocyanins were identified in the aqueous residue after EtOAc extraction. The major anthocyanin extracted into aqueous fraction was malvidin-3-glucoside, while the most abundant non-anthocyanin phenolic compounds from organic fractions were ethyl gallate and trans-caftaric acid. Radical scavenging activity differed significantly among fractions and IC50 values were 138.58 ?g/ml for water fraction, 17.83 and 3.47 ?g/ml for EtOAc fractions at pH 2.0 and pH 7.0, respectively. As the EtOAc fractions were found to be more potent radical scavengers, it could be assumed that non-anthocyanin phenolic compounds were responsible for such activity in Prokupac wine.
29
Teoh, Sian Hoon, Siti Syardia Erdina Mohamed, Parmjit Singh e Liew Kee Kor. "IN SEARCH OF STRATEGIES USED BY PRIMARY SCHOOL PUPILS FOR DEVELOPING FRACTION SENSE". Malaysian Journal of Learning and Instruction 17, Number 2 (31 luglio 2020): 25–61. http://dx.doi.org/10.32890/mjli2020.17.2.2.
Abstract (sommario):
Purpose – Most literature has focused solely on either knowledge about number sense or understanding of fractions. To fill the research gap, this study examined pupils’ abilities in both number sense and fractions. In particular, it investigated Year 4 and Year 5 pupils’ use of strategies in developing their fraction sense. Methodology – This study adopted a descriptive research design, utilising a mixed approach in data collection. An instrument called the Fraction Sense Test (FST) and a clinical interview were used to collect data. The FST comprised 3 strands: fraction concept, fraction representation and effect of operation. A two-stage cluster sampling method was employed to select 396 Year 4 and Year 5 pupils. The sampling involved random selection of the primary schools in the first stage, followed by pupils within the selected schools in the second stage. In addition to descriptive statistics, content analysis of interview transcripts was conducted to identify the presence of concepts and strategies applied among the pupils. Findings – The study found that the pupils scored lowest in effect of operation. It was also revealed that there were four strategies which helped the pupils to develop fraction sense, namely (1) comparing fractions using benchmark fractions of common fractions such as ½, ¼, zero and 1, (2) understanding denominators to determine the size of equal parts, (3) comparing fractions using unit fraction, and (4) applying the strategies in (1) and (2) to manipulate fractions in effect of operation. Significance – The findings provide useful input to facilitate the development of fraction sense ability.
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Sulistyani, Nanik, Lola Angelita e Nurkhasanah Nurkhasanah. "Inhibitory Activity of Parsea americana Mill. Peels Extract and Fraction Containing Phenolic Compound Against Staphylococcus aureus ATCC 25923". Journal of Pharmaceutical Sciences and Community 19, n. 1 (23 maggio 2022): 1–7. http://dx.doi.org/10.24071/jpsc.003005.
Abstract (sommario):
Parsea americana Mill. is a natural resource that has been studied for its antibacterial properties. The pulp, peel, and seed of Parsea americana Mill. have potential as an antibacterial agent. This study aimed to determine the inhibitory activity and phenolic content of Parsea americana Mill. peels extract and fraction against Staphylococcus aureus ATCC 25923. Parsea americana Mill. was macerated with 96% ethanol and then fractionated with n-hexane, ethyl acetate, and methanol solvent. Determination of the fraction that has the greatest antibacterial activity against S. aureus was carried out using the Kirby Bauer method. The total phenolic content in the extract and fraction was calculated as gallic acid equivalent (GAE) using the Folin-Ciocalteu method spectrometrically. Antibacterial activity test of the 96% ethanol extract, ethyl acetate fractions, and methanol fractions at a concentration of 10% w/v showed activity with a measurable inhibition zone. On the other hand, the n-hexane fraction showed no inhibition zone. The highest inhibition zone was the ethyl acetate fraction with approximately 8.33 ± 0.58 mm. The ethyl acetate fraction of Parsea americana Mill. resulted in 536.26 ± 14.29 mg GAE/g fraction. The conclusion was that the ethyl acetate fraction had the highest total phenolic content and was the most active fraction in inhibiting the growth of Staphylococcus aureus.
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Osman, Muhamad, Norazian Mohd Hassan, Alfi Khatib e Siti Tolos. "Antioxidant Activities of Dialium indum L. Fruit and Gas Chromatography-Mass Spectrometry (GC-MS) of the Active Fractions". Antioxidants 7, n. 11 (1 novembre 2018): 154. http://dx.doi.org/10.3390/antiox7110154.
Abstract (sommario):
The fruit of Dialium indum L. (Fabaceae) is one of the edible wild fruits native to Southeast Asia. The mesocarp is consumed as sweets while the exocarp and seed are regarded as waste. This study aimed to evaluate the antioxidant activities of the fruit by using four assays, which measure its capabilities in reducing phosphomolybdic-phosphotungstic acid reagents, neocuproine, 2,2-diphenyl-picrylhydrazyl (DPPH), and inhibiting linoleic acid peroxidation. The active fractions were then analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that the seed methanol fraction (SMF) exhibited the strongest antioxidant activity with significantly higher (p < 0.05) gallic acid equivalence (GAE), total antioxidant capacity (TAC), and DPPH radical scavenging activity (IC50 31.71; 0.88 µg/mL) than the other fractions. The exocarp dichloromethane fraction (EDF) was the discriminating fraction by having remarkable linoleic acid peroxidation inhibition (IC50 121.43; 2.97 µg/mL). A total of thirty-eight metabolites were detected in derivatized EDF and SMF with distinctive classes of phenolics and amino acids, respectively. Bioautography-guided fractionation of EDF afforded five antioxidant-enriched subfractions with four other detected phenolics. The results revealed the antioxidant properties of D. indum fruit, which has potential benefits in pharmaceutical, nutraceutical, and cosmeceutical applications.
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Sakul, Ernest Hanny. "IMPACT OF BOTANICAL INSECTICIDES DERIVED FROM Pangium edule Reinw AND Annona muricata L. SEED EXTRACTS ON THE “GAY GANTUNG” DIAMONDBACK MOTH, Plutella xylostella L." Agrotech Journal 2, n. 2 (30 novembre 2017): 27–35. http://dx.doi.org/10.31327/atj.v2i2.245.
Abstract (sommario):
Insecticidal properties of fractioned extracts from Pangium edule Reinw seed and Annona muricata seed against Plutella xylostella larvae were investigated in the laboratory. The study was initiated to investigate the possibility of using botanical pesticides to control P.xylostella, a serious cosmopolitan pest of crucifer plants. The study aims to determine the most effective concentration and the most active extract; to evaluate the different extract concentrations on the treated larvae; and to characterize the phytochemical contents of the most effective extracts fraction. The study was an experiment initiated by test of phytochemical screening test in order to discover the presence of secondary metabolites in the extracts. It was followed by the test of mortality of the diamondback moth larvae. Furthermore, the extracts hexane fraction and etanol fraction, were conducted with completely randomized design; The LC50 values were determined following probit analysis, the data were treated in the software programme IBM Statistic SPSS 20. Results showed that n-hexane fraction is the most effective againts larvae (LC50-48h = 12,71 mg/L) from P.edule seed extract, (LC50-48h = 50,81 mg/L) from A.muricata seed extract. Larva mortality was highest using 1000 ppm n-hexane fraction (96,6%) derived from P.edule seed extract, (93,3%) derived from A.muricata seed extract. The ethanol fraction tested positive for alkaloid, saponins, flavonoids, terpenoids, phenol and tannins. N-hexane fraction of P.edule seed extract, and A.muricata seed extract are an effective botanical insecticides exhibiting larvicidal and antifeedant properties against P.xylostella thus it can be alternative to synthethic insecticides. Results indicate that these botanical insecticides have good possibilities for control of P.xylostella. Further work is necessary to evaluate and characterize the active components of the extract fractions and its efficacy in the fieldInsecticidal properties of fractioned extracts from Pangium edule Reinw seed and Annona muricata seed against Plutella xylostella larvae were investigated in the laboratory. The study was initiated to investigate the possibility of using botanical pesticides to control P.xylostella, a serious cosmopolitan pest of crucifer plants. The study aims to determine the most effective concentration and the most active extract; to evaluate the different extract concentrations on the treated larvae; and to characterize the phytochemical contents of the most effective extracts fraction. The study was an experiment initiated by test of phytochemical screening test in order to discover the presence of secondary metabolites in the extracts. It was followed by the test of mortality of the diamondback moth larvae. Furthermore, the extracts hexane fraction and etanol fraction, were conducted with completely randomized design; The LC50 values were determined following probit analysis, the data were treated in the software programme IBM Statistic SPSS 20. Results showed that n-hexane fraction is the most effective againts larvae (LC50-48h = 12,71 mg/L) from P.edule seed extract, (LC50-48h = 50,81 mg/L) from A.muricata seed extract. Larva mortality was highest using 1000 ppm n-hexane fraction (96,6%) derived from P.edule seed extract, (93,3%) derived from A.muricata seed extract. The ethanol fraction tested positive for alkaloid, saponins, flavonoids, terpenoids, phenol and tannins. N-hexane fraction of P.edule seed extract, and A.muricata seed extract are an effective botanical insecticides exhibiting larvicidal and antifeedant properties against P.xylostella thus it can be alternative to synthethic insecticides. Results indicate that these botanical insecticides have good possibilities for control of P.xylostella. Further work is necessary to evaluate and characterize the active components of the extract fractions and its efficacy in the field
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Saha, Partha, Dipshikha Sharma, Suvakanta Dash, Kumar Saurav Dey e Samir Kumar Sil. "Identification of 2,4-Di-tert-butylphenol (2,4-DTBP) as the Major Contributor of Anti-colon cancer Activity of Active Chromatographic Fraction of Parkia javanica (Lamk.) Merr. Bark Extract". Biomedical and Pharmacology Journal 16, n. 1 (21 marzo 2023): 275–88. http://dx.doi.org/10.13005/bpj/2609.
Abstract (sommario):
Parkia javanica (Lamk.) Merr. is an ethnomedicinal leguminous plant species from northeastern India with a long history of medicinal use among various tribes of this region to treat cholera, dysentery, stomach aches, diarrhea and food poisoning, having antibacterial, wound-healing, anticancer and anti-inflammatory properties. Therefore, in this current study, the methanolic bark extract was carried out and fractionated by using flash chromatography, examined the cytotoxicity of the respective fractions on colon cancer cell lines, and evaluated the major phytochemical compounds present in the fractions using Gas Chromatography-Mass Spectrometry (GC-MS) chemical profiling. Chemical profiling of the fractions by GC-MS revealed in fraction-1 and -2, 2,4-Di-tert-butylphenol was the major compound (50.740% in fraction-1, 21.277% in fraction-2, and 7.859% in fraction-3) having reported anticancer activity. The gradation of the presence of this compound in the fractions was corroborated by the gradation of anti-colon cancer activity of the respective fractions on both the colon carcinoma cell lines. However, the presence of D-Allose in a substantial amount (20.870%) in only fraction-3 could not increase the anticancer activity of fraction-3 over the other two fractions. An in vitro cytotoxic assay guided evaluation of three flash chromatographic fractions (fraction-1, -2, and -3) of methanolic extract of Parkia javanica bark showed significant anticancer properties on two human colon carcinoma cell lines (HCT116 and SW480). The order of efficacy of the fractions was fraction-1> fraction-2 > fraction-3. In a time and dose-dependent experiment, fraction-1, being the most active one, showed an IC50 value of 16.25 µgml-1 (24 hrs), 9.94 µgml-1 (48 hrs), and 9.38 µgml-1 (72 hrs) on HCT116 and 35 µgml-1 (24 hrs), 20.14 µgml-1 (48 hrs), and 19.71 µgml-1 (72 hrs) on the SW480 cell line. Parkia javanica bark extract is bestowed with the potential of anti-colon cancer property and upon chemical profiling of different chromatographic fractions of the extract, 2,4-Di-tert-butylphenol has been identified as the primary anticancer component of the extract.
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Schoenlechner, Regine, Denisse Bender, Stefano D’Amico, Mathias Kinner, Sandor Tömösközi e Ram Yamsaengsung. "Dry Fractionation and Gluten-Free Sourdough Bread Baking from Quinoa and Sorghum". Foods 12, n. 16 (20 agosto 2023): 3125. http://dx.doi.org/10.3390/foods12163125.
Abstract (sommario):
The roller milling of sorghum and quinoa seeds into flour fractions (coarse, middle, and fine) was investigated, chemically analysed, and applied in the baking of gluten-free sourdough bread. The gap settings were adjusted to 0, 5, 8, and 10 for quinoa, and 3, 5, and 7 for sorghum. The fine fractions reached values of up to about 41% (gap 8) for quinoa and around 20% for sorghum (gap 5). SEM pictographs illustrated the clear separation of each fraction with the chemical analysis showing high contents of protein, TDF (total dietary fibre), and IDF (insoluble dietary fibre) in the coarse fraction. Up to 77% starch content was obtained in the fine fraction with significant amounts of SDF (soluble dietary fibre), which has good health benefits. Increasing the dough moisture up to 90% helped in decreasing the bread crumb firmness, while low Avrami parameters and RVA pasting behaviour indicated a slow bread-staling rate for both sourdough breads.
35
Obyed, Saleem Mohammed. "Preparation of Light Fuel Fractions from Heavy Vacuum Gas Oil by Thermal Cracking Reaction". Al-Khwarizmi Engineering Journal 13, n. 1 (31 marzo 2017): 103–9. http://dx.doi.org/10.22153/kej.2017.11.003.
Abstract (sommario):
This work deals with thermal cracking of heavy vacuum gas oil which produced from the top of vacuum distillation unit at Al- DURA refinery, by continuous process. An experimental laboratory plant scale was constructed in laboratories of chemical engineering department, Al-Nahrain University and Baghdad University. The thermal cracking process was carried out at temperature ranges between 460-560oC and atmospheric pressure with liquid hourly space velocity (LHSV) equal to 15hr-1.The liquid product from thermal cracking unit was distilled by atmospheric distillation device according to ASTM D-86 in order to achieve two fractions, below 220oC as a gasoline fraction and above 220oC as light cycle oil (LCO).The first fraction which was below 220oC was fractionated to light fractions (gasoline, kerosene and gas oil) by atmospheric distillation device. The fractions (gasoline, kerosene and gas oil) were distilled by atmospheric distillation device in order to obtained distillation curve for these fractions. Physical properties were recorded for these cuts to compare it with standard property test, in order to studying the possibilities of industrial uses. The maximum conversion of heavy vacuum gas oil was obtained by this process equal to 82 wt. % of feed at 540oC.
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Su, Xuefeng, e Theodore J. Heindel. "Effect of Perforated Plate Open Area on Gas Holdup in Rayon Fiber Suspensions". Journal of Fluids Engineering 127, n. 4 (14 aprile 2005): 816–23. http://dx.doi.org/10.1115/1.1994878.
Abstract (sommario):
Three different aeration plates are used to study their effect on gas holdup and flow regime transition in fiber suspensions. The aeration plates differ by their open-area ratios (A=0.57%, 0.99%, and 2.14%), where the hole diameter remains the same while the number of holes increase. Experiments are performed using three different Rayon fiber lengths (L=3, 6, and 12mm) over a range of superficial gas velocities (Ug⩽18cm∕s) and fiber mass fractions (0⩽C⩽1.8%) in a 15.24cm dia semi-batch bubble column. Experimental results show that the aeration plate with A=0.99% produces the highest gas holdup in an air-water system and low fiber mass fraction suspensions, and the plate with A=2.14% yields the lowest gas holdup in these systems. In medium fiber mass fraction suspensions, the plate with A=0.57% produces slightly higher gas holdup values, while the other two plates yield similar results. The effect of the aeration plate open area on gas holdup diminishes at high fiber mass fractions (C⩾1.2%). All aeration plates generate homogeneous, transitional, and heterogeneous flow regimes over the range of superficial gas velocities for air-water and low fiber mass fraction suspensions. However, the aeration plate with A=2.14% enhances the flow regime transition, i.e., the superficial gas velocity at which transitional flow appears is lower. Additionally, the fiber mass fraction at which pure heterogeneous flow is observed is lower when A=2.14%.
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Lu, Tao, Hao Ran Yuan, Shun Gui Zhou, Hong Yu Huang, Kobayashi Noriyuki e Yong Chen. "On the Pyrolysis of Sewage Sludge: The Influence of Pyrolysis Temperature on Biochar, Liquid and Gas Fractions". Advanced Materials Research 518-523 (maggio 2012): 3412–20. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.3412.
Abstract (sommario):
Pyrolytic conversion of sewage sludge to biochar, oil and gas is an environmentally and economically acceptable way comparable to conventional options for sewage sludge disposal. The aim of this paper is to investigate the influence of pyrolysis temperature on production of biochar fraction for agronomic application, oil and gas fractions for energy utilization. Sewage sludge samples collected from an urban sewage treatment plant were pyrolysed in a bench–scale quartz tubular furnace over the temperature range of 300-700°C.The results indicated that the biochar fraction yield decreased, the yields of liquid (oil and water) fraction and gas fraction increased by evaluating the pyrolysis temperature. Concentration of heavy metals and nutrient elements present in biochar varied with pyrolysis temperature, the heating value of oil from liquid fraction fluctuated between 26938.3 and 30757.9kJ/kg, the heating value of gas fraction increased from 4012kJ/Nm3 to 12077 kJ/Nm3 with the increasing pyrolysis temperature.
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Deuel, L. E., e G. H. Holliday. "Geochemical Partitioning of Metals in Spent Drilling Fluid Solids". Journal of Energy Resources Technology 120, n. 3 (1 settembre 1998): 208–14. http://dx.doi.org/10.1115/1.2795037.
Abstract (sommario):
Metals in oil and gas fluids have been of concern to the environmental and industrial communities since 1976. As a result, metals in 31 spent drilling fluids representative of the major oil and gas production provinces in the Continental United States, were fractionated into exchangeable, bound to carbonates, bound to Fe-Mn oxides, bound to organic matter, and residual forms using a sequential extraction (summation of fractions) technique. Bioavailability and mobility of metals in solid matrices follow in sequence of the operational defined fractions with chemical reactivity decreasing in the order of exchangeable > bound to carbonate > bound to Fe-Mn oxide > bound to organic matter > residual fractions. Metals evaluated in this study include arsenic, barium, cadmium, chromium, lead, and zinc. The summation of fractions was compared to independent total metals analysis using the United States Environmental Protection Agency (USEPA) SW-846 Method 3050 digest procedure to evaluate metal recoveries. No difference was observed in the summation of fractions and EPA Method 3050 total metal values for arsenic, barium, and cadmium. EPA Method 3050 digest was about 28 percent lower in chromium, and about 19 percent lower in lead and 16 percent lower in zinc than the total by summation of fractions. Almost all of the barium (95.6 percent) was recovered in the residual fraction. Arsenic was recovered primarily in the residual fraction (74.3 percent) and the Fe-Mn oxide fraction (16.1 percent). The highest quantity of cadmium was recovered in the residual fraction (43.3 percent), followed by the bound to organic (27.9 percent), and bound to Fe-Mn oxide (21.1 percent) fractions. Chromium was observed primarily in the residual (40.4 percent) and bound to Fe-Mn oxide (34 percent) fractions. Lead was distributed primarily in the bound to Fe-Mn oxide (49.3 percent), and residual (27 percent) fractions. Zinc was almost equally distributed in the bound to organic (36.2 percent), and bound to Fe-Mn oxide (33.1 percent) fractions. Cadmium (3.9 percent) and arsenic (2.7 percent) were the only metals with an exchangeable fraction >1 percent of the total. Low total and/or low exchangeable metal concentrations ultimately control the bioavailability and mobility of metals in spent drilling solids and limit the potential for an adverse impact on the environment.
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Jamalinia, Elahe, Jie Dai, Nicholas R. Vaughn, Roberta E. Martin, Kelly Hondula, Marcel König, Joseph Heckler e Gregory P. Asner. "Crop Canopy Nitrogen Estimation from Mixed Pixels in Agricultural Lands Using Imaging Spectroscopy". Remote Sensing 16, n. 8 (13 aprile 2024): 1382. http://dx.doi.org/10.3390/rs16081382.
Abstract (sommario):
Accurate retrieval of canopy nutrient content has been made possible using visible-to-shortwave infrared (VSWIR) imaging spectroscopy. While this strategy has often been tested on closed green plant canopies, little is known about how nutrient content estimates perform when applied to pixels not dominated by photosynthetic vegetation (PV). In such cases, contributions of bare soil (BS) and non-photosynthetic vegetation (NPV), may significantly and nonlinearly reduce the spectral features relied upon for nutrient content retrieval. We attempted to define the loss of prediction accuracy under reduced PV fractional cover levels. To do so, we utilized VSWIR imaging spectroscopy data from the Global Airborne Observatory (GAO) and a large collection of lab-calibrated field samples of nitrogen (N) content collected across numerous crop species grown in several farming regions of the United States. Fractional cover values of PV, NPV, and BS were estimated from the GAO data using the Automated Monte Carlo Unmixing algorithm (AutoMCU). Errors in prediction from a partial least squares N model applied to the spectral data were examined in relation to the fractional cover of the unmixed components. We found that the most important factor in the accuracy of the partial least squares regression (PLSR) model is the fraction of photosynthetic vegetation (PV) cover, with pixels greater than 60% cover performing at the optimal level, where the coefficient of determination (R2) peaks to 0.66 for PV fractions of more than 60% and bare soil (BS) fractions of less than 20%. Our findings guide future spaceborne imaging spectroscopy missions as applied to agricultural cropland N monitoring.
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CHEN, X., K. D. MATTHEWS, D. HAO, W. J. SCHAFF, L. F. EASTMAN, W. WALUKIEWICZ, J. W. AGER e K. M. YU. "MBE GROWTH AND CHARACTERIZATION OF Mg-DOPED III-NITRIDES ON SAPPHIRE". International Journal of High Speed Electronics and Systems 19, n. 01 (marzo 2009): 113–19. http://dx.doi.org/10.1142/s0129156409006151.
Abstract (sommario):
Plasma-assisted molecular beam epitaxial growth of Mg -doped GaN and InGaN on a sapphire substrate is investigated in this study. Electrical characteristics of p -type GaN strongly depend on the flux of Mg acceptors and the growth temperature. Only the intermediate range of Mg fluxes (beam equivalent pressures near 1×10-9T) produce p -type GaN with good electrical properties, and a maximum hole concentration of 3.5 × 1018 cm-3 is obtained with a Hall mobility of 2.1 cm2/V·s. Due to the strong surface accumulation of electrons, Hall measurements do not indicate p -type polarity for In fraction beyond 11%. In contrast, hot probe measurements show that p -polarity can be measured for the entire range of Mg -doped In mole fractions. Electroluminescence also indicates p -polarity for Ga -rich mole fractions. In x Ga1- x N p - n homojunctions are fabricated and tested. All GaN devices show low series resistance (0.03 ohm-cm2) and insignificant parasitic leakage. IV curves of all three InGaN homojunctions show rectifying characteristics under dark conditions and photo-response under outdoor sunlight, indicating the existence of holes in InGaN with up to 40% In content.
41
Amy, G., J. F. Debroux, R. Arnold e L. G. Wilson. "Emploi de la pré-ozonation pour augmenter la biodégradabilité d'un effluent secondaire dans un système de traitement par inflitration dans le sol". Revue des sciences de l'eau 9, n. 3 (12 aprile 2005): 365–80. http://dx.doi.org/10.7202/705258ar.
Abstract (sommario):
La réutilisation des eaux usées est reconnue comme une technique importante dans les régions arides et /ou grandes consommatrices d'eau. L'une des méthodes actuellement très employée consiste à recharger la nappe phréatique avec des effluents secondaires via des bassins d'infiltration. L'épuration biologique et / ou chimique à travers la zone non-saturée représente une caractéristique importante de cette technologie. Les procédés de ce type sont connus sous l'appellation de Soil Aquifer Treatment (SAT) ou géofiltration. Dans ce travail, le procédé a été étudié comme méthode de réhabilitation d'un effluent secondaire d'eaux usées jusqu'au stade d'eau potable. Cette recherche a été principalement axée sur le comportement, le transport des matières organiques (MO) de l'effluent et particulièrement sur leur rôle de précurseurs potentiels de sous-produits de désinfection lors de la réutilisation de la nappe. Dans la zone vadose, la matière organique est principalement éliminée par biodégradation, et à un degré moindre, par adsorption. Les simulations du procédé, en laboratoire, ont été réalisées en réacteurs recirculés aérobies, en mode cuvée, avec un biofilm acclimaté sur des particules de sable siliceux, afin de déterminer la fraction biodégradable des MO. L'évaluation de celle-ci est essentielle pour prédire leur potentiel de dégradation par la biomasse de la zone vadose. L'effluent mis en oeuvre est issu d'une station d'épuration de l'Arizona (États-Unis) avec biofiltre (lit filtrant à support plastique); sa concentration en carbone organique dissous (COD) se situe entre 10 et 15 mg/L. L'effluent mis 5 jours durant en contact avec le biofilm acclimaté du réacteur montre un abattement de 50-60 % du COD. Il a ainsi été déterminé qu'environ 80 % de l'élimination des MO de l'effluent survient dans les premières 24 heures d'expérimentation, alors que le reste, près de 20 %, est éliminé durant les 48 heures suivantes. Dans ces conditions, le délai de 5 jours apparait suffisant pour dégrader les MO présentes dans ces effluents. Les rendements observés augurent bien de la dégradation dans la zone vadose si l'on tient compte de la combinaison des taux et de la hauteur d'infiltration avec des temps de résidence de 2 à 14 jours ainsi qu'il est proposé dans le procédé. Afin d'accroître la biodégradabilité des MO, une ozonation a été effectuée, en amont du bio-traitement, avec un générateur d'ozone à l'échelle du banc d'essai fonctionnant en mode semi-continu (admission continue de gaz, volume stable de liquide). La pré-ozonation a permis d'accroître la biodégradation de 60-70 %. Bien qu'un fort pourcentage de MO soit éliminé dans ce schéma, il ressort que l'ozone n'a qu'un effet modeste sur la transformation des MO dissoutes non-biodégradables en matières biodégradables par rapport à des expériences similaires effectuées avec des matières organiques naturelles (MON) des eaux de surface. L'eau usée ainsi traitée présente des niveaux de COD comparables à ceux d'une eau de surface employée à des fins de consommation. Les caractéristiques des MO de l'effluent ont été comparées à celles des MON. Une ultrafiltration de l'effluent pour déterminer le poids moléculaire apparent des MO, donne une distribution bimodale de leur poids moléculaire par rapport à une distribution logarithmique normale observée avec des MON typiques. En utilisant des résines non- ioniques pour séparer les fractions hydrophobes et hydrophiles des MO, il ressort que l'ozonation ne transforme pas de façon significative la fraction hydrophobe des MO de l'effluent en fraction hydrophile, tel que cela a été observé durant l'ozonation des MON. Ces eaux ont été chlorées en pilote, selon des conditions similaires à celles des réseaux de distribution (CI2:COD=1:1mg/mg, période d'incubation=24 heures) afin de simuler la post-désinfection après récupération. Les sous-produits réglementés (Trihalométhanes THM) et ceux proposés (Acides holoacétiques, HAA6) ont été formés à des taux inférieurs ou proches des normes en vigueur (ou de celles proposées pour HAA6) pour l'eau potable aux États-Unis. Cependant, une nitrification significative a été observée dans nos simulations de traitement par le sol avec un effluent non-nitrifié, conduisant à des teneurs en nitrates supérieures à la norme américaine pour l'eau potable (10 mg/L).
42
Mariño, N. Carro, E. López Tamames e Y. C. M. García Jares. "Contribution to the Study of the Aromatic Potential of Three Muscat Vitis Vinifera Varieties: Identification of New Compounds". Food Science and Technology International 1, n. 2-3 (agosto 1995): 105–16. http://dx.doi.org/10.1177/108201329500100206.
Abstract (sommario):
About 60 components of the free and bound fractions of the aroma of three Vitis vinifera grape cultivars (i.e., Muscat d'Alexandrie, Muscat d'Hambourg, and Muscat de Frontignan) were determined. Free and bound fractions were isolated by selective retention on a nonionic resin (Amberlite XAD-2). The free fraction was directly analyzed by means of gas chromatography and gas chromatography–mass spectrometry (GC and GC-MS). The analysis of the bound fraction was performed following two methods: (1) by enzymttic hydrolysis, to release the volatile aglycons and (2) by TFA (trifluoroacetylation) of the glycosidic compounds. Several glycosidic compounds were identified as glucosides, arabinosides, rutinosides, and apiosides, which constitute an important grape aroma reserve.
43
Voronov, M. V., S. V. Popov, O. V. Khabibrakhmanov e A. D. Yulin. "Study of possible options for technological schemes of gas fractionation plants for a wide fraction of light hydrocarbons". Proceedings of the Voronezh State University of Engineering Technologies 85, n. 1 (21 febbraio 2023): 194–203. http://dx.doi.org/10.20914/2310-1202-2023-1-194-203.
Abstract (sommario):
Analysis of the component composition of the ethane-propane fraction obtained from the wide fraction of light hydrocarbons (NGL) at operating gas fractionation plants shows that due to the insufficiently clear separation of light hydrocarbons С1÷С3, a high propane content is observed in the ethane-propane fraction (EPF). SPE is used in the pyrolysis plant, where ethylene is obtained as the target intermediate, therefore, under industrial conditions, it is necessary to ensure the maximum possible extraction of propane from the SPE composition. In the technological scheme of operating plants, SME is obtained using a fractionating absorber or a distillation column. In both versions, the SME is taken from the top of the apparatus, and the bottom product containing C3+ hydrocarbons is fed for further fractionation. In order to analyze the operation of gas fractionation plants in the Honeywell UniSim Design software environment, a plant model was developed. A computational experiment using various industrial values of the hydrocarbon content in NGL showed that in order to achieve the maximum possible extraction of propane from the PSP, it is necessary to involve all the propane in the PSP obtained on the fractionating absorber (or distillation column) so that only the C4+ hydrocarbon fraction is in the bottom product of the apparatus for further separation. The ESP obtained in this way is sent to an additional distillation column, which provides a clear separation into ethane (distillate of the column) and propane (bottom product of the column) fractions, while in the obtained fractions concentration indicators are achieved that improve the corresponding indicators of standards according to TU 0272-022- 00151638-99. The calculated regime parameters and fractional compositions of technological flows of apparatuses are given, the modified scheme of the installation is described. The developed models can be used to optimize the operating modes of industrial devices and design new installations, as well as to train technologists in the methods of qualified process management.
44
Masłowski, P., J. Gniot-Sulżycka e G. Rześniowiecka. "The influence of gibberellin on the level of nucleic acids and other phosphate fractions in maize seedlings". Acta Societatis Botanicorum Poloniae 40, n. 3 (2015): 467–73. http://dx.doi.org/10.5586/asbp.1971.034.
Abstract (sommario):
Treatment of maize seedes with GA3 increased the content of water, the phosphate acid soluble fraction, the phospholipid fraction and the low molecular weight r-RNA, s-RNA, DNA-RNA fractions in 5-days-old seedlings. On the other hand, the contents of RNA and DNA in such seedlings decreased.
45
Nuhu, Aliyu, Ezzeldin M. Abdurahman, Umar H. Danmalam, Muhammed U. Kawu, Sadam A. Adebayo e Musa Bashir. "Isolation of pentacyclic triterpene, phenolic content and antioxidant activity of root bark of Irvingia gabonesis Baill. (Irvingiaceae)". Journal of Pharmacy & Bioresources 19, n. 2 (7 giugno 2022): 116–27. http://dx.doi.org/10.4314/jpb.v19i2.8.
Abstract (sommario):
The aim of this study was to investigate the phytochemical constituents and antioxidant potentials of the ethanol extract and fractions of Irvingia gabonensis root bark in order to establish the scientific basis and rationale for its folkloric use. The powdered root bark of I. gabonensis was macerated with 70% ethanol and then partitioned with different solvents based on their polarity to afford 4 fractions. The extract and fractions were subjected to phytochemical analysis. The in vitro antioxidant activity was evaluated using DPPH assay. The quantitative phytochemical determination showed that ethyl acetate fraction of I. gabonensis root bark (EFIGR) had the highest content of tannins (154.44 mg/GAE g), phenol (106.26 mg/GAE g and flavonoid (76.07 mg/QE g). The in vitro antioxidant activity of the extract and the fractions had IC50 values of 76.0±0.03, 27.0± 0.05, 39.0±0.07 and 28.0±0.10 μg/mL for Ethanol extract, EFIGR, Butanol fraction and Aqueous fraction respectively while the standard had 29.0±0.03 μg/mL.Further fractionation of EFIGR led to the isolation of hederagenin which was characterized using 1D-NMR and mass spectrometric data. The present study revealed that root bark of I. gabonensis is a potential sourceof natural antioxidant which justified its uses in the traditional medicine.
46
Dewi, I. K., S. Pramono, A. Rohman e R. Matien. "Potential of corncobs (Zea mays) fraction as tyrosinase inhibitor and natural antioxidant in vitro". Food Research 5, n. 2 (27 febbraio 2021): 67–73. http://dx.doi.org/10.26656/fr.2017.5(2).465.
Abstract (sommario):
Corncobs (Zea mays) are beneficial to human health as they contain tyrosinase inhibitors and natural antioxidants, but they are not used as they are considered as waste. This research evaluated the inhibition test towards tyrosinase enzyme and antioxidant activity of corncob fraction using in-vitro DPPH method and its correlation to phenolic and flavonoids. Corncob fraction was extracted using the maceration method applying 70% ethanol solvent. The ethanol extract of corncob was suspended by water and then partitioned with chloroform, ethyl acetate, and aquadest to produce three fractions (chloroform, ethyl acetate, and aquadest fractions). These fractions were analyzed through the tyrosinase inhibition test, applying in vitro tyrosinase enzyme inhibition and antioxidant activity using radical scavenging test DPPH (2 2,2-diphenyl-1-picrylhydrazyl). Meanwhile, the total phenolic and flavonoids content tests were determined spectroscopically. The results showed ethyl acetate fraction had the highest tyrosinase activity with IC50 values of 185.76 µg/mL, followed by the aquadest fraction (IC50 676.44µg/ml) and the chloroform fraction (IC50 709.26 µg/mL). The antioxidant activity using DPPH radical scavenging method exhibited that ethyl acetate fraction had the highest antioxidant activity with IC50 of 25.79 µg/mL followed by the chloroform fraction (IC50 of 29.15 µg/mL) and the aquadest fraction (IC50 of 32.41 µg/mL). The total phenolic content of the corncob fraction ranged between 1.73 to 7.43% (w/w) gallic acid equivalents (GAE), while the entire flavonoid content ranged between 0.01 to 1.34% (w/ w) quercetin equivalent (QE). The tyrosinase activity and antioxidants of the corncob fractions correlated with the total phenolic and flavonoid contents.
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Jubaidah, Siti, Reksi Sundu e Nur Sabriningsih. "PENETAPAN KADAR FENOLIK TOTAL FRAKSI POLR DAN NONPOLAR DAUN RAMBAI LAUT (Sonneratia caseolaris L.) DENGAN METODE SPEKTROFOTOMETRI UV-Vis". Jurnal Riset Kefarmasian Indonesia 1, n. 2 (22 maggio 2019): 140–47. http://dx.doi.org/10.33759/jrki.v1i2.23.
Abstract (sommario):
Rambai laut (Soneratia caseolaris L.) is a type of tree that grows in riverbank swamps or mangrove forests which contains one of the secondary metabolites in the form of phenolic compounds. The purpose of this study was to determine the total phenolic content of polar and nonpolar fractions of sea rambai leaves using UV-Vis spectrophotometry method.
Research conducted is non-experimental. The stages of the study included the determination of plants, sampling, making samples, making extracts, determining the water content of extracts, fractionation using polar and nonpolar fractions, phytochemical screening test of ethanol extract and fractionation results and determination of total phenolic levels by UV-Vis spectrophotometry.
The results showed that rambai laut leaf in polar fraction had a total phenolic content of 213.49 ± 1.2227 mg GAE / g, which means that in each gram the polar fraction is equivalent to 213.49 mg of gallic acid, whereas in the nonpolar fraction of rambai laut leaves is obtained 55.79 ± 1.0809 mg GAE / g which means that in each gram the nonpolar fraction is equivalent to 55.79 mg of gallic acid. Total phenolic content is greater in the polar fraction.
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Kozlovski, V. V., A. E. Vasil’ev, A. A. Lebedev, E. E. Zhurkin, M. E. Levinshtein e A. M. Strelchuk. "Formation of Radiation Defects in Wide-Band Semiconductors Based on Gallium (Ga<sub>2</sub>O<sub>3</sub>, GaN) under Proton Irradiation". Поверхность. Рентгеновские, синхротронные и нейтронные исследования, n. 12 (1 dicembre 2023): 63–69. http://dx.doi.org/10.31857/s1028096023120099.
Abstract (sommario):
Using mathematical modeling of the displacement cascade in two wide-gap semiconductors based on gallium, gallium oxide (Ga2O3) and gallium nitride (GaN), the features of the generation of Frenkel pairs during the scattering of protons with energies of 8 and 15 MeV are considered. The number of displacements created not only by primary knocked-on atoms, but also by recoil atoms generated in displacement cascades is calculated for the first time. Calculations have shown that under proton irradiation of Ga2O3, for example, the fraction of vacancies in the oxygen sublattice created directly by protons is only 12%. The remaining 88% are created by recoil atoms in cascade processes. For the gallium sublattice, these fractions are 25 and 75%, respectively. Therefore, the processes of compensating the conductivity of GaN and Ga2O3 observed under proton irradiation will be determined by deep centers created not by primary knocked-on atoms, but by recoil atoms formed in displacement cascades. A comparison with experimental data is made, and the fraction of Frenkel pairs dissociating during irradiation is estimated.
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Konate, Almamy, Roland Nâg-Tiéro Meda, Amadou Dicko, Eric Sami Kam, Benjamin Kouliga Koama, Hadidjatou Belem, Adama Kabore, Amadou Traore e Hamidou Hamadou Tamboura. "Polyphenols contents and antioxidant potential of Nauclea latifolia Smith (Rubiaceae) acetonic fractions from Burkina Faso". Journal of Drug Delivery and Therapeutics 11, n. 6 (15 novembre 2021): 101–7. http://dx.doi.org/10.22270/jddt.v11i6.5069.
Abstract (sommario):
Scientific information on antioxidant properties and phenolic content of Nauclea latifolia used in ethnoveterinary medicine in Burkina Faso are limited. Therefore, the quantification of the antioxidant activity of different parts of this specie remains an interesting and useful task, particularly for finding new sources for natural antioxidants. The aim of this study was to evaluate the antioxidant activity and total polyphenols of Nauclea latifolia Smith (Rubiaceae) acetonic fractions from Burkina Faso. n-hexane, dichloromethane, ethyl acetate and n-butanol fractions of leaves, barks and root barks were tested for their antioxidant activities using DPPH, ABTS and FRAP methods. Folin-Ciocalteu and AlCl3 reagents were used to quantify the polyphenols. n-butanol fraction of barks (58.16 ± 0.76 mg GAE/100 mg), dichloromethane fraction of barks (51.13 ± 0.99; 26.14 mg GAE/100 mg) have presented the best total phenolic contents while the best total flavonoid contents were found in n-butanol fraction of leaves and n-hexane fraction of leaves with 4.85 ± 0.14 mg EQ/100mg and 2.92 ± 0.13 mg EQ/100mg, respectively. It was observed that n-hexane fraction of leaves was scavenge more DPPH free radicals with a value of 1011.98± 17,01 µmol EAA/g. That of n-butanol fractions of barks was showed the best ferric reduction power (3056.37 ± 96.66 µmol EAA/g) and the highest ABTS cation radicals scavenging capacity (7031.52 ± 254.98 µmol EAA/g). Nevertheless, this work encourages investigations on Burkina Faso plant species used in the ethnoveterinary medicine as sources of antioxidants.
Keywords: Fraction; Ouagadougou; Barks, Total Polyphenols Contents; Radicals.
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Gioelli, F., E. Dinuccio, D. Cuk, L. Rollè e P. Balsari. "Acidification with sulfur of the separated solid fraction of raw and co-digested pig slurry: effect on greenhouse gas and ammonia emissions during storage". Animal Production Science 56, n. 3 (2016): 343. http://dx.doi.org/10.1071/an15618.
Abstract (sommario):
A study was performed to assess: (1) the feasibility to acidify the separated solid fraction of raw and co-digested pig slurry by using a powdery sulfur-based product; and (2) the effect of this acidification method on greenhouse gases and ammonia emissions during manure storage. Samples of raw and co-digested pig slurry were collected at two commercial farms and mechanically separated by a laboratory-scale screw press device. The sulfur powder (80% concentration) was added to the obtained separated solid fractions at three application rates: 0.5%, 1% and 2% (w/w). Carbon dioxide, methane, nitrous oxide and ammonia emissions were afterwards measured during storage of the acidified samples and compared with those measured from untreated samples (Control). Gaseous emissions were determined with dynamic chamber method by Infrared Photoacoustic Detection. Gaseous losses were monitored along 30 and 60 days of storage time for raw solid fraction and digested solid fraction, respectively. The addition of the tested sulfur powder to solid fractions showed to be a reliable and effective method to acidify raw and co-digested solid fractions. Results showed a significant reduction of both greenhouse gases and ammonia emission regardless of the separated solid fraction type. The highest sulfur application rate (2% w/w) led to a reduction of up to 78% of greenhouse gas emission and 65% of ammonia losses from raw separated solid fraction when compared with the Control. Similar results were achieved from the co-digested solid fraction, with emission reduction of up to 67% for ammonia and 61% for greenhouse gas.