No description available.

Thesis (Ph. D.)--Columbia University, 1933. / Vita. Bibliography: p. 29.

Thesis (Ph. D.)--Princeton University, 1925.

Dewatered sludges and biosolids generated from wastewater treatment facilities are known to emit malodorous odors causing public inconvenience. The odors typically comprise of reduced organo sulfur based compounds and nitrogen containing compounds. Lime stabilization is a technique which is commonly used in the wastewater industry to produce biosolids having reduced odors that can be safely land disposed. In this research, odors produced from dewatered sludges and lime stabilized biosolids were investigated. Lime dosing and incorporation in sludge play an important role in generation of reduced sulfur and trimethylamine (TMA) odor compounds. Results revealed that poor lime dosing can lead to an increase in odors due to biological generation of volatile sulfur compounds (VSCs) during storage. In this study, a belt filter press gave a higher production of sulfur and TMA odors compared to a vacuum filter for the same sludge, which is attributed to the shear imparted to sludge during the dewatering process. Preliming studies suggested incomplete mixing of lime with sludge led to biological activity. The achievement of the correct pH and its maintenance during storage is considered critical for effective odor management from lime stabilized biosolids. A positive linear relation was obtained between sulfur based odor production and labile protein content in sludge. Furthermore, as the Al/Fe ratio increased, the labile proteins was observed to decrease. Trivalent metals are found to play an important role in binding of labile proteins thus effecting odor potential contained in sludge/biosolids. This was found true for most sludge irrespective of their liming status and independent of upstream process conditions. Further work in this area is needed to be able to provide a better understanding of odor production to aid in development of odor control techniques. Trimethylamine odors, having a characteristic fishy odor, are commonly found in lime stabilized biosolids. Cationic polymers used as dewatering aids are the primary precursors for TMA production. Proteins present in sludge are also associated with odor forming compounds but they produce much lower levels than polymers. These two components under the action of shear present in dewatering devices such as centrifuge are more likely to cause an increase in odor production from lime stabilized biosolids. It was also determined that abiotic polymer degradation to produce TMA either does not occur, or the rate is so slow that TMA production in this way is insignificant for actual field situations. / Master of Science

Trimethylamine-N-oxide (TMAO) is an important biomarker of atherosclerosis. TMAO is the product of a hepatic conversion of trimethylamine (TMA). Releasing of TMA moieties is dependent on the adaptation of the gut microbiota to dietary TMA containing substrates such as phosphatidylcholine (PC), choline, and L-carnitine. A high-fat diet is an environmental risk factor that may increase TMAO production. However, it isn’t clear if the high dietary intake of TMA is sufficient to promote increased plasma TMAO or if a high-fat intake is also required. We hypothesized that TMAO would be increased after consuming a high-fat diet and a high PC diet independently, with greater increases when consumed together. Four groups of twelve mice each were maintained on different treatments that were either low or high-fat with or without PC over two weeks. Then, a meal containing 9.99 g of corn oil and 0.75 g soybean L-α-Lecithin per 1 kg body weight was provided to all mice to indirectly observe the adaptation of the microbiota to the altered diet. The results of circulating TMAO levels showed that fat appeared to suppress TMAO production, which is against previous evidence. The microbial adaptation to the different treatments wasn’t observed in the measurement of fecal TMA levels. As a result, our hypothesis was rejected. Future work addressing the impact of gene expressions of enzymes on the gut and the liver is needed. The use of another high TMA containing substrates such as choline and rats is recommended. / Master of Science in Life Sciences / Cardiovascular disease (CVD) is heart and blood vessel diseases - many of which are caused by atherosclerosis, a condition wherein fatty materials accumulate in the artery wall, reducing blood flow. The compound trimethylamine-N-oxide (TMAO) was found to be an important biomarker of atherosclerosis. TMAO levels increase in the body when gut microbiota releases trimethylamine (TMA) moieties from dietary phosphatidylcholine (PC), choline, and L-carnitine such as eggs and meat. A high-fat intake was believed to have an impact on increased levels of TMAO. However, it wasn’t clear if the dietary intake of high TMA containing substrates such as PC, is sufficient to promote TMAO formation or if a high-fat content is also required. We hypothesized that TMAO would be increased after consuming a high-fat diet and a high PC diet independently, with greater increases when consumed together. The results would suggest new dietary strategies to avoid CVD. Four groups of twelve mice each were maintained on different treatments that were either low or high-fat with or without PC over two weeks. Then, a meal containing corn oil and PC was provided to all mice to observe the adaptation of the microbiota to the altered diet. The results showed that fat reduces circulating TMAO production, which is against previous evidence. Fecal TMA levels showed that microbiota activities weren’t observed in the colon. As a results, no significant levels of TMA and its precursors were observed in feces.

No description available.

Notre travail a démontré l’implication du p-crésyl sulfate (PCS), de la zinc a2glycoprotéine (ZAG) et du triméthylamine-N-oxide (TMAO), représentants des 3 groupes de toxines urémiques décrits par le groupe EUTox, dans la survenue des complications métaboliques de la maladie rénale chronique (MRC). Nous avons démontré que l’augmentation du PCS induisait une insulino-résistance, une perte de masse grasse et une redistribution des lipides chez la souris, en montrant une altération de la voie de signalisation de l’insuline dans le muscle strié squelettique. Nous avons ensuite montré que la protéine ZAG était surexprimée par le tissu adipeux dans la MRC. Du fait de ses effets lipolytiques et anti-lipogeniques, l’élévation des concentrations tissulaires de cette adipokine pourrait être impliquée dans les phénomènes de dyslipidémies et dysfonction adipocytaire observés dans la MRC. Chez l’homme, notre étude a confirmé l’augmentation des concentrations de ZAG dans les stades 5 et 5D de la MRC uniquement, faiblement corrélée au débit de filtration glomérulaire (DFG). L’étude n’a en revanche pas permis de mettre en évidence de corrélation entre les taux circulants de ZAG et les critères de complications métaboliques, notamment la dénutrition. Enfin, en l’absence de données précises sur l’élimination rénale du TMAO et la physiopathologie de son augmentation dans la MRC, nous avons conduit une étude clinique mettant en évidence une forte corrélation entre les taux de TMAO et le DFG mesuré, excluant une contribution tubulaire à son excrétion. Les résultats d’une étude préliminaire chez l’animal suggèrent une possible implication du TMAO dans le développement de la fibrose rénale / Our work demonstrated the role of p-cresyl sulfate (PCS), zinc a2-glycoprotein (ZAG) and trimethylamine-N-oxide (TMAO) that belong to the 3 groups of uremic toxins described by the EUTox group, in the metabolic complications of chronic kidney disease (CKD). We demonstrated that the increase of PCS induced an insulin resistance, a loss of fat mass and a lipid redistribution in mice, showing an alteration of the insulin pathway in skeletal muscle. We showed a surexpression of ZAG by adipose tissue in CKD. Because of ZAG lipolytic and anti-lipogenic effects, the elevation of its tissu levels could be implicated in dyslipidemia and adipose dysfonction in CKD. In humans, our study confirmed the elevation of ZAG concentrations only in CKD stages 5 and 5D, with a poor correlation with the glomerular filtration rate (GFR). The study did not shown correlation between ZAG circulating levels and metabolic complications, as wasting. With the lack of data about renal elimination and physiopathology of TMAO, we conducted a clinical study that reported a strong correlation between TMAO levels and measured GFR, without proof of tubular excretion of TMAO. Results of a preliminary animal study suggests a possible implication of TMAO in the renal fibrosis

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No description available.

The research addresses two groups of reactions: chlorine atom reactions with fluorinated propenes and methyl amines. Most of the reactions were studied over a range of temperature and pressure with the goals of (i) assessing the potential importance of the reactions in atmospheric chemistry and (ii) obtaining kinetic and thermochemical information of fundamental physical–chemical interest. In the studies reported herein, laser flash photolysis (LFP) was coupled with time resolved atomic resonance fluorescence (RF) spectroscopic detection of chlorine atoms to investigate chlorine atom kinetics.