In vitro bioassays for the study of endocrine-disrupting food additives and contaminants

Endocrine-disrupting chemicals (EDCs) are capable of interfering with normal hormone homeostasis by acting on several targets and through a wide variety of mechanisms. Unwanted exposure to EDCs can lead to a wide spectrum of adverse health effects, especially when exposure is during critical windows of development. Feed and food are considered to be among the main routes of inadvertent exposure to EDCs, so there is an important need for efficient detection of EDCs in these matrices.

Biomass-derived Oxymethylene Ethers as Diesel Additives: A Thermodynamic Analysis

Conversion of biomass for production of liquid fuels can help in reducing the greenhouse gas (GHG) emissions which are predominantly generated by combustion of fossil fuels. Adding oxymethylene ethers (OMEs) in conventional diesel fuel has the potential to reduce soot formation during the combustion in a diesel engine. OMEs are downstream products of syngas, which can be generated by the gasification of biomass. In this research, a thermodynamic analysis has been conducted through development of data intensive process models of all the unit operations involved in production of OMEs from biomass. Based on the developed model, the key process parameters affecting the OMEs production including equivalence ratio, H2/CO ratio, and extra water flow rate were identified. This was followed by development of an optimal process design for high OMEs production. It was found that for a fluidized bed gasifier with heat capacity of 28 MW, the conditions for highest OMEs production are at an air amount of 317 tonne/day, at H2/CO ratio of 2.1, and without extra water injection. At this level, the total OMEs production is 55 tonne/day (13 tonne/day OME3 and 9 tonne/day OME4). This model would further be used in a techno-economic assessment study of the whole biomass conversion chain to determine the most attractive pathways.

Thermo-Mechanical Properties of Poly ε-Caprolactone/Poly L-Lactic Acid Blends: Addition of Nalidixic Acid and Polyethylene Glycol Additives Journal of the Mechanical Behavior of Biomedical Materials

The search for ideal biomaterials is still on-going for tissue regeneration. In this study, blends of Poly ε-caprolactone (PCL) with Poly l-lactic acid (PLLA), Nalidixic Acid (NA) and Polyethylene glycol (PEG) were prepared. Mechanical and thermal properties of the blends were investigated by tensile and flexural analysis, DSC, TGA, WXRD, MFI, BET, SEM and hot stage optical microscopy. Results showed that the loading of PLLA caused a significant decrease in tensile strength and almost total eradication of the elongation at break of PCL matrix, especially after PEG and NA addition. Increased stiffness was also noted with additional NA, PEG and PLLA, resulting in an increase in the flexural modulus of the blends.
Isothermal degradation indicated that bulk PCL, PLLA and the blends were thermally stable at 200°C for the duration of 2h making extrusion of the blends at this temperature viable. Morphological study showed that increasing the PLLA content and addition of the very low viscosity PEG and powder NA decreased the Melt Flow Indexer and increased the viscosity.
At the higher temperature the PLLA begins to soften and eventually melts allowing for increased flow and, coupling this with, the natural increase in MFI caused by temperature is enhanced further. The PEG and NA addition increased dramatically the pore volume which is important for cell growth and flow transport of nutrients and metabolic waste.

Biomass-derived oxymethylene ethers as diesel additives: A techno-economic assessment

Conversion of agricultural biomass such as wood chips, wheat straw and forest residue for the production of fuels can help in reducing GHG emissions since they are considered as nearly carbon neutral. Around the world there is a significant amount of forest and agricultural-biomass available which could be used for the production of liquid fuels that can be blended with the petroleum-based diesel. Oxymethylene ethers (OMEs) can be derived from biomass via gasification, water-gas shift reaction and methanol production. The addition of OMEs to conventional diesel fuel has great potential to reduce soot formation during the combustion in diesel engines. Unlike methanol and dimethyl ether (DMM) which can also reduce soot formation, the physical properties of OMEs allow the use in modern diesel engines without significant change of the engines infrastructure. In this study, a detailed and data intensive process simulation model was developed to simulate all the unit operations involved in the production of OMEs from biomass. The unit operation considered include biomass drying, gasification, gas cleaning, water gas shift reaction, methanol production and OMEs synthesis. The simulation results were then utilized to conduct a detailed techno-economic assessment study of the whole biomass conversion chain to determine the most attractive pathways for OMEs production. Our recent study shows that the key parameters affecting the OMEs production are equivalence ratio, H2/CO ratio and optimal air flow. Overall, the cost of production ($/liter) of OMEs from different biomass feedstock in Alberta will be determined

Methylamine as true template and TEAOH as purifying agent: unexpected roles of current organic additives in the hydrothermal synthesis of microporous aluminophosphates

Methylamine (MA), TEA+ and water were shown to play a concerted role during the synthesis of two new aluminophosphates IST-1 and IST-2. Both structures start to nucleate after the dramatic change of the gel composition due to preliminary interactions between TEA+ cations.

Brazilian fruit pulps as functional foods and additives: Evaluation of bioactive compounds

Eight tropical fruit pulps from Brazil were simultaneously characterised in terms of their antioxidant and antimicrobial properties. Antioxidant activity was screened by DPPH radical scavenging activity (126–3987 mg TE/100 g DW) and ferric reduction activity power (368–20819 mg AAE/100 g DW), and complemented with total phenolic content (329–12466 mg GAE/100 g DW) and total flavonoid content measurements (46–672 mg EE /100 g DW), whereas antimicrobial activity was tested against the most frequently found food pathogens. Acerola and açaí presented the highest values for the antioxidant-related measurements. Direct correlations between these measurements could be observed for some of the fruits. Tamarind exhibited the broadest antimicrobial potential, having revealed growth inhibition of Pseudomonas aeruginosa. Escherichia coli, Listeria monocytogenes, Salmonella sp. and Staphylococcus aureus. Açaí and tamarind extracts presented an inverse relationship between antibacterial and antioxidant activities, and therefore, the antibacterial activity cannot be attributed (only) to phenolic compounds.

The influence of use additives on nitrous oxide emission during swine slurry composting.

use of additives (Mg/P and nitrification inhibitor dicyandiamide - DCD), on nitrous oxide emission during swine slurry composting. The experiment was run in duplicate; the gas was monitored for 30 days in different treatments (control, DCD, Mg/P and DCD + Mg/P). Nitrous oxide emissions rate (mg of N2O-N.day-1) and the accumulated emissions were calculated to compare the treatments. Results has shown that emissions of N-N2O were reduced by approximately 70, 46 and 96% through the additions of DCD, MgCl2.6H2O + H3PO4 and both additives, respectively, compared to the control. Keywords Composting; swine slurry; additives; nitrous

Représentation d'un polynôme par un circuit arithmétique et chaînes additives

Un circuit arithmétique dont les entrées sont des entiers ou une variable x et dont les portes calculent la somme ou le produit représente un polynôme univarié. On assimile la complexité de représentation d'un polynôme par un circuit arithmétique au nombre de portes multiplicatives minimal requis pour cette modélisation. Et l'on cherche à obtenir une borne inférieure à cette complexité, et cela en fonction du degré d du polynôme. A une chaîne additive pour d, correspond un circuit arithmétique pour le monôme de degré d. La conjecture de Strassen prétend que le nombre minimal de portes multiplicatives requis pour représenter un polynôme de degré d est au moins la longueur minimale d'une chaîne additive pour d. La conjecture de Strassen généralisée correspondrait à la même proposition lorsque les portes du circuit arithmétique ont degré entrant g au lieu de 2. Le mémoire consiste d'une part en une généralisation du concept de chaînes additives, et une étude approfondie de leur construction. On s'y intéresse d'autre part aux polynômes qui peuvent être représentés avec très peu de portes multiplicatives (les d-gems). On combine enfin les deux études en lien avec la conjecture de Strassen. On obtient en particulier de nouveaux cas de circuits vérifiant la conjecture.

The effects of additives and chemical modification on the solution properties of thermo-sensitive polymers

Cette thèse concerne l’étude de phase de séparation de deux polymères thermosensibles connus-poly(N-isopropylacylamide) (PNIPAM) et poly(2-isopropyl-2-oxazoline) (PIPOZ). Parmi des études variées sur ces deux polymères, il y a encore deux parties de leurs propriétés thermiques inexplicites à être étudiées. Une partie concerne l’effet de consolvant de PNIPAM dans l’eau et un autre solvant hydromiscible. L’autre est l’effet de propriétés de groupes terminaux de chaînes sur la séparation de phase de PIPOZ. Pour ce faire, nous avons d’abord étudié l’effet de l’architecture de chaînes sur l’effet de cosolvant de PNIPAMs dans le mélange de méthanol/eau en utilisant un PNIPAM en étoile avec 4 branches et un PNIPAM cyclique comme modèles. Avec PNIPAM en étoile, l’adhérence de branches PNIPAM de à un cœur hydrophobique provoque une réduction de Tc (la température du point de turbidité) et une enthalpie plus faible de la transition de phase. En revanche, la Tc de PNIPAM en étoile dépend de la masse molaire de polymère. La coopérativité de déhydratation diminue pour PNIPAM en étoile et PNIPAM cyclique à cause de la limite topologique. Une étude sur l’influence de concentration en polymère sur l’effet de cosolvant de PNIPAM dans le mélange méthanol/eau a montré qu’une séparation de phase liquide-liquide macroscopique (MLLPS) a lieu pour une solution de PNIPAM dans le mélange méthanol/eau avec la fraction molaire de méthanol entre 0.127 et 0.421 et la concentration en PNIPAM est constante à 10 g.L-1. Après deux jours d’équilibration à température ambiante, la suspension turbide de PNIPAM dans le mélange méthanol/eau se sépare en deux phases dont une phase possède beaucoup plus de PNIPAM que l’autre. Un diagramme de phase qui montre la MLLPS pour le mélange PNIPAM/eau/méthanol a été établi à base de données expérimentales. La taille et la morphologie de gouttelettes dans la phase riche en polymère condensée dépendent de la fraction molaire de méthanol. Parce que la présence de méthanol influence la tension de surface des gouttelettes liquides, un équilibre lent de la séparation de phase pour PNIPAM/eau/méthanol système a été accéléré et une séparation de phase liquide-liquide macroscopique apparait. Afin d’étudier l’effet de groupes terminaux sur les propriétés de solution de PIPOZ, deux PIPOZs téléchéliques avec groupe perfluorodécanyle (FPIPOZ) ou groupe octadécyle (C18PIPOZ) comme extrémités de chaîne ont été synthétisés. Les valeurs de Tc des polymères téléchéliques ont beaucoup diminué par rapport à celle de PIPOZ. Des micelles stables se forment dans des solutions aqueuses de polymères téléchéliques. La micellization et la séparation de phase de ces polymères dans l’eau ont été étudiées. La séparation de phase de PIPOZs téléchéliques suit le mécanisme de MLLPS. Des différences en tailles de gouttelettes formées à l’intérieur de solutions de deux polymères ont été observées. Pour étudier profondément les différences dans le comportement d’association entre deux polymères téléchéliques, les intensités des signaux de polymères correspondants et les temps de relaxation T1, T2 ont été mesurés. Des valeurs de T2 de protons correspondants aux IPOZs sont plus hautes.

The Effect of Glass Additives on the Microwave Dielectric Properties of Ba(Mg 1 /3Ta2/3)03 Ceramics

The effect of glass additives on the densification , phase evolution, microstructure and microwave dielectric properties of Ba(Mg1;3 Ta2i3)03 (BMT) was investigated . Different weight percentages of quenched glass such as B203 , Si02, B203-SiO2, ZnO-B203, 5ZnO-2B2O3, Al203-SiO2, Na20-2B203.10H20, BaO-B203-SiO2, MgO-B203-SiO2, PbO-B203-SiO2 , ZnO-B203-SiO2 and 2MgO-Al203-5SiO2 were added to calcined BMT precursor . The sintering temperature of the glass -added BMT samples were lowered down to 1300 °C compared to solid-state sintering where the temperature was 1650 °C. The formation of high temperature satellite phases such as Ba5Ta4O15 and Ba7Ta6O22 were found to be suppressed by the glass addition . Addition of glass systems such as B203, ZnO-B203, 5ZnO-2B203 and ZnO-B203-SiO2 improved the densification and microwave dielectric properties. Other glasses were found to react with BMT to form low-Q phases which prevented densification . The microwave dielectric properties of undoped BMT with a densification of 93 . 1 % of the theoretical density were Cr = 24 . 8, Tr = 8 ppm/°C and Q„ x f= 80,000 GHz. The BMT doped with 1.0 wt% of B203 has Q„ x f = 124,700GHz, Cr = 24.2, and T f = -1.3 ppm /°C. The unloaded Q factor of 0.2 wt% ZnO-B203-doped BMT was 136,500 GHz while that of 1.0 wt% of 5ZnO-2B203 added ceramic was Q„ x f= 141,800 GHz . The best microwave quality factor was observed for ZnO -B203-SiO2 (ZBS) glass-added ceramics which can act as a perfect liquid-phase medium for the sintering of BMT. The microwave dielectric properties of 0.2wt% ZBS-added BMT dielectric was Q„ x f= 152,800 GHz, F,= 25.5, and Tr = - 1.5 ppm/°C

ANALYSIS, MODIFICATION, AND EVALUATION OF THE COLD FLOW PROPERTIES OF VEGETABLE OILS AS BASE OIL FOR INDUSTRIAL LUBRICANTS

Poor cold flow properties of vegetable oils are a major problem preventing the usage of many abundantly available vegetable oils as base stocks for industrial lubricants. The major objective of this research is to improve the cold flow properties of vegetable oils by various techniques like additive addition and different chemical modification processes. Conventional procedure for determining pour point is ASTM D97 method. ASTM D97 method is time consuming and reproducibility of pour point temperatures is poor between laboratories. Differential Scanning Calorimetry (DSC) is a fast, accurate and reproducible method to analyze the thermal activities during cooling/heating of oil. In this work coconut oil has been chosen as representative vegetable oil for the analysis and improvement cold flow properties since it is abundantly available in the tropics and has a very high pour point of 24 °C. DSC is used for the analysis of unmodified and modified vegetable oil. The modified oils (with acceptable pour points) were then subjected to different tests for the valuation of important lubricant properties such as viscometric, tribological (friction and wear properties), oxidative and corrosion properties.A commercial polymethacrylate based PPD was added in different percentages and the pour points were determined in each case. Styrenated phenol(SP) was added in different concentration to coconut oil and each solution was subjected to ASTM D97 test and analysis by DSC. Refined coconut oil and other oils like castor oil, sunflower oil and keranja oil were mixed in different proportions and interesterification procedure was carried out. Interesterification of coconut oil with other vegetable oils was not found to be effective in lowering the pour point of coconut oil as the reduction attained was only to the extent of 2 to 3 °C.Chemical modification by acid catalysed condensation reaction with coconut oil castor oil mixture resulted in significant reduction of pour point (from 24 ºC to -3 ºC). Instead of using triacylglycerols, when their fatty acid derivatives (lauric acid- the major fatty acid content of coconut oil and oleic acid- the major fatty acid constituents of monoand poly- unsaturated vegetable oils like olive oil, sunflower oil etc.) were used for the synthesis , the pour point could be brought down to -42 ºC. FTIR and NMR spectroscopy confirmed the ester structure of the product which is fundamental to the biodegradability of vegetable oils. The tribological performance of the synthesised product with a suitable AW/EP additive was comparable to the commercial SAE20W30 oil. The viscometric properties (viscosity and viscosity index) were also (with out additives) comparable to commercial lubricants. The TGA experiment confirmed the better oxidative performance of the product compared to vegetable oils. The sample passed corrosion test as per ASTM D130 method.