Fatty Acid Soaps Research Articles

Treatment of Highly Concentrated Wastewater with Spent Activated Carbon

Sorption of the main polluting components of the wastewater from production of emulsion butadiene-styrene rubbers, soaps of synthetic and fatty acids and Leukanol, was studied on a preliminarily ground spent AG-3 activated carbon.

Acid Soap and Phase Behavior of Stearic Acid and Triethanolamine Stearate

Crystals of partially neutralized stearic acid with triethanolamine (TEA) were prepared by mixing these two materials above 80 degrees C and then cooling. The crystalline composition and the structure and melting behavior of the resultant products were characterized with small-angle and wide-angle X-ray diffraction, thermal analysis, microscopy, and infrared spectroscopy. It was discovered that an acid-soap complex of 2:1 fixed stoichiometric ratio exists between stearic acid and TEA stearate. A binary phase diagram of stearic acid and TEA soap is built based on the experimental results; this is the first published record of a binary phase diagram for amine-based soap. Its behavior is significantly different from that of binary systems of fatty acid and alkali soap.

Effect of feeding lambs oleic acid calcium soaps on growth, adipose tissue development and composition

A study was performed to determine the influence of calcium soaps of olive fatty acids in the diet of lambs on animal and adipose tissue growth and fatty acid composition during the fattening period. After weaning (15 ± 1.2 kg BW, 45 ± 4 days of age), 18 male Rasa Aragonesa breed lambs were fed, for 35 days, in two groups (nine animals per group) on one of two diets. Control group animals were fed a concentrate diet mainly barley and soya, whereas olive group lambs were fed a similar isoproteic diet that included 5% calcium soaps of olive fatty acids and barley straw, both offered ad libitum. The ME intake of olive concentrate feeding was higher than of the control (289.1 kcal/kg versus 252.8 kcal/kg; P < 0.05), but daily gain, DMi and feed conversion of both groups were similar. The higher energy intake of Olive group lambs resulted in more omental (OM) and perirenal (PR) adipose tissue than in Control animals (446 versus 334 and 374 g versus 242 g, respectively; P < 0.05). Significant differences between groups were not observed with respect to back fat thickness (BFT), percentage subcutaneous (SC) and intermuscular (IN) shoulder adipose tissue, or Longissimus dorsi (L.D.) muscle lipid content. The greater OM and PR adipocyte size of the Olive group lambs and the lack of differences in adipocyte number, indicated that adipocyte hypertrophy was mainly responsible for the differences in accumulated fat observed between the groups of lambs. No changes in PR, SC and IM percentages of saturated and monounsaturated fatty acids or C18:1 content were observed between groups, indicating that compensatory mechanism exists to maintain the fatty acid composition of the depots or that fatty acid protection of calcium soaps was not absolute. The fact that PR polyunsaturated fatty acid percentage was greater in Control animals than in the Olive group (6.92 versus 4.19; P < 0.05) was related to a lower adipose tissue content and a smaller adipocyte size in the Controls. Finally, the inclusion of 5% calcium soaps of oleic acids in the diet, for a period exceeding 35 days, increased adipose tissue in internal depots by adipocyte hypertrophy, whereas adipose and meat C18:1 composition did not change.

Reagents in igneous phosphate ores flotation

The role of reagents utilised in igneous phosphate ores flotation is reviewed. Fatty acids soaps derived from different vegetable species are utilised as collectors. Less expensive species, such as rice and soybean bran oils replaced successfully the more expensive tall oil as the source for the apatite collector. Synthetic collectors such as sarcosinate and sulphosuccinate are also employed. The collector species plays also the frother role. Corn starch is the gangue depressant. Less pure starches, with oil contents equal to or higher than 3%, may be utilised without the risk of suppressing the froth. Actually they may act as a froth controller due to the fact that the fatty acid soap that plays the frother role is an ionic species, generating thus a voluminous froth. Non ionic ethoxylated surfactants may also be used to control the surface tension of the system. Barite, when present, may be either pre-floated with cetyl-stearyl sodium sulphate or depressed, in the fine apatite flotation circuit, at pH 12.

Extraction of heavy metals and ammonium from waters by unsaturated fatty acids and their soaps

The process including heavy metals and ammonium extraction from waters by an extraction medium based on unsaturated fatty acids and their soaps, up-concentration of the extracted metals, and regeneration of the extraction medium was investigated. The process corresponds to current hydroxides-precipitating, coagulation and biotreatment processes. The two synergistically effective ways are described: the basic process with the pretreatment of feed water by sodium or calcium hydroxide and extraction with unsaturated fatty acids, and the advanced process exploiting the extraction through sodium and/or calcium unsaturated fatty acids soaps. Oleine as a commercially available extraction medium was used. High bonding capacity and metals removal efficiency, fast kinetics and selectivity for the extraction process, and the self-adjustment of the pH value after the extraction process, as well as the high up-concentration of the metals salts limiting to saturated solutions, and the complete regeneration of the extraction medium were reached. Heavy metals hydroxides precipitation behaviour was investigated. Chemical and hydrophobisation metals-bonding mechanisms for the extraction process were observed. Regeneration and up-concentration behaviour, Oleine stability and organics residues in the water phases were investigated.

식물성유 첨가가 면양의 반추의 발효특성과 소화율 및 지방산염 형성에 미치는 영향

This experiment were conducted to determine the formation of fatty acid soaps, digestibility and ruminal characteristics when vegetable oils were added. Three Corriedale×Suffolk sheep fitted with rumen cannula were used in a 3 × 3 Latin square design. Sheep were fed one of three diets consisting of alfalfa hay and concentrates in a ratio of 70 : 30. Dietary treatments were 1) no oil, 2) 7% soybean oil and 3) 7% corn oil. At the end of each experimental period, rumen contents from each sheep were collected before feeding and at 1, 3, 6 and 9h after feeding. pH decreased up to the 3 hour after feeding and increased until the end of the collection(P < 0.0001). Whereas the concentration of NH3-N showed inverse changes to pH(P < 0.0001). Type of oil did not affect the molar concentration of total VFA, acetate, propionate and butyrate. Acetic/propionic acid (A/P) ratio decreased with increasing time(P < 0.0001), but the ratio at the end of the experiment became similar to the initial value. No effects were found in the digestibility of dry matter, total-N, crude fiber, ash, NFE, NDF and ADF. The formation of fatty acid soaps(FAS) increased after feeding than 1 hour before feeding(P < 0.05) and increased in 7% oils than no oil addition(P < 0.05). Long chain fatty acids formed mainly FAS. Since the formation of FAS might decrease negative effects on ruminal characteristics and total tract digestibility.

Flotação de diferentes tipologias de minério fosfático de Tapira/MG, usando o coletor óleo de soja hidrogenado

Esse trabalho teve por objetivo avaliar o desempenho do coletor óleo de soja hidrogenado na flotação de quatro tipologias de minérios fosfáticos da mina de Tapira/MG, denominadas piroxenito silicificado semicompacto, piroxenito silicificado compacto, silexito e piroxenito serpentinizado, cujas relações CaO/P2O5 eram de 2,1, 3,5, 2,5 e 1,33, respectivamente. Para a realização dos experimentos, foram aplicadas a metodologia estatística de planejamento e a análise fatorial de experimentos, onde foram estudadas as dosagens de coletor (óleo de soja), a dosagem de depressor (amido de milho gelatinizado) e o pH de flotação. Verificou-se que o valor de pH ideal para a flotação dos minérios foi igual a 11, exceto para o minério silexito, que foi igual a 8. A relação CaO/P2O5 dos concentrados foi maior para os minérios com maior conteúdo de carbonatos e aumentava com o aumento da dosagem de coletor, evidenciando a baixa seletividade desse reagente para a separação entre a apatita e a ganga carbonática a ela associada. Observou-se a necessidade de etapa cleaner para obtenção de concentrados dentro das especificações de mercado para todas as amostras estudadas.

Bacterial Poly(Hydroxyalkanoate) Polymer Production from the Biodiesel Co-product Stream

A co-product stream from soy-based biodiesel production (CSBP) containing glycerol, fatty acid soaps, and residual fatty acid methyl esters (FAME) was utilized as a fermentation feedstock for the bacterial synthesis of poly(3-hydroxybutyrate) (PHB) and medium-chain-length poly(hydroxyalkanoate) (mcl-PHA) polymers. Pseudomonas oleovorans NRRL B-14682 and P. corrugata 388 grew and synthesized PHB and mcl-PHA, respectively, when cultivated in up to 5% (w/v) CSBP. In shake flask culture, P. oleovorans grew to 1.3 ± 0.1 g/L (PHA cellular productivity = 13-27% of the bacterial cell dry weight; CDW) regardless of the initial CSBP concentration, whereas P. corrugata reached maximum cell yields of 2.1 g/L at 1% CSBP, which tapered off to 1.7 g/L as the CSBP media concentration was increased to 5% (maximum PHA cellular productivity = 42% of the CDW at 3% CSBP). While P. oleovorans synthesized PHB from CSBP, P. corrugata produced mcl-PHA consisting primarily of 3-hydroxyoctanoic acid (C8:0; 39 ± 2 mol%), 3-hydroxydecanoic acid (C10:0; 26 ± 2 mol%) and 3-hydroxytetradecadienoic acid (C14:2; 15 ± 1 mol%). The molar mass (Mn) of the PHB polymer decreased by 53% as the initial CSBP culture concentration was increased from 1% to 5% (w/v). In contrast, the Mn of the mcl-PHA polymer produced by P. corrugata remained constant over the range of CSBP concentrations used.

식물성유 첨가가 In vitro 발효성상, NDF 소실율 및 지방산염 형성에 미치는 영향

In vitro experiments were conducted to determine the formation of fatty acid soaps (FAS) and neutral detergent fiber (NDF) disappearance rate. The substrates were a basal alfalfa hay containing 1) no oil, 2) 10% soybean oil, 3) 10% corn oil, on a weight basis. All the substrates were incu bated in triplicate for 0, 3, 6, 12, 24 and 48h in each experiment. After the incubation in the first experiment serum bottles (60ml) were analyzed for nonesterified, esterifed and fatty acid soaps contents. The serum bottles (120ml) from the second experiment were analyzed for pH, NH3-N and VFA concentration, and dry matter and NDF disappearance rate. pH decreased and the concentration of NH3-N increased significantly with longer incubation time (P<0.0001). The disappearance rates of dry matter and NDF significantly varied with feed, incubation time and oils (P<0.05). The molar concentration of total VFA increased and proportion of acetate significantly decreased with incubation time (P<0.0001), but the proportion of propionate significantly increased with longer incubation time (P<0.0001). Addition of oils to diet lowered the ratio of acetate:propionate (P<0.05). The esterified fatty acids (EFA) decreased with increasing incubation time (P<0.0001), and nonesterified fatty acids (NEFA) increased due to lipolysis of EFA. NEFA then reacted with cations to increase formation of FAS. The formation of FAS increased significantly at 48h of incubation time (P<0.0001). Especially, formation of stearic acid soaps was 27.5 and 32.5 folds with soybean oil and corn oil supplements, respectively, by 48h of incubation time (P<0.0001). Alfalfa hay had higher cation contents, particularly Ca, which react with NEFA and FAS can be formed with longer incubation time. Saturated fatty acids had a higher proportion of FAS than did unsaturated fatty acids, suggesting that the former may react more extensively with cations. FAS contents increased with increasing chain length of the fatty acids. Since added vegetable oils formed FAS, it might decrease negative effects on in vitro fermentation characteristics and NDF disappearance rate.

Use of surfactants to remove water-based inks from plastic film: effect of calcium ion concentration and length of surfactant hydrophobe

Effective plastic film deinking could permit the reuse of recycled polymer to produce clear film, reduce solid waste for landfills, reduce raw material demand for polymer production, and aid process economics. In this study, the deinking of a commercial polyethylene film printed with water-based ink was studied using surfactants in the presence of hardness ions (calcium ions) at various pH levels. The electrostatic properties of ink particles in a washing bath were also investigated. Synthetic anionic surfactant or fatty acid soap in the presence of calcium ions at alkaline pH levels was found to be nearly as effective at deinking as cationic, nonionic, or amphoteric surfactants alone. However, adding calcium ions decreases the deinking effectiveness of cationic, nonionic, and amphoteric surfactants. Increasing the length of the ionic surfactant hydrophobe enhances deinking. Zeta potential measurements showed that water-based ink particles in water reach the point of zero charge (PZC) at a pH of about 3.6, above which ink particles are negatively charged, so cationic surfactant tends to adsorb better on the ink than anionic surfactant above the PZC in the absence of calcium. As the cationic surfactant concentration is varied between 0.005 and 25 mM, the zeta potential of the ink particles reverses from negative to positive owing to adsorption of cationic surfactant. For anionic surfactants, added calcium probably forms a bridge between the negatively charged ink and the negatively charged surfactant head groups, which synergizes adsorption of the surfactant and aids deinking. In contrast, calcium competes for adsorption sites with cationic and nonionic surfactants, which inhibits deinking. All the surfactants studied here disperse ink particles effectively in the washing bath above pH 3 except for the ethoxylated amine surfactant.

Imaging secondary ion mass spectrometry of a paint cross section taken from an early Netherlandish painting by Rogier van der Weyden.

Static secondary ion mass spectrometry (SIMS) is introduced as an analytical technique for the examination of paint cross sections to obtain simultaneous information about the nature and distribution of pigments and the binding medium from a single sample. A sample taken from the virgin's blue robe in the panel painting The Descent from the Cross (Museo del Prado, Madrid) of the Early Netherlandish painter Rogier van der Weyden (1399/1400-1464) was selected for investigation. Data were compared with reference compounds and reference lead white linseed oil paint and egg tempera paint. The static SIMS technique gave position-sensitive mass spectra that were used to image the elemental distribution of pigments and the molecular signature of components of the oleaginous binding medium. SIMS ion images of sodium and aluminum superimposed with the blue pigment ultramarine and those of copper, lead, and calcium with the position of the mineral pigments of azurite, lead white, and chalk, respectively. Preserved monocarboxylic acids of palmitic and stearic acids present as fatty acids and fatty acid lead soaps pointed to the use of linseed oil as a binding medium. Images from the oleaginous binding medium fatty acids show a correlation with the three main paint layers. The observed palmitic/stearic acid ratios for the two ultramarine layers and azurite layers are 1.3, 1.4, and 1.8, respectively. Fatty acids and fatty acid soaps show highest ion yields near lead white, a mineral pigment that serves as a natural chemical drier and is proposed to act as a template for the initial grafting of the polyunsaturated triglycerides of the linseed oil. Almost no fatty acids were detected in other layers visible by light microscopy. The fatty acid lead soaps point toward a mature ionomeric oil paint system that developed over centuries. SIMS evidence for egg tempera, still used in the 15th century, is not detected in the paint cross section. SIMS images correlate well with SEM/EDX, FT-IR and light microscopic images and the SIMS spectral data additionally support the identification of pigment particles, lead soaps, and other binding medium components.

143DIETARY CARBOHYDRATES AND LIPIDS AFFECT IN VITRO EMBRYO PRODUCTION FOLLOWING OPU IN HEIFERS

The superstimulation protocol of Blondin et al. (2002; Biol. Reprod. 66, 38–43) produces cumulus-oocyte complexes (COCs) of high developmental competence for IVP. Using a similar protocol we assessed the affects of alterations in oocyte donor carbohydrate and lipid metabolism during ovarian stimulation on the production and viability of blastocysts in vitro. A 2×2 factorial experiment offered two diets: Fiber (F) and Starch (S) alone (0) or with 6%w/w (6) protected lipid (calcium soaps of fatty acids). Thirty-two heifers ranked by body condition score (scale: 1=thin, 5=obese) were allocated within score to one of the 4 treatments: F0, F6, S0 and S6. COCs were collected 5 days after estrus by OPU for lipid analysis. Ovarian stimulation (4 doses of FSH (9mg NIADDK oFSH) given 12h apart) commenced 2 days later. COCs were collected 40h after the last FSH injection. GnRH (0.012mg Buserelin) was administered i.v. 6h prior to OPU. A second period of ovarian stimulation and OPU then followed. Following IVM/IVF, zygotes were cultured in SOF with 0.3%w/v fatty acid-free BSA under oil (38.8°C, 5% CO2, 5% O2, 90% N) until Day 8 of development, when blastocysts were subjected to total cell counts and TUNEL analysis. Data were analyzed by ANOVA. Neither follicles aspirated (25.9±1.87) nor oocytes recovered (12.1±0.92) differed between treatments. Total fatty acids in plasma were greater (P&amp;lt;0.001) for the F than for the S diets and increased with the inclusion of protected lipid (0.75, 1.82, 0.50 and 1.39μgmL−1 for F0, F6, S0 and S6, respectively; SED=0.076). The dietary lipid-induced increase in plasma fatty acids was reflected in an increase (P&amp;lt;0.05) in total fatty acids within the oocyte (70.4, 74.7, 69.9 and 78.4 ng/oocyte; SED=3.41). Retrospective analysis by body condition indicated that S diets reduced (P=0.006) blastocyst yields in thin heifers and reduced (P=0.02) cleavage rates in fat heifers (Table 1). Blastocyst yields were lower (P=0.1) for fat heifers on the F0 diet. Total cell numbers were greater for thin heifers on S0 than F0 diet. TUNEL-positive cells averaged 4.2±0.48% and did not differ between treatments. In conclusion, modification of oocyte donor carbohydrate and lipid metabolism prior to OPU can influence IVP outcome in a complex manner dependent on body composition. Supported by Defra and The Perry Foundation. Table 1 In vitro blastocyst yields and total cell numbers

Synergism and foaming properties in mixed nonionic/fatty acid soap surfactant systems

The synergism and foaming behavior of a mixed surfactant system consisting of a nonionic surfactant (polyethoxylated alkyl ether C n E m ) and a fatty acid soap (sodium oleate) were studied. The micellar interaction parameter (the β-parameter) was determined from the cmc following the approach of Rubingh's regular solution theory. For both the C 12E 6/sodium oleate and the C 14E 6/sodium oleate mixtures, the results indicate a fairly strong attractive interaction (negative β-values), which were in agreement with previous data reported for other nonionic/anionic surfactant systems. The characteristics of the foam produced from the surfactants were evaluated using a glass column equipped with a series of electrodes measuring the conductance of the foam, which enabled the water content of the foam to be determined. From these measurements, since the total foam volume was almost the same for all concentrations and surfactants, we compared the amount of liquid in the foam produced under dynamic foaming and the ability of the foam to entrain the liquid after the airflow was switched-off (static foam stability). The amount of liquid in the foam 100 s after the air was switched-off followed the order NaOl > C 12E 6 > C 14E 6. Also, the mixtures had the same foam volumes as the pure surfactants at the same concentration. However, both mixtures had higher concentrations of liquid in the foam when the mole fraction of the nonionic surfactant in the mixed surfactant system was greater than about >0.3 in the solution.

The characterisation of lead fatty acid soaps in ‘protrusions’ in aged traditional oil paint

Lead(II) carboxylate soaps of two fatty acids, palmitic (C 15H 31COOH) and stearic acids (C 17H 35COOH), and a dicarboxylic acid, azelaic acid (HOOCC 7H 14COOH), have been synthesised and characterised by FTIR spectroscopy. These acids are all encountered in aged traditional oil paint, the azelaic acid resulting from the oxidative degradation of unsaturated fatty acids in the oil. Lead(II) azelate synthesised by hydrothermal methods was characterised by single crystal structure determination. This has a 3D polymeric structure with lead(II) ions linked by carboxylate bridges to form an infinite stack of (PbO 4) n units. These layers are connected to adjacent layers by an infinite number of parallel C(CH 2) 7C chains arranged perpendicularly to the stacks. The lead(II) ions display an unusual 7-fold coordination. The first direct evidence that the ‘protrusions’ encountered in aged traditional lead-containing oil paints contain lead soaps is reported. Their mechanism of formation is discussed.

Preliminary assessment of alginic acid as a factor buffering triethanolamine interacting with artificial skin sebum

Triethanolamine is an ethanolamine used as counter-ion for fatty acid soaps. Interaction between triethanolamine and free fatty acids is suggested to be useful for cleansing sebaceous follicles in acne prevention. This study describes the preliminary assessment of alginic acid as a factor buffering triethanolamine interacting with stearic acid – a compound of artificial skin sebum. Penetration of triethanolamine into artificial sebum, induced by the above mentioned interaction, was measured using a specific optical method. The values of the penetration depth amounted to 0.07–5.74 mm. pH values were measured. The value of pH is reduced from 10.06 for pure 1.49% (w/w) aqueous triethanolamine solution to 6.61 with the increase of the alginic acid to triethanolamine ratio in the preparations. The data of this in vitro research will support further study on other anionic polymers as factors buffering ethanolamines penetrating artificial skin sebum.

Lead-revealed lipid organization in human hair

Human hair lipids form a complex mixture of composition close to that of sebum. Part of these lipids appears in an organized state that has been studied by diffraction techniques in the literature. Nevertheless, information on the structure of these lipids remains very scarce due to their low contribution to global hair diffraction pattern. Here we show that appropriate lead treatment considerably enhances organized lipid features observed by microbeam synchrotron radiation diffraction experiments. We attribute these features to the formation of lead soaps of free fatty acids. Specific orientation of hair “lipid crystals” in planes parallel to the hair axis is clearly demonstrated. Inclusion of these lipids in the bulk of the hair shaft is shown by diffraction experiments following removal of the cuticular outermost layer of hair. Moreover, microfluorescence and diffraction experiments are consistent with part of the lipids being present as calcium soaps in native hair. We therefore consider lead fixation as a powerful tool to evaluate the lipid organization in human hair for medical, environmental and archaeological purposes, including lead poisoning.

Conjugated bile acid replacement therapy reduces urinary oxalate excretion in short bowel syndrome

Background: Patients with short bowel syndrome (SBS) have steatorrhea, in part because of bile acid malabsorption that causes decreased bile acid secretion into the duodenum and consequent fat maldigestion. In SBS patients with colon in continuity, luminal calcium forms calcium fatty acid soaps rather than precipitating as insoluble calcium oxalate. Soluble oxalate is hyperabsorbed by the colon leading to hyperoxaluria and an increased risk for renal calcium oxalate stones and deposits. The authors hypothesized that oral ingestion of conjugated bile acids would increase fat absorption and thereby decrease calcium fatty acid soap formation and oxalate hyperabsorption. Methods: The effect of conjugated bile acid replacement therapy (9 g/d) on fecal fat excretion and urine oxalate excretion was measured in an appropriate patient, utilizing the metabolic balance technique. The effects of chronic bile acid replacement therapy on oxalate excretion and nutritional status also were measured in a 3-month outpatient study. Results: Natural conjugated bile acid replacement therapy reduced fecal fat excretion from 119 to 79 g/d (Δ40 g/d), and urinary oxalate excretion from 87 to 64 mg/d (966 to 710 μmol/d; Δ23 mg/d). Cholylsarcosine, a synthetic conjugated bile acid, had similar but less powerful effects. During a 3-month outpatient trial of natural conjugated bile acids (9 g/d), urine oxalate decreased to normal levels (27 mg/d) in association with weight gain, decreased hunger, and decreased hyperphagia. Conclusion: Conjugated bile acid replacement therapy reduced fecal fat excretion, reduced urinary oxalate excretion, and improved nutritional status in a patient with SBS with colon in continuity, hyperoxaluria, and oxalate nephrolithiasis. Am J Kidney Dis 41:230-237. © 2003 by the National Kidney Foundation, Inc.

Solid-state13C-NMR analysis of size components in handsheets prepared by fatty acid soap size-alum systems

The mechanism of paper sizing in fatty acid soap size-alum systems was studied by structural analyses of the size components in handsheets prepared with13C-labeled fatty acid soap size. Patterns of sizing performance and aluminum content of the handsheets were similar to those for the rosin soap size-alum sizing systems, although the patterns of calcium content were different. Solid-state13C-nuclear magnetic resonance analysis of the handsheets revealed that fatty acid calcium salt was the predominant size component in the handsheets prepared using tap water. This calcium salt is formed from the fatty acid soap size (fatty acid potassium salt) by ion exchange with calcium ion in pulp suspensions and retained on pulp fibers through aluminum compounds originating from alum added. On the other hand, when deionized water was used, free fatty acid was the major component in the handsheets. Fatty acid aluminum salt was present as a minor component in the handsheets prepared in both tap water and deionized water systems. Therefore, all size components (i.e., fatty acid calcium salt, free fatty acid, fatty acid aluminum salt) seem to contribute to the appearance of sizing features.

Effects of calcium salts of fatty acids on follicular characteristics and several blood parameters in two fat-tailed sheep breeds

There is substantial evidence that the increased consumption of fat by dairy cattle can result in an increase in the number ovarian follicles, and the number and size of corpora lutea; it also stimulates post-partum ovarian activity and improve pregnancy rate. Increased dietary lipid also increases plasma cholesterol and progesterone, and the supply of lipoproteins which play significant roles in regulating ovarian steroidogenesis (Willimas, 1996). In contrast to cattle, there are few observations on the effects of dietary lipid on reproductive function in sheep. Intravascular infusion of lipid into ewes stimulated progesterone and prostaglandin synthesis (Burke et al., 1996), and dietary supplementation of calcium soaps of fatty acids enhanced luteal function (Kuran et al., 1999). Calcium soaps of fatty acids have been manufactured in Iran in recent years and sold under the trade name of Megalac. The aim of the present experiment was to study the effects of this protected fat on follicular number and luteal activity in two fat-tailed sheep breeds.

Extraction of Material from Oil Paints by Solvents

ABSTRACTDrying oils used to formulate oil paints consist primarily of polyunsaturated triglycerides, along with smaller amounts of mono- and diglycerides, free fatty acids, and other compounds such as sterols. The drying of oils occurs through an oxidative crosslinking process that also produces smaller scission products such as short chain fatty acids and diacids. Compounds that are not attached to the crosslinked oil matrix include glycerin, the unreactive free saturated fatty acids and their glycerides, soaps of fatty acids produced by reaction with metal ions from the pigment, and scission products. As the oil ages, additional soluble material is produced by hydrolysis of glyceride esters. These relatively low molecular weight compounds can be extracted by exposure to solvents, as occurs during the cleaning of paintings. Excessive extraction of material canembrittle the paint film and affect the appearance of the paint. This paper examines the types and amounts of compounds extracted from oil paint films as a function of solvent, exposure time, pigment, and age of the paint. The results indicate that solvents vary more in the speed that they extract material than in their selectivity. The composition of the extracts is consistent with predictions based on the mechanisms of the drying and aging processes. These results confirm the importance of using the least polar solvent possible to clean paintings and to formulate varnishes.