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Discovery and dissemination of new knowledge in food science: Analytical methods for quantification of polyphenols and amino acids in fruits and the use of mobile phone-based instructional technology in food science educationMa, Sihui 11 June 2019 (has links)
The discovery and dissemination of new knowledge are essential in food science. To advance our understanding of fruit chemistry, analytical methods were compared and applied.
Polyphenols are secondary metabolites in fruits of particular importance in food science, as they contribute to the sensory attributes and health benefits of the products. Evaluation of common analytical methods for the quantification of polyphenols, including the Folin-Ciocalteu (F-C), Lowenthal permanganate (L-P), 4-dimethylaminocinnamaldehyde (DMAC) and the bovine serum albumin (BSA) precipitation methods, was conducted using analytical method validation procedures. The F-C method was not specific to polyphenols, and the L-P method had the widest working range but lacked accuracy. The DMAC method was the most specific to flavanols, and the BSA method was not suitable for quantification of smaller flavanols. Quantitative performance of these four methods was evaluated using a broad range of fruit-derived samples. Variation in quantitative results obtained using these four methods was explained by differences in polyphenol and matrix composition of these samples and differences in operating principles of the methods.
The reactivity of individual polyphenol compounds (catechin, epicatechin, PC B2, PC pentamer, chlorogenic acid, phloretin, and quercetin) to the polyphenol and flavanol quantification results using Prussian blue (P-B), F-C, DMAC and BSA precipitation methods were also assessed and determined to differ by up to thirteen-fold, depending on the assay. Furthermore, the contribution and interactions of polyphenol compounds (catechin, PC B2, and chlorogenic acid) and potentially interfering compounds likely to be found in fruit and fruit products (ascorbic acid, glucose, and SO2) to the quantitative results of these methods were evaluated using a full factorial design. Significant interactions among polyphenol compounds, and among the interfering compounds were found. The standardized coefficient (β) for all factors and interactions of polyphenol compounds varied from 0.347 to 129, and from near 0 to -46.8 for all factors and interactions of interfering compounds. Our findings indicate that the choice of standards, polyphenol and matrix composition of the sample may cause disparity among the quantitative results of these methods.
Amino acids in apple (Malus × domestica Borkh.) juice not only influence the quality of fermented cider through fermentation kinetics but also impact the flavor of the cider through yeast metabolism. Due to recent advances in analytical instrumentation, amino acids profiles in apple juice were determined much faster and more accurately than by previously applied methods. Twenty amino acids were quantified by UPLC-PDA in juices from 13 apple cultivars grown in Virginia. The relative amino acid profile was significantly different among the apple juices evaluated. The total amino acid concentration ranged from 18 mg/L in Blacktwig juice to 57 mg/L in Enterprise juice. L-Asparagine, L-aspartic acid and L-glutamine are the principal amino acids observed in most apple juices. These results will inform future research on yeast metabolism and nitrogen management during cider fermentation.
To better disseminate knowledge gained through research to the next generation of food scientists, the effectiveness of new instructional technology—a cellphone-based personal response system—in food science education was evaluated. Students' academic performance was improved by the incorporation of this technology into lectures, and its use was well perceived by the students (easy to use and positively impacted their learning). This finding contributes to the scholarship of teaching and learning in food science by providing useful insight into the potential for application of such tools with improved student engagement and learning outcomes.
Advances in food chemistry research will enable the development of value-added food products, and the pedagogical advancement in food science education will better convey new and existing knowledge to students, who will apply this knowledge to promote a safe and nutritious food supply that enhances human health and increases the value of specialty crops. / Doctor of Philosophy / In food science, both the discovery and dissemination of new knowledge are essential. To advance our understanding in fruit chemistry, several analytical methods were compared and applied. Polyphenols are important bioactive compounds in fruits associated with health benefits, and they also contribute to the bitterness and astringency of the products such as chocolate and red wines. Systematic evaluation of common analytical methods used to quantify polyphenols was conducted. When different methods were used to evaluate a broad range of fruit-derived samples, different results were obtained for a given sample, depending on the method applied. This was explained by the difference in polyphenol composition of these samples. Furthermore, different individual polyphenol compounds contributed differently to quantitative results for these methods. Interactions among polyphenol compounds and interference from constituents of the juice samples other than polyphenols were also found. These findings demonstrate that when comparing fruit chemistry (polyphenol concentration) results obtained using the methods evaluated, it is necessary to consider the polyphenol composition as well as the sample matrix composition. This knowledge will improve our ability to interpret and compare existing data on polyphenol content in fruits, advancing the understanding the polyphenols and health and informing producers to improve their fruit products with optimized quality and sensory characters.
Secondly, amino acids in apple juice influence the quality of fermented cider, through not only controlling the fermentation rate, but also impacting the flavor of the cider through yeast metabolism. Twenty amino acids were quantified in juices from 13 apple cultivars grown in Virginia with potential use in cider making using a recently developed method in analytical chemistry. The relative amino acid profile was significantly different among the apple juices evaluated. L-Asparagine, L-aspartic acid and L-glutamine are the principal amino acids observed in most apple juices. This knowledge will help with the development of fermentation strategies for production of ciders with targeted sensory attributes.
To better disseminate new knowledge in food science to the next generation, the effectiveness of a new educational technology application—a cellphone-based personal response system (similar to clickers)—in food science education was evaluated. Using this application during lecture resulted in improved quiz grades, and students felt that it was easy to use and positively impacted their learning. This application has the potential to improve effectiveness of lectures in higher education classrooms.
Advances in food chemistry research will enable development of value-added food products, and the pedagogical advancement in food science education will better convey new and existing knowledge to students, who will apply this knowledge to promote a safe and nutritious food supply that enhances human health and increases the value of specialty crops.
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The influence of different winemaking techniques on the extraction of grape tanninsNel, Anton Pieter 03 1900 (has links)
Thesis (MScAgric (Viticulture and Oenology))--University of Stellenbosch, 2011. / Includes bibliography. / ENGLISH ABSTRACT: Grape and wine phenols consist of flavanols which is the building blocks for tannins.
These building blocks are called monomers which consist of catechins, epicatechins,
epigallocatechins and epicatechin-gallate. Tannin is important in wine as it contributes
to bitterness, mouth feel (astringency) and maturation potential of the wine. Futhermore
it has a health benefit as an antioxidant. Anthocyanins are responsible for the colour of
red wine. The anthocyanins combine with tannins to form stable polymeric pigments.
Due to the importance of tannins and anthocyanins in wine, it is imperitative that
different winemaking techniques are used to extract as much of these components as
possible and that the analysis is done quickly and accurately.
The aim of this study was to evaluate different winemaking techniques and their
extraction of tannins and anthocyanins into the wine. Too much tannin extraction can
have a negative effect on the sensory quality of the wine. Therefore a second aim was
to evaluate the mouth feel properties of a Shiraz wine. A third aim was to compare the
two tannin precipitation methods in terms of time efficiency, repeatability and the ease
of practice.
To investigate the amount of tannin concentration extracted by different winemaking
techniques, two cultivars (Cabernet Sauvignon and Shiraz) were used. These
treatments included the addition of an enzyme during fermentation [E], cold maceration
[CM], post maceration [PM] and the combination of cold and post maceration [CM+PM].
The grapes were harvested in two different climatic areas during the 2008 and 2009
vintages. The two climatic areas were classified according to the Winkler scale as a III
(Morgenster) and a IV (Plaisir de Merle). The grapes were harvested at two different
ripeness levels in order to evaluate the effect of the different winemaking processes on
the extraction of tannins and anthocyanins. One harvest was before (LB) and the other
after (HB) the commercial harvest.
The results of this study showed significant differences in the phenolic composition of
the wines. It was found that the warmer area showed higher tannin concentrations than
the cooler area for both cultivars. In the 2008 Cabernet Sauvignon the CM extracted
higher concentrations of tannin from the cooler area at both ripeness levels. In the
warmer area, CM extracted the highest tannin concentration HB, but the CM+PM
extracted the highest tannin concentration from Cabernet Sauvignon at the LB and CM
at the HB of the warmer area. In 2009 the PM extracted the highest concentration of
tannin at the lower ripeness level, while the E treatment extracted the highest
concentration from the warmer area. In the cooler area the CM+PM extracted the
highest concentration of tannin at a lower ripeness level, while there were no siginicant
differences between the different treatments at the higher ripeness level. The highest
anthocyanin concentration was found in the cooler area. The CM treatment was found
to have no effect on anthocyanin extraction.
Different methods are available to quantify the tannin concentration in wine. Two of the
most popular tannin analytical methods are the bovine serum albumin (BSA) and the
methyl cellulose precipitable tannin (MCP) methods. The BSA method is a very complex
method which uses at least 3 times more reagents than the MCP method. The MCP
method only analyzes tannins, while the BSA method analyzes tannins, monomeric
pigments (MP), small polymeric pigments (SPP) and large polymeric pigments (LPP).
In this study a good correlation was found between the two tannin precipitation methods
(R2 – 0.88). There is controversy regarding the variability of these methods. Some
scientists found that the two methods show a good correlation with HPLC, while others
found that there was no such correlation between the precipitation methods and the
HPLC. The MCP method had a practical advantage as it could be performed in half the
time required for the BSA method. This has a significant impact in scenarios where a
high sample throughput is required although it only measures total tannin.
The phenolic composition and mouth feel of the wine was strongly influenced by the
climatic area. In the warmer area the effect of tannin concentration on mouth feel was
much less than in the cooler area. The wine made of riper grapes, was more grippy,
bitter and numbing than the wines made from greener grapes. The E treatment was
especially associated with a dry, grippy sensation. / AFRIKAANSE OPSOMMING: Druif en wyn fenole bestaan uit flavanole wat weer die boublokke is van tanniene.
Hierdie boublokke, wat bekend staan as monomere, betsaan uit katesjiene,
epikatesjiene, epigallokatesjiene an epikatesjien-gallaat. Tanniene is belangrik in wyn
aangesien dit bydra tot bitterheid, mondgevoel (vrankheid) asook die
verouderingspotensiaal van wyn. As antioksidante hou dit ook gesondheidsvoordele in.
Antosianiene dra by tot die kleur van rooiwyn. Antosianiene kombineer met tanniene om
meer stabiele polimeriese pigmente te vorm. As gevolg van die belangrikheid van
tanniene en antosianiene is dit van uiterse belang dat verskillende wynmaak tegnieke
gebruik word om ekstraksie in die wyn te bevoordeel en dat die analitiese metode so
vinnig en akkuraat as moontlik gedoen word.
Die eerste doel van hierdie studie was om die ekstraksie van tanniene en antosianiene
deur middel van verskillende wynmaak tegnieke te evalueer. Te veel tanniene in die
wyn kan negatiewe sensoriese kwaliteit tot gevolg het. Daarom is die tweede doel om
die sensoriese kwaliteit van Shiraz wyn te evalueer. Die derde doel van hierdie studie
was die twee tannien presipitasie metodes met mekaar te vergelyk in terme van die
moeilikheidsgraad van die metode, tyd doeltreffendheid en herhaalbaarheid.
Verskillende wynmaak tegnieke (ensiem byvoegings [E], koue maserasie [CM],
verlengde dopkontak [PM] en ‘n kombinasie van koue maserasie en verlengde
dopkontak [CM+PM]) is vergelyk ten opsigte van tannien en antiosianien ekstraksie. In
2008 en 2009 is twee kultivars (Cabernet Sauvignon en Shiraz) in twee verskillende
klimatologiese areas gepars. Hierdie areas is geklassifiseer in die Winklerskaal as ‘n IV
(Plaisir de Merle) en ‘n III (Morgenster). Om die effek van die verskillende wynmaak
tegnieke op die ekstraksie van antosianiene en tanniene te vergelyk, is hierdie twee
kultivars by twee verskillende rypheidsgrade geoes. Die eerste oes was net voor
kommersiële oes (LB) en die tweede oes het net na kommersiële oes (HB)
plaasgevind. Die 2009 Shiraz wyn is organolepties beoordeel om die effek van die
verskillende wynmaak tegnieke op die wyn se mondgevoel te vergelyk.
Die resultate van hierdie studie toon beduidende verskille in die fenoliese samestelling
van die wyne. Dit is gevind dat die warmer area hoër tannien konsentrasies het as die
koeler area. In 2008 het die CM+PM die meeste tanniene uit die Cabernet Sauvignon
geëkstraheer by LB en die CM by HB in die warmer area. Die CM het in die koeler area
meer tanniene geëkstraheer by beide die LB en HB rypheidsgrade. In 2009 het PM die
meeste tanniene geëkstraheer by LB terwyl E die meeste tanniene geëkstraheer in die
warmer area. In die koeler area het CM+PM die meeste tanniene geëkstraheer, terwyl
geen van die behandelings ‘n effek gehad het by HB. Die meeste antosianien
konsentrasie was in die koeler area gevind as in die warmer area. In beide 2008 (LB en
HB) en 2009 (LB) het CM die meeste antosianiene geëkstraheer, terwyl geen
behandeling ‘n effek gehad het by HB.
Twee van die mees populêre tannien analitiese metodes is die BSA (bovine serum
albumien) en die MCP (metielsellulose presipitasie) metodes. Die BSA metode is ‘n
baie meer ingewikkelde metode waarvoor drie keer meer reagense gebruik word as vir
die MCP metode. Maar waar die MCP net tanniene ontleed, ontleed die BSA metode
tanniene, monomere (MP), klein polimeriese pigmente (SPP) en groot polimeriese
pigmente (LPP). Dit help indien daar gekyk wil word na die evolusie van polimeriese
pigmente.
In hierdie studie is bevind dat daar ‘n redelike korrelasie (R2 – 0.88) tussen die BSA en
MCP metode bestaan. Die herhaalbaarheid van die metodes het redelike kontroversie
veroorsaak, waar sommige navorsers bevind het dat die BSA metode nie so
herhaalbaar is soos eers bevind is nie. Die MCP metode het ’n praktiese voordeel
aangesien dit in die helfde van die tyd van die BSA metode uitgevoer kan word. Dit het
‘n groot impak indien ‘n groot hoeveelheid monsters ontleed moet word.
Die fenoliese samestelling en mondgevoel word sterk beïnvloed deur die klimatologiese
area. In die warmer area was die effek van tannien konsentrasie op mondgevoel kleiner
as in die koeler area. Die wyn van ryper druiwe het meer harder, verdowingseffek en
bitter nasmaak gehad as by die wyn van groener druiwe. Die ensiem behandeling was
meer geassossieerd met droë mond gevoel.
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Interakce mezi proteiny a huminovými látkami při koagulaci / Interactions between proteins and humic substances during coagulationNovotná, Kateřina January 2015 (has links)
This diploma thesis is focused on coagulation of humic substances (HS) and BSA (Bovine Serum Albumin) protein which was chosen as a representative of proteins contained in AOM (Algal Organic Matter). Additionally, possible interactions between these compounds were also investigated. It was found that the optimal dosage of coagulant is much higher for HS compared to BSA. The best removal of both HS and BSA was reached in slightly acidic pH range and it is attributed mainly to charge neutralization and adsorption mechanisms. The maximum removal rate was 70 % for humic substances and 80 % for BSA. The results show that BSA has a positive effect on coagulation of HS (resulting in a lower coagulant demand) and vice versa while BSA was removed more efficiently than HS. The existence of interactions between BSA and humic substantces during coagulation was demonstrated in certain pH ranges and it can occur even without the presence of coagulant. These interactions are highly dependent on pH that determines charge properties (and hence reactivity) of organic matters. Finally, the comparison of BSA and cyanobacterial proteins shows that their behavior during coagulation is similar. Consequently, BSA can be used as a model compound representing AOM proteins, especially their high molecular weight fraction....
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Macromolecules at Interfaces / Makromolekyler på ytorLarsericsdotter, Helén January 2004 (has links)
<p>In this thesis, the structure and stability of globular proteins adsorbed onto nanometer-sized hydrophilic silica particles were investigated using differential scanning calorimetry (DSC), hydrogen/deuterium exchange (HDX), and mass spectrometry (MS). The adsorption process itself was characterized with fluorescence and absorption spectroscopy and surface plasmon resonance (SPR). The combination of these methods offered a unique insight into adsorption-induced changes within proteins related to their adsorption characteristics. DSC contributed with thermodynamic information on the overall structural stability within the protein population. HDX in combination with MS contributed information on the structure and stability of adsorbed proteins with focus on changes within the secondary structure elements. In order to increase the structural resolution in this part of the investigation, proteolysis was performed prior to the MS analyzing step. Knowledge on the protein adsorption process was utilized in a practical approach called ligand fishing. In this approach, SPR was used to monitor the chip-based affinity purification of a protein with MS used for protein identification.</p><p>Adsorption isotherms revealed that electrostatic interactions play an important role in the adsorption of proteins to hydrophilic surfaces. DSC investigation revealed that the thermal stability of proteins reduces with increasing electrostatic attraction between the protein and the surface and that this effect diminishes at higher surface coverage. The mass-increase due to exchange between protein hydrogen atoms and deuterium atoms in solution was investigated as a function of time. This gave insight into adsorption-induced changes in the structural stability of proteins. By combining DSC and HDX-MS, it was possible to differentiate between adsorption-induced changes in the secondary and tertiary structure. Additionally, if limited proteolysis was performed, the investigations gave insight into the orientation and protein segment specific changes in the stability of proteins adsorbed to silica surfaces. The adsorption of proteins to silica particles also provided the basis for a new experimental design that allows handling of minute amounts of proteins in a ligand fishing application, as used in the field of functional proteomics.</p>
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Macromolecules at Interfaces / Makromolekyler på ytorLarsericsdotter, Helén January 2004 (has links)
In this thesis, the structure and stability of globular proteins adsorbed onto nanometer-sized hydrophilic silica particles were investigated using differential scanning calorimetry (DSC), hydrogen/deuterium exchange (HDX), and mass spectrometry (MS). The adsorption process itself was characterized with fluorescence and absorption spectroscopy and surface plasmon resonance (SPR). The combination of these methods offered a unique insight into adsorption-induced changes within proteins related to their adsorption characteristics. DSC contributed with thermodynamic information on the overall structural stability within the protein population. HDX in combination with MS contributed information on the structure and stability of adsorbed proteins with focus on changes within the secondary structure elements. In order to increase the structural resolution in this part of the investigation, proteolysis was performed prior to the MS analyzing step. Knowledge on the protein adsorption process was utilized in a practical approach called ligand fishing. In this approach, SPR was used to monitor the chip-based affinity purification of a protein with MS used for protein identification. Adsorption isotherms revealed that electrostatic interactions play an important role in the adsorption of proteins to hydrophilic surfaces. DSC investigation revealed that the thermal stability of proteins reduces with increasing electrostatic attraction between the protein and the surface and that this effect diminishes at higher surface coverage. The mass-increase due to exchange between protein hydrogen atoms and deuterium atoms in solution was investigated as a function of time. This gave insight into adsorption-induced changes in the structural stability of proteins. By combining DSC and HDX-MS, it was possible to differentiate between adsorption-induced changes in the secondary and tertiary structure. Additionally, if limited proteolysis was performed, the investigations gave insight into the orientation and protein segment specific changes in the stability of proteins adsorbed to silica surfaces. The adsorption of proteins to silica particles also provided the basis for a new experimental design that allows handling of minute amounts of proteins in a ligand fishing application, as used in the field of functional proteomics.
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Brustschmerzambulanz - Chest Pain Unit am Herzzentrum der Universität Leipzig Eine retrospektive Analyse für das Jahr 2009Heumesser, Christian Eugen 15 October 2015 (has links) (PDF)
Brustschmerz ist ein häufiges Symptom. Er bedarf einer schnellen Differenzierung zum Ausschluss lebensbedrohlicher Erkrankungen wie zum Beispiel eines Myokardinfarktes oder einer Aortendissektion. Hierzu wurden Chest Pain Units (CPU) und Brustschmerzambulanzen (BSA) gegründet. Im Jahr 2008 führte die Deutsche Gesellschaft für Kardiologie Mindeststandards für deren Ausstattung und Struktur ein. 2009 wurde die zwei Jahre zuvor gegründete BSA am Herzzentrum Leipzig (HZL) zertifiziert.
In dieser Arbeit wurde eine retrospektive Analyse von 2.220 Patientendaten aus dem Jahr 2009 durchgeführt. Bei steigenden Patientenzahlen wurde die BSA am häufigsten montags sowie in den Mittagsstunden aufgesucht. Dabei zeigte die Symptomdauer eine Spannweite von wenigen Minuten bis zu mehreren Jahren. Der größte Anteil mit 19,1 % der Patienten kam mit einer Symptomdauer zwischen einer Woche und einem Monat, 11,6 % der Patienten innerhalb von sechs Stunden. Symptome und Begleiterkrankungen boten eine große Variabilität. 24,7 % der Patienten stellten sich ohne Schmerzen vor. 66,4 % der Patienten verblieben ambulant und durchschnittlich verbrachten die Patienten 4,8 Stunden in der BSA. 59,9 % der Patienten ohne primär ersichtliche, kardiale Symptomkonstellation zeigten eine kardiale Erkrankung. Selbsteinweiser und ärztlich eingewiesene Patienten sowie stationäre und ambulante Verläufe zeigten Unterschiede in Symptomen, Begleiterkrankungen, Untersuchungen, Interventionen und Entlassungsdiagnosen. 26,9 % der Patienten erhielten eine Herzkatheteruntersuchung. Davon erfolgte bei 31,4 % eine Intervention, in 62,4 % der Fälle eine medikamentöse Therapie. Eine KHK war bei 19,1 % der Patienten die Entlassungsdiagnose. In der Hälfte der Fälle wurde damit erstmals diese Diagnose gestellt. Aus Symptomen, Symptomdauer und kardiovaskulären Risikofaktoren wurde der Symptome-30-2-CRF-Score abgeleitet, welcher bei ≤ 9 Punkten eine KHK ablehnt und bei Werten ≥ 14 Punkten den Verdacht auf eine KHK bekräftigt.
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Produtos naturais e derivados, complexação com o rutênio visando aumento da atividade citotóxica / Natural products and derivatives, complexation with ruthenium targeting increased cytotoxicity activityGraminha, Angelica Ellen 26 February 2015 (has links)
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Previous issue date: 2015-02-26 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / This work involves the synthesis and characterization of three new series of ruthenium complexes containing gallic acid and derivatives cinnamic acid and salicylic acid and derivatives, as these ligands exhibit interesting biological properties. All ligands are synthetic and natural products can be found in the daily diet. The interest in studying these three ligands series is due to the antioxidant power that some of these natural products present. Thus, complexes of formula [Ru(O-O)(dppb)(bipy)]PF6 and [Ru(O-O)(dppe)2]PF6 , where O-O = gallic acid and derivatives, cinnamic acid and salicylic acid and derivatives (bipy = 2,2'-bipyridine, dppb = 1,4-bis(diphenylphosphino)butane and dppe = 1,2- bis(diphenylphosphino)ethane). All the synthesized compounds were characterized by molar conductivity, elemental analysis, absorption spectra in the infrared, absorption spectroscopy in the UV-visible region, mass spectrometry, nuclear magnetic resonance 31P {1H}, cyclic voltammetry and
differential pulse, and for some complexes, X-ray crystallography. The evaluation of the biological potential of ruthenium complexes with different series of ligands were evaluated: the partition coefficient, the antioxidant activity, morphological study, clonogenic assay in MDA-MB-231 and L929, cytotoxic activity in tumor cell lines MDA MB-231, MCF-7 and A549, and nontumor cell lines of mouse and hamster V79 and L929, respectively. Cell viability assays show promising results, indicating a greater cytotoxicity of the complexes in MDA-MB-231 line with respect to the other tumor cell line. Furthermore, the complexes of general formula [Ru(O-O)(dppe)2]PF6 exhibit the values lowest of IC50 in compared on the complexes of the general formula [Ru(O-O)(dppb)(bipy)]PF6 in all the cell line studied. Studies of the interaction of the complexes with bovine serum albumin (BSA), were performed, and compounds have moderate to strong interaction with the protein, and the complexes containing two dppe biphosphinas have smaller constant values in relation the complexes of the series [Ru(O-O)(dppb)(bipy)]PF6. / Este trabalho envolve a síntese e caracterização de três novas séries de complexos de rutênio contendo ácido gálico e derivados, ácidos cinâmicos e ácido salicílico e derivados, uma vez que estes ligantes apresentam propriedades biológicas interessantes. Todos os ligantes são produtos naturais sintéticos e podem ser encontrados diariamente na dieta alimentar. O interesse em estudar estas três séries de ligantes é devido ao poder antioxidante que alguns destes produtos naturais apresentam. Assim, complexos de fórmula geral [Ru(OO)(dppb)(bipy)]PF6 e [Ru(O-O)(dppe)2]PF6 onde O-O = ácido gálico e
derivados, ácidos cinâmicos e ácido salicílico e derivados (bipy = 2,2’-bipiridina, dppb = 1,4-bis(difenilfosfina)butano e dppe = 1,2-bis(difenilfosfina)etano). Todos os complexos sintetizados foram caracterizados por condutividade molar, análise elementar, espectroscopia de absorção na região do infravermelho, espectroscopia de absorção na região do UV-visível,
espectrometria de massa, ressonância magnética nuclear de 31P{1H}, voltametria cíclica e de pulso diferencial, e para alguns complexos, raios X de monocristal. A avaliação do potencial biológico dos complexos de rutênio com as diferentes séries dos ligantes foram avaliados: o coeficiente de partição, a atividade antioxidante, estudo morfológico, ensaio clonogênico nas linhagens MDA-MB-231 e L929, a atividade citotóxica nas linhagens tumorais MDA-MB-231, MCF-7 e A549, e nas linhagens não-tumorais de camundongo e hamster L929 e V79, respectivamente. Os ensaios de viabilidade celular apresentam resultados promissores, indicando uma maior citotoxidade dos complexos na linhagem MDA-MB-231 em relação às outras linhagens tumorais. Além disso, os complexos sintetizados com fórmula geral [Ru(O-O)(dppe)2]PF6, apresentam os menores valores de IC50 em relação aos complexos de fórmula geral [Ru(OO)(dppb)(bipy)]PF6, em todas as linhagens celular estudadas. Os estudos da interação dos complexos, com a albumina sérica bovina (BSA), foram realizados, e os compostos apresentam interação de moderada a forte com a proteína, sendo que os complexos contendo duas bifosfinas dppe apresentam valores de constante menores em relação a serie de complexos derivados [Ru(OO)(dppb)(bipy)]PF6.
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Fonctionnalisation de surfaces d'oxydes par chimie thiol-ène pour le contrôle de l'adsorption protéique et de l'adhésion cellulaire / Functionalization of oxide surfaces by thiol-ene chemistry for controlling protein adsorption and cell adhesionDellinger, Eric-Antoine 25 September 2014 (has links)
Ce travail a pour objectif l’élaboration de surfaces permettant le contrôle de l’adsorption protéique et de l’adhésion cellulaire. Deux axes d’études permettent de répondre à cette problématique : d’une part l’optimisation des conditions de greffage par réaction thiol-ène de chaînes éthylène glycol (OEG ou PEG) comportant une fonction thiol sur une monocouche auto-assemblée de trichlorosilane d’undécényle, d’autre part la caractérisation chimique de surface (mesures d’angle de contact, ellipsométrie, microscopie de fluorescence, infrarouge en réflexion totale atténuée IR-ATR, spectroscopie de photoélectrons induits par rayons X XPS, spectrométrie de masse d’ions secondaires à temps de vol ToF-SIMS) à l’issue de chaque étape de traitement. L’étude méthodologique des conditions de greffage thiol-ène montre la mise au point d’un système bicouche structuré après 1 minute de réaction pour le greffage OEG, 1 heure pour le greffage PEG. Par l’emploi de divers substrats (oxyde de silicium, titane, verre), différentes molécules OEG-thiol ou PEG-thiol (longues de 7 à 220 unités éthyléniques, terminées –méthyle, -carboxyle ou –amine), nous mettons en avant les déclinaisons possibles de cette stratégie. Ces terminaisons chimiques conduisent, au choix, à l’inhibition de l’adsorption protéique ou à l’adsorption de biomolécules, albumine de sérum bovin (BSA) ou fibronectine (Fn), permettant de faire de l’adhésion spécifique. Le contrôle, dans le plan de l’échantillon, des zones exposées à la lumière par photochimie lors du greffage thiol-ène autorise le photopatterning des surfaces permettant la maîtrise de l’adsorption protéique et également de l’adhésion cellulaire à la surface. / The aim of this work is to design surfaces allowing controlling cellular adhesion by the study of protein adsorption and cell adhesion. Two main parts were investigated in order to answer this challenge: on one side the optimization of grafting conditions using the thiol-ene reaction of thiol-terminated ethylene glycol chains (OEG or PEG) on a undecenyltrichlorosilane self-assembled monolayer, on the other side the surface chemical characterization (angle contact measurement, ellipsometry, fluorescence microscopy, attenuated total reflection infrared IR-ATR, X-ray Photoelectron Spectroscopy XPS, Time-of-Flight Secondary Ion Mass Spectrometry ToF-SIMS) after each reaction step. The methodological investigation of thiol-ene grafting conditions exhibits the development of a bilayer structured system after a 1 minute reaction time concerning OEG grafting, 1 hour in case of PEG grafting. By using different substrates (silicon oxide, titanium, glass), different molecules OEG-thiol or PEG-thiol (from 7 to 220 ethylene unit long, methyl-, carboxyl- or amine-terminated), we highlight the range of available versions of this strategy. These chemical extremities lead on demand either to protein adsorption inhibition or to biomolecule adsorption, bovine serum albumin (BSA) or fibronectin (Fn) giving access to specific adhesion.By controlling the light-exposed areas in the sample plan, the photochemistry occurring during the thiol-ene grafting allows to design surface patterning for addressing both protein adsorption and cell adhesion on the sample surface.
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Syntéza core/shell kvantových teček pro diagnostiku / Synthesis of core/shell quantum dots for diagnosticsMihajlović, Ana January 2014 (has links)
This thesis deals with biosensors based on modified semiconductor core/shell quantum dots (QDs) for diagnosis. The work is divided into four main parts. The first one discusses the theory required for the use of QDs in bioaplications, there are described methods of synthesis, modification, application and bioconjugation of QDs. In the experimental part, CdTe/ZnS QDs with core/shell structure were prepared, in which the core was modified by MPA, GSH and TGA. In the next step, these QDs were further modified using CDI, EDC and NHS as mediators in order to increase affinity to BSA (bovine serum albumine) and IgG (imunoglobuline G). Prepared conjugates were characterized by fluorescence spectroscopy (Infinite M200Pro, Tecan) and capillary electrophoresis (Agilent 7100).
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Brustschmerzambulanz - Chest Pain Unit am Herzzentrum der Universität Leipzig Eine retrospektive Analyse für das Jahr 2009: Brustschmerzambulanz - Chest Pain Unitam Herzzentrum der Universität LeipzigEine retrospektive Analyse für das Jahr 2009Heumesser, Christian Eugen 24 September 2015 (has links)
Brustschmerz ist ein häufiges Symptom. Er bedarf einer schnellen Differenzierung zum Ausschluss lebensbedrohlicher Erkrankungen wie zum Beispiel eines Myokardinfarktes oder einer Aortendissektion. Hierzu wurden Chest Pain Units (CPU) und Brustschmerzambulanzen (BSA) gegründet. Im Jahr 2008 führte die Deutsche Gesellschaft für Kardiologie Mindeststandards für deren Ausstattung und Struktur ein. 2009 wurde die zwei Jahre zuvor gegründete BSA am Herzzentrum Leipzig (HZL) zertifiziert.
In dieser Arbeit wurde eine retrospektive Analyse von 2.220 Patientendaten aus dem Jahr 2009 durchgeführt. Bei steigenden Patientenzahlen wurde die BSA am häufigsten montags sowie in den Mittagsstunden aufgesucht. Dabei zeigte die Symptomdauer eine Spannweite von wenigen Minuten bis zu mehreren Jahren. Der größte Anteil mit 19,1 % der Patienten kam mit einer Symptomdauer zwischen einer Woche und einem Monat, 11,6 % der Patienten innerhalb von sechs Stunden. Symptome und Begleiterkrankungen boten eine große Variabilität. 24,7 % der Patienten stellten sich ohne Schmerzen vor. 66,4 % der Patienten verblieben ambulant und durchschnittlich verbrachten die Patienten 4,8 Stunden in der BSA. 59,9 % der Patienten ohne primär ersichtliche, kardiale Symptomkonstellation zeigten eine kardiale Erkrankung. Selbsteinweiser und ärztlich eingewiesene Patienten sowie stationäre und ambulante Verläufe zeigten Unterschiede in Symptomen, Begleiterkrankungen, Untersuchungen, Interventionen und Entlassungsdiagnosen. 26,9 % der Patienten erhielten eine Herzkatheteruntersuchung. Davon erfolgte bei 31,4 % eine Intervention, in 62,4 % der Fälle eine medikamentöse Therapie. Eine KHK war bei 19,1 % der Patienten die Entlassungsdiagnose. In der Hälfte der Fälle wurde damit erstmals diese Diagnose gestellt. Aus Symptomen, Symptomdauer und kardiovaskulären Risikofaktoren wurde der Symptome-30-2-CRF-Score abgeleitet, welcher bei ≤ 9 Punkten eine KHK ablehnt und bei Werten ≥ 14 Punkten den Verdacht auf eine KHK bekräftigt.
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