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Cyanocobalamin is a Superoxide Scavenger and Neuroprotectant in Neuronal CellsChan, Wesley 04 1900 (has links)
Les dommages au nerf optique (neuropathie optique) peuvent entraîner la perte permanente de la vision ou la cécité causée par la mort des cellules ganglionnaires de la rétine (CGR). Nous avons identifié qu’une surproduction de l'anion superoxyde constitue un événement moléculaire critique précédant la mort cellulaire induite par des lésions. Récemment, Suarez-Moreira et al (JACS 131:15078, 2009) ont démontré que la vitamine B12 peut capter l’anion superoxyde aussi efficacement que l’enzyme superoxyde dismutase. La carence en vitamine B12 peut conduire à une neuropathie optique causée par des mécanismes inconnus. Nous avons étudié la relation entre la captation de superoxyde par la cyanocobalamine (forme de vitamine B12 la plus abondante) et ses propriétés neuroprotectrices dans les cellules neuronales.
La cyanocobalamine aux concentrations de 10 μM et 100 μM a réduit le taux de production de superoxyde respectivement par 34% et 79% dans les essais sans-cellule. Dans les cellules RGC-5 traités avec la ménadione, les concentrations de cyanocobalamine supérieures à 10 nM ont diminué l’anion superoxyde à des valeurs similaires à celles traitées par PEG-SOD. La cyanocobalamine aux concentrations de 100 μM et 1 μM a réduit la mort des cellules RGC-5 exposées à la ménadione par 20% et 32%, respectivement. Chez les rats avec section du nerf optique unilatérale, une dose intravitréenne de 667 μM de cyanocobalamine a réduit le nombre de CGRs exposées au superoxyde. Cette dose a également augmenté le taux de survie des CGRs comparativement aux rats injectés avec la solution témoin. Ces données suggèrent que la vitamine B12 peut être un neuroprotecteur important, et sa carence nutritionnelle pourrait causer la mort de CGRs. La vitamine B12 pourrait aussi potentiellement être utilisée comme une thérapie pour ralentir la progression de la mort CGR chez les patients avec les neuropathies optiques caractérisés par une surproduction de superoxyde. / Damage to the optic nerve (optic neuropathy) can result in permanent loss of vision or blindness through retinal ganglion cell (RGC) death. Our prior work identified a burst of superoxide anion as a critical molecular event in RGCs prior to injury-induced cell death. Recently, Suarez-Moreira et al (JACS 131:15078, 2009) demonstrated that vitamin B12 scavenges superoxide as effectively as superoxide dismutase. Vitamin B12 deficiency can lead to optic neuropathy through unknown mechanisms. We investigated the relationship between superoxide scavenging by cyanocobalamin, the most abundant vitamin B12¬¬ vitamer, and its neuroprotective properties in neuronal cells.
Cyanocobalamin at concentrations of 10 μM and 100 μM reduced the rate of superoxide generation by 34% and 79% in cell free assays, respectively. In menadione-treated RGC-5 cells, cyanocobalamin concentrations above 10 nM scavenged superoxide anion similar to those treated with pegylated-SOD. Cyanocobalamin at concentrations of 100 μM and 1 mM reduced RGC-5 cell death from menadione by 20% and 32%, respectively. In rats with unilateral optic nerve transection, a single intravitreal dose of 667 μM cyanocobalamin significantly reduced the number of RGCs with superoxide. This dose also increased RGC survival rate compared to rats injected with saline control.
These data suggest that vitamin B¬¬12 may be an important neuroprotectant, which could cause death of RGCs when depleted in nutritional deficiency. Vitamin B12 could also potentially be used as a therapy to slow progression of RGC death in patients with optic neuropathies characterized by overproduction of superoxide.
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Optimized Production and Purification of LCC DNA Minivectors for Applications in Gene Therapy and Vaccine DevelopmentSum, Chi Hong 21 January 2014 (has links)
Linear covalently closed (LCC) DNA minivectors serve to be superior to conventional circular covalently closed (CCC) plasmid DNA (pDNA) vectors due to enhancements to both transfection efficiency and safety. Specifically, LCC DNA minivectors have a heightened safety profile as insertional mutagenesis is inhibited by covalently closed terminal ends conferring double-strand breaks that cause chromosomal disruption and cell death in the low frequency event of chromosomal integration. The development of a one-step, E. coli based in vivo LCC DNA minivector production system enables facile and efficient production of LCC DNA minivectors referred to as DNA ministrings. This novel in vivo system demonstrates high versatility, generating DNA ministrings catered to numerous potential applications in gene therapy and vaccine development.
In the present study, numerous aspects pertaining to the generation of gene therapeutics with LCC DNA ministrings have been explored with relevance to both industry and clinical settings. Through systematic assessment of induction duration, cultivation strategy, and genetic/chemical modifications, the novel in vivo system was optimized to produce high yields of DNA ministrings at ~90% production efficiency. Purification of LCC DNA ministrings using anion exchange membrane chromatography demonstrated rapid, scalable purification of DNA vectors as well as its potential in the separation of different DNA isoforms. The application of a hydrogel-based strong Q-anion exchange membrane, with manipulations to salt gradient, constituted effective separation of parental supercoiled CCC precursor pDNA and LCC DNA. The resulting DNA ministrings were employed for the generation of 16-3-16 gemini surfactant based synthetic vectors and comparative analysis, through physical characterization and in vitro transfection assays, was conducted between DNA ministring derived and CCC pDNA derived lipoplexes. Differences in DNA topology were observed to induce differences in particle size and DNA protection/encapsulation upon lipoplex formation. Lastly, the in vivo DNA minivector production system successfully generated gagV3(BCE) LCC DNA ministrings for downstream development of a HIV DNA-VLP (Virus-like particle) vaccine, thus highlighting the capacity of such system to produce DNA ministrings with numerous potential applications.
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Uptake of natural organic matter (NOM) fractions by anion exchangers in demineralisation and drinking water plantsPürschel, Madlen 01 April 2014 (has links) (PDF)
The elimination of natural organic matter (NOM) is an important aim of water treatment in demineralisation plants of power stations. NOM is regarded as corrosion risk factor in the steam water cycle because of its potential to decompose into low-molecular-weight (LMW) acids and carbon dioxide. Further, the removal of NOM is also one of the main objectives in the drinking water production, since it can cause i) colour, taste and odour problems, ii) formation of carcinogen halogenated disinfection by-products (DBPs) after disinfection with chlorine and iii) bacterial growth in the water distribution system.
In earlier studies, it was found that anion exchange is a successful method to remove NOM fractions. However, NOM fractions with low charge density (LMW neutrals and hydrophobic organic carbon (HOC)) and/or large molecular size (biopolymers and particulate organic carbon (POC)) could not be removed in some cases in satisfying quantities. The aim of the present work was to investigate the uptake performance of different anion exchange resins (AERs) in regard to problematic NOM fractions. The AERs differ especially in their functional groups (tertiary versus quaternary amines) and matrix material (polystyrene versus polyacrylic resins). The use of different AERs provides an option to identify possible interactions between adsorbate (NOM fractions) and adsorber (AERs) as well as the mechanism which determine the removal efficiency.
The NOM fraction adsorption onto AERs was studied in equilibrium and fixed-bed experiments with three types of starch with different molecular size distributions (model substances for biopolymer fraction) as well as 2-naphthol (model substance for the LMW neutral fraction) at acidic pH (relevant for water in demineralisation plants of power stations) and neutral pH (covering most raw waters). Furthermore, the NOM fraction uptake from “real” acidic and neutral water samples, obtained from a demineralisation plant of a power station, was estimated for different AERs. Results were discussed in terms of size-exclusion, anion exchange and hydrophilic/hydrophobic repulsion.
In case that size-exclusion influences the NOM uptake onto AERs, it was found that the smaller the size of the NOM molecules and the higher the water content of the AERs, the more effective the uptake is. Thus, for the removal of biopolymers and POC, polyacrylic resins with high water content could be a good choice. Contrary, polystyrene AERs are the most effective resins in the removal of NOM fractions, if no size-exclusion occurs. They seem to be able to uptake more hydrophilic NOM fractions by polar/ionic interactions between acids/acidic components and tertiary/quaternary amines as well as to remove more hydrophobic NOM fractions by π-π stacking and/or hydrophobic interactions on the polystyrene matrix. Further, it was found that the higher the total volume (anion exchange) capacity of an AER, the higher its NOM removal by polar/ionic interactions can be. At acidic pH, weak/medium base AERs have higher total volume (anion exchange) capacities than strong base AERs, whereas, at neutral pH, strong base AERs have the highest ones.
In view of these results, the application of polyacrylic AERs with high water content can be recommended to remove NOM components with large molecular size in demineralisation and drinking water plants. If there is a higher amount of smaller NOM fractions, especially LMW neutrals, than polystyrene weak/medium base AERs should be favoured in demineralisation plants and polystyrene strong base AERs in drinking water treatment plants.
From the engineering point of view, breakthrough curve (BTC) prediction models are important for the design of fixed-bed filter. Therefore, two different BTC model approaches were tested in the present study to describe the single-solute adsorption onto AERs: i) the homogenous surface diffusion model (HSDM) with linear driving force (LDF) approach for surface diffusion, known from activated carbon adsorption, and ii) the Glueckauf/Helfferich formulae as an extension of the height equivalent to a theoretical plate (HETP) model, initially used to describe ion exchange processes. It was found that the Glueckauf/Helfferich approach is not only a suitable tool for the fast calculation of BTCs for ionic components, but it can also successfully be applied, after considering the Freundlich model for the mass balance, for the rapid prediction of BTCs for single-solute organic molecules. For competitive BTC predictions, the ideal adsorbed solution theory (IAST) within the LDF model was applied. All calculated BTCs fit the experimental data in a good manner. Thus, the investigated BTC models can be applied for estimating the breakthrough bed volumes of different AERs to avoid leakage of NOM in the drinking or demineralised water caused by overloading. / Die Entfernung von natürlichen organischen Substanzen (NOM) ist ein wichtiges Ziel für die Herstellung von Reinstwasser im Kraftwerksbetrieb, da diese sich im Wasser/Dampf-Kreislauf zu niedermolekularen Säuren und Kohlenstoffdioxid zersetzen können und so ein potentielles Korrosionsrisiko darstellen. Außerdem ist die Elimination von natürlichen organischen Substanzen einer der Schwerpunkte in der Trinkwasseraufbereitung, da NOM im Trinkwasser folgende Konsequenzen verursachen können i) Farb-, Geschmacks- und Geruchsprobleme, ii) Bildung von kanzerogen halogenierten Desinfektionsnebenprodukten nach der Desinfektion mit Chlor und iii) Bakterienwachstum im Wasserverteilungssystem.
In früheren Untersuchungen wurde festgestellt, dass Anionenaustauscherharze (AERs) die NOM-Fraktionen in der Regel erfolgreich aufnehmen können. Nur NOM-Fraktionen mit geringer Ladungsdichte (niedermolekulare Neutralstoffe und hydrophober organischer Kohlenstoff) und/oder großer Molekülgröße (Biopolymere und partikulärer organischer Kohlenstoff) können unter bestimmten Bedingungen nicht in zufriedenstellender Menge entfernt werden. Ziel dieser Arbeit war es, das Aufnahmeverhalten unterschiedlicher AERs hinsichtlich problematischer NOM-Fraktionen zu untersuchen. Die AERs unterscheiden sich vor allem in ihren funktionellen Gruppen (tertiäre versus quaternäre Amine) und ihrer Matrix (Polystyren- versus Polyacryl-Harze). Die Verwendung unterschiedlicher AERs erlaubt es, mögliche Wechselwirkungen zwischen Adsorbat (NOM-Fraktionen) und Adsorber (AERs) und die Mechanismen, die die NOM-Aufnahme entscheidend bestimmen, zu identifizieren.
Die Entfernung von NOM-Fraktionen durch AERs wurde in Gleichgewichts- und Festbett-versuchen mittels dreier Stärketypen mit unterschiedlicher Molekülgrößenverteilung (Modellsubstanzen für die Biopolymere) und 2-Naphthol (Modellsubstanz für die Neutralstoffe) unter sauren pH-Bedingungen (relevant für die Herstellung von Reinstwasser im Kraftwerksbetrieb) und neutralen pH-Bedingungen (bedeutsam für die meisten Rohwässer) untersucht. Außerdem sollte das Adsorptionsverhalten von AERs bezüglich verschiedener NOM-Fraktionen unter Einsatz von „real“ neutralen und sauren Wasserproben aus einer Wasseraufbereitungsanlage eines Kraftwerksbetriebes eingeschätzt werden.
In dieser Arbeit konnte gezeigt werden, dass falls Größenausschluss die NOM-Aufnahme von AERs beeinflusst, dann ist die Adsorption der NOM-Fraktionen umso größer, je kleiner die NOM-Moleküle sind und je höher der Wassergehalt der AERs ist. Daher kann für die Entfernung von größeren Biopolymeren, der Einsatz von AERs mit Polyacryl-Matrix und hohem Wassergehalt die beste Option sein. AERs mit Polystyren-Matrix besitzen die höchste Aufnahmekapazität für NOM-Fraktionen, falls kein Größenausschluss auftritt. Es scheint für sie möglich zu sein, sowohl hydrophile NOM-Fraktionen durch polare/ionische Wechselwirkungen zwischen NOM Säuren/sauren Komponenten und tertiären/quaternären Aminen aufzunehmen als auch hydrophobe NOM-Fraktionen durch π-π Anziehungen und/oder hydrophobe Interaktionen an die Polystyren-Matrix zu binden. Weiterhin konnte gezeigt werden, dass je höher die Gesamtvolumenkapazität eines AERs, desto größer ist die NOM-Entfernung auf Grund von polaren/ionischen Wechselwirkungen. Es gilt, dass schwach/mittel basische AERs im Vergleich zu stark basischen AERs höhere Gesamtvolumenkapazitäten unter sauren pH-Bedingungen besitzen und stark basische AERs die höchsten Gesamtvolumenkapazitäten unter neutralen pH-Bedingungen aufweisen.
Auf Grund dieser Ergebnisse ist es möglich, die Verwendung von AERs mit Polyacryl-Matrix und hohem Wassergehalt für die Entfernung von NOM-Fraktionen mit großer Molekülgröße in Reinst- und Trinkwasseraufbereitungsanlagen zu empfehlen. Falls es einen höheren Anteil von kleineren NOM-Fraktionen, im Besonderen Neutralstoffen, gibt, sollte die Verwendung von schwach/mittel basischen AERs in Vollentsalzungsanlagen von Kraft-werksbetrieben und stark basischen AERs in Trinkwasseraufbereitungsanlagen bevorzugt werden.
Vor allem im Hinblick auf technische Anwendungen ist es wichtig, Durchbruchskurven (BTC) vorausberechnen zu können. In der vorliegenden Arbeit wurden zwei Modellansätze für die Berechnung von BTCs für die Einkomponentenadsorption getestet: i) das homogene Oberflächendiffusionsmodell mit linearer Triebkraft (LDF), bekannt aus Untersuchungen zur Aufnahme von NOM an Aktivkohle, und ii) die Glueckauf/Helfferich-Formeln, primär verwendet für die Beschreibung von Ionenaustauschprozessen. Es konnte gezeigt werden, dass das Glueckauf/Helfferich-Verfahren nicht nur ein geeignetes Instrument für die schnelle Berechnung von BTCs für ionische Komponenten ist, sondern dass dieses, nach Berücksichtigung des Freundlich-Ansatzes in der Massenbilanz, auch erfolgreich angewendet werden kann, um BTCs für Einkomponentenadsorption von Organika zu berechnen. Für die Vorausberechnung von BTCs für Mehrkomponentensysteme wurde die Theorie der idealen adsorbierten Lösung im LDF-Modell genutzt. Die berechneten BTCs stimmen in guter Qualität mit den experimentell ermittelten BTCs überein. Die Ergebnisse verdeutlichen, dass die untersuchten BTC-Modelle eingesetzt werden können, um Durchbruchspunkte für die jeweiligen AERs zu bestimmen und damit die Gefahr des Schlupfes von NOM ins Trink- bzw. Reinstwasser zu minimieren.
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A Radio Frequency Quadrupole Instrument for use with Accelerator Mass Spectrometry: Application to Low Kinetic Energy Reactive Isobar Suppression and Gas–phase Anion Reaction StudiesEliades, John Alexander 21 August 2012 (has links)
A radio frequency (rf) quadrupole instrument, currently known as an Isobar Separator for Anions (ISA), has been integrated into an Accelerator Mass Spectrometry (AMS) system to facilitate anion–gas reactions before the tandem accelerator. An AMS Cs+ sputter source provided > 15 keV ions that were decelerated in the prototype ISA to < 20 eV for reaction in a single collision cell and re-accelerated for AMS analysis. Reaction based isobar suppression capabilities were assessed for smaller AMS systems and a new technique for gas–phase reaction studies was developed.
Isobar suppression of 36S– and 12C3– for 36Cl analysis, and YF3– and ZrF3– for 90Sr analysis were studied in NO2 with deceleration to < 12 eV. Observed attenuation cross sections, σ [x 10^–15 cm^2], were σ(S– + NO2) = 6.6, σ(C3– + NO2) = 4.2, σ(YF3– + NO2) = 7.6, σ(ZrF3– + NO2) = 19. With 8 mTorr NO2, relative attenuations of S–/Cl– ~ 10^–6, C3–/Cl– ~ 10^–7, YF3–/SrF3– ~ 5 x 10^–5 and ZrF3–/SrF3– ~ 4 x 10^–6 were observed with Cl– ~ 30% and SrF3– > 90% transmission. Current isobar attenuation limits with < 1.75 MV accelerator terminal voltage and ppm impurity levels were calculated to be 36S–/Cl– ~ 4 x 10^–16, 12C3–/Cl– ~ 1.2 x 10^–16, 90YF3–/SrF3– ~ 10^–15 and 90ZrF3–/SrF3– ~ 10^–16.
Using 1.75 MV, four 36Cl reference standards in the range 4 x 10^–13 < 36Cl/Cl < 4 x 10^–11 were analyzed with 8 mTorr NO2. The measured 36Cl/Cl ratios plotted very well against the accepted values. A sample impurity content S/Cl < 6 x 10^–5 was measured and a background level of 36S–/Cl < 9 x 10^–15 was determined.
Useful currents of a wide variety of anions are produced in AMS sputter sources and molecules can be identified relatively unambiguously by stripping fragments from tandem accelerators. Reactions involving YF3–, ZrF3–, S– and SO– + NO2 in the ISA analyzed by AMS are described, and some interesting reactants are identified.
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A Radio Frequency Quadrupole Instrument for use with Accelerator Mass Spectrometry: Application to Low Kinetic Energy Reactive Isobar Suppression and Gas–phase Anion Reaction StudiesEliades, John Alexander 21 August 2012 (has links)
A radio frequency (rf) quadrupole instrument, currently known as an Isobar Separator for Anions (ISA), has been integrated into an Accelerator Mass Spectrometry (AMS) system to facilitate anion–gas reactions before the tandem accelerator. An AMS Cs+ sputter source provided > 15 keV ions that were decelerated in the prototype ISA to < 20 eV for reaction in a single collision cell and re-accelerated for AMS analysis. Reaction based isobar suppression capabilities were assessed for smaller AMS systems and a new technique for gas–phase reaction studies was developed.
Isobar suppression of 36S– and 12C3– for 36Cl analysis, and YF3– and ZrF3– for 90Sr analysis were studied in NO2 with deceleration to < 12 eV. Observed attenuation cross sections, σ [x 10^–15 cm^2], were σ(S– + NO2) = 6.6, σ(C3– + NO2) = 4.2, σ(YF3– + NO2) = 7.6, σ(ZrF3– + NO2) = 19. With 8 mTorr NO2, relative attenuations of S–/Cl– ~ 10^–6, C3–/Cl– ~ 10^–7, YF3–/SrF3– ~ 5 x 10^–5 and ZrF3–/SrF3– ~ 4 x 10^–6 were observed with Cl– ~ 30% and SrF3– > 90% transmission. Current isobar attenuation limits with < 1.75 MV accelerator terminal voltage and ppm impurity levels were calculated to be 36S–/Cl– ~ 4 x 10^–16, 12C3–/Cl– ~ 1.2 x 10^–16, 90YF3–/SrF3– ~ 10^–15 and 90ZrF3–/SrF3– ~ 10^–16.
Using 1.75 MV, four 36Cl reference standards in the range 4 x 10^–13 < 36Cl/Cl < 4 x 10^–11 were analyzed with 8 mTorr NO2. The measured 36Cl/Cl ratios plotted very well against the accepted values. A sample impurity content S/Cl < 6 x 10^–5 was measured and a background level of 36S–/Cl < 9 x 10^–15 was determined.
Useful currents of a wide variety of anions are produced in AMS sputter sources and molecules can be identified relatively unambiguously by stripping fragments from tandem accelerators. Reactions involving YF3–, ZrF3–, S– and SO– + NO2 in the ISA analyzed by AMS are described, and some interesting reactants are identified.
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Untersuchungen zum peripartalen Festliegen bei Milchkühen in MittelgebirgsbetriebenSiebenaller, Cora 26 May 2011 (has links) (PDF)
Betriebe in Mittelgebirgslagen mit einem hohen Anteil Grassilagefütterung, der damit verbundenen größeren K-Aufnahme sowie höheren DCAD (Dietary-Cation-Anion-Difference) sollten für Gebärparese stärker prädisponiert sein. Ziel dieser Arbeit war es deshalb, Ursachen des Festliegens im Erzgebirge unter Berücksichtigung der DCAD zu ermitteln. Dazu wurden sowohl Fütterungsparameter und die Körperkondition analysiert, als auch Blut- und Harnuntersuchungen ante (a.p.) und post partum (p.p.) durchgeführt.
In 21 Betrieben wurden insgesamt 249 Kühe im Zeitraum von 2 Wochen ante partum (a.p.) bis eine Woche p.p. untersucht. Bei 206 gesunden Kühen erfolgte 2 Wochen a.p. eine jeweils einmalige Harn- und Blutentnahmen. Ferner wurden bei 43 peripartal festliegenden Kühen nur Blut- und Harnproben direkt vor der Behandlung analysiert. Die sonographische Ermittlung der Rückenfettdicke (RFD) erfolgte bei je zehn klinisch gesunden Kühen pro Betrieb je 2 Wochen a.p. Die Silageproben (Grundfutteranalyse) wurden hinsichtlich ihrer Inhaltsstoffe untersucht und die DCAD berechnet. Laktationsnummern, Milchleistungen und Krankheitsinzidenzen der Kühe wurden ermittelt. Im Blutserum wurden ß-Hydroxy-Butyrat (BHB), Cholesterol, Bilirubin, Aspartat-Aminotransferase (ASATS), Creatinkinase (CK), Alkalische Phosphatase (AP), Protein (TP), Albumin, Harnstoff, Creatinin, Calcium (Ca), anorganisches Phosphat (Pi), Magnesium (Mg), Natrium (Na), Kalium (K) und im Vollblut die Leukozytenanzahl bestimmt. Im Harn erfolgte die Analyse derselben Mineralstoffe wie im Serum sowie weiterhin des pH-Wertes, der NSBA (Netto-Säure-Basen-Ausscheidung) und des Creatinins. Errechnet wurden die fraktionierten Eliminationen der einzelnen Mineralstoffe, der BSQ (Basen-Säure-QuotienTS) aus den Mengen der Basen, Säuren und Ammoniumionen im Harn sowie der Creatininquotient aus Harn- und Serumcreatinin.
Befunde der Klinisch gesunden Kühe zwei Wochen a.p.:
Die durchschnittliche RFD der Kühe lag in den Betrieben im Mittel zwischen 19 bis 26 mm.
Muskel- und Knochenstoffwechsel charakterisierende Parameter waren physiologisch. Die Mediane der AP-Aktivität im Serum lagen in 15 der 21 Betriebe unter 100 U/l.
Energie- und Eiweißstoffwechsel, Leukozytenanzahlen sowie Mineralstoffe in Serum und Harn ergaben keine Hinweise für präpartale Stoffwechselstörungen. Die Mediane von pH-Wert, NSBA sowie K- und Creatininkonzentrationen im Harn überschritten in mindestens fünf Betrieben die Grenzwerte, da die K-Konzentrationen in den Silagen bis fünffach über dem empfohlenen Bereich lagen. Die DCAD lag im Mittel aller Betriebe mit 458 meq/kg T weit über –100 bis +150 meq/kg T. Eine gesicherte Korrelation zur Anzahl der Festlieger bestand nicht.
Befunde der Festlieger p.p.:
Die Festlieger hatten zu je 60% reduzierte Ca- sowie Pi- und zu 16% verminderte Mg-Konzentrationen. Die Verteilung auf die Gebärparesetypen war wie folgt: Typ I = 42% Typ II= 19%, Typ III = 5%, Typ IV = 12% und Typ V = 21%. Dies entspricht mehrheitlich den Literaturangaben. Die Ca-, Pi- und Mg-Konzentrationen im Harn lagen bei den Festliegern in den physiologischen Bereichen. Die Mehrzahl der Festlieger hatte gleichzeitig erhöhte CK- (74%) und AST-Aktivitäten (53%). In 38% der Fälle war die AP-Aktivität vermindert. Die K- und NSBA-Konzentrationen im Harn der Festlieger zeigten als Folge der reduzierten Futteraufnahme gegenüber den Befunden a.p. eine Abnahme bis in den unteren physiologischen Bereich und z.T. darunter. Störungen des Energiestoffwechsels in Form erhöhter Ketonkörper- (58%) und Bilirubin- (40%) sowie reduzierter Cholesterol- (58%) Konzentrationen hatte die Mehrheit der festliegenden Kühe. Dabei war die kombinierte Ca-Pi-BHB-Stoffwechselstörung die Regel, traf aber nicht in jedem Fall zu. Die moderat veränderten Parameter des Energiestoffwechsels sind offensichtlich Folge der reduzierten Futteraufnahme.
Eine Steigerung der Leukozytenzahl als Hinweis auf eine akut-entzündliche Reaktion bestand bei 44% der Festlieger, - die Leukopenie war die Ausnahme. Mit der Leukozytose waren in 36,8% respektive 42,1% der Fälle eine Hypokalz- resp. Hypophosphatämie gekoppelt. Bei dem größeren Teil (47,4%) der Leukozytosen waren die Ca- und Pi-Konzentrationen jedoch physiologisch. Das zeigt in Übereinstimmung mit den klinischen Befunden, dass entzündliche Prozesse und Verletzungen als weitere Ursache des Festliegens angesehen werden mussten.
Fazit: Die erhöhte DCAD war in den untersuchten Mittelgebirgsbetrieben kein prädisponierender Faktor für die Gebärparese. Neben den bekannten Ca-Pi-Störungen spielten entzündliche Prozesse dafür eine wichtige Rolle.
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N-methyl-6-hydroxyquinolinium: an investigation into the spectroscopy and applications of excited-state proton transferSalvitti, Michael Anthony 11 July 2008 (has links)
N-methyl-6-hydroxyquinolinium (NM6HQ) is a powerful excited-state proton donor, exhibiting a huge pKa drop from 7.2 in the ground state to -7 in the excited state. The zwitterionic nature of the proton transfer product encourages intramolecular electron transfer away from the hydroxyl moiety to the distal ring, allowing for a large pKa jump in the excited state. This process is reversible, making the NM6HQ salts powerful transient superacids. We have investigated the excited-state proton transfer (ESPT) from NM6HQ salts to various basic solvents (alcohols, DMSO). A model has been developed that adequately describes the ion-dipole interactions in the ESPT geminate-recombination process. Our studies have shown that the counterion plays a large role in the ESPT. Likewise, initiation of cationic polymerization is controlled by the counterion. NM6HQ perfluoroalkylsulfonates appear to be the first molecules reported which are capable of initiating aliphatic epoxide polymerization at room temperature through a proton transfer mechanism.
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Evaluation of the Removal Efficiency of Per- and Polyfluoroalkyl Substances in Drinking Water using Nanofiltration Membranes, Active Carbon and Anion Exchange / Utvärdering av reningseffektiviteten av per- och polyfluorerade alkylsubstanser i dricksvatten med nanofiltrering, aktivt kol och jonbytarmassaLindegren, Klara January 2015 (has links)
Per- and polyfluoroalkyl substances (PFASs) is a group of man-made, highly persistent chemicals. Due to the specific surface-active attributes of these molecules, applications are numerous and feed an economically important industry. During the last decade, PFASs have been detected globally in the environment, living organisms and tap water. The combination of toxic properties and high bioaccumulative potential, together with the discovery that conventional water treatment methods do not remove PFAS, renders further research on purification methods highly needed. Three techniques of purifying water from PFASs were examined. Nanofiltration technology (NF) is a membrane filtration technique, which produces a purified product (the permeate) by generating an effluent of high contaminant concentration (the reject water). To decontaminate the reject water, adsorption by granular activated carbon (GAC) or anion exchange (AE) have been proposed. The efficiency of these three technologies was studied at Bäcklösa drinking water treatment plant (DWTP) in Uppsala. A nanofiltration pilot with two 270NF membranes (Dow Filmtech™), connected in series, was used. A high removal efficiency (>90%) was found for all PFASs. Furthermore, it was confirmed that the concentration in the permeate water was a function of the concentration in the incoming raw water; increased PFAS raw water concentration resulted in increased PFAS permeate concentration. Size-exclusion and electrostatic repulsion were deemed important mechanisms. For the comparison of GAC (Filtrasorb 400®) and AE (Purolite® A-600), a column experiment was set up. The perfluoroalkane (-alkyl) sulfonic acids (PFSAs) and perfluorooctanesulfonamide (FOSA) had similar removal efficiencies using both GAC and AE, and the efficiency increased with increasing chain length. AE was found to have a higher average removal efficiency of perfluoroalkyl carboxylic acid (PFCAs) (62-95%) than GAC (49-81%). In conclusion, longer chain length PFASs were removed more effectively than shorter-chained, and the PFSAs and FOSA showed higher removal efficiency compared to the PFCAs. Furthermore, linear isomers were removed more effectively than branched for GAC and AE. In contrast, the opposite was found for the NF membrane, where branched isomers were better retained. / Per- och polyfluorerade alkylsubstanser (PFAS) är en grupp syntetiska, ytterst persistenta kemikalier. På grund av deras ytaktiva egenskaper är de lämpliga för användning i många produkter och tillverkningsprocesser, och är således viktiga för en ekonomiskt betydande industri. Under det senaste årtiondet har PFAS påträffats i miljön, levande organismer och kranvatten världen över. Kombinationen av toxiska egenskaper, en hög bioackumuleringspotential och upptäckten att konventionella reningsmetoder inte avlägsnar substanserna från vatten, gör att vidare forskning av reningsmetoder för PFAS är mycket angelägen. Tre reningsteknikers förmåga att rena vatten från PFAS undersöktes. Nanofiltrering (NF) är en membranfiltreringsteknik som utöver den renade produkten, permeatet, även framställer en biprodukt av hög föroreningsgrad, rententatet. För att rena rententatet har adsorption till granulärt aktivt kol (GAC) eller jonbytarmassa (AE) föreslagits. Teknikerna utvärderades på Bäcklösa Vattenverk i Uppsala. Nanofiltreringen undersöktes i en pilotanläggning där två 270NF (Dow Filmtech™) membran var seriekopplade. En hög reningsgrad (>90%) konstaterades för alla typer av PFAS. Vidare visades PFAS-koncentrationen i permeatet vara en funktion av PFAS-koncentrationen i råvattnet; en ökad råvattenkoncentration gav en ökad permeatkoncentration. Storleksseparation och elektrostatisk repulsion befanns vara viktiga mekanismer som påverkade reningsgraden. För att undersöka de mekanismer som påverkar PFAS-adsorption jämfördes GAC (Filtrasorb 400®) och AE (Purolite® A-600) i ett kolonnexperiment. Reningsgraden för GAC och AE av perfluorerade sulfonsyror (PFSA) och perfluorooktan sulfonamider (FOSA) var lika hög och reningseffektiviteten ökade med ökande kolkedjelängd. AE återfanns ha en högre genomsnittlig reningsgrad av perfluorkarboxylsyror (PFCA) (62-95%) än GAC (49-81%). Sammanfattningsvis avlägsnades PFAS av längre kolkedjelängd mer effektivt än kortare kolkedjor, och PFAS med sulfonsyror och sulfonamider som funktionella grupper uppvisade en högre reningsgrad än karboxylsyrorna. Vidare renades linjära isomerer mer effektivt än grenade både genom GAC och AE. Däremot konstaterades det motsatta för NF-membranen, där grenade isomerer renades mer effektivt. / SafeDrink
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Respostas de frangos de corte ao estresse térmico agudo ou crônico / Responses of broilers exposed to acute or chronic heat stressSandre, Danilo Gualberto de [UNESP] 03 June 2016 (has links)
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Previous issue date: 2016-06-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Dois experimentos envolvendo 1280 pintos machos Cobb 500, foram conduzidos para avaliar as possíveis interações entre condicionamento termo precoce e balanço eletrolítico da dieta sobre o desempenho de frangos de corte, bem como estudar os efeitos do estresse térmico agudo e crônico. No d 8, as aves foram transferidas para 32 boxes, com raspas de madeira e resíduo desidratado de acerola (proporção ½ a ½ ) como cama, mantendo os mesmos tratamentos com oito repetições cada. Os dados da Exp. 1 (stress agudo) e 2 (stress crónico) foram combinados num arranjo fatorial 2x2x2 (com e sem condicionamento térmico precoce (CTP); dieta com e sem equilíbrio eletrolítico (EE); e estresse térmico agudo ou crônico. A dieta com EE foi calculada como mEq / kg para a Na + K-Cl e o valor da relação (K + Cl) / Na, com 300 mEq / kg e uma proporção de 3: 1, respectivamente. As aves foram alimentadas com: (1) uma dieta tradicional (176 mEq / kg e a relação de 3,36: 1) sem CTP; (2) dieta tradicional com CTP; (3) dieta com EE e sem CTP e (4) dieta com EE e CTP. Ração e água foram fornecidas ad libitum. Metade das aves foram expostas a 36 °C durante 24 horas com a idade de 5, enquanto que a outra metade não foi exposto a CTP. Na idade de 38 d, metade dos pintos foram termicamente desafiados por estresse térmico agudo de 36 °C durante 6h e com a idade de 35 a 39 d, outra metade dos pintos foram termicamente desafiado por um estresse térmico crônico de 32 °C por 6h. O consumo de ração, peso corporal (PC), a umidade das fezes e deposição de gordura abdominal foram determinadas a 46 d de idade e taxa de conversão alimentar ajustado foi calculado através da inclusão de PC da mortalidade. Coordenadas tricromáticas (L*, a*, e b*) foram medidos no músculo do peito, às 24h. Nenhum efeito de interação foi encontrado com nenhum dos parâmetros avaliados. Assim, não existe sinergismo para qualquer um dos traços. Houve aumento expressivo da mortalidade [(3,06-65,62%) / P <0,0001] de estresse agudo. O EE aumentou a umidade nas fezes (P = 0,0202). Os conteúdos de lipídios dos tecidos abdominais foram afetados pela exposição ao calor e diminuiu significativamente (P <0,0001) para crônica (53.9g) versus estresse agudo (127.5g). Além disso, um efeito significativo (P <0,0001) valores mais elevados foi encontrado em carne para aguda (66,4 e 23,2) versus o estresse crônico (57,6 e 17,6), em L* e b*, respectivamente. Os resultados sugerem que as aves submetidas a estresse agudo estão sujeitos a síndrome do músculo pálida aves. / Two experiments involving 1280 male Cobb 500 chicks were conducted to evaluate the possible interactions between early thermal conditioning and electrolyte balance of the diet on the performance of broiler chickens, as well as studying the effects of acute and chronic heat stress. On d 8, the broilers were transferred to 32 floor pens with wood shavings as litter while maintaining the same treatments with eight replicates each. The data from Exp. 1 (acute stress) and 2 (chronic stress) were combined in a 2x2x2 factorial arrangement [with and without early thermal conditioning (ETC)]; diet with and without electrolyte balance (EB); and acute or chronic heat stress. The diet with EB was calculated as mEq/kg for Na+K-Cl and the value the ratio (K+Cl)/Na, with 300 mEq/kg and a ratio the 3:1, respectively. The birds were fed: (1) a traditional diet (176 mEq/kg and a ratio the 3.36:1) without ETC; (2) traditional diet with ETC; (3) diet with EB and without ETC and (4) diet with EB and ETC. Feed and water were supplied ad libitum. Half of birds were exposed to 36°C for 24h at the age of 5, whereas the remaining half was not exposed to ETC. At the age of 38 d, half chicks were thermally challenged by an acute heat stress of 36°C for 6h or at the age of 35 to 39 d, another half chicks were thermally challenged by a chronic heat stress of 32°C for 6h. Feed intake, body weight (BW), moisture of feces and abdominal fat deposition were determined at 46 d of age and adjusted feed conversion ratio was calculated by including BW of mortality. Trichromatic coordinates (L*, a*, and b*) were measured on the breast muscle at 24h. No interaction effects were found for any of the parameters evaluated. Thus, there is no synergism for any of the traits. There was expressive increase of mortality [(3.06 to 65.62%) / P<0.0001] from acute stress. The EB increased moisture of feces (P=0.0202). Lipid contents of abdominal tissues was affected by heat exposure with significantly decreased (P<0.0001) to chronic (53.9g) versus acute stress (127.5g). Also, a significant effect (P<0.0001) values higher was found in meat for acute (66.4 and 23.2) versus chronic stress (57.6 and 17.6) on L* and b*, respectively. The results suggest that birds submitted to acute stress are subject to pale poultry muscle syndrome.
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Respostas de frangos de corte ao estresse térmico agudo ou crônico /Sandre, Danilo Gualberto de. January 2016 (has links)
Orientador: Guilherme de Paula Nogueira / Cooientador: Garcia Neto, Manoel / Banca: Marcelo Vasconcelos Meireles / Banca: Antonio Celso Pezzato / Resumo: Dois experimentos envolvendo 1280 pintos machos Cobb 500, foram conduzidos para avaliar as possíveis interações entre condicionamento termo precoce e balanço eletrolítico da dieta sobre o desempenho de frangos de corte, bem como estudar os efeitos do estresse térmico agudo e crônico. No d 8, as aves foram transferidas para 32 boxes, com raspas de madeira e resíduo desidratado de acerola (proporção ½ a ½ ) como cama, mantendo os mesmos tratamentos com oito repetições cada. Os dados da Exp. 1 (stress agudo) e 2 (stress crónico) foram combinados num arranjo fatorial 2x2x2 (com e sem condicionamento térmico precoce (CTP); dieta com e sem equilíbrio eletrolítico (EE); e estresse térmico agudo ou crônico. A dieta com EE foi calculada como mEq / kg para a Na + K-Cl e o valor da relação (K + Cl) / Na, com 300 mEq / kg e uma proporção de 3: 1, respectivamente. As aves foram alimentadas com: (1) uma dieta tradicional (176 mEq / kg e a relação de 3,36: 1) sem CTP; (2) dieta tradicional com CTP; (3) dieta com EE e sem CTP e (4) dieta com EE e CTP. Ração e água foram fornecidas ad libitum. Metade das aves foram expostas a 36 °C durante 24 horas com a idade de 5, enquanto que a outra metade não foi exposto a CTP. Na idade de 38 d, metade dos pintos foram termicamente desafiados por estresse térmico agudo de 36 °C durante 6h e com a idade de 35 a 39 d, outra metade dos pintos foram termicamente desafiado por um estresse térmico crônico de 32 °C por 6h. O consumo de ração, peso corporal (PC)... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Two experiments involving 1280 male Cobb 500 chicks were conducted to evaluate the possible interactions between early thermal conditioning and electrolyte balance of the diet on the performance of broiler chickens, as well as studying the effects of acute and chronic heat stress. On d 8, the broilers were transferred to 32 floor pens with wood shavings as litter while maintaining the same treatments with eight replicates each. The data from Exp. 1 (acute stress) and 2 (chronic stress) were combined in a 2x2x2 factorial arrangement [with and without early thermal conditioning (ETC)]; diet with and without electrolyte balance (EB); and acute or chronic heat stress. The diet with EB was calculated as mEq/kg for Na+K-Cl and the value the ratio (K+Cl)/Na, with 300 mEq/kg and a ratio the 3:1, respectively. The birds were fed: (1) a traditional diet (176 mEq/kg and a ratio the 3.36:1) without ETC; (2) traditional diet with ETC; (3) diet with EB and without ETC and (4) diet with EB and ETC. Feed and water were supplied ad libitum. Half of birds were exposed to 36°C for 24h at the age of 5, whereas the remaining half was not exposed to ETC. At the age of 38 d, half chicks were thermally challenged by an acute heat stress of 36°C for 6h or at the age of 35 to 39 d, another half chicks were thermally challenged by a chronic heat stress of 32°C for 6h. Feed intake, body weight (BW), moisture of feces and abdominal fat deposition were determined at 46 d of age and adjusted feed conversio... (Complete abstract click electronic access below) / Mestre
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