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  • 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.
1

The rational design and synthesis of ionophores and fluoroionophores for the selective detection of monovalent cations

Benco, John S. January 2003 (has links)
Thesis (Pd. D.)--Worcester Polytechnic Institute. / Keywords: ionophore; fluoroionophore. Includes bibliographical references (p. 154-162).
2

Studies towards the biosynthesis of Monesnin A

Sherringham, John Andrew January 1990 (has links)
No description available.
3

The Rational Design and Synthesis of Ionophores and Fluoroionophores for the Selective Detection of Monovalent Cations

Benco, John S 10 April 2003 (has links)
The rational design, synthesis and complexation characteristics of several monovalent cation-selective ligands are described. Molecular modeling employing a combination of dynamics, mechanics (AMBER94) and electrostatics was used to design ligands for the complexation of ammonium, potassium, sodium and lithium ions. A modular technique was used to synthesize an ammonium selective ionophore based on a cyclic depsipeptide structure (8). The ionophore was incorporated into a planar ion selective electrode (ISE) sensor format and the selectivity tested versus a range of metal cations. It was found that the membrane containing the polar plasticizer NPOE (nitrophenyloctylether) in the absence of ionic additive exhibited near-Nernstian behavior (slope = 60.1 mV/dec @ 37¢ªC) and possessed high selectivity for ammonium ion over lithium and the divalent cations, calcium and magnesium (logK = -7.3, -4.4, -7.1 for lithium, calcium and magnesium ions, respectively). The same membrane also exhibited sodium and potassium selectivity that was comparable to that reported for nonactin (logK = -2.1, -0.6 for sodium and potassium, respectively, compared to -2.4, -0.9 in the case of nonactin). N-(9-methylanthracene)-25,27-bis(1-propyloxy)calix[4]arene-azacrown-5 (10) was synthesized and tested as a fluoroionophore for the selective detection of potassium ions. Compound 10 acts as an ¡°off-on¡± fluorescent indicator for ion complexation as a result of photoinduced intramolecular electron transfer (PET). Studies demonstrate that 10 is selective for potassium over other alkali metal cations, with excellent selectivity over sodium and lithium (log K ¡ -3.5) and moderate selectivity over rubidium and cesium (log K ~ -1). N-(9-methylanthracene)-25,27-bis(1-propyloxy)-4-tert-butylcalix[4]arene-azacrown-3 (11) was synthesized and tested as a fluoroionophore for the selective detection of lithium cations. When exposed to lithium ions in a 75:25 dichloromethane/THF solvent mixture, the molecule, which operates on PET, exhibited a >106-fold enhancement in fluorescence emission intensity. Selectivity studies demonstrated that 11 effectively discriminates against sodium and potassium ions log K ¡ -3.8 and log K ¡ -2.3. A fluorescent sodium optode based on a fluoroionophore consisting of aminorhodamine B covalently-linked through an amide bond to a calix[4]arene has also been developed (12). The optode, fashioned by incorporation of the fluoroionophore into a single component polymer matrix, operates on the basis of PET. The fluorescence intensity increased linearly with increasing sodium ion concentration in the range 0.01 M to 2.0 M, exhibiting a three-fold enhancement over this range. The optode provides selectivity for sodium ions compared to potassium ions that is sufficient for clinical determinations of sodium ion concentration.
4

Synthese, Struktur und Bindungseigenschaften neuer Ionophore

Fricke, Tom. Unknown Date (has links) (PDF)
Universiẗat, Diss., 2001--Regensburg. / Erscheinungsjahr an der Haupttitelstelle: 2001.
5

Fresh Approach for High-Throughput Studies of Ion-Selective Materials Using Reusable ChemFET Platform

Banning, Douglas 30 April 2019 (has links)
Aqueous anions play an important role in our world, and the ability to continuously measure them provides both environmental and health benefits. Chemically-sensitive field effect transistors (ChemFETs) are becoming increasingly popular in the field of aqueous measurement due to their relatively low-cost capability for real-time, continuous sensing. Receptor molecules or mixtures displaying affinity for a particular ion can also be utilized in a ChemFET gate membrane. Receptors can be incorporated into the gate oxide membrane and the entire ChemFET can utilized in an aqueous environment, thus utilizing hydrophobic receptors in an aqueous anion-sensing application. Demonstrating the ability to reuse the sensors validates an important characteristic for ChemFET-based research. Additionally, numerous other receptor molecules are evaluated against an array of common anions. Selectivity coefficients are compared to the Hofmeister Series. Additional membranes are evaluated for suitability for incorporation of receptors on the ChemFET gate oxide surface. This thesis includes previously unpublished co-authored material. / 2021-04-30
6

The Effects of Probiotic and Eimeria on Gut Morphology and Humoral Immunity in Broilers

Horrocks, Sadie Lyn 2010 December 1900 (has links)
Coccidiosis has a negative economic impact on the commercial poultry industry, and probiotics are beneficial bacteria that aid in maintaining healthy gut microflora. We hypothesized that probiotic administration would positively affect gut morphology and increase IgG secretion during an Eimeria challenge, which was evaluated by measuring total chicken IgG and gut morphology (villus height, villus width, villus surface area, crypt depth, villus height to crypt depth ratio and lamina propria thickness). On day-of-hatch, broilers were placed into floor pens with 50 percent pine shavings and 50 percent used litter. The broilers were exposed to Eimeria oocysts via the feed on day 14 and challenged on day 36. On days 6, 22, 36, and 43, tissue samples from the intestine were collected for morphological evaluation, and blood samples were taken to quantify chicken IgG from serum. Data were measured using a factorial ANOVA and main effect means were deemed significant at P ≤ 0.05. In cases where significant interactions were observed, data was subjected to a one-way ANOVA. All means were separated using a Duncan’s Multiple Range Test. On day 6 in the duodenum, a significant interaction was observed regarding vaccination and probiotic administration (Coccivac®-B, Intervet/Schlering-Plough Animal Health/Merck and Co., Inc., Whitehouse Station, NJ). Villus height to crypt depth ratio decreased in ionophore treated birds compared to control birds in the duodenum and lower ileum on day 6, 36, and 43. Villus crypt depth in vaccinated birds decreased in the duodenum after the challenge. On day 43, the ionophore treated birds had less villus height and surface area compared to control and vaccinated birds, while lamina propria thickness increased in the duodenum, and non probiotic birds had longer villi than probiotic birds. On day 22, vaccinated birds had significantly increased chicken IgG levels compared to the control and ionophore birds, and the non probiotic birds had significantly increased IgG secretion compared to probiotic fed birds. On day 36, the ionophore birds had significantly increased levels of IgG compared to the control birds, which could also support that the ionophore delayed exposure to the parasite. These results suggest that gut morphology and humoral immunity are affected by probiotic administration, coccidiosis vaccination, ionophore application and Eimeria challenge. Both the day 43 morphology results and day 36 chicken IgG results for the ionophore treated birds demonstrates that ionophore administration delays exposure of the avian gut to invasive coccidia. More research is necessary to evaluate how probiotics influence coccidiosis vaccination and humoral immunity, so that probiotics may be used to improve the effectiveness of coccidiosis vaccination and to evaluate if probiotics aid in ameliorating the effects of an Eimeria infection.
7

Amid- und esterfunktionalisierte Amine sowie deren Verwendung als Ionophore bzw. als Trägermaterialien in der Suzuki-Reaktion

Nicolai, Anja 03 August 2009 (has links) (PDF)
Die vorliegende Arbeit befasst sich mit der Synthese und Charakterisierung von amid- und esterfunktionalisierten Aminen. Dabei steht vor allem die Verwendung dieser Verbindungsklasse als Ionophore in der chemischen Sensorik im Vordergrund. Durch geeignete Voruntersuchungen, wie die Bestimmung der Lipophilie und UV/Vis-Spektroskopie, war es möglich, eine Selektion der Vielzahl von synthetisierten Ionophoren durchzuführen. Dennoch war es nur durch systematische Untersuchungen erreichbar, die für den Einsatz in der ISE am besten geeigneten Ionophore zu bestimmen. Die Anwendung als Katalysatorträgermoleküle für die Suzuki-Miyaura-Reaktion wurde nur von den ferrocenfunktionalisierten Molekülen in Betracht gezogen. Diese wurden an Palladiumallylchlorid koordiniert und auf ihr katalytisches Verhalten untersucht. Es konnte gezeigt werden, dass mit Zunahme der funktionellen Endgruppen im Molekül ein negativer dendritischer Effekt auftritt.
8

Efeitos da salinomicina no consumo, degradação no rúmen e in vitro, taxas de produção de gases e fermentação in vitro de dietas compostas por feno de capim coast cross (Cynodon dactylon) e sal proteinado / Effects of salinomycin on dry matter intake , in situ and in vitro degradability , rates of gas production and fermentation of cynodon (Cynodon dactylon) hay supplemented with proteic salt

Faftine, Olga Lurdes Jossias 17 February 2006 (has links)
Este trabalho pretende avaliar o efeito da salinomicina no consumo de feno coast cross e sal proteinado, na digestibilidade total, ruminal in situ e in vitro, taxas de produção de gases e taxas de fermentação. Para a avaliação da digestibilidade e degradabilidade in situ foram utilizados 4 novilhos Holandeses com peso médio de 350 kg ± 43 kg. O delineamento experimental utilizado foi o quadrado latino com 4x4. No ensaio in vitro foram utilizados 4 substratos *8 inóculos *2 corridas com delineamento em blocos e arranjo fatorial. Os tratamentos estudados foram: 0; 0,1; 0,2; 0,3 mg de salinomicina /kg de peso vivo. Não foram encontradas diferenças significativas (p>0,05) no consumo de MS(1,92; 1,73; 1,60; 1,63 %PV), digestibilidade aparente da MS (81,79; 80,32; 80,32 e 80,49), na degradação in situ da MS (52; 51,25; 49,20 e 51,38) e na degradação in vitro da MS (45,31; 45,64; 45,77; 45,03) entre os vários tratamentos. Os únicos parâmetros onde foram identificadas alterações significativas entre os tratamentos foram no volume final de gases in vitro e nas curvas de taxas de fermentação. Os valores encontrados de para o volume final de gases foi de 231,8; 204; 168 e 157,78 ml /g de MS para a dose de 0; 0,1; 0,2 e 0,3 mg de salinomicina/ kg de PV, respectivamente. O tratamento 3 foi o que teve menores perdas de energia. / This experiment was conducted to evaluate the effect of graded levels of salinomycin on feed intake, apparent di estibility, gas production and fermentation rate, degradability in situ and in vitro of cynodon hay supplemented with proteic salt with 0, 0.1, 0.2 and 0,3mg of salynomicin per kg LW. Intake , digestibility and degradabilty studies were analysed as a latine square design 4x4 and in vitro trials followed the block randomized design with a two factors (inocula and substrate). No differences (p>)0,05) were found between the treatments for DM intake (1.92, 1.73, 1.60, 1.63 per % LW), DM digestibility (81.79, 80.32, 80.32 and 80.49), DM in situ degradability (52, 51.25, 49.20 and 51.38) and in vitro DM degradability (45.31, 45.64, 45.77 and 51.38). Differences between treatments were found only for potencial gas production in vitro (231.8, 204, 168 and 157.78 ml/g DM) for 0, 0.1, 0.2 and 0,3 mg of salinomycin/kg LW. Therefore, wasting energy was minimized at treatment 3.
9

Suplementação com diferentes aditivos para bovinos em pastagem no período das águas / Supplemantion with different feed additives for grazing bovines during rainy season

Garcia, Simone Aparecida 24 October 2014 (has links)
Dois experimentos foram conduzidos com o intuito de avaliar os efeitos da suplementação com diferentes aditivos, sobre o consumo e ganho de peso, em bovinos mantidos em pastagem durante o período das águas. No experimento I, 48 novilhas Nelore, com 266 kg de peso vivo médio inicial, foram distribuídas no delineamento experimental inteiramente casualizado, em quatro tratamentos, sendo cada animal considerado uma unidade experimental. Os tratamentos foram arranjados em esquema fatorial 2 x 2, com dois tipos de suplemento (suplemento mineral e mineral protéico energético) e dois níveis de monensina (0 e 1200 ppm em suplemento mineral, 0 e 60 ppm em mineral protéico energético). No experimento II, foram utilizados 60 bezerros Nelore, com peso vivo médio inicial de 300 kg. Os animais foram distribuídos em um delineamento inteiramente casualizado em quatro tratamentos com 15 animais cada. Os animais foram submetidos aos tratamentos: com suplemento mineral (controle), suplemento mineral com virginiamicina (1333 ppm), suplemento mineral com salinomicina (1111 ppm) e suplemento mineral com monensina (1000 ppm). Em ambos os experimentos, os animais foram alocados em quatro piquetes de Brachiaria decubens, com 6,7 hectares cada, e eram rotacionados semanalmente. As análises estatísticas foram feitas utilizando o programa estatístico SAS. No experimento I, o consumo do suplemento mineral protéico energético, com e sem monensina, foi maior em relação aos demais tratamentos (P<0,05) e a monensina não provocou uma queda siginificativa no consumo dos suplementos. Os animais que receberam o suplemento mineral protéico energético ganharam mais peso do que os animais que receberam o suplemento mineral (P<0,05), não havendo influencia da monensina sobre o ganho de peso. No experimento II, a monensina promoveu uma redução no consumo em relação ao grupo controle (P<0,06). O suplemento com virginiamicina não afetou o consumo aos 56 dias, mas os suplementos com salinomicina e monensina reduziram o consumo em relação ao controle (P<0,05). Não houve diferença siginificativa no consumo entre os tratamentos aos 28 dias e aos 84 dias, porém houve uma redução no consumo de todos os suplementos. O ganho de peso diário entre os animais que consumiram os aditivos não apresentaram diferenças significativas, mas os tratamentos com virginiamicina e salinomicina proporcionaram ganhos maiores do que o tratamento controle. A virginiamicina e a salinomicina ocasionaram um aumento no ganho de peso, e a salinomicina e a monensina reduziram o consumo. / Two experiments were conducted to evaluate the effects of the supplementation with different feed additives on feed intake and average daily gain for grazing Nellore bovines during the rainy season. On the experiment I, 48 Nellore heifers (266 kg BW) were distributed in four treatments, and each animal was considered one experimental unit. The treatments were organized in a factorial 2x2, two types of supplements (mineral supplement and mineral protein-energy supplement) and two levels of monensin (0 and 1200 ppm in the mineral supplement, 0 and 60 ppm in the mineral protein- energy supplement). In the study II, 60 Nellore calves of 300 kg (BW) were distributed in 4 treatments of 15 animals each. Treatments consisted of the inclusion of: mineral supplement (control treatment), mineral supplement with virginiamycin (1333ppm), mineral supplement with salinomycin (1111 ppm) e mineral supplement with monensin (1000ppm). In both studies, animals were allocated in four rotational stocking areas (6,7 hectares each area) of Brachiariadecubens. Statistical analyses were conducted using the software SAS. In the experiment I, the consumption of the mineral proteic supplement, with and without monensin, was higher compared to the others treatments (P<0.05) and the monensin did not cause any significant decrease on the supplement intake. Animals who received protein mineral supplement had higher average daily gain than animals who received mineral supplement (P<0.05) and there was no effect of monensin on the weight gain. In the experiment II, the inclusion of monensin reduced the consumption compared to the control treatment (P<0.06). The supplement with virginiamycin did not affect the consumption on the day 56, however the supplements with salinomycin and monesin reduced the consumption compared to the control treatment (P<0.05). The average daily gain was statically different among treatments on the days 28 and 84, however there was a reduction on consumption of all treatments. The average daily gain among animals supplemented with different feed additives did not differ statically, but the treatments with the inclusion of virginiamycin and salinomycin had higher gains than the control treatment. The virginiamycin anda salinomycin caused increase weight gain and the salinomycin and monensin reduced the consume.
10

Utilização de óleo essencial das folhas e dos frutos de aroeira (Schinus terebinthifolius) na nutrição de cordeiros confinados / Effect of essential oils from leaves and fruits of aroeira (Schinus terebinthifolius) on nutrition of the feedlot sheep

Bertoloni, Analisa Vasques 08 January 2018 (has links)
Dois experimentos foram conduzidos com o objetivo de avaliar os efeitos da inclusão de óleos essenciais (OE) extraídos das folhas e dos frutos da aroeira em dietas de alto concentrado sobre o desempenho e características de carcaça de cordeiros confinados. Experimento I: Foram utilizados 44 cordeiros, 16 machos e 28 fêmeas, sendo o delineamento experimental de blocos completos casualizados, com 4 tratamentos e 11 repetições. O experimento teve a duração de 56 dias, divididos em 2 períodos de 28 dias cada. Os animais foram alimentados com as dietas experimentais compostas por 10% de volumoso (feno de coastcross) e 90% de concentrado. Os tratamentos foram definidos pela inclusão de: 8 ppm de monensina sódica (MON) e as doses 0,140% (140 OE), 0,280% (280 OE), 0,420% (420 OE) do OE das folhas de aroeira (em % na matéria seca (MS). Ao final dos 56 dias, 31 animais foram abatidos para a mensuração dos parâmetros de carcaça. Os tratamentos não afetaram (P > 0,05) o ganho de peso médio diário, consumo de matéria seca e eficiência alimentar. A infestação por coccidiose foi menor (P <0,05) no tratamento com monensina. O rendimento de carcaça fria foi maior (P < 0,05) nos animais alimentados com maiores doses de OE. Os demais parâmetros de carcaça avaliados não foram afetados pelos tratamentos (P > 0,05). As maiores doses de OE das folhas de aroeira aumentaram (P < 0,05) a porcentagem de proteína bruta e matéria mineral na composição química da carne dos cordeiros. Apesar de não alterar o desempenho dos cordeiros, a inclusão das doses mais elevadas de OE das folhas de aroeira apresentaram respostas positivas para o rendimento de carcaça fria, demonstrando o potencial de utilização desse aditivo em dietas para cordeiros confinados. Experimento II: Foram utilizados 48 cordeiros, 24 machos e 24 fêmeas, sendo o delineamento experimental de blocos completos casualizados, com 4 tratamentos e 12 repetições. O experimento teve duração de 56 dias, divididos em 2 períodos de 28 dias cada. Os animais foram alimentados com as dietas experimentais compostas por 10% de volumoso (feno de coastcross) e 90% de concentrado. Os tratamentos foram definidos pela inclusão de: 8 ppm de monensina sódica (MON) e as 11 doses 0,140% (140 OE), 0,280% (280 OE), 0,420% (420 OE) do OE dos frutos de aroeira (em % na MS). Ao final dos 56 dias, 32 animais foram abatidos para a mensuração dos parâmetros de carcaça. Não houve efeito (P > 0,05) dos tratamentos no ganho de peso médio diário, consumo de matéria seca, eficiência alimentar, coccidiose e parâmetros de carcaça. A infestação por coccidiose não interferiu (P < 0,05) no ganho médio diário e consumo de matéria seca. Os tratamentos com as maiores doses de OE dos frutos de aroeira reduziram o teor de matéria mineral da carne dos cordeiros em relação à monensina. O desempenho e os parâmetros de carcaça dos cordeiros alimentados com as dietas contendo OE dos frutos de aroeira foram semelhantes aos que receberam monensina sódica. / Two experiments were carried out to evaluate the effects of the inclusion of essential oils (EO) extracted from leaves and fruits of aroeira on performance and carcass characteristics of feedlot sheep fed high concentrate diets. Experiment I: Fourty-four lambs (16 males and 28 females) were assingned in a randomized complete block design to receive one of treatments: 8 ppm of sodium monensin (MON) and doses of 0.140% (140 EO), 0.280% (280 EO) and 0.420% (420 EO) of aroeira leaves EO (% in a DM basis). The experiment lasted 56 days, divided in 2 periods of 28 days each. The animals were fed a diet containing 10% roughage (coastsross hay) and 90% concentrate. At the end of experiment, 31 lambs were slaughtered to access the carcasses characteristics. The treatments did not affect (P > 0.05) the average daily gain, the dry matter intake and the feed efficiency. Infestation by coccidiosis was lower (P < 0.05) in the monensin treatment. Cold carcass dressing was higher (P < 0.05) for the animals fed higher doses of EO. The other carcass parameters were not affected by the treatments (P > 0.05). The higher doses of aroeira leaves EO increased (P < 0.05) the percentage of crude protein and mineral matter in the meat. Despite did not affect the lambs performance, the inclusion of aroeira leaves EO at the higher doses did present positive results for the cold carcass dressing, showing a potential of this additive in feedlot sheep diets. Experiment II: fourty-eight lambs (24 males and 24 females) were assingned in a randomized complete block design to recive one of treatments: 8 ppm of sodium monensin (MON) and doses of 0.140% (140 EO), 0.280% (280 EO) and 0.420% (420 EO) of aroeira fruits EO (% in a DM basis). The experiment lasted 56 days, divided in 2 periods of 28 days each. The animals were fed a diet containing 10% roughage (coastsross hay) and 90% concentrate. At the end of the experiment, 32 lambs were slaughtered to access the carcasses characteristics. The treatments did not affect (P > 0.05) the average daily gain, dry matter intake, feed efficiency, the coccidiosis infestation and the carcasses parameters. In addition, the infestation by coccidiosis did not interfere (P < 0.05) on average daily gain and dry matter intake. The treatments with 13 higher doses of the EO from aroeira fruits reduced the percentage of mineral matter of meat compared to monensin. The performance and carcass parameters of the lambs fed diets containing essential oils were similar to those fed monensina.

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