• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 120
  • 56
  • 23
  • 16
  • 11
  • 7
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 3
  • Tagged with
  • 283
  • 225
  • 116
  • 110
  • 25
  • 20
  • 19
  • 15
  • 14
  • 14
  • 14
  • 14
  • 13
  • 12
  • 11
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

Effects of plant extracts and phytoconstituents on the intestinal transport of indinavir / K.H. Roos.

Roos, Karin Hester January 2012 (has links)
There is a global rise in the use of herbal products in combination with allopathic medicines, while most patients do not inform their health care providers of the use of these natural products. Both pharmacodynamic and pharmacokinetic interactions between herbal products and conventional drugs must be avoided for the wellbeing of the patient. Increasing evidence from in vitro and in vivo studies indicate that changed drug pharmacokinetics by co-administered herbs may be attributed to modulation of efflux drug transporters such as P-glycoprotein (P-gp). Garlic (Allium sativum), lemon (Citrus limonum) and beetroot (Beta vulgaris) are widely used by human immunodeficiency virus (HIV) patients, especially following the pronouncement by a former President of South Africa and the Ministers of Health at that time who promoted the use of these botanicals in HIV patients. The aim of this study was to measure the bi-directional in vitro transport of indinavir, a protease inhibitor, in the presence of crude extracts and pure phytoconstituents of A. sativum (L-alliin and diallyl disulphide), C. limonum (hesperidin and eriocitrin) and B. vulgaris (betaine monohydrate and ß-carotene) across excised porcine intestinal tissue in Sweetana-Grass diffusion chambers. In the negative control group, the transport of indinavir alone (200 M) was determined with no modulator added. In the positive control group, the transport of indinavir was determined in the presence of verapamil (100 M), a known P-gp related efflux inhibitor. The control experiments were used to indicate that the effects of the test compounds were caused by their action and not by chance interferences or external factors. Samples collected at pre-determined time intervals were analysed by means of a validated high performance liquid chromatography (HPLC) method and the transport was expressed as the apparent permeability coefficient (Papp) and the transepithelial flux (J) from which the efflux ratio (ER) and the net flux (Jnet) values were calculated. Statistical analysis was used to compare the results of the test compounds with the control groups in order to indicate significant differences. The mean ER value for indinavir in the negative control group was 1.41 ± 0.170 and in the positive control group it was 0.56 ± 0.0426. Statistically significant (p < 0.05) inhibition of indinavir efflux as indicated by reduced ER values was obtained for L-alliin (ER = 0.280 ± 0.030), diallyl disulphide (ER = 0.505 ± 0.034) and ß-carotene (ER = 0.664 ± 0.075). Inhibition of indinavir efflux will lead to increased transport and therefore a potentially higher bioavailability. Statistically significant (p < 0.05) promotion of indinavir efflux as indicated by increased ER values was obtained for C. limonum crude extract (ER = 5.551 ± 0.575) and hesperidin (ER = 3.385 ± 0.477), which potentially may lead to lower bioavalability. B. vulgaris crude extract (p = 0.8452), betaine monohydrate (p = 0.9982), A. sativum crude extract (p = 0.7161) and eriocitrin (p = 0.4431) displayed no statistically significant effect compared to the negative control group on indinavir transport across excised porcine intestinal tissue. The results from this study demonstrate that L-alliin, diallyl disulphide and ß-carotene have an inhibitory effect on indinavir efflux, which may significantly increase indinavir plasma levels after oral administration. C. limonum crude extract and hesperidin promote indinavir efflux, which may significantly reduce indinavir plasma levels. These pharmacokinetic interactions between certain drugs and plant extracts may negatively affect the anti-retroviral treatment of HIV patients, but deliberate and controlled inclusion of L-alliin, diallyl disulphide and ß-carotene in dosage forms may possibly cause more effective delivery of protease inhibitors after oral administration resulting in less frequent dosing intervals. / Thesis (MSc (Pharmaceutics))--North-West University, Potchefstroom Campus, 2013.
272

Effects of plant extracts and phytoconstituents on the intestinal transport of indinavir / K.H. Roos.

Roos, Karin Hester January 2012 (has links)
There is a global rise in the use of herbal products in combination with allopathic medicines, while most patients do not inform their health care providers of the use of these natural products. Both pharmacodynamic and pharmacokinetic interactions between herbal products and conventional drugs must be avoided for the wellbeing of the patient. Increasing evidence from in vitro and in vivo studies indicate that changed drug pharmacokinetics by co-administered herbs may be attributed to modulation of efflux drug transporters such as P-glycoprotein (P-gp). Garlic (Allium sativum), lemon (Citrus limonum) and beetroot (Beta vulgaris) are widely used by human immunodeficiency virus (HIV) patients, especially following the pronouncement by a former President of South Africa and the Ministers of Health at that time who promoted the use of these botanicals in HIV patients. The aim of this study was to measure the bi-directional in vitro transport of indinavir, a protease inhibitor, in the presence of crude extracts and pure phytoconstituents of A. sativum (L-alliin and diallyl disulphide), C. limonum (hesperidin and eriocitrin) and B. vulgaris (betaine monohydrate and ß-carotene) across excised porcine intestinal tissue in Sweetana-Grass diffusion chambers. In the negative control group, the transport of indinavir alone (200 M) was determined with no modulator added. In the positive control group, the transport of indinavir was determined in the presence of verapamil (100 M), a known P-gp related efflux inhibitor. The control experiments were used to indicate that the effects of the test compounds were caused by their action and not by chance interferences or external factors. Samples collected at pre-determined time intervals were analysed by means of a validated high performance liquid chromatography (HPLC) method and the transport was expressed as the apparent permeability coefficient (Papp) and the transepithelial flux (J) from which the efflux ratio (ER) and the net flux (Jnet) values were calculated. Statistical analysis was used to compare the results of the test compounds with the control groups in order to indicate significant differences. The mean ER value for indinavir in the negative control group was 1.41 ± 0.170 and in the positive control group it was 0.56 ± 0.0426. Statistically significant (p < 0.05) inhibition of indinavir efflux as indicated by reduced ER values was obtained for L-alliin (ER = 0.280 ± 0.030), diallyl disulphide (ER = 0.505 ± 0.034) and ß-carotene (ER = 0.664 ± 0.075). Inhibition of indinavir efflux will lead to increased transport and therefore a potentially higher bioavailability. Statistically significant (p < 0.05) promotion of indinavir efflux as indicated by increased ER values was obtained for C. limonum crude extract (ER = 5.551 ± 0.575) and hesperidin (ER = 3.385 ± 0.477), which potentially may lead to lower bioavalability. B. vulgaris crude extract (p = 0.8452), betaine monohydrate (p = 0.9982), A. sativum crude extract (p = 0.7161) and eriocitrin (p = 0.4431) displayed no statistically significant effect compared to the negative control group on indinavir transport across excised porcine intestinal tissue. The results from this study demonstrate that L-alliin, diallyl disulphide and ß-carotene have an inhibitory effect on indinavir efflux, which may significantly increase indinavir plasma levels after oral administration. C. limonum crude extract and hesperidin promote indinavir efflux, which may significantly reduce indinavir plasma levels. These pharmacokinetic interactions between certain drugs and plant extracts may negatively affect the anti-retroviral treatment of HIV patients, but deliberate and controlled inclusion of L-alliin, diallyl disulphide and ß-carotene in dosage forms may possibly cause more effective delivery of protease inhibitors after oral administration resulting in less frequent dosing intervals. / Thesis (MSc (Pharmaceutics))--North-West University, Potchefstroom Campus, 2013.
273

Produção de beterraba (beta vulgaris L.) irrigada com efluente agroindustrial. / Beet production (Beta vulgaris L.) irrigated with wastewater agribusiness,

FERREIRA NETO, João. 17 May 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-05-17T19:18:57Z No. of bitstreams: 1 JOÃO FERREIRA NETO - DISSERTAÇÃO PPGHT 2015..pdf: 2485362 bytes, checksum: ae621132dd09471389ed9d552ba29f75 (MD5) / Made available in DSpace on 2018-05-17T19:18:57Z (GMT). No. of bitstreams: 1 JOÃO FERREIRA NETO - DISSERTAÇÃO PPGHT 2015..pdf: 2485362 bytes, checksum: ae621132dd09471389ed9d552ba29f75 (MD5) Previous issue date: 2015-05-12 / A agricultura irrigada é uma atividade que demanda o maior volume de água no tocante ao consumo deste recurso pelo diversos seguimentos como o doméstico industrial e animal. O objetivo deste trabalho foi utilizar efluente agroindustrial bruto e diluído proveniente do processamento de leite e frutas, na irrigação das plantas da beterraba avaliando o crescimento e suas características físico-química e microbiológica, bem como os efeitos do efluente no solo. O experimento foi de campo, instalado no setor de Horticultura pertencente ao Instituto Federal da Paraíba Campus Sousa. O delineamento experimental empregado foi em blocos casualizados em esquema fatorial (3x5), três tipos de água e cinco doses de N, com 4 repetições totalizando 15 tratamentos e 60 parcelas experimentais, correspondendo aos tipos de água: água do açude de São Gonçalo, água de açude + efluente (1:1) e efluente bruto e as doses de Nitrogênio nas quantidades de 0, 30, 60, 90 e 120% ou 0, 3, 6, 9 e 12g/m2 de N, definidas com base na análise do solo e na recomendação adubação em cobertura para beterraba do Estado de Pernambuco. A água residuária diluída e bruta apresentou maior CE e RAS e menor pH, classificando-se como água de salinidade e sodicidade média, porém apresentou baixa população microbiana do grupo coliformes fecais, encontrando-se dentro da faixa adequada para irrigação da beterraba. Foram analisadas as seguintes variáveis: desenvolvimento aéreo da cultura, determinação dos teores de NPK na folha da beterraba, massa fresca e seca da parte aérea, peso, diâmetro, teores de sólidos solúveis, pH, acidez total e em ácido cítrico e os parâmetros microbiológicos do tubérculo da beterraba e atributos químicos do solo após experimento. Observou-se que é possível produzir beterraba com água de reuso diluída e bruta com produção igualando ao irrigar com água de açude empregando-se de 30 a 60% para efluente diluído 1:1 e de 90% da recomendação de adubação para a cultura da beterraba, respectivamente. O efluente causou alteração nas características química do solo, sendo aconselháveis práticas preventivas para evitar a salinização ou sodificação do mesmo. O efluente diluído e bruto não alterou as características, química e microbiológica da beterraba, sendo possível produzir beterraba quanto a esses atributos própria para o consumo sem dano ao consumidor. / Irrigated agriculture is an activity that requires the largest volume of water in relation to the consumption of this resource for a lot of segments such as industrial, domestic and animal. The aim of this study was to use gross agribusiness and diluted effluent from processing milk and fruit, irrigation of sugar beet plants evaluating the growth and its physico-chemical and microbiological characteristics, as well as the effluent effects on the ground. The experiment was field, installed on Horticulture sector belonging to the Federal Institute of Paraiba Campus Sousa. The experimental design was randomized in blocks in a factorial scheme (3x5), three types of water and five doses of N, with 4 repetitions totaling 15 treatments and 60 experimental plots, corresponding to the water types: water from the São Gonçalo dam, dam water + effluent (1:1) and pure effluent and nitrogen doses in amounts of 0, 30, 60 90 and 120% or 0, 3, 6, 9 and 12g / m2 N, defined based on soil analysis and fertilization recommendation in coverage for beet of the State of Pernambuco. The diluted and raw wastewater showed higher EC and RAS and lower pH, ranking as salinity and medium sodicity water, but showed a lower microbial population of fecal coliform, lying within the range for beet irrigation. The following variables were analyzed: air development of culture, determination of NPK content in the beet leaf, fresh and shoot dry, weight, diameter, soluble solids, pH, total acid and citric acid and microbiological parameters tuber beet and soil chemical properties after experiment. It was observed that it is possible to produce beet with diluted gross reuse water to irrigate with matching production with pond water employing 3060% for effluent diluted 1:1 and 90% of fertilizer recommendation for beet culture, respectively. The effluent caused changes in the chemical characteristics of the soil, being advisable preventive practices to prevent the salinization or sodification of it. The diluted and raw wastewater didn’t change the chemical and microbiological beet characteristics, being possible to produce beet related to these very attributes appropriated to the consumption with no damage to consumer.
274

Cukrovarnický průmysl v České republice - geografická analýza / Sugar industrie in Czech Republic - geography analisis

STEINBAUEROVÁ, Simona January 2010 (has links)
This thesis deals with a growing trend of the sugar industry in the Czech Republic. The first part of the work is focused on analysing of the agriculture aspects of the cane sugar cultivation. The following chapters are given to the world sugar production. The most important section the thesis is focused on development of the sugar industry and cultivation of sugarbeet in the Czech Republic, i.e development of the acreage of sugarbeet, rate of sugarbeet acreage on czech districts. Final part is given to the analysing of the sugar industry restrukturalization and influence of the European Union on the common trade of the given industry.
275

Application des électrotechnologies pour une valorisation optimisée de la betterave à sucre dans un concept de bioraffinerie / Application of electrotechnologies for an optimized valorization of sugar beet in biorefinery concept

Almohammed, Fouad 24 January 2017 (has links)
Ce travail de thèse concerne l’utilisation des électrotechnologies pour une valorisation optimisée de la betterave à sucre conformément au concept de bioraffinerie. Les électro-technologies appliquées sont les champs électriques pulsés (CEP) et les décharges électriques de haute tension (DEHT). L’étude s’attache d’une part à l’optimisation d’un procédé alternatif pour l’extraction du sucre par pressage alcalin à froid assisté par CEP. D’autre part, elle propose des nouvelles voies pour la valorisation de deux coproduits de l’industrie betteravière qui sont les radicelles et la pulpe de betterave. Dans la première partie, le traitement électrique par CEP couplé au chaulage permet une meilleure désintégration du tissu betteravier. Il permet d’accélérer les cinétiques du pressage, d’améliorer le rendement ainsi que la qualité du jus et d’alléger la procédure de purification en aval de l’extraction. Une étude paramétrique d’optimisation a permis d’identifier le meilleur itinéraire d’application de ce nouveau procédé d’extraction. Les cossettes fraîches de betterave sont prétraitées par CEP à 600 V/cm pour 10 ms (Q = 2,7 Wh/kg). Les cossettes électroporées sont ensuite pressées à froid pour extraire 75 % du jus. Les cossettes pressées subissent un pressage alcalin avec 10 % du lait de chaux. Afin d’extraire le sucre résiduel dans le gâteau de pressage obtenu, deux étapes de pressage supplémentaires avec une étape intermédiaire d’hydratation sont nécessaires. Ce procédé optimisé permet de bien épuiser les cossettes en sucre (perte en sucre de 0,23 % et matière sèche de pulpes de 39 %) pendant une courte durée d’extraction (30 min) avec un faible soutirage (108 %) par rapport au procédé de diffusion. Il permet ainsi des économies significatives de matière et d’énergie surtout pour les étapes d’extraction du jus et de séchage de pulpes. Par rapport au procédé conventionnel, le gain énergétique s’élève à 91,96 × 106 kWh pour une usine traitant 10 000 t/j de betteraves pendant une campagne de 110 jours. De plus, le procédé proposé permet de simplifier la procédure de purification et de réduire de 50 à 60 % la quantité de chaux utilisée. Dans la deuxième partie de cette étude, deux procédés de transformation ont été proposés et optimisés à l’échelle laboratoire pour la valorisation des radicelles et de la pulpe de betterave à sucre. Les radicelles ont été utilisées pour produire du bioéthanol. Le jus brut de radicelles a été extrait par pressage à froid assisté par CEP. La production du bioéthanol a été achevée par fermentation alcoolique. Le prétraitement par CEP (450 V/cm, 10 ms) a permis d’accélérer la cinétique de pressage, d’augmenter le rendement en solutés (79,85 % vs. 16,8 %) et d’obtenir un jus plus concentré (10 % vs. 5,2 %). Le procédé optimisé permet de produire environ 41,75 L de bioéthanol par tonne de radicelles lorsque l’on applique un prétraitement par CEP contre seulement 8,2 L de bioéthanol sans prétraitement électrique confirmant ainsi le potentiel de ce nouveau schéma de valorisation. La pulpe de betterave déshydratée ayant une matière sèche de 92,8 % a été utilisée pour l’extraction de pectines. L’étude réalisée a montré que l’application d’un prétraitement par DEHT permet d’intensifier l’extraction des pectines. Le gain relatif de rendement en pectines est de 25,3 % pour une énergie consommée de 76,2 kJ/kg. Le schéma de bioraffinage proposé pourra aider au maintien de la filière betteravière en France après la suppression de système de quotas sucriers dans l’Union européen qui entrera en vigueur le 1er octobre 2017. / This work discusses the use of electrotechnologies for an optimized valorization of sugar beet according to the concept of biorefinery. The applied electrotechnologies are pulsed electric fields (PEF) and high-voltage electrical discharges (HVED). The study firstly aims at optimizing an alternative method for sugar extraction by PEF assisted cold alkaline pressing. On the other hand, it proposes new ways for valorizing two by-products of sugar beet industry, which are sugar beet tails and pulps. In the first part, PEF treatment combined with liming leads to a better disintegration of beet tissue. It permits accelerating of pressing kinetics, improvement of juice yield and quality, and reduction of subsequent purification procedure. A parametric optimization study identified the best application itinerary of the proposed extraction process. Fresh sugar beet cossettes are pretreated by PEF at 600 V/cm for 10 ms (Q = 2.7 Wh/kg). The electroporated cossettes are then pressed to extract 75% of intracellular juice. Compressed cossettes are subjected to an alkaline pressing with 10% lime milk. In order to extract the residual sucrose in the obtained press-cake, two additional steps of pressing with an intermediate hydration are required. This optimized process allows well exhausting the sugar cossettes (sugar loss of 0.23% and pulp dry matter of 39%) for a short extraction (30 min) and with low draft (108%) compared to diffusion method. Thus, it allows substantial saving in materials and energy especially for juice extraction and pulp drying. Compared to the conventional method, the energy saving amounted to 91.96 × 106 kWh for a sugar beet factory treating 10 000 tons per day for a campaign of 110 days. In addition, the proposed method simplifies the purification procedure of raw juice and reduces the used amount of lime from 50 to 60%. In the second part of this study, two processing methods were proposed and optimized at lab-scale for valorization of sugar beet tails and pulps. Sugar beet tails were used to produce bioethanol. Raw juice of beet tails was extracted by PEF assisted cold pressing. Bioethanol production was then done by alcoholic fermentation. Pretreatment of beet tails with PEF (450 V/cm, 10 ms) permits accelerating the pressing kinetics, increasing the yield of solutes (79.85% vs. 16.8%), and leads to a more concentrated juice (10% vs. 5.2%). The optimized process permits the production of about 41.75 L of bioethanol per ton of beet tails when PEF pretreatment is applied against only 8.2 L of bioethanol without PEF confirming the potential of this new valorization scheme. Dried beet pulp having a dry matter of 92.8% was used for pectin recovery. The present study showed that the application of HVED pretreatment leads to intensify pectin extraction. The relative gain of pectin yield is 25.3% with an energy consumption of 76.2 kJ/kg. The proposed biorefinery scheme could protect the sugar beet industry in France after the suppression of the sugar quota system in the European Union, which will take effect on 1st October 2017.
276

Cytosine Methylation of an Ancient Satellite Family in the Wild Beet Beta procumbens

Schmidt, Martin, Hense, Sarah, Minoche, André E., Dohm, Juliane C., Himmelbauer, Heinz, Schmidt, Thomas, Zakrzewski, Falk 20 May 2020 (has links)
DNA methylation is an essential epigenetic feature for the regulation and maintenance of heterochromatin. Satellite DNA is a repetitive sequence component that often occurs in large arrays in heterochromatin of subtelomeric, intercalary and centromeric regions. Knowledge about the methylation status of satellite DNA is important for understanding the role of repetitive DNA in heterochromatization. In this study, we investigated the cytosine methylation of the ancient satellite family pEV in the wild beet Beta procumbens. The pEV satellite is widespread in species-specific pEV subfamilies in the genus Beta and most likely originated before the radiation of the Betoideae and Chenopodioideae. In B. procumbens , the pEV subfamily occurs abundantly and spans intercalary and centromeric regions. To uncover its cytosine methylation, we performed chromosome-wide immunostaining and bisulfite sequencing of pEV satellite repeats. We found that CG and CHG sites are highly methylated while CHH sites show only low levels of methylation. As a consequence of the low frequency of CG and CHG sites and the preferential occurrence of most cytosines in the CHH motif in pEV monomers, this satellite family displays only low levels of total cytosine methylation.
277

Elaboración de bloques de concreto adicionado con nanoplaquetas de beterraga azucarera para prevenir las patologías en unidades de concreto tradicional usadas en edificaciones cercanas al mar / Concrete blocks for structural masonry homes built in a marine atmosphere zone using tuber waste from the food industry

Olarte Breña, Karen Gabriela, Sánchez Riveros, María de los Ángeles 28 October 2020 (has links)
Las manifestaciones patológicas de mayor importancia en los bloques de concreto de la albañilería armada son las eflorescencias y las fisuras; las primeras son estéticas y las segundas son estructurales. Estas patologías se originan por la porosidad del bloque; la cual facilita el ingreso de las sales procedentes de la brisa marina y niebla salina presentes en la atmósfera marina. Estas sales, por efecto del viento son arrastradas y depositadas en las viviendas construidas fuera del mar. Una solución a este problema es utilizar un material que minimice el avance de las fisuras y grietas, como son las nanoplaquetas de beterraga azucarera (NPB); las cuales son residuos vegetales procedentes de la industria alimentaria. En la presente investigación se aborda el estudio de los bloques de concreto fisurados, estudiándose para ello algunas propiedades mecánicas, físicas y químicas; los resultados muestran que con la adición de NPB la resistencia a la compresión y flexión aumentan, y la absorción y carbonatación disminuyen cuando se comparan con el concreto sin nanoaditivo. / The most important pathological manifestations in the concrete blocks of the armed masonry are the efflorescence and the fissures; the former are aesthetic and the latter are structural. These pathologies are caused by the porosity of the block; which facilitates the entry of salts from the sea breeze and salt mist present in the marine atmosphere. These salts, as a result of the wind are dragged and deposited in homes built outside the sea. A solution to this problem is to use a material that minimizes the progress of fissures and cracks, such as sugar beet nanoplatelets (BNP); which are plant residues from the food industry. In the present investigation the study of cracked concrete blocks is approached, studying some mechanical, physical and chemical properties; the results show that with the addition of BNP the compressive strength increases, and the absorption and carbonation decrease when compared to concrete without nanoadditive. / Tesis
278

Characterization of Pol IV and Pol V-Dependent Non-Coding RNAs Derived from aGeminivirus Genome

Ostler, Jeffery Brent, Jr. 15 August 2017 (has links)
No description available.
279

Hochbeete: Pillnitzer Empfehlungen

12 August 2024 (has links)
Hochbeete sind eine ideale Ergänzung, um ungünstige Bodenverhältnisse zu umgehen und in angenehmer Haltung zu gärtnern. Im Faltblatt wird sowohl ein Überblick über Aufbau und Befüllung von Hochbeeten als auch einige Hinweise zu Pflanzenauswahl, Pflege sowie Ernte gegeben. Redaktionsschluss: 10.06.2024
280

Zur Bedeutung der Bodenstruktur für den Ertrag von Zuckerrüben / eine pflanzenbauliche und ökonomische Analyse in einer Zuckerrüben - Getreide - Fruchtfolge mit dauerhaft differenzierter Bodenbearbeitung / Relevance of soil structure for sugar beet yield / - an agronomical and economical analysis in a sugar beet - winter wheat rotation with long term variable cultivation tillage systems

Dieckmann, Jan 23 January 2008 (has links)
No description available.

Page generated in 2.6059 seconds