447 research outputs found

    Evaluation of foam properties of saponin from Ilex paraguariensis A. St. Hil. (Aquifoliaceae) fruits

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    Saponins are natural compounds able to form abundant foam, a desirable quality required in some chemical, foods, cosmetic and pharmaceutical processes. Ilex paraguariensis A. St. Hil. (Aquifoliaceae) known as mate, is a South American widely cultivated specie due to the preparation of a tea-like beverage from its leaves. Moreover, its green fruits are a rich source of non-toxic and very low haemolytic saponins. In this study, mate saponin fraction (MSF) was evaluated as a foam former, focusing on its foamability, foam lifetime, and film drainage in the presence of different electrolytes (ionic strength I = 0.024 M). Sodium dodecyl sulphate (SDS) and polysorbate 80 (Poly-80) were used as reference surfactants. The critical micelle concentration (CMC), the minimum attainable surface tension (γCMC), surface excess concentration (Γ) and cross-section molecular surface (A) values of MSF were comparable to those of Poly-80. The foamability of MSF and both reference surfactants was equivalent. The addition of MgCl2 resulted in a negative effect on MSF foamability. The salts NaCl, KBr, and KNO3 exhibited a negative influence on MSF foam lifetime. Similar behavior was observed for MSF film drainage (order of activity: Na2HPO4 >; MgCl2 ≈ NaCl ≈ KNO3 >; KBr), where a primary fast film drainage rate was followed by film thinning stabilization after around 5 min. The behavior described above seems to be uncorrelated to the solutions' zeta potential.As saponinas são compostos naturais capazes de formar espuma abundante, qualidade desejável exigida em alguns processos químicos, alimentícios, cosméticos e farmacêuticos. Ilex paraguariensis A. St. Hil. (Aquifoliaceae), mais conhecida como mate, é uma espécie largamente cultivada devido ao consumo do chimarrão. Além disso, seus frutos verdes representam uma fonte rica de saponinas pouco tóxicas e pouco hemolíticas. Nesse trabalho avaliou-se a fração de saponinas de mate (MSF) como formadora de espuma, com ênfase na espumabilidade, permanência da espuma e drenagem do filme na presença de diferentes eletrólitos (I = 0,024 M). Dodecil sulfato de sódio (SDS) e polissorbato 80 (Poly-80) foram utilizados como tensoativos-referência. Os valores de concentração micelar crítica (CMC), tensão superficial na CMC (γCMC), concentração de excesso de superfície (Γ) e área do grupamento polar na interface (A) referente à MSF foram comparáveis ao Poly-80. A espumabilidade da MSF e de ambos os tensoativos-referência foram equivalentes. A adição de MgCl2 resultou em um efeito negativo sobre a espumabilidade de MSF. Os sais NaCl, KBr e KNO3 tiveram influência negativa sobre a estabilidade da espuma. Em relação à drenagem do filme de MSF, após 60 min. seguiu-se a ordem Na2HPO4 >; MgCl2 ≈ NaCl ≈ KNO3 >; KBr, caracterizando uma drenagem inicial acelerada seguida pelo equilíbrio hidrodinâmico do filme após 5 min. O comportamento observado parece não estar relacionado com o potencial zeta das soluções

    Alkaloid isomerization induced by spray drying of Uncaria tomentosa bark extracts

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    Cat's claw (Uncaria tomentosa (Willd) DC) is an alkaloid rich-liana from the Peruvian Amazon rainforest. Regarding several oxindole alkaloids from cat's claw bark, the isomerization induced by pH, temperature and solvent polarity is reported in the literature. Some industrial drying processes, such as spray drying, can provide therefore favorable conditions of heating and moisture for isomerization, and it is expected to have effects on the alkaloid composition during technological processing. In this work we focused on the effect of spray drying on the isomerization of alkaloids of dried extracts obtained from Uncaria tomentosa bark. High isomerization levels were observed in all dried extracts. A loss in mitraphylline (15%) and pteropodine (12%) content is related to an equivalent content increase of isomitraphylline and isopteropodine, respectively. Since different biological and pharmacological activities had been ascribed to these alkaloids, the influence of the thermal effect inherent to the spray drying technique and excipient type should be worth of special attention.Colegio de Farmacéuticos de la Provincia de Buenos Aire

    Determination of galangin in commercial extracts of Alpinia officinarum by RP-HPLC-DAD

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    Alpinia officinarum has been used by long time in the traditional medicine and several commercial extracts containing it are available on the market. In this paper a reversed phase high performance liquid chromatography-diode array detection (RP-HPLC-DAD) method for Alpinia officinarum preparations was proposed using galangin as a marker. The quantification was undertaken by a combination of RP-HPLC-DAD. The LC system employed a Gemini Phenomenex RP-18 column with phosphoric acid, tetrahydrofuran and acetonitrile as mobile phase and detection at 267 nm. The method validation was throughout satisfactory. The determination coefficient was r2 = 0.998 with LOD 0.48 µg mL-1 and LOQ 1.59 µg mL-1 The results of precision (RSD < 2.82) and accuracy (99.9 %, 100.4 %, 102.2 %) with . RSD less than 2.7 %, were satisfactory. The analytical method was applied to commercial extracts, and was suitable to provide qualitative and quantitative information for the quality control to commercial preparations.Colegio de Farmacéuticos de la Provincia de Buenos Aire

    Anti-trichomonas vaginalis activity of saponins from Ilex paraguariensis ("mate") fruits

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    This study evaluates the in vitro anti-trichomonads activity of a saponin enriched fraction (MSF) obtained from the fruits of Ilex paraguariensis A. St. Hil. (Aquifoliaceae). The MSF showed better anti-trichomonads activity than polysorbate and tyloxapol. A similar activity was obtained for quillaja saponins, but this fraction presented the highest cytotoxicity to mammalian cells as follows: quillaja > tyloxapol > polysorbate 80 > MSF. Neither the co-addition of MSF and metronidazole (MTZ) nor the pretreatment of the trophozoites with MSF prior to the addition of MTZ elicited a significant effect on MTZ activity.Colegio de Farmacéuticos de la Provincia de Buenos Aire

    Measurement of the production cross section for W-bosons in association with jets in pp collisions at s=7 TeV with the ATLAS detector

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    Psychosocial Risk Factors in Disordered Gambling: A Descriptive Systematic Overview of Vulnerable Populations

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    Background: Gambling is a behaviour engaged in by millions of people worldwide; for some, gambling can become a severely maladaptive behaviour, and previous research has identified a wide range of psychosocial risk factors that can be considered important for the development and maintenance of disordered gambling. Although risk factors have been identified, the homogeneity of risk factors across specific groups thought to be vulnerable to disordered gambling is to date, unexplored. Methods: To address this, the current review sought to conduct a systematic overview of literature relating to seven vulnerable groups: young people and adolescents, older adults, women, veterans, indigenous peoples, prisoners, and low socio-economic/income groups. Results: Multiple risk factors associated with disordered gambling were identified; some appeared consistently across most groups, including being male, co-morbid mental and physical health conditions, substance use disorders, accessibility and availability of gambling, form and mode of gambling, and experience of trauma. Further risk factors were identified that were specific to each vulnerable group. Conclusion: Within the general population, certain groups are more vulnerable to disordered gambling. Although some risk factors are consistent across groups, some risk factors appear to be group specific. It is clear that there is no homogenous pathway in to disordered gambling, and that social, developmental, environmental and demographic characteristics can all interact to influence an individual’s relationship with gambling

    CropPol: a dynamic, open and global database on crop pollination

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    Seventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop yield, as well as to anticipate changes in this service, develop predictions, and inform management actions. Here, we present CropPol, a dynamic, open and global database on crop pollination. It contains measurements recorded from 202 crop studies, covering 3,394 field observations, 2,552 yield measurements (i.e. berry weight, number of fruits and kg per hectare, among others), and 47,752 insect records from 48 commercial crops distributed around the globe. CropPol comprises 32 of the 87 leading global crops and commodities that are pollinator dependent. Malus domestica is the most represented crop (32 studies), followed by Brassica napus (22 studies), Vaccinium corymbosum (13 studies), and Citrullus lanatus (12 studies). The most abundant pollinator guilds recorded are honey bees (34.22% counts), bumblebees (19.19%), flies other than Syrphidae and Bombyliidae (13.18%), other wild bees (13.13%), beetles (10.97%), Syrphidae (4.87%), and Bombyliidae (0.05%). Locations comprise 34 countries distributed among Europe (76 studies), Northern America (60), Latin America and the Caribbean (29), Asia (20), Oceania (10), and Africa (7). Sampling spans three decades and is concentrated on 2001-05 (21 studies), 2006-10 (40), 2011-15 (88), and 2016-20 (50). This is the most comprehensive open global data set on measurements of crop flower visitors, crop pollinators and pollination to date, and we encourage researchers to add more datasets to this database in the future. This data set is released for non-commercial use only. Credits should be given to this paper (i.e., proper citation), and the products generated with this database should be shared under the same license terms (CC BY-NC-SA). This article is protected by copyright. All rights reserved

    Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

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    The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

    Comparing Notes: Recording and Criticism

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    This chapter charts the ways in which recording has changed the nature of music criticism. It both provides an overview of the history of recording and music criticism, from the advent of Edison’s Phonograph to the present day, and examines the issues arising from this new technology and the consequent transformation of critical thought and practice
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