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Sample records for cholesteryl ester andtriglyceride-rich

  1. Cultured human astrocytes secrete large cholesteryl ester- andtriglyceride-rich lipoproteins along with endothelial lipase

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Lin; Liu, Yanzhu; Forte, Trudy M.; Chisholm, Jeffrey W.; Parks, John S.; Shachter, Neil S.

    2003-12-01

    We cultured normal human astrocytes and characterized their secreted lipoproteins. Human astrocytes secreted lipoproteins in the size range of plasma VLDL (Peak 1), LDL (Peak 2), HDL (Peak 3) and a smaller peak (Peak 4), as determined by gel filtration chromatography, nondenaturing gradient gel electrophoresis and transmission electron microscopy. Cholesterol enrichment of astrocytes led to a particular increase in Peak 1. Almost all Peak 2, 3 and 4 cholesterol and most Peak 1 cholesterol was esterified (unlike mouse astrocyte lipoproteins, which exhibited similar peaks but where cholesterol was predominantly non-esterified). Triglycerides were present at about 2/3 the level of cholesterol. LCAT was detected along with two of its activators, apolipoprotein (apo) A-IV and apoC-I. ApoA-I and apoA-II mRNA and protein were absent. ApoJ was present equally in all peaks but apoE was present predominantly in peaks 3 and 4. ApoB was not detected. The electron microscopic appearance of Peak 1 lipoproteins suggested partial lipolysis leading to the detection of a heparin-releasable triglyceride lipase consistent with endothelial lipase. The increased neuronal delivery of lipids from large lipoprotein particles, for which apoE4 has greater affinity than does apoE3, may be a mechanism whereby the apoE {var_epsilon}4 allele contributes to neurodegenerative risk.

  2. Cholesteryl ester transfer activity. Localization and role in distribution of cholesteryl ester among lipoproteins in man.

    Science.gov (United States)

    Groener, J E; Van Rozen, A J; Erkelens, D W

    1984-03-01

    The cholesteryl ester exchange/transfer protein is involved in the transport of cholesteryl ester from high density lipoproteins (HDL) to very low density lipoproteins (VLDL) and low density lipoproteins (LDL). Localization of cholesteryl ester transfer activity (CETA) in plasma was studied by measuring CETA in various delipidated fractions from a single step density ultracentrifugation gradient of plasma. CETA was measured in an in vitro system by calculating the exchange of cholesteryl ester in a standard mixture of [3H]CE-HDL and LDL. The method used for the delipidation of plasmas and fractions to be tested was critical. Optimal results were obtained by delipidation with diisopropylether-butanol (60: 40, v/v) at O degrees C. The bulk of CETA was detected in HDL3 (1.125 less than d less than 1.210 g/ml) when the lipoproteins were separated by single-step density gradient ultracentrifugation and in the 'lipoprotein-free' fraction (d greater than 1.250 g/ml) when the lipoproteins were separated by flotation ultracentrifugation including two washes. To determine whether CETA plays a role in the distribution of cholesteryl ester among the various lipoproteins, it was measured in whole plasma from normal and hyperlipidemic subjects. Plasma was delipidated before the assay in order to prevent bias due to variation of cholesterol content. CETA was higher in delipidated plasma of hyperlipidemic subjects (117.3 +/- 36.5 nmol CE/ml/h) than in delipidated plasma of normolipidemic controls (68.7 +/- 17.6 nmol CE/ml/h) (P less than 0.005). A positive correlation (r = 0.80, P less than 0.005) was found between CETA and (VLDL + LDL) cholesterol levels. A negative correlation (r = 0.57, P less than 0.05) existed between CETA and HDL cholesterol. This correlation was found both in the group as a whole and within the normal and the hyperlipidemic groups separately. The activity of the cholesteryl ester transfer appears to be a regulatory factor in the distribution of cholesteryl

  3. Anaerobic degradation kinetics of a cholesteryl ester.

    Science.gov (United States)

    Gutiérrez, S; Viñas, M

    2003-01-01

    The most important components of wool scouring effluent grease are esters of sterols. Cholesteryl palmitate (CP) is the main ester in this grease. In this paper, the influence of the ester concentration in the anaerobic digestion and the relative rate of the different degradation steps, are studied. The experiment was carried out to measure methane production in the anaerobic degradation of acetate, palmitic acid (PA) and CP. A first-order kinetic model was assumed for hydrolysis and Monod models were assumed for both the methanogenic and acetogenic steps. Maximum hydrolysis rate was found to be around 20 times faster than the maximum methanogenic reaction rate during the experience. The lanolin emulsion drop size effect was also evaluated employing fine and coarse stock lanolin emulsions and no adapted sludge. Concentrations of 13.7 to 4.6 gCOD x l(-1) were employed. In a previous study, the effect of palmitic acid emulsion size was found important when similar sludge was tested. When esters are degraded, a significant effect of drop size on the degradation rate was not found. The difference between CP and PA emulsions behavior could be due to the fact that cholesterol produced during the ester degradation has a protective effect on the sludge. PMID:14640211

  4. Mechanism of plasma cholesteryl ester transfer in hypertriglyceridemia.

    OpenAIRE

    Mann, C J; Yen, F T; Grant, A M; Bihain, B E

    1991-01-01

    Plasma net cholesteryl ester (CE) transfer and optimum cholesteryl ester transfer protein (CETP) activity were determined in primary hypertriglyceridemic (n = 11) and normolipidemic (n = 15) individuals. The hypertriglyceridemic group demonstrated threefold greater net CE transfer leading to enhanced accumulation of CE in VLDL. This increased net transfer was not accompanied by a change in CETP activity. In normolipidemia, but not in hypertriglyceridemia, net CE transfer correlated with VLDL ...

  5. How Well Does BODIPY-Cholesteryl Ester Mimic Unlabeled Cholesteryl Esters in High Density Lipoprotein Particles?

    DEFF Research Database (Denmark)

    Karilainen, Topi; Vuorela, Timo; Vattulainen, Ilpo

    2015-01-01

    the partitioning of CE between HDL and the water phase. However, BODIPY-CE was observed to diffuse more slowly and locate itself closer to the HDL-water interface than CE due to the BODIPY probe that is constrained to the surface region, and because the CE body in BODIPY-CE prefers to align itself......We compare the behavior of unlabeled and BODIPY-labeled cholesteryl ester (CE) in high density lipoprotein by atomistic molecular dynamics simulations. We find through replica exchange umbrella sampling and unbiased molecular dynamics simulations that BODIPY labeling has no significant effect on...

  6. The micromethod for determination of cholesterol, cholesteryl esters and phospholipids

    Directory of Open Access Journals (Sweden)

    Okabe,Akinobu

    1974-12-01

    Full Text Available We examined the method for determining microquantities of lipids, including cholesterol, cholesteryl esters and phospholipids. A standard colorimetric procedure of cholesteryl esters was modified to accommodate a quantitative thin-layer chromatography. This method involved the following steps. (1 Separation of lipids by a thin-layer chromatography: Lipids were applied to Silica gel G plates. Plates were developed with petroleum ether-diethyl etheracetic acid (82: 18: 2, vIvIv. (2 Elution of cholesterol and its esters from scraped silica gel: After scraping the silica gel with adhered cholesterol and its esters, they were eluted with chloroform-methanol (4: 1, v,tv. In the case of phspholipids, the silica gel was calcified. (3 Colorimetric determination of the lipids: Cholesterol and its esters eluted from the silica gel were determined by the method of ZAK with ROSENTHAL'S color reagent directly and after saponification, respectively. Phospholipids were calculated from the phosphorous content determined by the method of KATES. On the basis of examination of recovery and analyses of lipids extracted from tissue, it was concluded that this method permitted a reliable estimation of microquantities of cholesterol, its esters and phospholipids from small amounts of biological materials.

  7. Preferential enrichment of large-sized very low density lipoprotein populations with transferred cholesteryl esters

    International Nuclear Information System (INIS)

    The effect of lipid transfer proteins on the exchange and transfer of cholesteryl esters from rat plasma HDL2 to human very low (VLDL) and low density (LDL) lipoprotein populations was studied. The use of a combination of radiochemical and chemical methods allowed separate assessment of [3H]cholesteryl ester exchange and of cholesteryl ester transfer. VLDL-I was the preferred acceptor for transferred cholesteryl esters, followed by VLDL-II and VLDL-III. LDL did not acquire cholesteryl esters. The contribution of exchange of [3H]cholesteryl esters to total transfer was highest for LDL and decreased in reverse order along the VLDL density range. Inactivation of lecithin: cholesterol acyltransferase (LCAT) and heating the HDL2 for 60 min at 56 degrees C accelerated transfer and exchange of [3H]cholesteryl esters. Addition of lipid transfer proteins increased cholesterol esterification in all systems. The data demonstrate that large-sized, triglyceride-rich VLDL particles are preferred acceptors for transferred cholesteryl esters. It is suggested that enrichment of very low density lipoproteins with cholesteryl esters reflects the triglyceride content of the particles

  8. Radioiodinated cholesteryl ester analogs as residualizing tracers of lipoproteins disposition

    International Nuclear Information System (INIS)

    Due to the importance of low density lipoprotein (LDL) in lipid metabolism and atherosclerosis, efforts were made to incorporate 125I-cholesteryl iopanoate (125I-CI), a residualizing cholesteryl ester (CE) analog, into the lipid core of LDL. This preparation is potentially useful as a scintigraphically detectable tracer of LDL uptake into atheroma and tissues such as the adrenal and liver. Initial studies using a cholesterol-fed rabbit model of atherosclerosis validated the use of 125I-CI as a tracer of CE deposition. However, scintigraphy revealed considerable nonspecific 125I-CI uptake due to tissue cholesterol loading. An alternative animal model was the guinea pig, which responds moderately to cholesterol feeding and carries the plasma cholesterol predominantly as LDL. Dietary fat and cholesterol, coupled with chronic aortic injury caused by an indwelling catheter, resulted in lipid containing, smooth muscle cell proliferative lesions in many animals. However, further studies are necessary to fully characterize this model. In additional studies, in vitro methods for incorporating 125I-CI into LDL were examined. These included a reconstitution procedure described by Krieger et al. and a procedure involving incubation of detergent (Tween 20)-solubilized 125I-CI with plasma. Although both LDL preparations were taken up normally by cultured fibroblasts, the plasma clearance rate of reconstituted LDL was markedly abnormal in guinea pigs. In contrast, LDL labeled by the detergent method cleared from the plasma identically to a radioiodinated LDL control. Therefore, this latter procedure was also used to incorporate two novel radioiodinated cholesteryl ether analogs 125I-CI cholesteryl m-iodobenzyl ether [125I-CIDE] and 125I-cholesteryl 12-(miodophenyl)dodecyl ether [125I-CIDE] into LDL

  9. ESR studies on the orientation of cholesteryl ester in phosphatidylcholine multilayers.

    Science.gov (United States)

    Grover, A K; Forrest, B J; Buchinski, R K; Cushley, R J

    1979-01-19

    The alignment of cholesteryl esters in multilayer phosphatidylcholine membranes was investigated using two spin-labelled cholesteryl esters: 10 : 3 ester (I) and 1 : 14 ester (II). The nitroxide label of I is aligned in the membrane with a very large angle of tilt (47 degrees +/- 1.5 degrees) with respect to the normal to the membrane surface; II does not show such a tilt. I gives spectra corresponding to immobilized label while II gives nearly isotropic spectra. Ascorbate treatment of the multilayers shows that the labels in I and II are not present at the phosphatidylcholine-water interphase. The data supports a 'horseshoe' configuration for the cholesteryl ester in the bilayer, with both the fatty acid chain and the cholesteryl moiety extending deep into the hydrophobic region of the membrane and with the ester linkage near the surface. PMID:215228

  10. Neutral-lipid transfers and cholesteryl ester transfer protein in hemodialyzed patients.

    Science.gov (United States)

    Reade, V; Mezdour, H; Reade, R; Kandoussi, M; Dracon, M; Fruchart, J C; Cachera, C

    1996-01-01

    Abnormalities in cholesteryl ester transfers may play a role in the development of atherosclerosis observed in patients with end-stage renal failure treated by chronic hemodialysis. Net neutral-lipid transfers and cholesteryl ester transfer protein activity and mass were investigated in 20 hemodialyzed patients, arbitrarily divided into two groups based on fasting triglyceride levels, and compared to triglyceride-matched control groups. In the hypertriglyceridemic subjects (plasma triglyceride values > 150 mg/dl), high-density lipoprotein cholesterol was decreased, and the net cholesteryl ester transfer rates were significantly higher than the rates in normolipidemic subjects. The comparison of subjects matched for plasma triglyceride and cholesterol levels showed no significant difference in cholesteryl ester or triglyceride transfer rates between patients and controls. Our results suggest that normal or elevated net neutral-lipid transfers are not related to the renal status of the subjects, but rather to their plasma triglyceride levels. PMID:8886176

  11. [3H]cholesteryl ester labeling and transfer among human and honhuman primate plasma lipoproteins

    International Nuclear Information System (INIS)

    Aliquots of human and nonhuman primate plasma containing 5,5'-dithiobis (2-nitrobenzoic acid) were incubated at 370C in tubes previously coated with trace amounts of tritium-labeled cholesteryl oleate ([3H]CO). Initially, cholesteryl esters were transferred at a rapid rate into plasma after which the rate slowed. During 24 h of incubation, an average of 55% of the [3H]CO transferred from the side of the tube into African green monkey plasma, 44% into human plasma and 21% into rat plasma. Greater than 98% of the radioactive ester transferred into plasma was found to be associated with plasma lipoproteins that were then rapidly separated using vertical rotor density gradient ultracentrifugation. In very low density lipoprotein (VLDL)-poor plasma after 30 min incubations, high density lipoproteins (HDL) contained most of the [3H]CO while 5- to 24-h incubations resulted in increased labeling of low density proteins (LDL). In VLDL-rich plasma, it was found that in addition to the labeling of HDL, VLDL contained about 25% of the labeled cholesteryl esters after 30-min incubations and, as above, the proportion in LDL subsequently increased. Compositional analyses showed that intermediate-sized LDL (ILDL) were accumulating cholesteryl ester mass while transfer occurred. LDL labeled using this method were injected intravenously into monkeys and their removal from plasma was found to be similar to that found for LDL labeled in vivo. It was concluded that this method of plasma lipoprotein cholesteryl ester labeling, presumably a result of cholesteryl ester transfer protein activity, was efficient, resulted in lipoproteins labeled only in the cholesteryl ester moiety, and induced minimal modification of lipoprotein particles that did not alter their biological activity

  12. Improved estimation of cholesteryl ester transfer/exchange activity in serum or plasma

    International Nuclear Information System (INIS)

    This simple, routine assay for measuring cholesteryl ester transfer/exchange activity in human plasma is based on the removal of interfering lipoproteins--very-low-density (VLDL) and low-density lipoproteins (LDL)--by precipitation with polyethylene glycol. High-density lipoproteins (HDL) in the samples do not affect the results. The supernate after precipitation is mixed with [14C]cholesteryl ester-labeled LDL as donor and with HDL as the acceptor for the cholesteryl ester. After incubation for 16 h at 37 degrees C, LDL is separated from HDL by precipitation with dextran sulfate and the radioactivity measured in the supernate, which contains the HDL. The assay is applicable to samples containing as much as 10 mmol of triglycerides per liter. The within-assay CV was 2.7%, the day-to-day CV 6.8%. Results compared well with those by conventional procedures

  13. Plasma cholesteryl ester transfer protein mass and phospholipid transfer protein activity are associated with leptin in type 2 diabetes mellitus

    NARCIS (Netherlands)

    Dullaart, R. P. F.; de Vries, R.; Dallinga-Thie, G. M.; van Tol, A.; Sluiter, W. J.

    2007-01-01

    Adipose tissue contributes to plasma levels of lipid transfer proteins and is also the major source of plasma adipokines. We hypothesized that plasma cholesteryl ester transfer protein (CETP) mass, phospholipid transfer protein (PLTP) activity and cholesteryl ester transfer (CET, a measure of CETP a

  14. In vitro incorporation of radiolabeled cholesteryl esters into high and low density lipoproteins

    International Nuclear Information System (INIS)

    We have developed and validated a method for in vitro incorporation of radiolabeled cholesteryl esters into low density (LDL) and high density lipoproteins (HDL). Radiolabeled cholesteryl esters dissolved in absolute ethanol were mixed with LDL or HDL in the presence of lipoprotein-deficient serum (LPDS) as a source of core lipid transfer activity. The efficiency of incorporation was dependent on: (a) the core lipid transfer activity and quantity of LPDS, (b) the mass of added radiolabeled cholesteryl esters, (c) the length of incubation, and (d) the amount of acceptor lipoprotein cholesterol. The tracer incorporation was documented by repeat density gradient ultracentrifugation, agarose gel electrophoresis, and precipitation with heparin-MnCl2. The radiolabeling conditions did not affect the following properties of the lipoproteins: (1) chemical composition, (2) electrophoretic mobility on agarose gels, (3) hydrated density, (4) distribution of apoproteins on SDS gels, (5) plasma clearance rates, and (6) immunoprecipitability of HDL apoproteins A-I and A-II. Rat HDL containing radiolabeled cholesteryl esters incorporated in vitro had plasma disappearance rates identical to HDL radiolabeled in vivo

  15. Cholesteryl ester transfer protein, low density lipoprotein particle size and intima media thickness in patients with coronary heart disease

    OpenAIRE

    Tosheska, Katerina; Labudovic, Danica; Jovanova, Silvana; Jaglikovski, Branko; Alabakovska, Sonja

    2011-01-01

    Cholesteryl ester transfer protein (CETP) plays a key role in reverse cholesterol transport and high density lipoprotein (HDL) metabolism. Predominance of small, dense LDL particles is associated with an increased risk of atherosclerosis and coronary heart disease (CHD).

  16. Kinetics of Non-Isothermal Crystallization of Coconut-based Cholesteryl Ester: Avrami and Ozawa Approache

    OpenAIRE

    J. F. Joson; L. T. Davila; Z. B. Domingo

    2003-01-01

    Kinetics of non-isothermal crystallization of coconut-based cholesteryl ester was performed by differentialscanning calorimetry under various heating rates. Different analysis methods were used to describe theprocess of non-isothermal crystallization. The results showed that the Avrami equation could describe thesystem very well. However, the Ozawa analysis failed. A probable reason is the difference in the crystallizationkinetics at high and low relative crystallization. The phase transition...

  17. Lecithin:Cholesterol Acyltransferase Activity and Cholesteryl Ester Transfer Rate in Patients with Diabetes Mellitus

    OpenAIRE

    DİRİCAN, Melahat

    2003-01-01

    Several factors may be responsible for the high prevalence of atherosclerosis in diabetes mellitus, including alterations in reverse cholesterol transport. In the present study, the activity of plasma lecithin:cholesterol acyltransferase (LCAT) and the cholesteryl ester transfer rate, and concentrations of lipids and lipoproteins were measured in 11 patients with insulin-dependent diabetes mellitus (type 1), 42 patients with noninsulin-dependent diabetes mellitus (type 2) and compared with th...

  18. Comparison of methods for incorporating a radioiodinated residualizing cholesteryl ester analog into low density lipoprotein

    International Nuclear Information System (INIS)

    Two different methods were evaluated for incorporating [125I]cholesteryl iopanoate([I125I]CI), a non-hydrolyzable cholesteryl ester analog, into LDL. The first procedure was an organic solvent delipidation-reconstitution procedure (R[125I-CI]LDL) while the second involved incubation of detergent (Tween-20) solubilized [125I]CI with whole plasma (D[125I-CI]LDL). R [125I-CI]LDL behaved similar to native LDL in vitro, but was markedly different in vivo, apparently due to a heterogeneity in particle size. D[125I-CI]LDL, however, was metabolized normally both in vitro and in vivo. These results, combined with the residualizing nature of [125I]CI, demonstrate that D[125I-CI]LDL is appropriate for tracing LDL uptake in vivo. (Author)

  19. How anacetrapib inhibits the activity of the cholesteryl ester transfer protein? Perspective through atomistic simulations.

    Directory of Open Access Journals (Sweden)

    Tarja Äijänen

    2014-11-01

    Full Text Available Cholesteryl ester transfer protein (CETP mediates the reciprocal transfer of neutral lipids (cholesteryl esters, triglycerides and phospholipids between different lipoprotein fractions in human blood plasma. A novel molecular agent known as anacetrapib has been shown to inhibit CETP activity and thereby raise high density lipoprotein (HDL-cholesterol and decrease low density lipoprotein (LDL-cholesterol, thus rendering CETP inhibition an attractive target to prevent and treat the development of various cardiovascular diseases. Our objective in this work is to use atomistic molecular dynamics simulations to shed light on the inhibitory mechanism of anacetrapib and unlock the interactions between the drug and CETP. The results show an evident affinity of anacetrapib towards the concave surface of CETP, and especially towards the region of the N-terminal tunnel opening. The primary binding site of anacetrapib turns out to reside in the tunnel inside CETP, near the residues surrounding the N-terminal opening. Free energy calculations show that when anacetrapib resides in this area, it hinders the ability of cholesteryl ester to diffuse out from CETP. The simulations further bring out the ability of anacetrapib to regulate the structure-function relationships of phospholipids and helix X, the latter representing the structural region of CETP important to the process of neutral lipid exchange with lipoproteins. Altogether, the simulations propose CETP inhibition to be realized when anacetrapib is transferred into the lipid binding pocket. The novel insight gained in this study has potential use in the development of new molecular agents capable of preventing the progression of cardiovascular diseases.

  20. Kinetics of Non-Isothermal Crystallization of Coconut-based Cholesteryl Ester: Avrami and Ozawa Approache

    Directory of Open Access Journals (Sweden)

    J. F. Joson

    2003-06-01

    Full Text Available Kinetics of non-isothermal crystallization of coconut-based cholesteryl ester was performed by differentialscanning calorimetry under various heating rates. Different analysis methods were used to describe theprocess of non-isothermal crystallization. The results showed that the Avrami equation could describe thesystem very well. However, the Ozawa analysis failed. A probable reason is the difference in the crystallizationkinetics at high and low relative crystallization. The phase transitions of the coconut-based cholesterylester were also observed through optical polarizing microscopy

  1. Cholesteryl ester transfer activity in plasma measured by using solid-phase-bound high-density lipoprotein

    International Nuclear Information System (INIS)

    We studied the ability of lipid-transfer factors in plasma to promote transfer, to endogenous lipoproteins, of [3H]cholesteryl ester from high-density lipoprotein (HDL) covalently bound to Sepharose 4B beads. After incubation for 2 h at 37 degrees C, 12 to 14% of the [3H]cholesteryl ester had been transferred to the lipoproteins of the plasma, in the proportions 57% to HDL and 43% to low- and very-low-density lipoproteins. This process was a function of the amount of plasma present and was stimulated by addition of partly purified lipid-transfer protein. Transfer also depended on the concentration of donor HDL but was independent of the amount of acceptor lipoprotein. This simple evaluation of cholesteryl ester transfer does not require removal of lipoproteins from the plasma before incubation

  2. Plasma cholesteryl ester transfer is a determinant of intima-media thickness in type 2 diabetic and nondiabetic subjects: Role of CETP and triglycerides

    NARCIS (Netherlands)

    R. de Vries (Rindert); F.G. Perton (Frank G.); G.M. Dallinga-Thie (Geesje); A.M.M. van Roon (Arie); B.H.R. Wolffenbuttel (Bruce); A. van Tol (Arie); R.P.F. Dullaart (Robin)

    2005-01-01

    textabstractWe tested whether carotid artery intima-media thickness (IMT) is associated with plasma cholesteryl ester transfer (CET) and/or the plasma cholesteryl ester transfer protein (CETP) concentration in type 2 diabetic and control subjects. In 87 male and female subjects with type 2 diabetes

  3. In vivo transfer of cholesteryl ester from high and low density plasma lipoproteins into human aortic tissue

    International Nuclear Information System (INIS)

    For the study of cholesteryl ester transfer from different plasma lipoproteins into human aortic tissue, patients scheduled for reconstructive aortic surgery were intravenously injected with autologous in vitro labeled lipoproteins 20 to 24 hours before aortic intima-media samples were obtained during the operation. The injectate contained high density lipoproteins (d greater than 1.063) labeled with 3H-cholesteryl ester and lipoproteins of lower density (d less than 1.063) labeled with 14C-cholesteryl ester or lipoproteins with the opposite labeling. In 16 aortic tissue samples (some with visible atherosclerosis) from 11 normocholesterolemic patients, the aortic influx of total cholesteryl ester was 1 to 50 nmol x cm-2 x day-1. Some 39% +/- 3% (mean +/- SEM) of the influx was derived from high density lipoproteins, which in plasma accounted for only 22% +/- 2% (mean +/- SEM) of the esterified cholesterol. The findings suggest that: 1) esterified cholesterol from the two lipoprotein fractions in plasma enter the aortic intima by the same mechanism, and 2) influx of cholesteryl ester from the smaller, high density lipoproteins is greater than influx from the larger, lower density lipoproteins considering their concentrations in plasma. In some patients, the cholesterol content in the intima-media tissue with no visible atherosclerosis corresponded to only a few months of continuous cholesteryl ester influx. This time is short considering the age of the patients and, therefore, indicates that removal of esterified cholesterol from the intima-media is of major importance in preventing cholesterol deposition in the arterial wall

  4. Statin and Fibrate Combination Does not Additionally Lower Plasma Cholesteryl Ester Transfer in Type 2 Diabetes Mellitus

    NARCIS (Netherlands)

    de Vries, Rindert; Dikkeschei, Bert D.; Sluiter, Wim J.; Dallinga-Thie, Geesje M.; van Tol, Arie; Dullaart, Robin P. F.

    2012-01-01

    Background: Plasma cholesteryl ester transfer (CET) from high density lipoproteins (HDL) to very low and low density lipoproteins (VLDL+LDL) may predict (subclinical) atherosclerosis. We tested the extent to which plasma CET and cholesterol esterification (EST) are decreased by statin and fibrate co

  5. Cholesteryl ester accumulation in macrophages incubated with low density lipoprotein pretreated with cigarette smoke extract

    International Nuclear Information System (INIS)

    Although cigarette smoking is one of the major risk factors for atherosclerosis and coronary heart disease, the precise mechanisms of its adverse effects have not been fully elucidated. We incubated low density lipoprotein (LDL) with cigarette smoke (CS) extract and examined the incorporation of the lipoprotein by macrophages in vitro. When incubated with macrophages, LDL pretreated with CS extract (100 micrograms/ml) stimulated cholesteryl [14C]oleate synthesis approximately equal to 12.5-fold that with unmodified LDL and transformed macrophages to cells rich in lipid droplets positively stained with oil red O. Enhancement in cholesteryl ester synthesis was dependent on the concentration of CS-modified LDL and exhibited saturation kinetics. When subjected to electrophoreses, CS-modified LDL migrated to a more anionic position than did unmodified LDL and showed extensive fragmentation of apolipoprotein B. This LDL modification depended upon the incubation time and concentration of the CS extract. Superoxide dismutase inhibited modification of LDL by 52%, suggesting that superoxide anion is, at least in part, involved. These results suggest that CS extract alters LDL into a form recognized and incorporated by macrophages. Such modification if it occurs in vivo, could explain the increased incidence of atherosclerosis and coronary heart disease in smokers

  6. Severe chronic diarrhea and weight loss in cholesteryl ester storage disease: A case report

    Institute of Scientific and Technical Information of China (English)

    Uta Drebber; Matthias Andersen; Hans U Kasper; Peter Lohse; Manfred Stolte; Hans P Dienes

    2005-01-01

    AIM: An inherited deficiency of human lysosomal acid lipase (LAL)results in the rare conditions of Wolman disease and cholesteryl ester storage disease (CESD). We want to present the rare case of CESD in an adult.METHODS: We report about an adult female patient with severe chronic diarrhea and weight loss as a consequence of CESD. Clinical examination revealed signs of malabsorption and slightly elevated liver enzymes.RESULTS: Histopathologic changes in the liver tissue and DNA sequence analysis confirmed the diagnosis of CESD due to homozygosity for the most common CESD mutation,a G934A splice site defect encoded by exon 8 of the lysosomal acid lipase (LIPA) gene.CONCLUSION: It is the first case in the literature with diarrhea as a putative symptom of CESD in adult patients.

  7. Cholesteryl ester hydroperoxides increase macrophage CD36 gene expression via PPARα

    International Nuclear Information System (INIS)

    The uptake of oxidized LDL by macrophages is a key event in the development of atherosclerosis. The scavenger receptor CD36 is one major receptor that internalizes oxidized LDL. In differentiated human macrophages, we compared the regulation of CD36 expression by copper-oxidized LDL or their products. Only oxidized derivatives of cholesteryl ester (CEOOH) increased the amount of CD36 mRNA (2.5-fold). Both oxidized LDL and CEOOH treatment increased two to fourfold the transcription of promoters containing peroxisome-proliferator-activated-receptor responsive elements (PPRE) in the presence of PPARα or γ. Electrophoretic-mobility-shift-assays with nuclear extracts prepared from macrophages treated by either oxidized LDL or CEOOH showed increased binding of PPARα to the CD36 gene promoter PPRE. In conclusion, CEOOH present in oxidized LDL increase CD36 gene expression in a pathway involving PPARα

  8. Expression and secretion of rabbit plasma cholesteryl ester transfer protein by Pichia pastoris.

    Science.gov (United States)

    Kotake, H; Li, Q; Ohnishi, T; Ko, K W; Agellon, L B; Yokoyama, S

    1996-03-01

    The rabbit cholesteryl ester transfer protein (CETP) was expressed in the methylotrophic yeast Pichia pastoris by introducing the CETP cDNA under the control of the methanol-inducible alcohol oxidase promoter. The cDNA was cloned from in vitro amplified cDNA of rabbit liver mRNA. The nucleotide sequence of the cloned cDNA differed slightly from the previously published sequence that changed the amino acid sequence in six residues. Interestingly, five of these replacements are identical to the corresponding residues in human CEPT. In addition, the encoded mature N-terminal sequence was changed from Cys- to Arg-Glu-Phe- to link the CETP sequence to the yeast acid phosphatase signal peptide. The culture medium of the transformed cells induced with 1% methanol contained both cholesteryl ester and triglyceride transfer activity comparable to that of rabbit plasma. Like rabbit plasma, the lipid transfer activity in the medium could be inhibited by monoclonal antibodies that block CE/TG transfer or TG transfer alone. Immunoblot analysis of M(r) = 80 K and minor species of M(r) = 60-100 K. In spite of these differences, the specific transfer activity of the recombinant CETP was indistinguishable from that of rabbit plasma CETP of M(r) = 74 K. N-Glycosidase F treatment converted both the recombinant and plasma CETP to a single species of M(r) = 55 K. Both the plasma and recombinant CETP lost their activity after removal of N-linked carbohydrate and sialic acid. A single 55 K component was found in the cell-lysates. The intracellular form of the recombinant CETP was not modified by N-glycosidase F treatment. In conclusion, the recombinant CETP is synthesized as an inactive polypeptide that is processed and secreted as a functional glycoprotein. In addition, the N-terminal Cys residue of the plasma CETP is not required for its activity. PMID:8728322

  9. Lysosomal acid lipase deficiency: diagnosis and treatment of Wolman and Cholesteryl Ester Storage Diseases.

    Science.gov (United States)

    Porto, Anthony F

    2014-09-01

    Lysosomal acid lipase (LAL) is responsible for the hydrolysis of cholesterol esters and triglycerides. LAL is coded by the LIPA gene on chromosome 10q23.31. Its deficiency leads to two autosomal recessive disorders, Wolman disease (WD) and Cholesteryl Ester Storage Disease (CESD). WD has an estimated incidence of 1 in 500,000 live births and is the result of a complete loss of LAL and presents in infancy with vomiting, diarrhea, poor weight gain and hepatomegaly subsequently leading to death. CESD is the result of partial loss of LAL and its presentation is more variable. Patients may be asymptomatic or present with nonspecific gastrointestinal symptoms, hepatomegaly, elevated transaminases and dystipidemia which may be confused with the diagnosis of Non-alcoholic Fatty Liver Disease. CESD is currently underdiagnosed and has an estimated prevalence as high as I in 40,000 individuals. Radiologic findings in WD is calcification of the adrenal glands. Hepatomegaly is noted on CT scan in both WD and CESD. MRI may demonstrate accumulation of cholesterol esters and may be useful to study effects of potential medical therapies. The diagnosis of WD and CESD is based on LIPA gene sequencing and the measurement of LAL levels in peripheral blood leukocytes. Treatment of LAL deficiency is currently limited to control of cholesterol levels and to prevent premature atherosclerosis. Use of enzyme replacement therapy with recombinant human LAL in short-term studies has shown to be safe and effective. PMID:25345094

  10. Use of 3H-cholesteryl linoleyl ether as a quantitative marker for loss of cholesteryl ester during regression of cholesterol-induced aortic atheromas in rabbits

    International Nuclear Information System (INIS)

    In this study, use was made of 3H-cholesteryl linoleyl ether (3H-CLE) to follow regression of aortic atheromatosis induced by feeding cholesterol to rabbits. After a 3-month induction period, the rabbits were divided into two groups with an attempt to match them by plasma cholesterol levels. They were injected with rabbit plasma labeled with 3H-CLE, and the baseline group rabbits were killed 10 to 12 days after injection. The experimental (regression) group rabbits were given rabbit chow containing 3% cholestyramine and were killed up to 330 days thereafter. Aortic 3H-CLE of both the baseline and the regression groups correlated highly with the plasma cholesterol levels at the time of injection of label. The radioactivity recovered in the aortas of the baseline and regression groups was not significantly different, indicating retention of label between day 12 and 330 days after injection. During that time, the mean aortic cholesteryl ester content decreased from 7.6 +/- 1.3 mg to 3.1 +/- 0.7 mg (p less than 0.01). The specific activity of 3H-CLE/cholesteryl ester determined in the aortic arch and the thoracic and abdominal aorta was significantly increased in all three regions examined in the regression group as compared to the baseline group. The present data show that 3H-CLE is retained in the atheromatous aorta for at least 330 days and that its use may add another dimension to the quantitative evaluation of regression of atherosclerotic lesions

  11. Estrogen suppression of I-125-cholesteryl ester uptake in atherosclerotic lesions in a rabbit model

    International Nuclear Information System (INIS)

    Cholesteryl esters (CE) are the principal lipids found in atherosclerotic lesions. A nonhydrolyzable CE analog, I-125-cholesteryl iopanoate (I-125-CI), that is rapidly associated with circulating lipoproteins was administered to New Zealand White rabbits rendered hypercholesterolemic to assess the effect of hypercholesterolemia and estrogen therapy upon the uptake of CI into developing atherosclerotic lesions. Atherosclerosis (A) was induced by aortic deendothelialization in 10 rabbits with a balloon embolectomy catheter introduced via the femoral artery, followed by a 2% cholesterol-enriched diet. Five of these 10 rabbits were treated with estradiol (AE) (0.5mg/Kg/week x 5); an additional 4 animals served as untreated, non-A controls. I-125-CI was administered intravenously in multiple doses over a 5 week interval. Gamma camera images and selected tissues were obtained 6 days after the completion of I-125-CI administration (total cumulative dose 82.6-87.3μCi/rabbit). Plasma cholesterol levels were 268 +- 162, 1940 +- 248 and 2484 +- 209 mg/dl in the untreated controls, A and AE groups, respectively. Atherosclerotic aortas were readily visualized in the A > AE groups as compared to untreated controls. Abdominal aortic tissues contained 0.013 +- 0.004, 0.187 +- 0.021, and 0.067 +- 0.015 %-Kg/dose/gm of I-125-CI from the untreated controls, A and AE groups, respectively. Thus, CI analogs can be used as probes to scintigraphically depict CE distribution and the effects of pharmacologic manipulation upon the accumulation of CE by vascular lesions in an animal model of atherosclerosis

  12. Lipid Exchange Mechanism of the Cholesteryl Ester Transfer Protein Clarified by Atomistic and Coarse-grained Simulations

    DEFF Research Database (Denmark)

    Koivuniemi, A.; Vuorela, T.; Kovanen, P. T.; Vattulainen, I.; Hyvonen, M. T.

    2012-01-01

    change of helix X of CETP to an open state, in which we found the accessibility of cholesteryl esters to the C-terminal tunnel opening of CETP to increase. Furthermore, in the absence of helix X, cholesteryl esters rapidly diffused into CETP through the C-terminal opening. The results provide compelling...... through its charged and tryptophan residues. Upon binding, CETP rapidly (in about 10 ns) induced the formation of a small hydrophobic patch to the phospholipid surface of the droplet, opening a route from the core of the lipid droplet to the binding pocket of CETP. This was followed by a conformational...... evidence that helix X acts as a lid which conducts lipid exchange by alternating the open and closed states. The findings have potential for the design of novel molecular agents to inhibit the activity of CETP....

  13. Macrophage-specific transgenic expression of cholesteryl ester hydrolase significantly reduces atherosclerosis and lesion necrosis in Ldlr–/– mice

    OpenAIRE

    Zhao, Bin; Song, Jingmei; Chow, Woon N.; St. Clair, Richard W.; Rudel, Lawrence L.; Ghosh, Shobha

    2007-01-01

    Accumulation of cholesteryl esters (CEs) in macrophage foam cells, central to atherosclerotic plaque formation, occurs as a result of imbalance between the cholesterol influx and efflux pathways. While the uptake, or influx, of modified lipoproteins is largely unregulated, extracellular acceptor-mediated free cholesterol (FC) efflux is rate limited by the intracellular hydrolysis of CE. We previously identified and cloned a neutral CE hydrolase (CEH) from human macrophages and demonstrated it...

  14. Role of HDL in cholesteryl ester metabolism of lipopolysaccharide-activated P388D1 macrophages[S

    OpenAIRE

    Uda, Sabrina; Spolitu, Stefano; Angius, Fabrizio; Collu, Maria; Accossu, Simonetta; Banni, Sebastiano; Murru, Elisabetta; Sanna, Francesca; Batetta, Barbara

    2013-01-01

    Infections share with atherosclerosis similar lipid alterations, with accumulation of cholesteryl esters (CEs) in activated macrophages and concomitant decrease of cholesterol-HDL (C-HDL). Yet the precise role of HDL during microbial infection has not been fully elucidated. Activation of P388D1 by lipopolysaccharide (LPS) triggered an increase of CEs and neutral lipid contents, along with a remarkable enhancement in 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate-HDL uptake...

  15. The proteome of cholesteryl-ester-enriched versus triacylglycerol-enriched lipid droplets.

    Directory of Open Access Journals (Sweden)

    Victor K Khor

    Full Text Available Within cells, lipids are stored in the form of lipid droplets (LDs, consisting of a neutral lipid core, surrounded by a phospholipid monolayer and an outer layer of protein. LDs typically accumulate either triacylglycerol (TAG and diacylglycerol or cholesteryl ester (CE, depending on the type of tissue. Recently, there has been an increased interest in the proteins that surround LDs. LD proteins have been found to be quite diverse, from structural proteins to metabolic enzymes, proteins involved in vesicular transport, and proteins that may play a role in LD formation. Previous proteomics analyses have focused on TAG-enriched LDs, whereas CE-enriched LDs have been largely ignored. Our study has compared the LD proteins from CE-enriched LDs to TAG-enriched LDs in steroidogenic cells. In primary rat granulosa cells loaded with either HDL to produce CE-enriched LDs or fatty acids to produce TAG-enriched LDs, 61 proteins were found to be elevated in CE-enriched LDs and 40 proteins elevated in TAG-enriched LDs with 278 proteins in similar amounts. Protein expression was further validated by selected reaction monitoring (SRM mass spectrometry (MS. SRM verified expression of 25 of 27 peptides that were previously detected by tandem mass tagging MS. Several proteins were confirmed to be elevated in CE-enriched LDs by SRM including the intermediate filament vimentin. This study is the first to compare the proteins found on CE-enriched LDs with TAG-enriched LDs and constitutes the first step in creating a better understanding of the proteins found on CE-enriched LDs in steroidogenic cells.

  16. Acute and chronic effects of a 24-hour intravenous triglyceride emulsion challenge on plasma lecithin : cholesterol acyltransferase, phospholipid transfer protein, and cholesteryl ester transfer protein activities

    NARCIS (Netherlands)

    Riemens, SC; Van Tol, A; Sluiter, WJ; Dullaart, RPF

    1999-01-01

    Lecithin:cholesterol acyltransferase (LCAT), phospholipid transfer protein (PLTP), and cholesteryl ester transfer protein (CETP) are key factors in remodeling of high density lipoproteins (HDL) and triglyceride-rich lipoproteins. We examined the effect of a large, 24 h intravenous fat load on plasma

  17. Important role for bone marrow-derived cholesteryl ester transfer protein in lipoprotein cholesterol redistribution and atherosclerotic lesion development in LDL receptor knockout mice

    NARCIS (Netherlands)

    Van Eck, Miranda; Ye, Dan; Hildebrand, Reeni B.; Kruijt, J. Kar; de Haan, Willeke; Hoekstra, Menno; Rensen, Patrick C. N.; Ehnholm, Christian; Jauhiainen, Matti; Van Berkel, Theo J. C.

    2007-01-01

    Abundant amounts of cholesteryl ester transfer protein (CETP) are found in macrophage-derived foam cells in the arterial wall, but its function in atherogenesis is unknown. To investigate the role of macrophage CETP in atherosclerosis, LDL receptor knockout mice were transplanted with bone marrow fr

  18. Renin-angiotensin-aldosterone responsiveness to low sodium and blood pressure reactivity to angiotensin-II are unrelated to cholesteryl ester transfer protein mass in healthy subjects

    NARCIS (Netherlands)

    Krikken, Jan A.; Dallinga-Thie, Geesje M.; Navis, Gerjan; Dullaart, Robin P. F.

    2008-01-01

    Background: The blood pressure increase associated with the cholesteryl ester transfer protein (CETP) inhibitor, torcetrapib is probably attributable to an off-target effect but it is unknown whether activation of the renin-angiotensin-aldosterone system (RAAS) may be related to variation in the pla

  19. Cholesteryl ester transfer protein inhibitors in the treatment of dyslipidemia: a systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Chuanwei Li

    Full Text Available Cholesteryl ester transfer protein (CETP inhibitors are gaining substantial research interest for raising high density lipoprotein cholesterol levels. The aim of the research was to estimate the efficacy and safety of cholesteryl ester transfer protein inhibitors as novel lipid modifying drugs. Systematic searches of English literature for randomized controlled trials (RCT were collected from MEDLINE, EBASE, CENTRAL and references listed in eligible studies. Two independent authors assessed the search results and only included the double-blind RCTs by using cholesteryl ester transfer protein inhibitors as exclusively or co-administrated with statin therapy irrespective of gender in enrolled adult subjects. Two independent authors extracted the data by using predefined data fields. Of 503 studies identified, 14 studies met the inclusion criteria, and 12 studies were included into the final meta-analysis. Our meta-analysis revealed that CETP inhibitors increased the HDL-c levels (n = 2826, p<0.00001, mean difference (MD = 20.47, 95% CI [19.80 to 21.15] and total cholesterol (n = 3423, p = 0.0002, MD = 3.57, 95%CI [1.69 to 5.44] to some extent combined with a reduction in triglyceride (n = 3739, p<0.00001, MD = -10.47, 95% CI [-11.91 to -9.03] and LDL-c (n = 3159, p<0.00001, MD = -17.12, 95% CI [-18.87 to -15.36] irrespective of mono-therapy or co-administration with statins. Subgroup analysis suggested that the lipid modifying effects varied according to the four currently available CETP inhibitors. CETP inhibitor therapy did not increase the adverse events when compared with control. However, we observed a slight increase in blood pressure (SBP, n = 2384, p<0.00001, MD = 2.73, 95% CI [2.14 to 3.31], DBP, n = 2384, p<0.00001, MD = 1.16, 95% CI [0.73 to 1.60] after CETP inhibitor treatment, which were mainly ascribed to the torcetrapib treatment subgroup. CETP inhibitors therapy is associated with significant increase in HDL-c and decrease in

  20. Modification of composition of a nanoemulsion with different cholesteryl ester molecular species: Effects on stability, peroxidation, and cell uptake

    Directory of Open Access Journals (Sweden)

    Cristina P Almeida

    2010-09-01

    Full Text Available Cristina P Almeida1, Carolina G Vital1, Thais C Contente1, Durvanei A Maria2, Raul C Maranhão1,31Lipid Metabolism Laboratory, Heart Institute (InCor, Medical School Hospital, 2Biochemistry and Biophysics Laboratories, Butantan Institute, 3Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, BrazilPurpose: Use of lipid nanoemulsions as carriers of drugs for therapeutic or diagnostic purposes has been increasingly studied. Here, it was tested whether modifications of core particle constitution could affect the characteristics and biologic properties of lipid nanoemulsions. Methods: Three nanoemulsions were prepared using cholesteryl oleate, cholesteryl stearate, or cholesteryl linoleate as main core constituents. Particle size, stability, pH, peroxidation of the nanoemulsions, and cell survival and uptake by different cell lines were evaluated.Results: It was shown that cholesteryl stearate nanoemulsions had the greatest particle size and all three nanoemulsions were stable during the 237-day observation period. The pH of the three nanoemulsion preparations tended to decrease over time, but the decrease in pH of cholesteryl stearate was smaller than that of cholesteryl oleate and cholesteryl linoleate. Lipoperoxidation was greater in cholesteryl linoleate than in cholesteryl oleate and cholesteryl stearate. After four hours’ incubation of human umbilical vein endothelial cells (HUVEC with nanoemulsions, peroxidation was minimal in the presence of cholesteryl oleate and more pronounced with cholesteryl linoleate and cholesteryl stearate. In contrast, macrophage incubates showed the highest peroxidation rates with cholesteryl oleate. Cholesteryl linoleate induced the highest cell peroxidation rates, except in macrophages. Uptake of cholesteryl oleate nanoemulsion by HUVEC and fibroblasts was greater than that of cholesteryl linoleate and cholesteryl stearate. Uptake of the three nanoemulsions by monocytes was equal. Uptake of

  1. Influence of insulin sensitivity and the TaqIB cholesteryl ester transfer protein gene polymorphism on plasma lecithin : Cholesterol acyltransferase and lipid transfer protein activities and their response to hyperinsulinaemia in nondiabetic men.

    NARCIS (Netherlands)

    Riemens, SC; Van Tol, A; Stulp, BK; Dullaart, RPF

    1999-01-01

    Lecithin:cholesteryl acyltransferase (LCAT), cholesteryl ester transfer protein (CETP), phospholipid transfer protein (PLTP), and lipoprotein lipases are involved in high density lipoprotein (HDL) metabolism. We evaluated the influence of insulin sensitivity and of the TaqIB CETP gem polymorphism (B

  2. Cholesteryl ester transfer-protein modulator and inhibitors and their potential for the treatment of cardiovascular diseases

    Directory of Open Access Journals (Sweden)

    Shinkai H

    2012-05-01

    Full Text Available Hisashi ShinkaiCentral Pharmaceutical Research Institute, JT Inc, Osaka, JapanAbstract: Elevated low-density lipoprotein (LDL cholesterol and lowered high-density lipoprotein (HDL cholesterol are important risk factors for cardiovascular disease. Accordingly, raising HDL cholesterol induced by cholesteryl ester transfer protein (CETP inhibition is an attractive approach for reducing the residual risk of cardiovascular events that persist in many patients receiving low-density LDL cholesterol-lowering therapy with statins. The development of torcetrapib, a CETP inhibitor, was terminated due to its adverse cardiovascular effects. These adverse effects did not influence the mechanism of CETP inhibition, but affected the molecule itself. Therefore a CETP modulator, dalcetrapib, and a CETP inhibitor, anacetrapib, are in Phase III of clinical trials to evaluate their effects on cardiovascular outcomes. In the dal-VESSEL (dalcetrapib Phase IIb endothelial function study and the dal-PLAQUE (safety and efficacy of dalcetrapib on atherosclerotic disease using novel non-invasive multimodality imaging clinical studies, dalcetrapib reduced CETP activity by 50% and increased HDL cholesterol levels by 31% without changing LDL cholesterol levels. Moreover, dalcetrapib was associated with a reduction in carotid vessel-wall inflammation at 6 months, as well as a reduced vessel-wall area at 24 months compared with the placebo. In the DEFINE (determining the efficacy and tolerability of CETP inhibition with anacetrapib clinical study, anacetrapib increased HDL cholesterol levels by 138% and decreased LDL cholesterol levels by 36%. In contrast with torcetrapib, anacetrapib had no adverse cardiovascular effects. The potential of dalcetrapib and anacetrapib in the treatment of cardiovascular diseases will be revealed by two large-scale clinical trials, the dal-OUTCOMES (efficacy and safety of dalcetrapib in patients with recent acute coronary syndrome study and the

  3. Accumulation and aberrant composition of cholesteryl esters in Scrapie-infected N2a cells and C57BL/6 mouse brains

    Directory of Open Access Journals (Sweden)

    Di Bari Michele A

    2011-08-01

    Full Text Available Abstract Objective Cholesterol changes have been described in prion-cell models and in experimental rodent scrapie; yet, the pattern of this association is still controversial. Methods To shed light on the matter, we analysed and compared cholesterol variations in ScN2a cells and in brains of Scrapie-infected C57Bl/6 mice, using two different methods: a fluorimetric-enzymatic cholesterol assay, and high performance liquid chromatography-mass spectroscopy (HPLC-MS. Results Compared to uninfected controls, similar cholesterol metabolism anomalies were observed in infected cells and brains by both methods; however, only HPLC-MS revealed statistically significant cholesterol variations, particularly in the cholesteryl esters (CE fraction. HPLC-MS analyses also revealed different fatty acid composition of the CE fraction in cells and brains. In N2a cells, their profile reflected that of serum, while in normal brains cholesteryl-linoleate only was found at detectable levels. Following prion infection, most CE species were increased in the CE pool of ScN2a cells, whereas a conspicuous amount of cholesteryl-arachidonate only was found to contribute to the cerebral increase of CE. Of interest, oral pravastatin administration to Scrapie-infected mice, was associated with a significant reduction of cerebral free cholesterol (FC along with a concomitant further increase of the CE pool, which included increased amounts of both cholesteryl-linoleate and cholesteryl-arachidonate. Conclusion Although mechanistic studies are needed to establish the pathophysiological relevance of changes in cerebral CE concentrations, to the best of our knowledge this is the first report to provide evidence of increased cholesterol esterification in brains of prion-infected mice, untreated and treated with pravastatin.

  4. Fluorescent Sterols and Cholesteryl Esters as Probes for Intracellular Cholesterol Transport

    Science.gov (United States)

    Solanko, Katarzyna A.; Modzel, Maciej; Solanko, Lukasz M.; Wüstner, Daniel

    2015-01-01

    Cholesterol transport between cellular organelles comprised vesicular trafficking and nonvesicular exchange; these processes are often studied by quantitative fluorescence microscopy. A major challenge for using this approach is producing analogs of cholesterol with suitable brightness and structural and chemical properties comparable with those of cholesterol. This review surveys currently used fluorescent sterols with respect to their behavior in model membranes, their photophysical properties, as well as their transport and metabolism in cells. In the first part, several intrinsically fluorescent sterols, such as dehydroergosterol or cholestatrienol, are discussed. These polyene sterols (P-sterols) contain three conjugated double bonds in the steroid ring system, giving them slight fluorescence in ultraviolet light. We discuss the properties of P-sterols relative to cholesterol, outline their chemical synthesis, and explain how to image them in living cells and organisms. In particular, we show that P-sterol esters inserted into low-density lipoprotein can be tracked in the fibroblasts of Niemann–Pick disease using high-resolution deconvolution microscopy. We also describe fluorophore-tagged cholesterol probes, such as BODIPY-, NBD-, Dansyl-, or Pyrene-tagged cholesterol, and eventual esters of these analogs. Finally, we survey the latest developments in the synthesis and use of alkyne cholesterol analogs to be labeled with fluorophores by click chemistry and discuss the potential of all approaches for future applications. PMID:27330304

  5. Fluorescent Sterols and Cholesteryl Esters as Probes for Intracellular Cholesterol Transport.

    Science.gov (United States)

    Solanko, Katarzyna A; Modzel, Maciej; Solanko, Lukasz M; Wüstner, Daniel

    2015-01-01

    Cholesterol transport between cellular organelles comprised vesicular trafficking and nonvesicular exchange; these processes are often studied by quantitative fluorescence microscopy. A major challenge for using this approach is producing analogs of cholesterol with suitable brightness and structural and chemical properties comparable with those of cholesterol. This review surveys currently used fluorescent sterols with respect to their behavior in model membranes, their photophysical properties, as well as their transport and metabolism in cells. In the first part, several intrinsically fluorescent sterols, such as dehydroergosterol or cholestatrienol, are discussed. These polyene sterols (P-sterols) contain three conjugated double bonds in the steroid ring system, giving them slight fluorescence in ultraviolet light. We discuss the properties of P-sterols relative to cholesterol, outline their chemical synthesis, and explain how to image them in living cells and organisms. In particular, we show that P-sterol esters inserted into low-density lipoprotein can be tracked in the fibroblasts of Niemann-Pick disease using high-resolution deconvolution microscopy. We also describe fluorophore-tagged cholesterol probes, such as BODIPY-, NBD-, Dansyl-, or Pyrene-tagged cholesterol, and eventual esters of these analogs. Finally, we survey the latest developments in the synthesis and use of alkyne cholesterol analogs to be labeled with fluorophores by click chemistry and discuss the potential of all approaches for future applications. PMID:27330304

  6. The Relationship Between Genetic Variations of the Cholesteryl Ester Transfer Protein Gene and Coronary Artery Disease in Turkish Subjects

    Science.gov (United States)

    Gundogdu, Fuat; Gurlertop, Yekta; Pirim, Ibrahim; Sevimli, Serdar; Dogan, Hasan; Arslan, Sakir; Aksoy, Hulya; Karakelloglu, Sule; Senocak, Huseyin

    2009-01-01

    Objective Although the relationship between cholesteryl ester transfer protein (CETP) and cholesterol metabolism has been characterized in recent years, the effect of CETP genetic variants associated with coronary artery disease (CAD) is still unclear. Therefore, we investigated the association between CETP gene polymorphism and levels of lipid in patients with CAD. Materials and Methods We conducted a case-control study that included 194 unrelated subjects who underwent coronary angiography for suspected ischemic heart disease. This group was divided into 96 patients with angiographically documented CAD and 98 subjects (individuals matched for age and gender) without angiographically documented CAD (CAD-free subjects), all of whom were studied to examine the genotypic distribution of the CETP gene polymorphism in CAD. Genotyping was performed via polymerase chain reaction. Results Of the 96 patients with CAD, 38 (40%) were B1B1, 42 (44%) B1B2 and 16 (16%) B2B2, compared with the control subjects, of which 35 (36%) were B1B1, 44 (45%) B1B2 and 19 (19%) B2B2. There were no significant differences between patients with CAD and control subjects in the distribution of the CETP gene polymorphism. Patients with the B1B1 genotype had lower high-density lipoprotein-cholesterol (HDL-C) and higher triglyceride (TG) levels than patients with the B2B2 genotype (p<0.05). In addition, among control subjects HDL-C levels were significantly higher in subjects with the B2B2 genotype than in subjects with the B1B1 genotype (p<0.01). Conclusion Our results suggest that genetic variations of the CTEP gene may be responsible for low HDL-C levels but may not be considered as a risk factor for CAD in the Turkish population. PMID:25610061

  7. Cholesteryl Ester Transfer Protein Expression Partially Attenuates the Adverse Effects of SR-BI Receptor Deficiency on Cholesterol Metabolism and Atherosclerosis*

    OpenAIRE

    El Bouhassani, Majda; Gilibert, Sophie; Moreau, Martine; Saint-Charles, Flora; Tréguier, Morgan; Poti, Francesco; Chapman, M. John; Le Goff, Wilfried; Lesnik, Philippe; Huby, Thierry

    2011-01-01

    Scavenger receptor SR-BI significantly contributes to HDL cholesterol metabolism and atherogenesis in mice. However, the role of SR-BI may not be as pronounced in humans due to cholesteryl ester transfer protein (CETP) activity. To address the impact of CETP expression on the adverse effects associated with SR-BI deficiency, we cross-bred our SR-BI conditional knock-out mouse model with CETP transgenic mice. CETP almost completely restored the abnormal HDL-C distribution in SR-BI-deficient mi...

  8. Cholesteryl Ester Transfer Protein (CETP polymorphisms affect mRNA splicing, HDL levels, and sex-dependent cardiovascular risk.

    Directory of Open Access Journals (Sweden)

    Audrey C Papp

    Full Text Available Polymorphisms in and around the Cholesteryl Ester Transfer Protein (CETP gene have been associated with HDL levels, risk for coronary artery disease (CAD, and response to therapy. The mechanism of action of these polymorphisms has yet to be defined. We used mRNA allelic expression and splice isoform measurements in human liver tissues to identify the genetic variants affecting CETP levels. Allelic CETP mRNA expression ratios in 56 human livers were strongly associated with several variants 2.5-7 kb upstream of the transcription start site (e.g., rs247616 p = 6.4 × 10(-5, allele frequency 33%. In addition, a common alternatively spliced CETP isoform lacking exon 9 (Δ9, has been shown to prevent CETP secretion in a dominant-negative manner. The Δ 9 expression ranged from 10 to 48% of total CETP mRNA in 94 livers. Increased formation of this isoform was exclusively associated with an exon 9 polymorphism rs5883-C>T (p = 6.8 × 10(-10 and intron 8 polymorphism rs9930761-T>C (5.6 × 10(-8 (in high linkage disequilibrium with allele frequencies 6-7%. rs9930761 changes a key splicing branch point nucleotide in intron 8, while rs5883 alters an exonic splicing enhancer sequence in exon 9.The effect of these polymorphisms was evaluated in two clinical studies. In the Whitehall II study of 4745 subjects, both rs247616 and rs5883T/rs9930761C were independently associated with increased HDL-C levels in males with similar effect size (rs247616 p = 9.6 × 10(-28 and rs5883 p = 8.6 × 10(-10, adjusted for rs247616. In an independent multiethnic US cohort of hypertensive subjects with CAD (INVEST-GENE, rs5883T/rs9930761C alone were significantly associated with increased incidence of MI, stroke, and all-cause mortality in males (rs5883: OR 2.36 (CI 1.29-4.30, p = 0.005, n = 866. These variants did not reach significance in females in either study. Similar to earlier results linking low CETP activity with poor outcomes in males, our results suggest genetic, sex

  9. Cholesteryl Ester Transfer Protein (CETP) polymorphisms affect mRNA splicing, HDL levels, and sex-dependent cardiovascular risk.

    Science.gov (United States)

    Papp, Audrey C; Pinsonneault, Julia K; Wang, Danxin; Newman, Leslie C; Gong, Yan; Johnson, Julie A; Pepine, Carl J; Kumari, Meena; Hingorani, Aroon D; Talmud, Philippa J; Shah, Sonia; Humphries, Steve E; Sadee, Wolfgang

    2012-01-01

    Polymorphisms in and around the Cholesteryl Ester Transfer Protein (CETP) gene have been associated with HDL levels, risk for coronary artery disease (CAD), and response to therapy. The mechanism of action of these polymorphisms has yet to be defined. We used mRNA allelic expression and splice isoform measurements in human liver tissues to identify the genetic variants affecting CETP levels. Allelic CETP mRNA expression ratios in 56 human livers were strongly associated with several variants 2.5-7 kb upstream of the transcription start site (e.g., rs247616 p = 6.4 × 10(-5), allele frequency 33%). In addition, a common alternatively spliced CETP isoform lacking exon 9 (Δ9), has been shown to prevent CETP secretion in a dominant-negative manner. The Δ 9 expression ranged from 10 to 48% of total CETP mRNA in 94 livers. Increased formation of this isoform was exclusively associated with an exon 9 polymorphism rs5883-C>T (p = 6.8 × 10(-10)) and intron 8 polymorphism rs9930761-T>C (5.6 × 10(-8)) (in high linkage disequilibrium with allele frequencies 6-7%). rs9930761 changes a key splicing branch point nucleotide in intron 8, while rs5883 alters an exonic splicing enhancer sequence in exon 9.The effect of these polymorphisms was evaluated in two clinical studies. In the Whitehall II study of 4745 subjects, both rs247616 and rs5883T/rs9930761C were independently associated with increased HDL-C levels in males with similar effect size (rs247616 p = 9.6 × 10(-28) and rs5883 p = 8.6 × 10(-10), adjusted for rs247616). In an independent multiethnic US cohort of hypertensive subjects with CAD (INVEST-GENE), rs5883T/rs9930761C alone were significantly associated with increased incidence of MI, stroke, and all-cause mortality in males (rs5883: OR 2.36 (CI 1.29-4.30), p = 0.005, n = 866). These variants did not reach significance in females in either study. Similar to earlier results linking low CETP activity with poor outcomes in males, our results suggest genetic, sex

  10. Metabolism of high density lipoproteins reconstituted with [3H]cholesteryl ester and [14C]cholesterol in the rat, with special reference to the ovary

    International Nuclear Information System (INIS)

    In order to study the metabolism of high density lipoprotein (HDL)-carried sterol in the rat, human HDL was reconstituted with [14C]cholesterol and [3H]cholesteryl ester. After iv injection into immature PMSG-human CG primed rats pretreated with 4-aminopyrazolopyrimidine and aminoglutethimide, there was time-dependent accumulation of 3H and 14C in various organs which reached a maximum by 15-90 min. On a milligram wet weight basis, uptake of 3H and 14C was greatest in the adrenals, next in ovaries, followed by the liver, with little uptake by kidneys and spleen. On an organ basis, accumulation was greatest by the liver. Coadministration of excess unlabeled HDL, but not human low density lipoprotein, reduced accumulation of radioactivity by the ovaries and adrenals by 60%, indicating a specific and saturable uptake process. Granulosa cells cultured in lipoprotein-deficient medium with reconstituted HDL formed 3H- and 14C-labeled 20 alpha-hydroxypregn-4-en-3-one. Over a 24-h period, utilization of both [14C]cholesterol and [3H]cholesteryl ester was linear, but rates of utilization of the two sterol moieties were not parallel. Lysosomotropic agents had no effect on utilization of either free or esterified cholesterol for steroidogenesis but reduced degradation of 125I-labeled low density lipoprotein apoprotein. These findings lend further support to the concept of a distinct HDL pathway in steroidogenic cells of the rat

  11. Feeding probiotic Lactobacillus paracasei to Ossabaw pigs on a high fat diet prevents cholesteryl-ester accumulation and LPS modulation of the Liver X receptor and inflammatory axis in alveolar macrophages

    Science.gov (United States)

    Liver X receptors (LXR) play an integral role in regulation of cholesterol metabolism and the inflammatory response, and high fat (HF) diets and microbial infection can antagonize the LXR pathway leading to accumulation of cholesteryl-esters (CE) and increased expression of pro-inflammatory mediator...

  12. Cholesteryl ester transfer protein inhibitor torcetrapib and off-target toxicity: A pooled analysis of the rating atherosclerotic disease change by imaging with a new CETP inhibitor (RADIANCE) trials

    OpenAIRE

    Vergeer, Menno; Bots, Michiel; Leuven, Sander; Basart, Dick; Sijbrands, Eric; Evans, Gregory; Grobbee, Diederick; Visseren, Frank; Stalenhoef, Anton; Stroes, Erik; Kastelein, John

    2008-01-01

    textabstractBackground - Torcetrapib, an inhibitor of cholesteryl ester transfer protein, has been shown to increase the cardiovascular event rate despite conferring a significant high-density lipoprotein cholesterol increase. Using data from the Rating Atherosclerotic Disease Change by Imaging with a New CETP Inhibitor (RADIANCE) trials, which assessed the impact of torcetrapib on carotid intima-media thickness (cIMT), we sought to explore potential mechanisms underlying this adverse outcome...

  13. Alcohol consumption, TaqIB polymorphism of cholesteryl ester transfer protein, high-density lipoprotein cholesterol, and risk of coronary heart disease in men and women

    DEFF Research Database (Denmark)

    Jensen, Majken K; Mukamal, Kenneth J; Overvad, Kim; Rimm, Eric B

    2008-01-01

    effects of alcohol among B2 carriers. In the NHS we did not find an inverse association between alcohol and CHD in B2 non-carriers (P trend: 0.5), but did among B2 carriers (P trend <0.01). Among non-carriers the odds ratio (OR) for CHD among women with an intake of 5-14 g/day was 1.4 (95% CI: 0......AIMS: To investigate whether a common polymorphism in the cholesteryl ester transfer protein (CETP) gene modifies the relationship of alcohol intake with high-density lipoprotein cholesterol (HDL-C) and risk of coronary heart disease (CHD). METHODS AND RESULTS: Parallel nested case-control studies...... among women [Nurses' Health Study (NHS)] and men [Health Professionals Follow-up Study (HPFS)] where 246 women and 259 men who developed incident CHD were matched to controls (1:2) on age and smoking. The TaqIB variant and alcohol consumption were associated with higher HDL-C, with the most pronounced...

  14. Stimulation of cholesteryl ester synthesis in mouse peritoneal macrophages by cholesterol-rich very low density lipoproteins from the Watanabe heritable hyperlipidemic rabbit, an animal model of familial hypercholesterolemia

    International Nuclear Information System (INIS)

    Cholesterol-rich very low density lipoproteins (VLDL) from the homozygous Watanabe heritable hyperlipidemic (WHHL) rabbit induced marked cholesteryl ester accumulation in mouse peritoneal macrophages. This WHHL rabbit, an animal model of human familial hypercholesterolemia, has severe hypercholesterolemia, cutaneous xanthomas, and fulminant atherosclerosis due to the deficiency of the low density lipoprotein (LDL) receptor. When incubated with mouse peritoneal macrophages, the VLDL from WHHL rabbit (WHHL-VLDL) stimulated cholesteryl [14C]oleate synthesis 124-fold more than did VLDL from the normal Japanese White rabbit (control-VLDL). The enhancement in cholesteryl ester synthesis and accumulation of WHHL-VLDL was due to the presence of a high affinity binding receptor site on the macrophage cell surface that mediated the uptake and lysosomal degradation of WHHL-VLDL. Competition studies showed that the uptake and degradation of 125I-WHHL-VLDL was inhibited by unlabeled excess WHHL-VLDL and beta-migrating VLDL (beta-VLDL), but not LDL. Furthermore, the degradation of WHHL-VLDL was not blocked by either fucoidin, polyinosinic acid, or polyguanylic acid, potent inhibitors of the acetylated (acetyl)-LDL binding site, or by acetyl-LDL. These results suggest that macrophages possess a high affinity receptor that recognizes the cholesterol-rich VLDL present in the plasma of the WHHL rabbit and that the receptor which mediates ingestion of WHHL-VLDL seems to be the same as that for beta-VLDL and leads to cholesteryl ester deposition within macrophages. Thus, the uptake of the cholesterol-rich VLDL from the WHHL rabbit by macrophages in vivo may play a significant role in the pathogenesis of atherosclerosis in the WHHL rabbit

  15. Ciprofibrate increases cholesteryl ester transfer protein gene expression and the indirect reverse cholesterol transport to the liver

    Directory of Open Access Journals (Sweden)

    Berti Jairo A

    2009-11-01

    Full Text Available Abstract Background CETP is a plasma protein that modulates atherosclerosis risk through its HDL-cholesterol reducing action. The aim of this work was to examine the effect of the PPARα agonist, ciprofibrate, on the CETP gene expression, in the presence and absence of apolipoprotein (apo CIII induced hypertriglyceridemia, and its impact on the HDL metabolism. Results Mice expressing apo CIII and/or CETP and non-transgenic littermates (CIII, CIII/CETP, CETP, non-Tg were treated with ciprofibrate during 3 weeks. Drug treatment reduced plasma triglycerides (30-43% and non-esterified fatty acids (19-47% levels. Cholesterol (chol distribution in plasma lipoprotein responses to ciprofibrate treatment was dependent on the genotypes. Treated CIII expressing mice presented elevation in VLDL-chol and reduction in HDL-chol. Treated CETP expressing mice responded with reduction in LDL-chol whereas in non-Tg mice the LDL-chol increased. In addition, ciprofibrate increased plasma post heparin lipoprotein lipase activity (1.3-2.1 fold in all groups but hepatic lipase activity decreased in treated CETP and non-Tg mice. Plasma CETP activity and liver CETP mRNA levels were significantly increased in treated CIII/CETP and CETP mice (30-100%. Kinetic studies with 3H-cholesteryl ether (CEt labelled HDL showed a 50% reduction in the 3H-CEt found in the LDL fraction in ciprofibrate treated compared to non-treated CETP mice. This means that 3H-CEt transferred from HDL to LDL was more efficiently removed from the plasma in the fibrate treated mice. Accordingly, the amount of 3H-CEt recovered in the liver 6 hours after HDL injection was increased by 35%. Conclusion Together these data showed that the PPARα agonist ciprofibrate stimulates CETP gene expression and changes the cholesterol flow through the reverse cholesterol transport, increasing plasma cholesterol removal through LDL.

  16. Reversible flow of cholesteryl ester between high-density lipoproteins and triacylglycerol-rich particles is modulated by the fatty acid composition and concentration of triacylglycerols

    Directory of Open Access Journals (Sweden)

    E.C.R. Quintão

    2010-12-01

    Full Text Available We determined the influence of fasting (FAST and feeding (FED on cholesteryl ester (CE flow between high-density lipoproteins (HDL and plasma apoB-lipoprotein and triacylglycerol (TG-rich emulsions (EM prepared with TG-fatty acids (FAs. TG-FAs of varying chain lengths and degrees of unsaturation were tested in the presence of a plasma fraction at d > 1.21 g/mL as the source of CE transfer protein. The transfer of CE from HDL to FED was greater than to FAST TG-rich acceptor lipoproteins, 18% and 14%, respectively. However, percent CE transfer from HDL to apoB-containing lipoproteins was similar for FED and FAST HDL. The CE transfer from HDL to EM depended on the EM TG-FA chain length. Furthermore, the chain length of the monounsaturated TG-containing EM showed a significant positive correlation of the CE transfer from HDL to EM (r = 0.81, P < 0.0001 and a negative correlation from EM to HDL (r = -041, P = 0.0088. Regarding the degree of EM TG-FAs unsaturation, among EMs containing C18, the CE transfer was lower from HDL to C18:2 compared to C18:1 and C18:3, 17.7%, 20.7%, and 20%, respectively. However, the CE transfer from EMs to HDL was higher to C18:2 than to C18:1 and C18:3, 83.7%, 51.2%, and 46.3%, respectively. Thus, the EM FA composition was found to be the rate-limiting factor regulating the transfer of CE from HDL. Consequently, the net transfer of CE between HDL and TG-rich particles depends on the specific arrangement of the TG acyl chains in the lipoprotein particle core.

  17. Association of -971 G/A Cholesteryl-Ester Transfer Protein Gene Polymorphism with Lipid Profile in Primary Hyperlipidemia

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    A Barkhordari

    2012-10-01

    Full Text Available Background: Coronary heart disease (CHD is a leading cause of death worldwide and hypertriglyceridemia and hypercholesterolemia are major risk factors for the disease. Considering the role of hyperlipidemia as the underlying cause of cardiovascular mortalities and morbidities, and the limited and conflicting results of studies on CETP gene polymorphisms in Iran, we aimed to study -971 G/A polymorphism of cholesterol ester transfer protein gene in patients with primary hyperlipidemia.Methods: In this case-control study performed in Hamadan University of Medical Sciences (from May 2010 to April 2011, we recruited 200 patients with primary hyperlipidemia (total cholesterol >250 mg/dl and/or triglyceride >200 mg/dl as the cases and 200 healthy individuals with normal cholesterol and triglyceride as the control group. Gene segments were replicated by polymerase chain reaction (PCR and -971 G/A polymorphism genotypes were identified by RFLP technique. Subsequently, plasma CETP activity was measured enzymeatically by a kit in a fluorescence spectrometer.Results: The allele and genotype frequencies were not significantly different (P>0.05 between the two groups (in the control group: AA 24%, GA 47% and GG 28.5% and in the case group: AA 18%, GA 51% and GG 31%. In the case group, homozygous individuals with A alleles (AA genotype had greater cholesterol and HDL-c concentrations than those with other alleles (GG and GA. In both cases and controls, individuals with AA genotype had lower CETP concentrations.Conclusion: We conclude that -971 G/A polymorphism in CETP gene promoter can affect lipid profile and alter CETP activity.

  18. Multidrug resistance P-glycoprotein dampens SR-BI cholesteryl ester uptake from high density lipoproteins in human leukemia cells.

    Science.gov (United States)

    Spolitu, Stefano; Uda, Sabrina; Deligia, Stefania; Frau, Alessandra; Collu, Maria; Angius, Fabrizio; Batetta, Barbara

    2016-01-01

    Tumor cells are characterised by a high content of cholesterol esters (CEs), while tumor-bearing patients show low levels of high-density lipoproteins (HDLs). The origin and significance of high CE levels in cancer cell biology has not been completely clarified. Recent evidence that lymphoblastic cells selectively acquire exogenous CE from HDL via the scavenger receptor SR-BI has drawn attention to the additional membrane proteins involved in this pathway. P-glycopotein-MDR1 (P-gp) is a product of the MDR1 gene and confers resistance to antitumor drugs. Its possible role in plasma membrane cholesterol trafficking and CE metabolism has been suggested. In the present study this aspect was investigated in a lymphoblastic cell line selected for MDR1 resistance. CEM were made resistant by stepwise exposure to low (LR) and high (HR) doses of vincristine (VCR). P-gp activity ((3)H-vinblastine), CE content, CE and triglycerides (TG) synthesis ((14)C-oleate), neutral lipids and Dil-HDL uptake (fluorescence), SR-BI, ABCA1 and P-gp protein expression (western blotting) were determined. To better evaluate the relationship between CE metabolism and P-gp activity, the ACAT inhibitor Sandoz-58035 and the P-gp inhibitors progesterone, cyclosporine and verapamil were used. CE content and synthesis were similar in the parental and resistant cells. However, in the latter population, SR-BI protein expression increased, whereas CE-HDL uptake decreased. These changes correlated with the degree of VCR-resistance. As well as reverting MDR1-resistance, the inhibitors of P-gp activity induced the CE-HDL/SR-BI pathway by reactivating membrane cholesterol trafficking. Indeed, CE-HDL uptake, SRBI expression and CE content increased, whereas there was a decrease in cholesterol esterification. These results demonstrated that P-gp overexpression impairs anticancer drug uptake as well as the SR-BI mediated selective CE-HDL uptake. This suggests that these membrane proteins act in an opposite

  19. TaqIB polymorphism in the cholesteryl ester transfer protein (CETP) gene influences lipid responses to the consumption of kiwifruit in hypercholesterolaemic men.

    Science.gov (United States)

    Gammon, Cheryl S; Minihane, Anne M; Kruger, Rozanne; Conlon, Cathryn A; von Hurst, Pamela R; Jones, Beatrix; Stonehouse, Welma

    2014-03-28

    Fruit and vegetables are key elements of a cardioprotective diet, but benefits on plasma lipids, especially HDL-cholesterol (HDL-C), are inconsistent both within and between studies. In the present study, we investigated whether four selected HDL-C-related polymorphisms (cholesteryl ester transfer protein (CETP) Taq1B, APOA1 - 75G/A, hepatic lipase (LIPC) - 514C → T, and endothelial lipase (LIPG) I24582) modulate the plasma lipid response to a kiwifruit intervention. This is a retrospective analysis of data collected during a 12-week randomised controlled cross-over trial. A total of eighty-five hypercholesterolaemic men completed a 4-week healthy diet run-in period before being randomised to one of two 4-week intervention sequences of two green kiwifruit/d plus healthy diet (kiwifruit intervention) or healthy diet alone (control intervention). The measurement of anthropometric parameters and collection of fasting blood samples were carried out at baseline 1 and after the run-in (baseline 2) and intervention periods. At baseline 2, B1/B1 homozygotes of the CETP Taq1B gene had significantly higher total cholesterol:HDL-C, TAG:HDL-C, and apoB:apoA1 ratios and small-dense LDL concentrations than B2 carriers. A significant CETP Taq1B genotype × intervention interaction was observed for the TAG:HDL-C ratio (P= 0·03). B1/B1 homozygotes had a significantly lower TAG:HDL-C ( - 0·23 (sd 0·58) mmol/l; P= 0·03) ratio after the kiwifruit intervention than after the control intervention, whereas the ratio of B2 carriers was not affected. The lipid response was not affected by other gene polymorphisms. In conclusion, the significant decrease in the TAG:HDL-C ratio in B1/B1 homozygotes suggests that regular inclusion of green kiwifruit as part of a healthy diet may improve the lipid profiles of hypercholesterolaemic men with this genotype. PMID:24176024

  20. Microsomal Triglyceride Transfer Protein Enhances Cellular Cholesteryl Esterification by Relieving Product Inhibition*

    OpenAIRE

    Iqbal, Jahangir; Rudel, Lawrence L.; Hussain, M. Mahmood

    2008-01-01

    Cholesteryl ester synthesis by the acyl-CoA:cholesterol acyltransferase enzymes ACAT1 and ACAT2 is, in part, a cellular homeostatic mechanism to avoid toxicity associated with high free cholesterol levels. In hepatocytes and enterocytes, cholesteryl esters are secreted as part of apoB lipoproteins, the assembly of which is critically dependent on microsomal triglyceride transfer protein (MTP). Conditional genetic ablation of MTP reduces cholesteryl esters and enhances ...

  1. Triphenylethanamine Derivatives as Cholesteryl Ester Transfer Protein Inhibitors: Discovery of N-[(1R)-1-(3-Cyclopropoxy-4-fluorophenyl)-1-[3-fluoro-5-(1,1,2,2-tetrafluoroethoxy)phenyl]-2-phenylethyl]-4-fluoro-3-(trifluoromethyl)benzamide (BMS-795311).

    Science.gov (United States)

    Qiao, Jennifer X; Wang, Tammy C; Adam, Leonard P; Chen, Alice Ye A; Taylor, David S; Yang, Richard Z; Zhuang, Shaobin; Sleph, Paul G; Li, Julia P; Li, Danshi; Yin, Xiaohong; Chang, Ming; Chen, Xue-Qing; Shen, Hong; Li, Jianqing; Smith, Daniel; Wu, Dauh-Rurng; Leith, Leslie; Harikrishnan, Lalgudi S; Kamau, Muthoni G; Miller, Michael M; Bilder, Donna; Rampulla, Richard; Li, Yi-Xin; Xu, Carrie; Lawrence, R Michael; Poss, Michael A; Levesque, Paul; Gordon, David A; Huang, Christine S; Finlay, Heather J; Wexler, Ruth R; Salvati, Mark E

    2015-11-25

    Cholesteryl ester transfer protein (CETP) inhibitors raise HDL-C in animals and humans and may be antiatherosclerotic by enhancing reverse cholesterol transport (RCT). In this article, we describe the lead optimization efforts resulting in the discovery of a series of triphenylethanamine (TPE) ureas and amides as potent and orally available CETP inhibitors. Compound 10g is a potent CETP inhibitor that maximally inhibited cholesteryl ester (CE) transfer activity at an oral dose of 1 mg/kg in human CETP/apoB-100 dual transgenic mice and increased HDL cholesterol content and size comparable to torcetrapib (1) in moderately-fat fed hamsters. In contrast to the off-target liabilities with 1, no blood pressure increase was observed with 10g in rat telemetry studies and no increase of aldosterone synthase (CYP11B2) was detected in H295R cells. On the basis of its preclinical profile, compound 10g was advanced into preclinical safety studies. PMID:26524347

  2. Enhancement of High-Density Lipoprotein Cholesterol Functions by Encapsulation of Policosanol Exerts Anti-Senescence and Tissue Regeneration Effects Via Improvement of Anti-Glycation, Anti-Apoptosis, and Cholesteryl Ester Transfer Inhibition.

    Science.gov (United States)

    Lim, So-Mang; Yoo, Jeong-Ah; Lee, Eun-Young; Cho, Kyung-Hyun

    2016-02-01

    Consumption of policosanol (PCO), a refined mixture of sugar cane wax alcohols, can elevate serum levels of high-density lipoprotein cholesterol (HDL-C), although the molecular mechanism is still unknown. To investigate the mechanism of action responsible for the anti-senescence effects of PCO on lipoprotein metabolism and HDL functionality, we synthesized reconstituted HDL (rHDL) containing PCO. Encapsulation of PCO by rHDL (PCO-rHDL) enhanced anti-oxidant activity against cupric ion-mediated low-density lipoprotein (LDL) oxidation. PCO-rHDL (final concentration, 9 μM PCO) showed more potent anti-oxidant activity than vitamin C treatment (final concentration, 100 μM). PCO-rHDL inhibited fructose-mediated glycation, which is a major pathological mechanism of diabetic complications, in a dose-dependent manner. PCO also showed cytoprotective effects in monocytes and macrophages with less triggering of apoptotic processes and reactive oxygen species (ROS) production in the presence of hydrogen peroxide (H2O2). PCO-rHDL strongly inhibited uptake of acetylated LDL into macrophages, which is an initial atherosclerotic process. Surprisingly, PCO-rHDL inhibited human serum cholesteryl ester transfer protein (CETP) activity by up to 47% (final concentration, 10 μM PCO). Subcutaneous injection of PCO-rHDL dose-dependently enhanced tissue regeneration activity by 2.4-fold and 3.6-fold compared to that of the phosphate-buffered saline (PBS) control. In conclusion, PCO in HDL showed potent anti-oxidant, anti-glycation, and CETP inhibitory activities along with tissue regenerative activity, especially upon incorporation into HDL. These results suggest that PCO can enhance functionality of HDL in serum to exert anti-senescence and longevity effects. PMID:26161621

  3. TaqI B1/B2 and -629A/C cholesteryl ester transfer protein (CETP gene polymorphisms and their association with CETP activity and high-density lipoprotein cholesterol levels in a Tehranian population. Part of the Tehran Lipid and Glucose Study (TLGS

    Directory of Open Access Journals (Sweden)

    Maryam S Daneshpour

    2007-01-01

    Full Text Available We examined the cholesteryl ester transfer protein (CETP gene TaqI intron 1 B1/B2 polymorphism and the -629A/C CETP promoter polymorphism in respect to high-density lipoprotein cholesterol (HDL-C in a healthy Iranian population taken from the Tehran Lipid and Glucose Study (TLGS. The relationship between CETP activity and HDL-C level was also determined along with body mass index, blood pressure and tobacco smoking status. PCR-RFLP used to amplify a segment of the CETP intron 1 TaqI (B2/B1 polymorphism from 1021 individuals and we selected 345 individuals from the lowest, middle and highest HDL-C deciles and investigated the -629A/C polymorphism. We also evaluated the CETP activity of 103 of these individuals, each with at least one homozygous allele. The presence of the TaqI B2 and -629A/C A alleles were significantly associated with increased HDL-C levels (B2B2 = 1.19 ± 0.31 mmolL-1 vs. B1B1 = 1.01 ± 0.2 mmol L-1 for p < 0.001; AA = 1.15 ± 0.41 mmol L-1 vs. CC = 0.95 ± 0.28 mmol L-1 for p < 0.001 and decreased the CETP activity (B1B1 = 67.8 ± 8.9 pmol L-1 vs. B2B2 = 62.6 ± 9.6 pmol L-1 for p < 0.01; CC = 68.6 ± 8.4 pmol L-1 vs. AA = 62.7 ± 9.7 pmol L-1 for p < 0.002. The frequencies were 0.382 for the TaqI B2 allele and 0.462 for the -629A/C A allele, with linkage disequilibrium analysis giving D = 0.0965 and D' = 0.4695. We demonstrated that the TaqI B1 and B2 alleles and the -629A/C A and C alleles were in linkage disequilibrium in our population and that there was a significant association between the B2 and A alleles and high HDL-C levels and low CETP activity. Linkage disequilibrium between the TaqI A and B2 alleles also detected.

  4. Molecular dynamics simulation of interaction mode between tanshinone ⅡA and cholesteryl ester transfer protein%分子动力学模拟法研究丹参酮ⅡA与胆固醇酯转运蛋白的相互作用模式

    Institute of Scientific and Technical Information of China (English)

    张洁; 谭初兵; 徐为人; 李晓博; 汤立达

    2013-01-01

    Objective To investigate the interaction between tanshinone ⅡA (TS ⅡA) and cholesteryl ester transfer protein (CETP),and to explore the ways of impact on CETP.Methods The various structures of TS ⅡA and CETP were built based on the crystal structure and then performed molecular dynamics (MD).The simulation software is Gromacs 4.0 with force field of Gromos 96 53a6.The temperature is 300 K and the simulation time is 20 ns.All trajectories were recorded to analyze the changes of overall shape and local structures of CETP,and the interaction energy between TS ⅡA and CETP.Results When the phosphatidyl choline zones of CETP were full,the structure was rigid.When only the cavity was loaded,CETP was easy to change.The out area of two side,phosphatidyl choline area and cavity change greatly corresponded to the frame changes of CETP.Stronger interaction between TS ⅡA and CETP occured in the two phosphatidyl choline area and the left side of cavity.Conclusion CETP is a carrier protein with easily changed structure which changes according to the differences in the number and structures of loading ligands.TS ⅡA might affect the morphology of the CETP and then inhibit its transportation ability under the help ofphosphatidyl choline or cholesterol ester.%目的 通过研究丹参酮ⅡA与胆固醇酯转运蛋白(CETP)的相互作用,探索其对CETP的影响模式.方法 基于晶体结构构建丹参酮ⅡA与CETP多种形式的复合结构,并以此为起始结构进行分子动力学模拟,模拟软件为Gromacs 4.0,力场Gromos 96 53a6,温度300 K,模拟时间20 ns,记录轨迹,分析CETP整体形状和局部结构变化,考察丹参酮ⅡA与CETP的相互作用能量.结果 磷酯酰胆碱出口区和空腔都装满后CETP结构比较刚性,单装空腔CETP结构容易变化.对应于CETP框架结构的形态变化,在与不同配体复合形式下CETP两侧的出口区和磷酯酰胆碱出口区以及空腔差异较大,丹参酮ⅡA与CETP相互

  5. Assessment of anti-atherogenic drugs in vivo and reconstitution of lipoproteins using radioiodinated cholesteryl iopanoate

    International Nuclear Information System (INIS)

    A nonhydrolyzable radioiodinated cholesteryl ester, 125I-cholesteryl iopanoate (125I-Cl), was found to accumulate in high concentrations in atherosclerotic aortas of cholesterol-fed rabbits after intravenous administration. Aortas from normal chow-fed rabbits did not exhibit significant 125I-Cl accumulation. When cholesterol-fed rabbits were intravenously administered Tween-solubilized 125I-Cl and simultaneously treated with either of two anti-atherogenic compounds, estradiol 17β-cypionate or colestipol, the extent of aortic atherosclerosis was found to dramatically decrease. Measurement of aortic radioactivity was found to strongly correlate with the severity of atherosclerosis. Although the specificity of 125I-Cl for atheromatous lesions was very good, gamma-camera scintigraphy of the abdomens of these rabbits 6 days after cessation of 125I-Cl administration was not able to consistently predict the severity of atherosclerosis. Tissue distribution studies suggested that high blood and spinal column bone marrow radioactivity produced aorta:nontarget radioactivity ratios unfavorable with respect to imaging. To improve this ratio so as to permit noninvasive imaging, attempts were made to incorporate 125I-Cl into serum lipoproteins. Labelling of either rabbit LDL by in vivo incorporation or human LDL by transfer of 125I-Cl from liposomes using cholesteryl ester transfer protein resulted in lipoproteins with low specific activity. Higher specific activity was achieved by reconstituting delipidated human LDL with a mixture of 125I-Cl and unlabeled cholesteryl oleate. These particles were taken up in high amounts by monolayers of human fibroblasts but not by fibroblasts deficient in LDL receptors or by normal fibroblasts during competition with unlabeled native LDL

  6. Experimental determination and computational interpretation of biophysical properties of lipid bilayers enriched by cholesteryl hemisuccinate

    DEFF Research Database (Denmark)

    Kulig, Waldemar; Jurkiewicz, Piotr; Olzyńska, Agnieszka;

    2015-01-01

    © 2014 Elsevier B.V. Cholesteryl hemisuccinate (CHS) is one of the cholesterol-mimicking detergents not observed in nature. It is, however, widely used in protein crystallography, in biochemical studies of proteins, and in pharmacology. Here, we performed an extensive experimental and theoretical...... experimental and atomistic simulation data, we conclude that these differences originate from the fact that the ester group of CHS does not anchor it in an optimal position at the water-membrane interface. The implications of these findings for considerations of protein-cholesterol interactions are briefly...

  7. Pancreatic carboxyl ester lipase: a circulating enzyme that modifies normal and oxidized lipoproteins in vitro.

    OpenAIRE

    Shamir, R; W.J. Johnson; Morlock-Fitzpatrick, K; Zolfaghari, R; Li, L.; E. Mas; Lombardo, D; Morel, D W; Fisher, E A

    1996-01-01

    Pancreatic carboxyl ester lipase (CEL) hydrolyzes cholesteryl esters (CE), triglycerides (TG), and lysophospholipids, with CE and TG hydrolysis stimulated by cholate. Originally thought to be confined to the gastrointestinal system, CEL has been reported in the plasma of humans and other mammals, implying its potential in vivo to modify lipids associated with LDL, HDL (CE, TG), and oxidized LDL (lysophosphatidylcholine, lysoPC). We measured the concentration of CEL in human plasma as 1.2+/-0....

  8. Absence of association of the L296Q polymorphism in the cholesteryl ester transfer protein gene with type2 diabetes mellitus in Chinese%胆固醇酯转运蛋白基因L296Q多态性与中国人2型糖尿病和脂代谢关系的研究

    Institute of Scientific and Technical Information of China (English)

    高赘; 祝琳; 龙洋; 任艳; 陈涛; 张祥迅; 田浩明

    2008-01-01

    Objective To investigate the association between L296Q polymorphism in the cholesterol ester transfer protein(CETP) gene and type 2 diabetes mellitus(T2DM) and blood lipids. Methods Plasma glucose and lipid levels were measured in a total of 303 subjects recruited from the West China Hospital of Siehuan University. The subjects were divided into 4 groups according to the levels of plasma glucose and triglycefide, namely T2DM with hypertriglyceridemia group, group of T2DM with normal tfiglyceride, group of hypertfiglycefidemia without DM and group of normal controls,respectively. Cenotypes of L296Q polymorphism in the CETP gene of all subjects were analyzed by real-time fluorescent quantitative PCR(FQ-PCR). Results No significant differences were observed in the frequencies of genotypes LL and LQ and the 296Q allele among the four groups (X2 =3.459 P >0.05; X2 :3.155 P >0.05, respectively), nor the frequencies of genotypes LL and LQ between the T2DM and non-T2DM, or plasma lipid levels between the 296Q allele carriers and those of genotype LL. Conclusion No association was found between the L296Q polymorphism in the CETP gene and T2DM as well as plasma lipid levels in various groups of Chinese in this study.%目的 研究中国人群胆固醇酯转运蛋白(cholesterol ester transier protein,CETP)基因L296Q多态性与2型糖尿病及血脂水平问的关系.方法 根据血糖及甘油三脂水平将303名研究对象分4组后测糖代谢和脂代谢相关指标;应用实时荧光定量PCR技术对研究对象的CETP基因L296Q多态性进行筛查.结果 LL和LQ两种基因型的频率以及变异的296Q等位基因的频率在4组人群中的差异无统计学意义;两种基因型频率在糖尿病与非糖尿病人群问的差异也无统计学意义;LQ基因型者的血脂水平(甘油三酯,高密度脂蛋白胆固醇,总胆固醇,低密度脂蛋白胆固醇)与IJJ基因型者差异无统计学意义.结论 在中国成都地区

  9. Optoelectronic properties of a perylene substituted (cholesteryl)benzoateethynylene co-polymer

    International Nuclear Information System (INIS)

    A perylene cholesteryl-benzoateethynylene co-polymer was synthesized by Sonogashira reaction and characterized by NMR, UV–Vis, static and dynamic fluorescence spectroscopy and cyclic voltammetry. The optical and electrochemical properties in solution are consistent with photoinduced energy transfer from the electron donor conjugated backbone to the electron acceptor perylene substituent. Photovoltaic properties are indeed found, even if the performance of the solar cells is quite low due to the formation of aggregates. The incorporation of (6,6)-phenyl C61–butyric acid methyl ester (PCBM), however, increases by an order of magnitude the efficiency of the prototype (from 10−4 to 10−3%) due to both better phase mixing and improved electrical continuity as supported by Atomic Force Microscopy (AFM) and Electrical Force Microscopy (EFM) studies. - Highlights: • Synthesis of a benzoateethynylene backbone co-polymer with perylene substituent. • Optical and electrochemical properties consistent with photoinduced energy transfer. • Enhancement of photovoltaic efficiency when PCBM is added to the co-polymer. • EFM studies of active layers

  10. Optoelectronic properties of a perylene substituted (cholesteryl)benzoateethynylene co-polymer

    Energy Technology Data Exchange (ETDEWEB)

    Zappia, Stefania [Dipartimento di Chimica e Chimica Industriale, Università di Genova, Via Dodecaneso 31, 16146 Genoa (Italy); Centro de Investigación en Química Aplicada, Boulevard Enrique Reyna 140, 25294 Saltillo, Coahuila (Mexico); León, Arxel de [Centro de Investigación en Química Aplicada, Boulevard Enrique Reyna 140, 25294 Saltillo, Coahuila (Mexico); Alloisio, Marina [Dipartimento di Chimica e Chimica Industriale, Università di Genova, Via Dodecaneso 31, 16146 Genoa (Italy); Arias, Eduardo [Centro de Investigación en Química Aplicada, Boulevard Enrique Reyna 140, 25294 Saltillo, Coahuila (Mexico); Dellepiane, Giovanna; Petrillo, Giovanni [Dipartimento di Chimica e Chimica Industriale, Università di Genova, Via Dodecaneso 31, 16146 Genoa (Italy); Moggio, Ivana, E-mail: ivana.moggio@ciqa.edu.mx [Centro de Investigación en Química Aplicada, Boulevard Enrique Reyna 140, 25294 Saltillo, Coahuila (Mexico); Thea, Sergio [Dipartimento di Chimica e Chimica Industriale, Università di Genova, Via Dodecaneso 31, 16146 Genoa (Italy); Gallardo-Vega, Carlos; Rodríguez, Marlene [Centro de Investigación en Química Aplicada, Boulevard Enrique Reyna 140, 25294 Saltillo, Coahuila (Mexico)

    2014-10-15

    A perylene cholesteryl-benzoateethynylene co-polymer was synthesized by Sonogashira reaction and characterized by NMR, UV–Vis, static and dynamic fluorescence spectroscopy and cyclic voltammetry. The optical and electrochemical properties in solution are consistent with photoinduced energy transfer from the electron donor conjugated backbone to the electron acceptor perylene substituent. Photovoltaic properties are indeed found, even if the performance of the solar cells is quite low due to the formation of aggregates. The incorporation of (6,6)-phenyl C61–butyric acid methyl ester (PCBM), however, increases by an order of magnitude the efficiency of the prototype (from 10{sup −4} to 10{sup −3}%) due to both better phase mixing and improved electrical continuity as supported by Atomic Force Microscopy (AFM) and Electrical Force Microscopy (EFM) studies. - Highlights: • Synthesis of a benzoateethynylene backbone co-polymer with perylene substituent. • Optical and electrochemical properties consistent with photoinduced energy transfer. • Enhancement of photovoltaic efficiency when PCBM is added to the co-polymer. • EFM studies of active layers.

  11. Influence of preparation conditions and heat treatment on the properties of supercooled smectic cholesteryl myristate nanoparticles

    DEFF Research Database (Denmark)

    Kuntsche, Judith; Bunjes, H

    2007-01-01

    stability of cholesteryl myristate nanoparticles stabilized with different surface active agents during heat treatment was investigated as well. The dispersions were characterized by particle size and zeta potential measurements, differential scanning calorimetry (DSC) and high performance thin layer...... stable against hydrolysis during prolonged heat treatment in the phospholipid/bile salt containing cholesteryl myristate dispersions....

  12. Insertion stability of poly(ethylene glycol)-cholesteryl-based lipid anchors in liposome membranes.

    Science.gov (United States)

    Molnar, Daniel; Linders, Jürgen; Mayer, Christian; Schubert, Rolf

    2016-06-01

    Liposomes consist of a hydrophilic core surrounded by a phospholipid (PL) bilayer. In human blood, the half-life of such artificial vesicles is limited. To prolong their stability in the circulation, liposomal bilayers can be modified by inserting poly(ethylene glycol) (PEG) molecules using either PL or sterols as membrane anchors. This establishes a hydrophilic steric barrier, reducing the adsorption of serum proteins, recognition and elimination by cells of the immune system. In addition, targeting ligands (such as antibodies) are frequently coupled to the distal end of the PEG chains to direct the vesicles (then called 'immuno-liposomes') to specific cell types, such as tumor cells. To our knowledge, experiments on the stability of ligand anchoring have so far only been conducted with PL-based PEGs and not with sterol-based PEGs after insertion via the sterol-based post-insertion technique (SPIT). Therefore, our study examines the insertion stability of PEG-cholesteryl ester (Chol-PEG) molecules with PEG chains of 1000, 1500 and 2000Da molecular mass which have been inserted into the membranes of liposomes using SPIT. For this study we used different acceptor media and multiple analytical techniques, including pulsed-field-gradient nuclear magnetic resonance (PFG-NMR), free-flow electrophoresis, size exclusion chromatography and ultracentrifugation. The obtained data consistently showed that a higher molar mass of PEG chains positively correlates with higher release from the liposome membranes. Furthermore, we could detect and quantify the migration of Chol-PEG molecules from radioactively double-labeled surface-modified liposomes to negatively charged acceptor liposomes via free-flow electrophoresis. Insertion of Chol-PEG molecules into the membrane of preformed liposomes using SPIT is an essential step for the functionalization of liposomes with the aim of specific targeting. For the first time, we present a kinetic analysis of this insertion process using PFG

  13. Kapok oil methyl esters

    International Nuclear Information System (INIS)

    The increased need for biodiesel feedstocks has caused various vegetable oils to be examined for this purpose. In the present work, the methyl esters of kapok (Ceiba pentandra) oil were prepared. The essential fuel properties were comprehensively determined and evaluated in comparison to specifications in biodiesel standards and some prior results. The kinematic viscosity of kapok oil methyl esters was greater than expected, an observation traced to the elevated amounts of methyl esters with cyclic moieties. Overall, kapok oil is a potential biodiesel feedstock. The 1H and 13C NMR spectra of kapok methyl esters are reported. - Highlights: • Methyl esters of kapok oil generally acceptable as a biodiesel fuel. • Kapok oil methyl esters a fuel with elevated content of fatty acid methyl esters containing cyclic moieties. • Kinematic viscosity of kapok oil methyl esters elevated likely due to fatty ester methyl esters with cyclic moieties. • Discusses and compares present results with prior literature

  14. Fatty acid methyl ester profiles of bat wing surface lipids.

    Science.gov (United States)

    Pannkuk, Evan L; Fuller, Nathan W; Moore, Patrick R; Gilmore, David F; Savary, Brett J; Risch, Thomas S

    2014-11-01

    Sebocytes are specialized epithelial cells that rupture to secrete sebaceous lipids (sebum) across the mammalian integument. Sebum protects the integument from UV radiation, and maintains host microbial communities among other functions. Native glandular sebum is composed primarily of triacylglycerides (TAG) and wax esters (WE). Upon secretion (mature sebum), these lipids combine with minor cellular membrane components comprising total surface lipids. TAG and WE are further cleaved to smaller molecules through oxidation or host enzymatic digestion, resulting in a complex mixture of glycerolipids (e.g., TAG), sterols, unesterified fatty acids (FFA), WE, cholesteryl esters, and squalene comprising surface lipid. We are interested if fatty acid methyl ester (FAME) profiling of bat surface lipid could predict species specificity to the cutaneous fungal disease, white nose syndrome (WNS). We collected sebaceous secretions from 13 bat spp. using Sebutape(®) and converted them to FAME with an acid catalyzed transesterification. We found that Sebutape(®) adhesive patches removed ~6× more total lipid than Sebutape(®) indicator strips. Juvenile eastern red bats (Lasiurus borealis) had significantly higher 18:1 than adults, but 14:0, 16:1, and 20:0 were higher in adults. FAME profiles among several bat species were similar. We concluded that bat surface lipid FAME profiling does not provide a robust model predicting species susceptibility to WNS. However, these results provide baseline data that can be used for lipid roles in future ecological studies, such as life history, diet, or migration. PMID:25227993

  15. Concerted actions of cholesteryl ester transfer protein and phospholipid transfer protein in type 2 diabetes : effects of apolipoproteins

    NARCIS (Netherlands)

    Dallinga-Thie, Geesje M.; Dullaart, Robin P. F.; van Tol, Arie

    2007-01-01

    Purpose of review Type 2 diabetes frequently coincides with dyslipidemia, characterized by elevated plasma triglycerides, low high-density lipoprotein cholesterol levels and the presence of small dense low-density lipoprotein particles. Plasma lipid transfer proteins play an essential role in lipopr

  16. Where Are We With HDL Raising and Inhibition of Cholesteryl Ester Transfer for Heart Disease Risk Reduction?

    Science.gov (United States)

    Purpose: To review recent research in the area of high density lipoprotein (HDL) raising and coronary heart disease (CHD) risk reduction. Recent Findings: It is known that a decreased HDL cholesterol is an important CHD risk factor, and that raising HDL cholesterol has been associated with CHD risk...

  17. Click chemistry-assisted, bis-cholesteryl-appended, isosorbide-based, dual-responsive organogelators and their self-assemblies.

    Science.gov (United States)

    Balamurugan, R; Zhang, Y-S; Fitriyani, S; Liu, J-H

    2016-06-21

    A new series of symmetric, bis-cholesteryl-appended, isosorbide derivatives (BCIE, BCIC2 and BCIC4) were designed as gelators to respond to changes in their environment and were synthesized successfully. Among these derivatives, BCIE can gel a wide variety of organic solvents (23 solvents), suggesting that BCIE acts as a more versatile gelator than BCIC2 and BCIC4. The CGC of the gels varies from 1.53 mM in 1-hexanol to 23 mM in pyridine. The results of the gelation ability in different solvents revealed that changing the linking group (ester/carbamate) attached to the cholesteryl units can produce a dramatic change in the gelation behavior of the compounds. The morphology of the as-formed organogels can be regulated by changing the types of organic solvents. The results from electron microscopy studies revealed that the gelator molecule self-assembled into different aggregates, from wrinkled fibers to dense fibers, with the change of solvents. The gels of BCIE in 1-hexanol and 1-octanol exhibited strong CD (circular dichroism) signals, indicating that the gelation induced supramolecular chirality in these gel systems. Secondary forces of van der Waals and π-π stacking (from both 1,2,3-triazole and aromatic units) played important roles in the aggregation of compounds in the solvents according to FTIR and variable temperature (1)H-NMR analysis, and a mechanism for the gel formation was proposed. The gel-to-sol phase transition can be triggered by the addition of trifluoroacetic acid (TFA), and the gel state was obtained slowly (after 1 day) when neutralizing with triethyl amine (TEA), which indicated that the sol ⇄ gel phase transitions are tunable by pH, which is further supported by (1)H-NMR and SEM analysis. In addition, the gel stability of BCIE was investigated using Cu(2+), Cd(2+), Ag(2+), Fe(3+), Hg(2+), Mg(2+), Pd(2+), Al(3+) and Zn(2+), and the results showed that the gel-to-sol phase transition process could be selectively controlled by interaction

  18. Crystallization behavior of supercooled smectic cholesteryl myristate nanoparticles containing phospholipids as stabilizers

    DEFF Research Database (Denmark)

    Kuntsche, Judith; Koch, Michel; Drechsler, M;

    2005-01-01

    . Phospholipid and phospholipid/bile salt stabilized cholesteryl myristate dispersions were prepared by high-pressure melt homogenization and characterized by particle size measurements, differential scanning calorimetry, X-ray diffraction and electron microscopy. To obtain fractions with very small smectic...... recrystallization tendency upon storage. The observed peculiarities of the crystallization behavior seem to be mainly caused by the presence of particles with different shapes (cylindrical and spherical) as observed in electron microscopy. Alterations in the composition of the nanoparticles may also play a role....

  19. Helicobacter pylori cholesteryl α-glucosides contribute to its pathogenicity and immune response by natural killer T cells.

    Directory of Open Access Journals (Sweden)

    Yuki Ito

    Full Text Available Approximately 10-15% of individuals infected with Helicobacter pylori will develop ulcer disease (gastric or duodenal ulcer, while most people infected with H. pylori will be asymptomatic. The majority of infected individuals remain asymptomatic partly due to the inhibition of synthesis of cholesteryl α-glucosides in H. pylori cell wall by α1,4-GlcNAc-capped mucin O-glycans, which are expressed in the deeper portion of gastric mucosa. However, it has not been determined how cholesteryl α-glucosyltransferase (αCgT, which forms cholesteryl α-glucosides, functions in the pathogenesis of H. pylori infection. Here, we show that the activity of αCgT from H. pylori clinical isolates is highly correlated with the degree of gastric atrophy. We investigated the role of cholesteryl α-glucosides in various aspects of the immune response. Phagocytosis and activation of dendritic cells were observed at similar degrees in the presence of wild-type H. pylori or variants harboring mutant forms of αCgT showing a range of enzymatic activity. However, cholesteryl α-glucosides were recognized by invariant natural killer T (iNKT cells, eliciting an immune response in vitro and in vivo. Following inoculation of H. pylori harboring highly active αCgT into iNKT cell-deficient (Jα18(-/- or wild-type mice, bacterial recovery significantly increased in Jα18(-/- compared to wild-type mice. Moreover, cytokine production characteristic of Th1 and Th2 cells dramatically decreased in Jα18(-/- compared to wild-type mice. These findings demonstrate that cholesteryl α-glucosides play critical roles in H. pylori-mediated gastric inflammation and precancerous atrophic gastritis.

  20. Facile synthesis and characterization of novel thermo-chromism cholesteryl-containing hydrogen-bonded liquid crystals

    Institute of Scientific and Technical Information of China (English)

    Wan Li He; Tao Liu; Zhou Yang; Dong Yu Zhao; Wei Huang; Hui Cao; Guo Jie Wang; Huai Yang

    2009-01-01

    Two series of novel cholesteryl-containing H-bonded liquid crystals were prepared through facile self-assembly between cholesteryl isonicotinate (proton acceptor) exhibiting a monotropic cholesteric phase, and the 4-alkoxy-benzoic acid or 4-alkoxy cinnamic acid (proton donor). It was found that the increase of the conjugate length as well as the terminal length can contribute to enhance the interaction of molecules and thus significantly influenced the thermal behaviors of H-bonded LCs. The cholesteric reflection spectra of the induced mesogenic complexes were located in the visible region with the color tuneable thermo-sensitivity, which could be used for display application.

  1. Interactions of egg yolk phosphatidylcholine with cholesteryl polyethoxy neoglycolipids containing N-acetyl- D-glucosamine

    Science.gov (United States)

    Kemoun, Rachida; Gelhausen, Micaèle; Besson, Françoise; Lafont, Dominique; Buchet, René; Boullanger, Paul; Roux, Bernard

    1999-03-01

    Series of neoglycolipids containing cholesteryl and N-acetyl- D-glucosaminyl groups were synthesized with various ethoxy linkers. Their self aggregations and intermolecular interactions, without and with egg yolk phosphatidylcholine (EYPC), were characterized in dry and hydrated states, by using infrared spectroscopy. The neoglycolipids in the dry state formed intermolecular hydrogen bonds between the CO and N-H or O-H groups of N-acetyl- D-glucosamine (GlcNAc). In the presence of EYPC, these intermolecular interactions were broken and new hydrogen bonds, involving the phosphate group of EYPC and N-H or O-H groups of GlcNAc of neoglycolipid, were formed. The presence of water molecules altered these intermolecular hydrogen bonds. The CO groups of EYPC were not affected by the presence of neoglycolipids, either in hydrated or in dry states, indicating that the GlcNAc polar groups interacted mostly with EYPC phosphate residues. The phase transition-temperature of mixtures of EYPC containing either cholesterol or neoglycolipid were similar, indicating that the cholesteryl group of the neoglycolipid interacted in the same manner as cholesterol with hydrocarbon chains of EYPC. Some structural models of molecular interactions of neoglycolipids were discussed in relation with the molecular recognition of wheat germ agglutinin.

  2. LDL cholesteryl oleate as a predictor for atherosclerosis: evidence from human and animal studies on dietary fat

    OpenAIRE

    Degirolamo, Chiara; Shelness, Gregory S.; Rudel, Lawrence L.

    2009-01-01

    This review focuses on the relationships among dietary fat type, plasma and liver lipid, and lipoprotein metabolism and atherosclerosis. Dietary polyunsaturated fatty acids are beneficial for the prevention of coronary artery atherosclerosis. By contrast, dietary monounsaturated fatty acids appear to alter hepatic lipoprotein metabolism, promote cholesteryl oleate accumulation, and confer atherogenic properties to lipoproteins as shown in data from experimental animal studies. Polyunsaturated...

  3. Apomorphine and its esters

    DEFF Research Database (Denmark)

    Borkar, Nrupa; Chen, Zhizhong; Saaby, Lasse;

    2016-01-01

    Oral delivery of apomorphine via prodrug principle may be a potential treatment for Parkinson's disease. The purpose of this study was to investigate the transport and stability of apomorphine and its esters across Caco-2 cell monolayer and their affinity towards chylomicrons. Apomorphine...

  4. Lubricants based on synthetic esters; Schmierstoffe auf Basis synthetischer Ester

    Energy Technology Data Exchange (ETDEWEB)

    Fahl, J. [Forschung und Entwicklung Kaeltemaschinenoele, Fuchs DEA Schmierstoffe GmbH, Hamburg (Germany)

    2000-07-01

    This article describes the synthetic esters that are being used in refrigeration applications that use chlorine-free working fluids. The chemical basics involved in these high-performance lubricants, their manufacture and their lubricating properties are looked at in detail. The history of their development from their use as machining oils, lubricants for weapons and two-stroke engines through to turbine lubricants and as hydraulic oil in aeronautics is reviewed. Modern neopentyl-polyol esters used in refrigeration applications are described. Further, the chemical structures and applications of complex esters, carbonate esters, aromatic and silicate esters are looked at.

  5. Synthesis and structural characterization of three unique Helicobacter pylori α-cholesteryl phosphatidyl glucosides.

    Science.gov (United States)

    Nguyen, Huy Q; Davis, Ryan A; Gervay-Hague, Jacquelyn

    2014-12-01

    Steryl glycosides produced by bacteria play important biological roles in the evasion and modulation of host immunity. Step-economical syntheses of three cholesteryl-6-O-phosphatidyl-α-D-glucopyranosides (αCPG) unique to Helicobacter pylori have been achieved. The approach relies upon regioselective deprotection of per-O-trimethylsilyl-α-D-cholesterylglucoside at C6 followed by phosphoramidite coupling. Global TMS ether deprotection in the presence of oxygen and subsequent deprotection of the cyano ethyl phosphoester afforded the target compounds in 16-21 % overall yield starting from D-glucose. The structures of these natural products were determined using a combination of 2D NMR methods and mass spectrometry. These robust synthesis and characterization protocols provide analogues to facilitate glycolipidomic profiling and biological studies. PMID:25195783

  6. Formation of the 5,6-epoxy derivatives of 7-liydroxy-cholesteryl 3β-acetates during peroxidation of cholesteryl acetate.

    Directory of Open Access Journals (Sweden)

    Lercker, G.

    1999-06-01

    Full Text Available The thermal peroxidation of cholesteryl acetate (CA generates many compounds, most of which have been identified in previous studies. The trimethylsilyl (TMS derivatives of the thermodegradation products of the single hydroperoxides of CA (7α- and 7β- gave GCMS spectra that were almost identical to those of the thermal peroxidation of CA, except for four compounds that were only detected as TMS derivatives. These substances were identified by comparing their mass spectra and their GC retention time against those of the four synthesized isomers of the epoxy-hydroxy derivatives of CA. The presence of a considerable amount of epoxy-hydroxy derivates of CA, especially at low-temperature degradations, provides an explanation for the formation of other substances that have been previously identified.

    La peroxidación térmica del colesteril acetato (OA produce varios compuestos, la mayoría de los cuales fueron ya identificados en estudios precedentes. Los trimetilsilil (TMS derivados de los productos de la termodegradación de los hidroperóxidos simples del CA (7α- y 7β- producen espectros GC-MS que son siempre idénticos a aquellos de la peroxidación de CA, a excepción de los cuatro compuestos que son únicamente detectados como derivados TMS. Estas substancias fueron identificadas comparando los espectros de masa y los tiempos de retención GC con los cuatro isómeros de los derivados epoxi-hidroxi del CA. La presencia de una considerable cantidad de derivados epoxi- hidroxi del CA, especialmente a bajas temperaturas de degradación, proveen una explicación de la formación de otras substancias que fueron Identificadas precedentemente.

  7. Valyl benzyl ester chloride

    Directory of Open Access Journals (Sweden)

    Grzegorz Dutkiewicz

    2010-02-01

    Full Text Available In the title compound (systematic name: 1-benzyloxy-3-methyl-1-oxobutan-2-aminium chloride, C12H18NO2+·Cl−, the ester group is approximately planar, with a maximum deviation of 0.040 (2 Å from the least-squares plane, and makes a dihedral angle of 28.92 (16° with the phenyl ring. The crystal structure is organized by N—H...Cl hydrogen bonds which join the two components into a chain along the b axis. Pairs of chains arranged antiparallel are interconnected by further N—H...Cl hydrogen bonds, forming eight-membered rings. Similar packing modes have been observed in a number of amino acid ester halides with a short unit-cell parameter of ca 5.5 Å along the direction in which the chains run.

  8. Improved thermooxidation and sedimentation stability of covalently-coated carbonyl iron particles with cholesteryl groups and their influence on magnetorheology

    Czech Academy of Sciences Publication Activity Database

    Mrlík, M.; Ilčíková, M.; Pavlínek, V.; Mosnáček, J.; Peer, Petra; Filip, Petr

    2013-01-01

    Roč. 396, april (2013), s. 146-151. ISSN 0021-9797 R&D Projects: GA ČR GA202/09/1626 Grant ostatní: GA MŠk(CZ) ED2.1.00/03.0111 Institutional support: RVO:67985874 Keywords : covalent coating * carbonyl iron * cholesteryl chloroformate * thermooxidation * Magnetorheology Subject RIV: BK - Fluid Dynamics Impact factor: 3.552, year: 2013

  9. Cholesteryl-coated carbonyl iron particles with improved anti-corrosion stability and their viscoelastic behaviour under magnetic field

    Czech Academy of Sciences Publication Activity Database

    Mrlik, M.; Ilčíková, M.; Sedlačík, M.; Mosnáček, J.; Peer, Petra; Filip, Petr

    2014-01-01

    Roč. 292, č. 9 (2014), s. 2137-2143. ISSN 0303-402X R&D Projects: GA ČR(CZ) GP14-32114P Grant ostatní: GA MŠk(CZ) ED2.1.00/03.0111 Institutional support: RVO:67985874 Keywords : carbonyl iron * cholesteryl chloroformate * silicone oil suspensions * viscoelasticity * magnetorheology Subject RIV: BK - Fluid Dynamics Impact factor: 1.865, year: 2014

  10. Method of making alkyl esters

    Science.gov (United States)

    Elliott, Brian

    2010-09-14

    Methods of making alkyl esters are described herein. The methods are capable of using raw, unprocessed, low-cost feedstocks and waste grease. Generally, the method involves converting a glyceride source to a fatty acid composition and esterifying the fatty acid composition to make alkyl esters. In an embodiment, a method of making alkyl esters comprises providing a glyceride source. The method further comprises converting the glyceride source to a fatty acid composition comprising free fatty acids and less than about 1% glyceride by mass. Moreover, the method comprises esterifying the fatty acid composition in the presence of a solid acid catalyst at a temperature ranging firm about 70.degree. C. to about 120.degree. C. to produce alkyl esters, such that at least 85% of the free fatty acids are converted to alkyl esters. The method also incorporates the use of packed bed reactors for glyceride conversion and/or fatty acid esterification to make alkyl esters.

  11. Solid state NMR methods for coal science. Progress report, October 1-December 31, 1985. [Cholesteryl acetate

    Energy Technology Data Exchange (ETDEWEB)

    Zilm, K.W.

    1986-04-01

    This report covers the progress made on the title project during the last quarter. During the last three months we have concentrated on further developing a new 2-D NMR method that should be useful for coals. As outlined in a previous report this new technique separates the contribution of methines, methylenes and methyl or quaternary carbons to the carbon-13 CPMAS spectra of coals. In contrast to the heteronuclear shift correlation method, which observes only protonated carbons, this method observes all carbon centers seen in a standard CPMAS spectrum. The method has been successfully applied to a rather complex molecule, cholesteryl acetate. Even though there is severe spectral overlap in this model compound's CPMAS spectrum, the dipolar-shift correlation method allows us to assign each resonance. The distribution of functional types of carbon determined in this experiment appears to be close to quantitative. In addition we have begun to test our ultra high field CPMAS equipment on chemically modified coals. 4 figs.

  12. Surface components of chylomicrons from rats fed glyceryl or alkyl esters of fatty acids: minor components.

    Science.gov (United States)

    Yang, L Y; Kuksis, A; Myher, J J; Pang, H

    1992-08-01

    The lipid class, fatty acid and molecular species composition of the minor polar surface components of rat lymph chylomicrons were determined during absorption of menhaden oil and corn oil or of the corresponding fatty acid ethyl esters. In addition to the previously reported minor polar lipids (sphingomyelin, phosphatidylserine, phosphatidylinositol, phosphatidic acid and lysophosphatidylcholine), we identified phosphatidylglycerol, dimethylphosphatidylethanolamine, ceramide and cholesteryl sulfate in the chylomicrons from both oil and ester feeding. The dietary fatty acids were found to be incorporated to a variable extent into the different phospholipid classes, the proportions of which remained the same during both types of feeding. No evidence was obtained for the presence of the minor glycerophospholipids characteristic of the lysosomal membranes (e.g., bis-phosphatidic, lysobisphosphatidic and semilysobis-phosphatidic acids), although special efforts were made to identify them. These results indicate that the chylomicrons arising from the monoacylglycerol and phosphatidic acid pathways of triacylglycerol biosynthesis become enveloped in closely similar monolayers of phospholipids. Hence, all triacylglycerols may be secreted from the villus cells via a common mechanism as suggested by the previously demonstrated convergence (at the 2-monoacylglycerol stage) of the monoacylglycerol and the phosphatidic acid pathways of mucosal triacylglycerol formation [Yang, Y.L., and Kuksis, A. (1991) J. Lipid Res. 32, 1173-1186]. PMID:1406072

  13. Sintesis Metil Ester Sulfonat Dari Asam Stearat Dan Metil Ester Sulfonat Dari Asam Oleat

    OpenAIRE

    Samosir, Yustina

    2011-01-01

    The Synthesis of Methyl Ester Sulfonate (MES) from stearic acid and from oleic acid through the stages of esterification reaction, that are esterification from stearic acid and oleic acid that forms methyl ester stearic acid and methyl ester oleic acid next stage was sulfonating the two of methyl esters to form a methyl ester sulfonate stearic acid and methyl ester oleic acid sulfonate. Furthermore, both fatty acid methyl ester sulfonate is neutralized with NaOH to obtain sulfonate salt. ...

  14. Pretilt Angles of Vertically Aligned Nematic Liquid Crystal (NLC) with the Application of Copolymers Possessing Chalconyl and Cholesteryl Moieties

    Science.gov (United States)

    Hwang, Jeoung-Yeon; Seo, Dae-Shik; Son, Jong Ho; Suh, Dong Hack

    2000-11-01

    We performed the synthesis of a new copoly (M4Ch-ChMA), copoly ((4-methacryloyloxy) chalcone-cholestery methacrylate), with chalconyl and cholesteryl moiety characteristics for photoalignment materials. Good thermal stabilities of the synthesized copolymers are confirmed by thermogravimetric analysis (TGA) measurement. The pretilt angles of the nematic liquid crystal (NLC) are reduced as UV exposure time is increased on the copolymer surfaces. A pretilt angle of 81° in NLC was observed with UV exposure of 3 min on the copolymer-3 surface. The NLCs pretilt angle is attributed to increased chalcone with increasing the UV exposure time.

  15. Environmental effect of rapeseed oil ethyl ester

    International Nuclear Information System (INIS)

    Exhaust emission tests were conducted on rapeseed oil methyl ester (RME), rapeseed oil ethyl ester (REE) and fossil diesel fuel as well as on their mixtures. Results showed that when considering emissions of nitrogen oxides (NOx), carbon monoxide (CO) and smoke density, rapeseed oil ethyl ester had less negative effect on the environment in comparison with that of rapeseed oil methyl ester. When fuelled with rapeseed oil ethyl ester, the emissions of NOx showed an increase of 8.3% over those of fossil diesel fuel. When operated on 25-50% bio-ester mixed with fossil diesel fuel, NOx emissions marginally decreased. When fuelled with pure rapeseed oil ethyl ester, HC emissions decreased by 53%, CO emissions by 7.2% and smoke density 72.6% when compared with emissions when fossil diesel fuel was used. Carbon dioxide (CO2) emissions, which cause greenhouse effect, decreased by 782.87 g/kWh when rapeseed oil ethyl ester was used and by 782.26 g/kWh when rapeseed oil methyl ester was used instead of fossil diesel fuel. Rapeseed oil ethyl ester was more rapidly biodegradable in aqua environment when compared with rapeseed oil methyl ester and especially with fossil diesel fuel. During a standard 21 day period, 97.7% of rapeseed oil methyl ester, 98% of rapeseed oil ethyl ester and only 61.3% of fossil diesel fuel were biologically decomposed. (author)

  16. Avocado and olive oil methyl esters

    International Nuclear Information System (INIS)

    Biodiesel, the mono-alkyl esters of vegetable oils, animal fats or other triacylglycerol-containing materials and an alternative to conventional petroleum-based diesel fuel, has been derived from a variety of feedstocks. Numerous feedstocks have been investigated as potential biodiesel sources, including commodity oils, however, the methyl esters of avocado and olive oil would likely be suitable as biodiesel fuel. In order to expand the database and comprehensive evaluation of the properties of vegetable oil esters, in this work the fuel-related properties of avocado and olive oil methyl esters, which exhibit similar fatty acid profiles including high oleic acid content, are determined. The cetane numbers of avocado oil methyl esters and olive oil methyl esters are relatively high, determined as 59.2 and 62.5, respectively, due to their elevated content of methyl oleate. Other properties are well within the ranges specified in biodiesel standards. The cloud points of both esters are slightly above 0 °C due to their content of saturated esters, especially methyl palmitate. Overall, avocado and olive oil yield methyl esters with fuel properties comparable to methyl esters from other commodity vegetable oils. The 1H and 13C NMR spectra of avocado and olive oil methyl esters are reported. -- Highlights: • Methyl esters of avocado and olive oil meet biodiesel fuel standards. • Provides comparison for methyl esters of other vegetable oils with high oleic content. • Discusses and compares present results with prior literature

  17. Synthesis of substituted 2-cyanoarylboronic esters

    DEFF Research Database (Denmark)

    Lysén, Morten; Hansen, Henriette M; Begtrup, Mikael; Kristensen, Jesper L

    2006-01-01

    The synthesis of substituted 2-cyanoarylboronic esters is described via lithiation/in situ trapping of the corresponding methoxy-, trifluoromethyl-, fluoro-, chloro-, and bromobenzonitriles. The crude arylboronic esters were obtained in high yields and purities and with good regioselectivities....

  18. Fabrication and humidity sensing performance studies of a fluorescent film based on a cholesteryl derivative of perylene bisimide.

    Science.gov (United States)

    Zhang, Shujuan; Zhou, Feng; Peng, Haonan; Liu, Taihong; Ding, Liping; Fang, Yu

    2016-08-01

    A fluorescent film based on a cholesteryl derivative of perylene bisimide (PTCDI-co-CholDEA) was fabricated via utilization of an electrostatic spinning technique on a glass plate surface. SEM studies revealed that the film was characterized by fibrous network structure. It is the structure and the chemical composition that make the fluorescence emission of the film sensitive to the variation of local environmental humidity. The sensitivity of the sensing is 0.1497 (×10(4)a.u. of the intensity)/1% RH, of which RH is the abbreviation of relative humidity. The maximum quenching efficiency of the film is 55.4% when humidity reaches 97% RH. Furthermore, the sensing process is fully reversible, and presence of other commonly found liquids shows little effect to the monitoring process. PMID:27131145

  19. Fabrication and humidity sensing performance studies of a fluorescent film based on a cholesteryl derivative of perylene bisimide

    Science.gov (United States)

    Zhang, Shujuan; Zhou, Feng; Peng, Haonan; Liu, Taihong; Ding, Liping; Fang, Yu

    2016-08-01

    A fluorescent film based on a cholesteryl derivative of perylene bisimide (PTCDI-co-CholDEA) was fabricated via utilization of an electrostatic spinning technique on a glass plate surface. SEM studies revealed that the film was characterized by fibrous network structure. It is the structure and the chemical composition that make the fluorescence emission of the film sensitive to the variation of local environmental humidity. The sensitivity of the sensing is 0.1497 (× 104 a.u. of the intensity)/1% RH, of which RH is the abbreviation of relative humidity. The maximum quenching efficiency of the film is 55.4% when humidity reaches 97% RH. Furthermore, the sensing process is fully reversible, and presence of other commonly found liquids shows little effect to the monitoring process.

  20. Scanning Tunneling Imaging of Bio-Organic Molecules and Their Tunneling Properties: Fatty Acids, Their Derivatives and Cholesteryl Stearate

    Science.gov (United States)

    Yoshimura, Kousei; Arakawa, Hideo; Ikai, Atsushi

    1995-06-01

    Scanning tunneling microscopy imaging was applied to long-chain fatty acids, their derivatives and cholesteryl stearate in the adsorbed state at the liquid-solid interface between phenyloctane and highly oriented pyrolytic graphite. Cerotic acid, lignoceric acid, stearic acid, sodium stearate, stearoyl amide, and stearoyl anilide all produced regular arrays of dark and bright bands. Bright bands in the images of all execept the last compound were assigned as side-by-side alignment of hydrocarbon chains based on the variation of the band width between the three fatty acids. In the case of stearoyl anilide, the bright part was assigned to aromatic ring structure and the wider dark area to the hydrocarbon part.

  1. Biodiesel With Optimized Fatty Ester Composition

    Science.gov (United States)

    Biodiesel is largely composed of the mono-alkyl esters, usually methyl esters, of vegetable oils or animal fats with its fatty acid profile corresponding to that of the parent oil or fat. The different fatty esters have varying properties of relevance to biodiesel. The feedstock-dependent variatio...

  2. Enantiospecific Alkynylation of Alkylboronic Esters

    OpenAIRE

    Wang, Yahui; Noble, Adam; Myers, Eddie L.; Aggarwal, Varinder K.

    2016-01-01

    Enantioenriched secondary and tertiary alkyl pinacolboronic esters undergo enantiospecific deborylative alkynylation through a Zweifel-type alkenylation followed by a 1,2-elimination reaction. The process involves the use of α-lithio vinyl bromide or vinyl carbamate, species whose application to Zweifel-type reactions has not previously been explored. The resulting functionalized 1,1-disubstituted alkenes undergo facile base-mediated elimination to generate the terminal alkyne products in hig...

  3. Methods of making alkyl esters

    Science.gov (United States)

    Elliott, Brian

    2010-08-03

    A method comprising contacting an alcohol, a feed comprising one or more glycerides and equal to or greater than 2 wt % of one or more free fatty acids, and a solid acid catalyst, a nanostructured polymer catalyst, or a sulfated zirconia catalyst in one or more reactors, and recovering from the one or more reactors an effluent comprising equal to or greater than about 75 wt % alkyl ester and equal to or less than about 5 wt % glyceride.

  4. Sesquiterpene Esters from Salvia roborowskii

    Institute of Scientific and Technical Information of China (English)

    Ya LI; Ning LOU; Yan Qi WU; Xian Feng LIN; Yu LI

    2003-01-01

    Two new sesquiterpene esters, 3β, 6β, 8α-triacetyl-4β, 5α-epoxy -1- oxogermacr-10(14)-ene (1) and 3β, 6β, 8α-triacetyl-4β, 5α-epoxygermacr-1(10)-ene (2) were isolated from the whole plant of Salvia roborowskii Maxim. Their structures were elucidated by means of spectral data (2DNMR and HRMS).

  5. Facile synthesis of linear-dendritic cholesteryl-poly(epsilon-caprolactone)-b-(L-lysine)(G2) by thiol-ene and azide-alkyne "click" reactions

    DEFF Research Database (Denmark)

    Javakhishvili, Irakli; Binder, W.H.; Tanner, S.;

    2010-01-01

    The construction of a linear-dendritic block copolymer consisting of terminal cholesteryl moiety, poly(epsilon-caprolactone), and a second generation L-lysine dendron has been accomplished by the combination of copper(I) catalyzed azide-alkyne and UV-triggered thiol-ene "click" reactions. Ring-op...... thiocholesterol. Near to quantitative functionalization of the intermediate and final products has been attained as confirmed by NMR spectroscopy and MALDI-TOF spectrometry....

  6. Ester Tuiksoo. Proua Suhkru kibedad päevad / Ester Tuiksoo ; interv. Piret Tali

    Index Scriptorium Estoniae

    Tuiksoo, Ester, 1965-

    2005-01-01

    Põllumajandusminister Ester Tuiksoo, kellel peagi täitub ministri ametis aasta Euroopa Liidu suhkrutrahvist, maaettevõtlusest, põllumajandusest, Euroopa Liidu toetustest, ministri elu- ja teenistuskäigust. Lisa: Ester Tuiksoo

  7. Carboxylic Acid Esters as Substrates of Cholinesterases

    Science.gov (United States)

    Brestkin, A. P.; Rozengart, E. V.; Abduvakhabov, A. A.; Sadykov, A. A.

    1983-10-01

    Data on the kinetics of the hydrolysis of various carboxylic acid esters by two main types of cholinesterases — acetylcholinesterase from human erythrocytes and butyrylcholinesterase from horse blood serum — are surveyed. It is shown that the rate of enzyme hydrolysis depends significantly on the structure of the acyl part of the ester molecule, the nature of the ester heteroatom, the structure of the alcohol component, and particularly the structure of the onium group. Esters based on natural products are of special interest as specific substrates of these enzymes. The role of the productive and non-productive sorption of the substrates in enzyme catalysis is demonstrated. The bibliography includes 81 references.

  8. Synthesis of insecticidal sucrose esters

    Institute of Scientific and Technical Information of China (English)

    Song Zi-juan; Li Shu-jun; Chen Xi; Liu Li-mei; Song Zhan-qian

    2006-01-01

    Some synthetic sucrose esters (SE) are a relatively new class of insecticidal compounds produced by reacting sugars with fatty acids, which are safe for the environment. Especially, sucrose esters composed of C6-C12 fatty acids have desirable insecticidal properties against many soft-bodied arthropod pests. In our study, sucrose octanoate which has the highest activity against a range of arthropod species was synthesized by a trans-esterification method and proved its insecticidal property. Under the condition of a homogeneous liquid, sucrose octanoate was prepared by reacting ethyl octanoate with sucrose at reduced pressure; the yield was 79.11%. Sucrose octanoate synthesized was identified and its property analyzed by IR, TLC and spectrophotometric analysis. It was shown that the ratio of monoester to polyester in sucrose octanoate was 1.48:1. The insecticidal activity of the synthetic sucrose octanoate was evaluated at a concentration of 4 and 8 mg·mL-1. The mortality of first-instar larvae ofLymantria dispar from its contact toxicity was 72.5% after 36 hours, the revision insect reduced rate of Aphis glycines reached above 80% at 4 and 8 mg·mL-1 after being treated for 5 days. Since the SE products are nontoxic to humans and higher animals, fully biodegradable and hydrolyzed to readily metabolizable sucrose and fatty acid, they are not harmful to crops and appear to be good insecticide candidates.

  9. Synthesis, biological evaluation, and baboon PET imaging of the potential adrenal imaging agent cholesteryl-p-[18f]fluorobenzoate

    International Nuclear Information System (INIS)

    Cholesteryl-p-[18F]fluorobenzoate ([18F]CFB) was investigated as a potential adrenal positron emission tomography (PET) imaging agent for the diagnostic imaging of adrenal disorders. We describe the synthesis, biodistribution, adrenal autoradiography, and baboon PET imaging of [18F]CFB. The synthesis of [18F]CFB was facilitated by the use of a specially designed microwave cavity that was instrumental in effecting 70-83% incorporation of fluorine-18 in 60 s via [18F]fluoro-for-nitro exchange. Tissue distribution studies in mature female Sprague-Dawley rats showed good accumulation of [18F]CFB in the steroid-secreting tissues, adrenals and ovaries, at 1 h postinjection. The effectiveness of [18F]CFB to accumulate in diseased adrenals was shown through biodistribution studies in hypolipidemic rats, which showed a greater than threefold increase in adrenal uptake at 1 h and increased adrenal/liver and adrenal/kidney ratios. Analysis of the metabolites at 1 h in the blood, adrenals, spleen, and ovaries of hypolipidemic and control rats showed the intact tracer representing greater than 86%, 93%, 92%, and 82% of the accumulated activity, respectively. [18F]CFB was confirmed to selectively accumulate in the adrenal cortex versus the adrenal medulla by autoradiography. Normal baboon PET imaging with [18F]CFB effectively showed adrenal localization as early as 15 min after injection of the tracer, with enhanced adrenal contrast seen at 60-70 min. These results suggest that [18F]CFB may be useful as an adrenal PET imaging agent for assessing adrenal disorders

  10. Cold Flow Properties of Fatty Esters

    Directory of Open Access Journals (Sweden)

    Andrea Kleinová

    2007-09-01

    Full Text Available The article is devoted to the study of cold fl ow properties of neat esters of branched chain alcohols with fatty acids and blends of these esters with fossil diesel fuel. According to the determined CFPP values, the influence of alcohol branching on the fuel filterability is negligible and was detected only in the case of 2-ethyl hexanol. Fossil fuel blending with fatty esters up to 10 % vol. does not substantially change the cold flow properties of fossil fuel. DSC cooling scan parameters should be employed to predict CFPP of blended diesel fuel.

  11. Space-Qualifiable Cyanate Ester Elastomer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cornerstone Research Group, Inc. (CRG) proposes to design and develop a space-qualifiable cyanate ester elastomer for application in self-deployable space...

  12. Space-Qualifiable Cyanate Ester Elastomer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In Phase 1, CRG demonstrated the feasibility of a novel approach to prepare cyanate ester based elastomers. This approach polymerizes in-situ siloxane within a...

  13. Rapid Output Growth of Special Acrylic Esters

    Institute of Scientific and Technical Information of China (English)

    Wang Lianzhi

    2007-01-01

    @@ Acrylic esters are usually classified into general-purpose varieties and special varieties. The production and application of general-purpose varieties is already quite matured in the world and their output growth tends to be flat. Owing to the development of coatings, electronics, automobiles,textiles, printing and construction sectors, especially the application of radiation curing technology in various sectors, special acrylic esters have developed rapidly.

  14. Synthesis of a new energetic nitrate ester

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, David E [Los Alamos National Laboratory

    2008-01-01

    Nitrate esters have been known as useful energetic materials since the discovery of nitroglycerin by Ascanio Sobrero in 1846. The development of methods to increase the safety and utility of nitroglycerin by Alfred Nobel led to the revolutionary improvement in the utility of nitroglycerin in explosive applications in the form of dynamite. Since then, many nitrate esters have been prepared and incorporated into military applications such as double-based propellants, detonators and as energetic plasticizers. Nitrate esters have also been shown to have vasodilatory effects in humans and thus have been studied and used for treatments of ailments such as angina. The mechanism of the biological response towards nitrate esters has been elucidated recently. Interestingly, many of the nitrate esters used for military purposes are liquids (ethylene glycol dinitrate, propylene glycol dinitrate, etc). Pentaerythritol tetranitrate (PETN) is one of the only solid nitrate esters, besides nitrocellulose, that is used in any application. Unfortunately, PETN melting point is above 100 {sup o}C, and thus must be pressed as a solid for detonator applications. A more practical material would be a melt-castable explosive, for potential simplification of manufacturing processes. Herein we describe the synthesis of a new energetic nitrate ester (1) that is a solid at ambient temperatures, has a melting point of 85-86 {sup o}C and has the highest density of any known nitrate ester composed only of carbon, hydrogen, nitrogen and oxygen. We also describe the chemical, thermal and sensitivity properties of 1 as well as some preliminary explosive performance data.

  15. Co-liposomes having anisamide tagged lipid and cholesteryl tryptophan trigger enhanced gene transfection in sigma receptor positive cells.

    Science.gov (United States)

    Misra, Santosh K; Moitra, Parikshit; Kondaiah, Paturu; Bhattacharya, Santanu

    2016-06-01

    Selective gene transfection could be strategy of interest for reducing off-target gene expression and toxicity. In this respect, sigma receptors are found to be over-expressed in many human tumors and liposomal formulations with ability to target these sigma receptors may improve the transfection efficiency to a significant level. To this direction, six novel lipids have been synthesized with different hydrophobic segments such as a long hydrophobic chain or a cholesteryl group and L-tryptophan as the head group. Three of them, Lipid 1, 3 and 5 possessed cationic Me3N(+) moiety at the distal end. In contrast each of the other three Lipid 2, 4 and 6 possessed sigma receptor targeting anisamide group with no cationic charge. Mixing of cationic and anisamide counterparts of the same lipid in a molar ratio of 1:1 produced co-liposomes L-M-1 (Lipid 1+2), L-M-2 (Lipid 3+4) and L-M-3 (Lipid 5+6). These co-liposomes, while keeping the sigma targeting anisamide tag intact, showed good DNA binding and release which were optimized from EB intercalation and gel electrophoresis assays. Inclusion of a zwitterionic, fusogenic natural lipid, DOPE, into the co-liposomes further improved the binding efficiencies of the lipid mixtures with DNA. These co-liposomes having cationic and anisamide lipids and DOPE were highly selective toward sigma positive HEK293 and HEK293T cells compared to the sigma negative HeLa cells. As evidenced from both FACS and luciferase assay, a lipid mixture comprising Lipid 3, 4 and DOPE in a molar ratio of 1:1:1 (L-M-2D1) was the best for transfection of reporter pEGFP-C3 and functional pCEP4-p53 gene plasmids. Anisamide mediated sigma receptor selectivity was further probed by pre-incubating the transfecting cells with lipids possessing anisamide and by quantification of the un-transfected plasmid DNA. Also each formulation was highly non-toxic in the cell lines examined. PMID:26945165

  16. Allied, MGC link on cyanate esters

    International Nuclear Information System (INIS)

    In the latest of a line of joint ventures in its plastics business, Allied Signal has reached agreement with Mitsubishi Gas Chemical (MGC) to jointly develop thermoset cyanate ester resins and blends. The deal will involve further development of Allied Signal's Primaset phenol-formaldehyde cyanate ester resins, a new entrant in the thermoset arena. Although the Primaset resins were discovered in the 1960s, this would be the first time they are available commercially. The deal will marry Primaset technology with MGC's Skylex bisphenol A cyanate ester resins, says Fred DiAntonis, director/advanced materials at Allied Signal. The two firms are looking at marketing blends of the two materials. The potential market for these resins, used commercially by the electronics industry in printed circuit boards and by the aerospace industry in composites, is significant, says Robert P. Viarengo, Allied Signal president/performance materials. By aligning ourselves with MGC, the world leader in cyanate ester resin, we anticipate moving forward aggressively. The main competitor is Ciba, which acquired bisphenol A cyanate ester resins with its purchase of Rhone-Poulenc's high temperature resins business. DiAntonis estimates the market for cyanate ester resins could be worth $150 million by the end of the decade, although development costs have been in the tens of millions of dollars range

  17. Detection of testosterone esters in blood.

    Science.gov (United States)

    Forsdahl, Guro; Erceg, Damir; Geisendorfer, Thomas; Turkalj, Mirjana; Plavec, Davor; Thevis, Mario; Tretzel, Laura; Gmeiner, Günter

    2015-01-01

    Injections of synthetic esters of testosterone are among the most common forms of testosterone application. In doping control, the detection of an intact ester of testosterone in blood gives unequivocal proof of the administration of exogenous testosterone. The aim of the current project was to investigate the detection window for injected testosterone esters as a mixed substance preparation and as a single substance preparation in serum and plasma. Furthermore, the suitability of different types of blood collection devices was evaluated. Collection tubes with stabilizing additives, as well as non-stabilized serum separation tubes, were tested. A clinical study with six participants was carried out, comprising a single intramuscular injection of either 1000 mg testosterone undecanoate (Nebido(®)) or a mixture of 30 mg testosterone propionate, 60 mg testosterone phenylpropionate, 60 mg testosterone isocaproate, and 100 mg testosterone decanoate (Sustanon(®)). Blood was collected throughout a testing period of 60 days. The applied analytical method for blood analysis included liquid-liquid extraction and preparation of oxime derivatives, prior to TLX-sample clean-up and liquid chromatography-tandem mass spectrometry (LC-MS/MS) detection. All investigated testosterone esters could be detected in post-administration blood samples. The detection time depended on the type of ester administered. Furthermore, results from the study show that measured blood concentrations of especially short-chained testosterone esters are influenced by the type of blood collection device applied. The testosterone ester detection window, however, was comparable. PMID:26695486

  18. Self-associating poly(ethylene oxide)-b-poly(alpha-cholesteryl carboxylate-epsilon-caprolactone) block copolymer for the solubilization of STAT-3 inhibitor cucurbitacin I.

    Science.gov (United States)

    Mahmud, Abdullah; Patel, Sarthak; Molavi, Ommoleila; Choi, Phillip; Samuel, John; Lavasanifar, Afsaneh

    2009-03-01

    An increase in the degree of chemical compatibility between drug and polymeric structure in the core has been shown to raise the encapsulation efficiency and lower the rate of drug release from polymeric micelles. In this study, to achieve an optimized polymeric micellar delivery system for the solubilization and controlled delivery of cucurbitacin I (CuI), the Flory-Huggins interaction parameter (chi(sc)) between CuI and poly(epsilon-caprolactone) (PCL), poly(alpha-benzylcarboxylate-epsilon-caprolactone) (PBCL) and poly(alpha-cholesteryl carboxylate-epsilon-caprolactone) (PChCL) structures was calculated by group contribution method (GCM) as an indication for the degree of chemical compatibility between different micellar core structures and CuI. The results pointed to a better compatibility between CuI and PChCL core rationalizing the synthesis of self-associating methoxy poly(ethylene oxide)-b-poly(alpha-cholesteryl carboxylate-epsilon-caprolactone) block copolymer (MePEO-b-PChCL). Novel block copolymer of MePEO-b-PChCL was synthesized through, first, preparation of substituted monomer, that is, alpha-cholesteryl carboxylate-epsilon-caprolactone, and further ring opening polymerization of this monomer by methoxy PEO (5000 g mol(-1)) using stannous octoate as catalyst. Synthesized block copolymers were characterized for their molecular weight and polydispersity by (1)H NMR and gel permeation chromatography. Self-assembled MePEO-b-PChCL micelles were characterized for their size, morphology, critical micellar concentration (CMC), capacity for the physical encapsulation of CuI, and mode of CuI release in comparison to MePEO-b-PCL and MePEO-b-PBCL micelles. Overall, the experimental order for the level of CuI encapsulation in different polymeric micellar formulations was consistent with what was predicted by the Flory-Huggins interaction parameter. Although MePEO-b-PChCL micelles exhibited the highest level of CuI loading, this structure did not show any significant

  19. ESTER - a European source term evaluation system

    International Nuclear Information System (INIS)

    The Commission of the European Communities (CEC) sponsors considerable model development and validation in the area of Light Water Reactor (LWR) source term, and naturally wishes to see the results used as widely as possible. It also has a role in fostering collaboration between European teams involved in source term analysis, for which purpose Phebus-Fission Product (FP) is acting as a focal point. To further both aims the Joint Research Centre (JRC) decided in 1989 to sponsor the development of the best-estimate code ESTER, which is both a software environment and a set of coupled source term modules which when completed should offer potentialities not currently available within Europe. This paper describes first the overall architecture of ESTER, then the component parts: the tools and services, the user interface, and the modules which perform the physics and chemistry calculations, emphasizing the design choices which have been made. The quality assurance system for the whole system is also reviewed. Contributions from the model developers, both underway, and expected, are then surveyed in the context of the overall development of ESTER, and the planning of the creation and extension of ESTER is given. The paper closes with some proposals for sharing ESTER within Europe and for ensuring its maintenance and continued rational development. (Author)

  20. Synthesis of bioreductive esters from fungal compounds.

    Science.gov (United States)

    Weerapreeyakul, Natthida; Anorach, Rutchayaporn; Khuansawad, Thidarut; Yenjai, Chavi; Isaka, Masahiko

    2007-06-01

    Four new bioreductive esters (7-10) have been synthesized. Their structures composed of trimethyl lock containing quinone propionic acid with an ester linkage to the fungal cytotoxic compounds; preussomerin G (1), preussomerin I (2), phaseolinone (3) and phomenone (4). The synthesized esters are aimed to act via reductive activation specifically at the cancer cells, resulting from hypoxia and overexpression of reductases. Hence, the toxicity will be lessened during distribution across the normal cells. The anticancer activity was determined in cancer cell lines with reported reductase i.e., BC-1 cells and NCI-H187 as well as in non-reductase containing cancer cells; KB cells. When considering each cell lines, result showed that structure modification giving to 7-10 led to less cytotoxicity than their parent compounds (1-4). Both 7 and 8 were strongly cytotoxic (IC50 < or = 5 microg/ml) to NCI-H187, whereas 9 and 10 were moderately cytotoxic (IC50 = 6-10 microg/ml) to BC-1 cells. Additional study of stability of represented phenolic ester (8) and an alcoholic ester (9) were performed. Result illustrated that both 8 and 9 were stable in the presence of esterase. Therefore, the cytotoxicity of the synthesized compounds (8-10) might be due to partial bioreductive activation in the cancer cells. PMID:17541198

  1. Affinity labelling enzymes with esters of aromatic sulfonic acids

    Science.gov (United States)

    Wong, Show-Chu; Shaw, Elliott

    1977-01-01

    Novel esters of aromatic sulfonic acids are disclosed. The specific esters are nitrophenyl p- and m-amidinophenylmethanesulfonate. Also disclosed is a method for specific inactivation of the enzyme, thrombin, employing nitrophenyl p-amidinophenylmethanesulfonate.

  2. NF EN 14103. July 2003. Fatty compounds derived products. Fatty acids methylic esters (FAME). Determination of the ester and methylic ester content of linoleic acid; NF EN 14103. Juillet 2003. Produits derives des corps gras. Esters methyliques d'acides gras (EMAG). Determination de la teneur en ester et en ester methylique de l'acide linolenique

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

    This European standard aims at determining the ester and methylic ester content of fatty acids methylic esters (FAME) used as pure bio-fuels or as constituent of a heating or diesel fuel. This method allows also to determine the methylic ester content of linoleic acid. It allows to verify that the ester content of FAMEs is greater than 90% (m/m) and that the linoleic acid content is comprised between 1% (m/m) and 15% (m/m). The method is applicable to FAMEs with methylic ester contents comprised between C14 and C24. (J.S.)

  3. Long-lived testosterone esters in the rat.

    OpenAIRE

    Borg, W; Shackleton, C. H.; Pahuja, S L; Hochberg, R B

    1995-01-01

    Over the past decade it has become increasingly clear that steroid hormones are enzymatically esterified with fatty acids. These steroidal esters are the natural analogs of synthetic esters that are used therapeutically. One such family of pharmacological steroids is the synthetic alkyl esters of testosterone, androgens with great hormonal potency. We have investigated whether testosterone esters exist naturally by using the rat as a model. Most tissues of male rats, including blood, have ver...

  4. Acrylic Acid and Esters Will Be Oversupply

    Institute of Scientific and Technical Information of China (English)

    Zheng Chengwang

    2007-01-01

    @@ Drastic capacity growth The production capacity of acrylic acid in China has grown drastically in recent years. With the completion of the 80 thousand t/a acrylic acid and 130 thous and t/a acrylic ester project in Shenyang Paraffin Chemical Industrial Co., Ltd., (CCR2006,No. 31) the capacity of acrylic acid in China has reached 882 thousand t/a.

  5. Correlation and prediction of mixing thermodynamic properties of ester-containing systems: Ester + alkane and ester + ester binary systems and the ternary dodecane + ethyl pentanoate + ethyl ethanoate

    International Nuclear Information System (INIS)

    Highlights: ► Excess enthalpies and volumes were measured for ester–ester–alkane. ► Mixing behaviour for ester–ester, ester–alkane and ester–ester–alkane are analyzed. ► Correlations with a new polynomial model reproduce well the mixing properties. ► UNIFAC predictions for hE result acceptable excluding the ester–ester mixtures. - Abstract: Excess thermodynamic properties VmE and HmE, have been measured for the ternary mixture dodecane + ethyl pentanoate + ethyl ethanoate and for the corresponding binaries dodecane + ethyl pentanoate, dodecane + ethyl ethanoate, ethyl pentanoate + ethyl ethanoate at 298.15 K. All mixtures show endothermic and expansive effects. Experimental results are correlated with a suitable equation whose final form for the excess ternary quantity ME contains the particular contributions of the three binaries (i–j) and a last term corresponding to the ternary, all of them obtained considering fourth-order interactions. The fit goodness for all mixtures is good and comparable to others equations taken from the literature. In this work the dissolution model for the binaries and ternary is analyzed with a special attention to ester–ester binaries whose behaviour is discussed. The application of the UNIFAC group contribution model to estimate the HmE yields acceptable results for the binaries (with the exception of ester–ester) and for the ternary mixture.

  6. Technetium and rhenium tracers with metabolizable ester functions

    International Nuclear Information System (INIS)

    Re-DMSA (dimercaptosuccinic acid) ester complexes were prepored by ligand exchange reactions. To determine whether the ester band in Re-DMSA ester complexes is susceptible to cleavage by esterases, incubation experiments with tissue homogenates and plasma were carried out. (BBR)

  7. 40 CFR 721.3085 - Brominated phthalate ester.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Brominated phthalate ester. 721.3085... Substances § 721.3085 Brominated phthalate ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as brominated phthalate ester (PMN P-90-581)...

  8. 21 CFR 175.210 - Acrylate ester copolymer coating.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acrylate ester copolymer coating. 175.210 Section... COATINGS Substances for Use as Components of Coatings § 175.210 Acrylate ester copolymer coating. Acrylate ester copolymer coating may safely be used as a food-contact surface of articles intended for...

  9. Determination of Mass Spectrometric Sensitivity of Different Metalloporphyrin Esters Relative to Porphyrin Ester

    DEFF Research Database (Denmark)

    Larsen, Elfinn; Egsgaard, Helge; Møller, J.;

    1977-01-01

    Quantitative determination of metalloporphyrin contamination in preparations of biologically important porphyrins was achieved mass spectrometrically by application of the integrated ion current technique. For this purpose, the relative molecular ion sensitivities of the contaminating metal...... complexes were determined from the ratios of the integrated molecular ion currents of a series of calibration samples containing a porphyrin ester and one of its metal complexes in known molar ratio. Complexes formed with divalent ions of Cu, Zn, Fe, Co and Ni of copro- as well as uro......-prophyrin permethylester were all found to have the same molecular ion sensitivities as their metal-free porphyrin ester. The relative metalloporphyrin ester content in a sample of porphyrin ester was thus obtained directly as the integrated ion current ratios of the normalized molecular ions. The preparation of...

  10. Ester Tuiksoo - Eesti esimene naissoost põllumajandusminister / Ester Tuiksoo ; interv. Toomas Verrev

    Index Scriptorium Estoniae

    Tuiksoo, Ester, 1965-

    2007-01-01

    Ametist lahkuv põllumajandusminister Ester Tuiksoo räägib saadud juhtimiskogemusest, Euroopa Liidu ühise põllumajanduspoliitika juurutamisest, rahvuskala valimisest, Rahvaliidu käekäigust parlamendivalimistel

  11. Half esters and coating compositions comprising reactions products of half esters and polyepoxides

    OpenAIRE

    Blaauw, R; Mulder, W J; Koelewijn, R.; Boswinkel, G.

    2006-01-01

    The present invention relates to half esters based on dicarboxylic acid derivatives and dimer fatty diols, wherein the dimer fatty dio ls are based on dimerised and/or trimerised and/or oligomerised unsaturated fatty acids. The present invention further relates to resin compositions based on the half ester and an polyepoxide. The resin composition can be used in high solids coatings, inks, adhesives, wall covering products, flooring products and plastic products

  12. Expanding the modular ester fermentative pathways for combinatorial biosynthesis of esters from volatile organic acids.

    Science.gov (United States)

    Layton, Donovan S; Trinh, Cong T

    2016-08-01

    Volatile organic acids are byproducts of fermentative metabolism, for example, anaerobic digestion of lignocellulosic biomass or organic wastes, and are often times undesired inhibiting cell growth and reducing directed formation of the desired products. Here, we devised a general framework for upgrading these volatile organic acids to high-value esters that can be used as flavors, fragrances, solvents, and biofuels. This framework employs the acid-to-ester modules, consisting of an AAT (alcohol acyltransferase) plus ACT (acyl CoA transferase) submodule and an alcohol submodule, for co-fermentation of sugars and organic acids to acyl CoAs and alcohols to form a combinatorial library of esters. By assembling these modules with the engineered Escherichia coli modular chassis cell, we developed microbial manufacturing platforms to perform the following functions: (i) rapid in vivo screening of novel AATs for their catalytic activities; (ii) expanding combinatorial biosynthesis of unique fermentative esters; and (iii) upgrading volatile organic acids to esters using single or mixed cell cultures. To demonstrate this framework, we screened for a set of five unique and divergent AATs from multiple species, and were able to determine their novel activities as well as produce a library of 12 out of the 13 expected esters from co-fermentation of sugars and (C2-C6) volatile organic acids. We envision the developed framework to be valuable for in vivo characterization of a repertoire of not-well-characterized natural AATs, expanding the combinatorial biosynthesis of fermentative esters, and upgrading volatile organic acids to high-value esters. Biotechnol. Bioeng. 2016;113: 1764-1776. © 2016 Wiley Periodicals, Inc. PMID:26853081

  13. Synthesis of 11C labelled methyl esters: transesterification of enol esters versus BF3 catalysed esterification-a comparative study

    International Nuclear Information System (INIS)

    C-11 labelled methyl esters have been synthesized via the transesterification of enol esters in the presence of C-11 methanol and 1,3 dichlorodibutylstannoxane as catalyst. This method leaves functional groups intact and allows access to a wider variety of C-11 labelled methyl esters compared to the BF3 catalysed ester formation, which uses carboxylic acids and C-11 methanol as starting materials

  14. A novel capsule-like structure of micro-sized particles formed by phytosterol ester and γ-cyclodextrin in water.

    Science.gov (United States)

    Sasako, Hiroshi; Kihara, Fukashi; Koyama, Kazuo; Higashi, Kenjirou; Yamamoto, Keiji; Moribe, Kunikazu

    2016-11-01

    The composite material formed by phytosterol ester (PSE) and γ-cyclodextrin (γ-CD) disperses readily in water and has been used to mask undesirable flavours. This paper elucidates the structure of the PSE/γ-CD particle. Cryogenic scanning electron microscopy and contact angle measurements showed that the PSE/γ-CD particles formed a capsule-like structure with a hydrophilic surface. A phase-solubility study using cholesteryl oleate (ChO), one of the components of PSE, showed that ChO formed a hydrophilic and stoichiometric inclusion complex with γ-CD at a molar ratio of 2:5. The structure of the PSE/γ-CD inclusion complex was similar to that of ChO/γ-CD, based on differential scanning calorimetry and powder X-ray diffractometry results. Thus, we propose that the PSE/γ-CD particle has a capsule-like structure wherein a hydrophobic PSE droplet is surrounded by an outer layer of the hydrophilic PSE/γ-CD inclusion complex. PMID:27211647

  15. Atmospheric oxidation of selected alcohols and esters

    Energy Technology Data Exchange (ETDEWEB)

    Becker, K.H.; Cavalli, F.

    2001-03-01

    The decision whether it is appropriate and beneficial for the environment to deploy specific oxygenated organic compounds as replacements for traditional solvent types requires a quantitative assessment of their potential atmospheric impacts including tropospheric ozone and other photooxidant formation. This involves developing chemical mechanisms for the gasphase atmospheric oxidation of the compounds which can be reliably used in models to predict their atmospheric reactivity under a variety of environmental conditions. Until this study, there was very little information available concerning the atmospheric fate of alcohols and esters. The objectives of this study were to measure the atmospheric reaction rates and to define atmospheric reaction mechanisms for the following selected oxygenated volatile organic compounds: the alcohols, 1-butanol and 1-pentanol, and the esters, methyl propionate and dimethyl succinate. The study has successfully addressed these objectives. (orig.)

  16. Photoenolization of o-Methylvalerophenone Ester Derivative.

    Science.gov (United States)

    Das, Anushree; Lao, Emily A; Gudmundsdottir, Anna D

    2016-05-01

    Photolysis of ester 1 in argon-saturated methanol and acetonitrile does not produce any product, whereas irradiation of 1 in oxygen-saturated methanol yields peroxide 2. Laser flash photolysis studies demonstrate that 1 undergoes intramolecular H atom abstraction to form biradical 3 (λmax ~340 nm), which intersystem crosses to form photoenols Z-4 and E-4 (λmax ~380 nm). Photoenols 4 decay by regenerating ester 1. With the aid of density functional theory calculations, it was concluded the photoenol E-4 does not undergo spontaneous lactonization or electrocyclic ring closure because the transition state barriers for these reactions are too large to compete with reketonization of E-4 to form 1. PMID:27061950

  17. Naturally occurring antifungal aromatic esters and amides

    International Nuclear Information System (INIS)

    During the search of antifungal natural products from terrestrial plants, a new long chained aromatic ester named grandiflorate along with spatazoate from Portulaca grandiflora and N-[2-methoxy-2-(4-methoxyphenyl) ethyl]-trans-cinnamide and aegeline from Solanum erianthum of Nigeria were isolated and tested against six fungal species. The known constituents have not been reported so far from mentioned investigated plants. Structures of the isolated compounds were elucidated with the aid of spectroscopic techniques including two dimensional NMR experiments. Among the compounds, the esters found more potent than amides against Candida albicans and Aspergillus flavus. The new compound grandiflorate gave response against all tested fungal species while aegeline was found to give lowest inhibition during this study. (author)

  18. Gas chromatographic retention data of wax esters

    Czech Academy of Sciences Publication Activity Database

    Stránský, Karel; Zarevúcka, Marie; Valterová, Irena; Wimmer, Zdeněk

    2006-01-01

    Roč. 1128, č. 1/2 (2006), s. 208-219. ISSN 0021-9673 R&D Projects: GA ČR(CZ) GA203/04/0120; GA AV ČR(CZ) IAA4055403 Institutional research plan: CEZ:AV0Z40550506 Keywords : Wax esters * gas chromatography * Kováts index * Reduced Kováts index Subject RIV: CC - Organic Chemistry Impact factor: 3.554, year: 2006

  19. Synthesis of ester-siloxane multiblock copolymers

    OpenAIRE

    Antić Vesna V.; Vučković Marija V.; Govedarica Milutin N.

    2004-01-01

    It was shown that the two-stage transesterification/polycondensation reaction in the melt, can successfully be applied for the preparation of poly(butylene terephtalate-dimethylsiloxane) multiblock copolymers. Three series of co-polymers were synthesized, using poly(dimethylsiloxanes) bearing ester (two series) and hydroxy -end groups as reactants. The structure and composition of the obtained copolymers were determined by 1H NMR spectroscopy A mechanism, i.e. an order of reaction steps, invo...

  20. Ethyl ester production from (RBD palm oil

    Directory of Open Access Journals (Sweden)

    Oscar Mauricio Martínez Ávila

    2010-07-01

    Full Text Available This work develops a methodology for obtaining ethyl esters from RBD (refined, bleached and deodorised palm oil by evaluating the oil’s transesterification and separation. Two catalysts were first tested (KOH and NaOH by studying the effect of water presence on the reaction. The separation process was then evaluated by using water and water-salt and water-acid mixtures, establishing the agent offering the best results and carrying out the purification stage. Raw materials and products were characterised for comparing the latter with those obtained by traditional means and verifying the quality of the esters so produced; minimum differences were found bet-ween both. The proposed methodology thus allows esters to be used as raw material in petrochemical industry applications. A more profitable process can be obtained compared to those used today, given the amounts of separation agent so established (1% H3PO4 solution, in water. The overall process achieved 74.4% yield, based on the oil being used.

  1. Pengaruh Katalis H2SO4 pada Reaksi Epoksidasi Metil Ester PFAD (Palm Fatty Acid Distillate)

    OpenAIRE

    Sinaga, Mersi Suriani

    2010-01-01

    Ester epoksi selain sebagai pelunak juga dapat memperbaiki ketahanan komponen polivinil klorida (PVC) terhadap panas dan cahaya. Penelitian ini dilakukan untuk merumuskan kondisi katalis yang sesuai bagi pembuatan senyawa epoksi metil ester PFAD dari senyawa metil ester PFAD. Metil ester PFAD terdiri dari ester lemak jenuh dan tidak jenuh., metode pemisahan kristalisasi dengan pelarut metanol untuk memisahkan ester lemak jenuh dari ester lemak tak jenuh, yang bertujuan meningkatkan kemamp...

  2. Environmentally friendly properties of vegetable oil methyl esters

    Directory of Open Access Journals (Sweden)

    Gateau Paul

    2005-07-01

    Full Text Available Measurements were carried out on Vegetable Oil Methyl Esters (VOME or FAME answering the most recent specifications. The products tested are RME (Rapeseed oil Methyl Ester, ERME (Erucic Rapeseed oil Methyl Esters, SME (Sunflower oil Methyl Esters, and HOSME (High Oleic Sunflower oil Methyl Esters. They contain more than 99.5% of fatty acid mono esters. The compositions are given. VOME are not volatile and they are not easily flammable. They are not soluble in water and they are biodegradable. According to the methods implemented for the determination of the German classification of substances hazardous to waters WGK, they are not toxic on mammals and unlike diesel fuel they are not toxic on fish, daphnia, algae and bacteria. The RME is not either toxic for shrimps. According to tests on rabbits, RME and SME are not irritating for the skin and the eyes. VOME display particularly attractive environmental properties.

  3. Synthesis, Characterization and Properties of Vinyl Ester Matrix Resins

    OpenAIRE

    Li, Hui III

    1998-01-01

    Vinyl ester oligomers diluted with styrene are important matrix resins for thermosetting polymer composites. A major objective of this work has been to study the chemistry and kinetics of the cure reactions of vinyl ester resins at elevated curing temperatures, which are consistent with typical composite processing conditions. The crosslinking reaction of vinyl ester resins was studied by FTIR and the loss of the carbon-carbon double bonds of the methacrylate (943 cm-1) and styrene (910 cm-1...

  4. Tandem transformation of glycerol to esters.

    Science.gov (United States)

    Sotenko, Maria V; Rebroš, Martin; Sans, Victor S; Loponov, Konstantin N; Davidson, Matthew G; Stephens, Gill; Lapkin, Alexei A

    2012-12-31

    Tandem transformation of glycerol via microbial fermentation and enzymatic esterification is presented. The reaction can be performed with purified waste glycerol from biodiesel production in a continuous mode, combining continuous fermentation with membrane-supported enzymatic esterification. Continuous anaerobic fermentation was optimized resulting in the productivity of 2.4 g L⁻¹ h⁻¹ of 1,3-propanediol. Biphasic esterification of 1,3-propanediol was optimized to achieve ester yield of up to 75%. A hollow fibre membrane contactor with immobilized Rhizomucor miehei lipase was demonstrated for the continuous tandem fermentation-esterification process. PMID:22796408

  5. Stereoselective Formation of Trisubstituted Vinyl Boronate Esters by the Acid-Mediated Elimination of α-Hydroxyboronate Esters

    OpenAIRE

    Guan, Weiye; Michael, Alicia K.; McIntosh, Melissa L.; Koren-Selfridge, Liza; Scott, John P.; Clark, Timothy B.

    2014-01-01

    The copper-catalyzed diboration of ketones followed by an acid-catalyzed elimination leads to the formation of 1,1-disubstituted and trisubstituted vinyl boronate esters with moderate to good yields and selectivity. Addition of tosic acid to the crude diboration products provides the corresponding vinyl boronate esters upon elimination. The trisubstituted vinyl boronate esters are formed as the (Z)-olefin isomer, which was established by subjecting the products to a Suzuki–Miyaura coupling re...

  6. SwissProt search result: AK243532 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243532 J100077E15 (Q9Z0M5) Lysosomal acid lipase/cholesteryl ester hydrolase prec...ursor (EC 3.1.1.13) (LAL) (Acid cholesteryl ester hydrolase) (Sterol esterase) (Lipase A) (Cholesteryl esterase) LICH_MOUSE 6e-35 ...

  7. SwissProt search result: AK100511 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK100511 J023099N19 (Q9Z0M5) Lysosomal acid lipase/cholesteryl ester hydrolase prec...ursor (EC 3.1.1.13) (LAL) (Acid cholesteryl ester hydrolase) (Sterol esterase) (Lipase A) (Cholesteryl esterase) LICH_MOUSE 2e-52 ...

  8. SwissProt search result: AK107138 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK107138 002-124-C12 (P38571) Lysosomal acid lipase/cholesteryl ester hydrolase pre...cursor (EC 3.1.1.13) (LAL) (Acid cholesteryl ester hydrolase) (Sterol esterase) (Lipase A) (Cholesteryl esterase) LICH_HUMAN 4e-40 ...

  9. SwissProt search result: AK064554 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK064554 002-112-C03 (Q64194) Lysosomal acid lipase/cholesteryl ester hydrolase pre...cursor (EC 3.1.1.13) (LAL) (Acid cholesteryl ester hydrolase) (Sterol esterase) (Lipase A) (Cholesteryl esterase) LICH_RAT 1e-11 ...

  10. Physical and monolayer film properties of potential fatty ester biolubricants

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Linxing [Iowa State University; Hammond, Earl G [Iowa State University; Wang, Tong [Iowa State University; Bu, Wei [Ames Laboratory; Vaknin, David [Ames Laboratory

    2014-04-03

    The desire to replace petroleum-based lubricants with alternatives that are environmentally friendly and made from sustainable sources has encouraged the development of biolubricants based on vegetable oils. To be good lubricants, the materials should have low melting points, appropriate viscosity and oxidative stability. In this paper, we report the melting point and viscosity of oleate esters of ethylene glycol, 1,2-propanediol, 2,3-butanediol, and pentaerythritol as well as the decanoate esters of 2,3-butanediol and the 12-methyltetradecanoate esters of 1,2-propanediol. Polyol esters that have a free hydroxy group had lower melting points than the completely esterified polyols, but the completely esterified polyol esters exhibited less change in viscosity with temperature than those having a free hydroxy group. 2, 3-Butanediol monooleate, which melted at -48.6°C shows promise as a biolubricant, but its viscosity index was estimated to be 100. Pentaerythritol oleate esters, with melting points below -10°C and viscosity indices in the range of 170–197, may be suitable candidates as biolubricants. The behavior of esters spread as a monomolecular film at air/water interface may provide insight into the way they behave when spread on metal or polar surfaces, so the pressure-area isotherms of 2,3-butanediol monoleate and selected esters are also reported.

  11. 40 CFR 721.2950 - Carboxylic acid glycidyl esters.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Carboxylic acid glycidyl esters. 721... Substances § 721.2950 Carboxylic acid glycidyl esters. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as carboxylic acid glycidyl...

  12. Analysis of Adipate Ester Contents in PVC Plastics

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    2006-01-01

    Plasticizers are needed in flexible PVC (PolyVinylChloride) products. There is serious concern that commonly used phthalate esters may harm life reproduction systems. To avoid the problems, instead adipate di-esters (AEs) of C8 to C10 alcohols are used as higher prized alternatives; e.g. di-2...

  13. The Preparation and Enzymatic Hydrolysis of a Library of Esters

    Science.gov (United States)

    Sanford, Elizabeth M.; Smith, Traci L.

    2008-01-01

    An investigative case study involving the preparation of a library of esters using Fischer esterification and alcoholysis of acid chlorides and their subsequent enzymatic hydrolysis by pig liver esterase and orange peel esterase is described. Students work collaboratively to prepare and characterize the library of esters and complete and evaluate…

  14. Synthesis, biological evaluation, and baboon PET imaging of the potential adrenal imaging agent cholesteryl-p-[{sup 18}f]fluorobenzoate

    Energy Technology Data Exchange (ETDEWEB)

    Jonson, Stephanie D.; Welch, Michael J. E-mail: welch@mirlink.wustl.edu

    1999-01-01

    Cholesteryl-p-[{sup 18}F]fluorobenzoate ([{sup 18}F]CFB) was investigated as a potential adrenal positron emission tomography (PET) imaging agent for the diagnostic imaging of adrenal disorders. We describe the synthesis, biodistribution, adrenal autoradiography, and baboon PET imaging of [{sup 18}F]CFB. The synthesis of [{sup 18}F]CFB was facilitated by the use of a specially designed microwave cavity that was instrumental in effecting 70-83% incorporation of fluorine-18 in 60 s via [{sup 18}F]fluoro-for-nitro exchange. Tissue distribution studies in mature female Sprague-Dawley rats showed good accumulation of [{sup 18}F]CFB in the steroid-secreting tissues, adrenals and ovaries, at 1 h postinjection. The effectiveness of [{sup 18}F]CFB to accumulate in diseased adrenals was shown through biodistribution studies in hypolipidemic rats, which showed a greater than threefold increase in adrenal uptake at 1 h and increased adrenal/liver and adrenal/kidney ratios. Analysis of the metabolites at 1 h in the blood, adrenals, spleen, and ovaries of hypolipidemic and control rats showed the intact tracer representing greater than 86%, 93%, 92%, and 82% of the accumulated activity, respectively. [{sup 18}F]CFB was confirmed to selectively accumulate in the adrenal cortex versus the adrenal medulla by autoradiography. Normal baboon PET imaging with [{sup 18}F]CFB effectively showed adrenal localization as early as 15 min after injection of the tracer, with enhanced adrenal contrast seen at 60-70 min. These results suggest that [{sup 18}F]CFB may be useful as an adrenal PET imaging agent for assessing adrenal disorders.

  15. Methods of refining and producing dibasic esters and acids from natural oil feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Snead, Thomas E.; Cohen, Steven A.; Gildon, Demond L.

    2016-06-14

    Methods and systems for making dibasic esters and/or dibasic acids using metathesis are generally disclosed. In some embodiments, the methods comprise reacting a terminal olefin ester with an internal olefin ester in the presence of a metathesis catalyst to form a dibasic ester and/or dibasic acid. In some embodiments, the terminal olefin ester or the internal olefin ester are derived from a renewable feedstock, such as a natural oil feedstock. In some such embodiments, the natural oil feedstock, or a transesterified derivative thereof, is metathesized to make the terminal olefin ester or the internal olefin ester.

  16. Phosphorylation of Kraft fibers with phosphate esters.

    Science.gov (United States)

    Shi, Ying; Belosinschi, Dan; Brouillette, François; Belfkira, Ahmed; Chabot, Bruno

    2014-06-15

    Phosphate esters, derived from two different long-chain aliphatic alcohols, were used as phosphorylating reagents for Kraft pulp fibers. High phosphorus contents and almost non-degraded fibers were obtained by following this pathway. The phosphorylation efficiency was influenced by the alkyl chain length of PEs since the phosphorus content in modified fibers was higher for the shorter chain reagent. Due to the heterogeneous reaction environment, the amount of grafted phosphorus was found to be almost three times higher at the surface than in the bulk of the fibers. Analyses also indicated that the phosphorus was bonded to fibers as a phosphate-like structure. Furthermore, the situation seemed to be different for the fiber surface where significant amounts of phosphorus were present in more complex structures like pyrophosphate or even oligo-phosphate. PMID:24721058

  17. The plasma physics measurement unit ESTER

    International Nuclear Information System (INIS)

    The ESTER measurement station on board of the landing unit of the Phobos spacecraft has three distinct units for cosmic radiation measurements on the Martian moon Phobos. They are the LET, SLED and HARP. The Low Energy Telescope (LET) has been designed to measure solar cosmic radiation (flux, energy spectra, angular distribution and ion composition) in the interplanetary space. The Solar Low-Energy Detectors (SLED) are used to detect interplanetary flux of the low-energy cosmic rays, and the galactic background radiation. The Hyperbolic Analyzer in Retarding Potential (HARP) module is used for the studies of energy and directional distributions of very low energy ions and electrons. The DPU, a unit for control and data processing of the three plasma physics measurement units is also described. (R.P.) 3 refs.; 2 figs

  18. Electrochemistry of polyamidoamine dendrimers ester gel electrolytes

    Institute of Scientific and Technical Information of China (English)

    CHEN Hong; MO Zunli

    2004-01-01

    This paper described the first example of polyamidoamine dendrimers ester (PAMAM) used as a gel electrolyte with a short-chain polyethylene glycol (MPEG-400) as a plasticizer. The polymer films are solid and sticky. Background cyclic voltammetry (CV) shows a potential window between +0.7 and -0.7 V vs. Ag/AgCl. The voltammetry of ferrocene and 7,7,8,8-tetracyanoquinodimethane (TCNQ) indicates that diffusion coefficients are in the range of 10-a-10-9 cm2/s.Ionic conductivities are approximately 10-6 S/cm. Similar films using dimethyl sulfoxide (DMSO) as a plasticizer instead of MPEG-400 have demonstrated ionic conductivities of 10-4 S/cra and reversible voltammetry. However, UV spectrophotometry shows that 70% of the DMSO is lost under vacuum, indicating the difficulty in quantifying the DMSO content when exposed to vacuum.

  19. Spasmolytic Activity of Chiral Monoterpene Esters

    Directory of Open Access Journals (Sweden)

    Damião P. de Sousa

    2011-01-01

    Full Text Available The present study aimed to investigate the correlation between structure and spasmolytic activity of racemate and enantiomers of linalyl and citronellyl acetates, chemical constituents of several bioactive essential oils, such as Thymus leptophyllus essential oil, which contains linalyl acetate as major constituent. The monoterpene esters showed significant spasmolytic activity in guinea-pig isolated ileum. Therefore, these result confirm that linalyl acetate should be involved at spasmolytic activity of the Thymus leptophyllus essential oil. The (+-, (--, and (±-linalyl acetates exhibited a relaxant effect equipotent. (+- and (--Citronellyl acetates also showed a similar effect, however, synergistic action was presented on constituents of citronellyl acetate racemate. The study showed that the racemate and enantiomers of linalyl and citronellyl acetates are bioactives and that the position of the functional group on the molecule structures influences the effect of relaxation of the ileum.

  20. Sintesis Surfaktan Metil Ester Sulfonat dari Sulfonasi Metil Ester Asam Lemak Minyak Kastor (Ricinus communis L)

    OpenAIRE

    Aritonang, Rianti E J

    2011-01-01

    Methyl ester sulfonate (MES) surfactant is an anionic surfactant which could be synthesized from oil. Surfactant have a capability to reduce surface tension, interface tension and elevate the stability of emulsion system. The material sources to produce surfactant was derived from petroleum oil, vegetables oil and animals fats. One of vegetables oil is polar castor oil, because it contained of ricinoleic acid as the major compound which has –OH group. Castor oil could be synthesize became ...

  1. Short-chain aliphatic ester synthesis using Thermobifida fusca cutinase.

    Science.gov (United States)

    Su, Lingqia; Hong, Ruoyu; Guo, Xiaojie; Wu, Jing; Xia, Yongmei

    2016-09-01

    Short-chain aliphatic esters are commonly used as fruit flavorings in the food industry. In this study, Thermobifida fusca (T. fusca) cutinase was used for the synthesis of aliphatic esters, and the maximum yield of ethyl caproate reached 99.2% at a cutinase concentration of 50U/ml, 40°C, and water content of 0.5%, representing the highest ester yield to date. The cutinase-catalyzed esterification displayed strong tolerance for water content (up to 8%) and acid concentration (up to 0.8M). At substrate concentrations ⩽0.8M, the ester yield remained above 80%. Moreover, ester yields of more than 98% and 95% were achieved for acids of C3-C8 and alcohols of C1-C6, respectively, indicating extensive chain length selectivity of the cutinase. These results demonstrate the superior ability of T. fusca cutinase to catalyze the synthesis of short-chain esters. This study provides the basis for industrial production of short-chain esters using T. fusca cutinase. PMID:27041308

  2. Effects of phorbol esters in carp (Cyprinus carpio L).

    Science.gov (United States)

    Becker, K; Makkar, H P

    1998-04-01

    Carp (Cyprinus carpio L) were fed diets containing phorbol esters at concentrations of 0, 3.75, 7.5, 15, 31, 62.5, 125, 250, 500 and 1,000 micrograms/g feed. Phorbol esters were from Jatropha curcas nuts. Jatropha curcas toxicity has been reported in humans, rodents and livestock, and phorbol esters have been identified as the main toxic agent. The adverse effects observed in carp at phorbol esters concentrations of 31 micrograms/g or higher were lower average metabolic growth rate, fecal mucus production and rejection of feed. Average metabolic growth rates (g/kg 0.8/d) in a 7-d experimental period during which diets containing phorbol esters were fed to carp (values with different letters being significantly different) were 15.4a, 14.4a, 12.5ab, 12.4ab, 10.9b, 3.4c, 0.2c, -3.8d, -4.9d and -5.6d, respectively, at the above mentioned concentrations. The values for the recovery phase of 9-d during which phorbol esters were not included in the diet were 16.0a, 15.6a, 14.9a, 15.6a, 5.3b, 1.6b, 4.6bc, 6.3bc, 7.8c and 8.2c, respectively. The adverse effects of phorbol esters were reversible since withdrawal of the esters from the diets led to gain in body mass. None of the fish died at any of the concentrations studied. Incorporation of vitamin C, an antioxidant, at levels of 0.4 and 2% in the feed did not prevent occurrence of the adverse effects of the phorbol esters. The threshold level at which phorbol esters appeared to cause adverse effects in carp was 15 micrograms/g feed or 15 ppm in the diet. Carp were highly sensitive to phorbol esters, thus making them a useful species for bioassay of these compounds. This bioassay together with other analytic procedures could be of immense use in the development of detoxification processes for agro-industrial products containing phorbol esters, such as jatropha meal or jatropha oil, and as a quality control method to monitor successive stages in industrial detoxification processes. PMID:9554059

  3. Distillative self-sorting of dynamic ester libraries.

    Science.gov (United States)

    Ji, Qing; Miljanić, Ognjen Š

    2013-12-20

    Metal alkoxides, such as NaOt-Bu or Ti(OBu)4, can initiate acyl exchange within complex ester libraries. Reactive distillation of such dynamic combinatorial libraries (DCLs) isolates the most volatile ester at the expense of the less volatile library members that share a constituent with it. This process can be iteratively repeated to yield up to four industrially relevant esters as pure products from a single reaction setup. An algorithm has been developed to predict reactive distillation products in DCLs of as many as 121 members. PMID:24245808

  4. Stereoselective formation of trisubstituted vinyl boronate esters by the acid-mediated elimination of α-hydroxyboronate esters.

    Science.gov (United States)

    Guan, Weiye; Michael, Alicia K; McIntosh, Melissa L; Koren-Selfridge, Liza; Scott, John P; Clark, Timothy B

    2014-08-01

    The copper-catalyzed diboration of ketones followed by an acid-catalyzed elimination leads to the formation of 1,1-disubstituted and trisubstituted vinyl boronate esters with moderate to good yields and selectivity. Addition of tosic acid to the crude diboration products provides the corresponding vinyl boronate esters upon elimination. The trisubstituted vinyl boronate esters are formed as the (Z)-olefin isomer, which was established by subjecting the products to a Suzuki-Miyaura coupling reaction to obtain alkenes of known geometry. PMID:24915498

  5. Methods of refining and producing dibasic esters and acids from natural oil feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Snead, Thomas E.; Cohen, Steven A.; Gildon, Demond L.

    2016-03-15

    Methods are provided for refining natural oil feedstocks and producing dibasic esters and/or dibasic acids. The methods comprise reacting a terminal olefin with an internal olefin in the presence of a metathesis catalyst to form a dibasic ester and/or dibasic acid. In certain embodiments, the olefin esters are formed by reacting the feedstock in the presence of a metathesis catalyst under conditions sufficient to form a metathesized product comprising olefins and esters, separating the olefins from the esters in the metathesized product, and transesterifying the esters in the presence of an alcohol to form a transesterified product having olefin esters.

  6. Rare linking hydrogels based on acrylic acid and carbohydrate esters

    Directory of Open Access Journals (Sweden)

    U. Akhmedov

    2012-09-01

    Full Text Available The process of copolymerization of acrylic acid and esters poliallil sucrose; pentaerythritol and sorbitol, some of its laws are identified. The kinetic regularities of copolymerization and the optimum conditions of synthesis was established.

  7. Alternating Poly(ester-anhydride) by Insertion Polycondensation.

    Science.gov (United States)

    Haim-Zada, Moran; Basu, Arijit; Hagigit, Tal; Schlinger, Ron; Grishko, Michael; Kraminsky, Alexander; Hanuka, Ezra; Domb, Abraham J

    2016-06-13

    We report on a synthetic method where polyanhydride is used as starting material and the ester monomers are inserted through complete esterification, leading to an alternating ester-anhydride copolymer. The molar ratio of ricinoleic acid (RA) and sebacic acid (SA) was optimized until polysebacic acid is completely converted to carboxylic acid-terminated RA-SA and RA-SA-RA ester-dicarboxylic acids. These dimers and trimers were activated with acetic anhydride, polymerized under heat and vacuum to yield alternating RA-SA copolymer. The resulting alternating poly(ester-anhydride) have the RA at regular intervals. The regular occurrences of RA side chains prevent anhydride interchange, enhancing hydrolytic stability, which allows storage of the polymer at room temperature. PMID:27198864

  8. Syntheses of glucomannan esters and their thermal and mechanical properties.

    Science.gov (United States)

    Enomoto-Rogers, Yukiko; Ohmomo, Yusuke; Takemura, Akio; Iwata, Tadahisa

    2014-01-30

    Fully substituted glucomannan (GM) acylates with acyl carbon numbers (n) of 2, 3, 4, 5, 6, 8, 10, and 12 were prepared from konjac GM (KGM) in carboxylic acid/trifluoroacetic anhydride (TFAA). GM acetate acylates (n=3, 4, 5, 8, 12, 16, and 18) were prepared from KGM in acetic acid/carboxylic acid/TFAA. Differential scanning calorimetry (DSC) and X-ray diffraction revealed that the GM esters did not exhibit melting peaks and reflections derived from crystal, indicating they were amorphous. The glass-transition temperatures (Tgs) of the GM esters tended to decrease with increasing acyl carbon number, ranging from 174°C for GM acetate (GMAc) to 64°C for GM laurate (GMLa). Colorless and transparent GM ester films were obtained by solvent casting and thermo-pressing. The mechanical properties of the GM ester films were controlled by the acyl group structure. PMID:24299815

  9. Decarbonylative organoboron cross-coupling of esters by nickel catalysis.

    Science.gov (United States)

    Muto, Kei; Yamaguchi, Junichiro; Musaev, Djamaladdin G; Itami, Kenichiro

    2015-01-01

    The Suzuki-Miyaura cross-coupling is a metal-catalysed reaction in which boron-based nucleophiles and halide-based electrophiles are reacted to form a single molecule. This is one of the most reliable tools in synthetic chemistry, and is extensively used in the synthesis of pharmaceuticals, agrochemicals and organic materials. Herein, we report a significant advance in the choice of electrophilic coupling partner in this reaction. With a user-friendly and inexpensive nickel catalyst, a range of phenyl esters of aromatic, heteroaromatic and aliphatic carboxylic acids react with boronic acids in a decarbonylative manner. Overall, phenyl ester moieties function as leaving groups. Theoretical calculations uncovered key mechanistic features of this unusual decarbonylative coupling. Since extraordinary numbers of ester-containing molecules are available both commercially and synthetically, this new 'ester' cross-coupling should find significant use in synthetic chemistry as an alternative to the standard halide-based Suzuki-Miyaura coupling. PMID:26118733

  10. Methods of refining and producing isomerized fatty acid esters and fatty acids from natural oil feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Snead, Thomas E.; Cohen, Steven A.; Gildon, Demond L.; Beltran, Leslie V.; Kunz, Linda A.; Pals, Tessa M.; Quinn, Jordan R; Behrends, Jr., Raymond T.; Bernhardt, Randal J.

    2016-07-05

    Methods are provided for refining natural oil feedstocks and producing isomerized esters and acids. The methods comprise providing a C4-C18 unsaturated fatty ester or acid, and isomerizing the fatty acid ester or acid in the presence of heat or an isomerization catalyst to form an isomerized fatty ester or acid. In some embodiments, the methods comprise forming a dibasic ester or dibasic acid prior to the isomerizing step. In certain embodiments, the methods further comprise hydrolyzing the dibasic ester to form a dibasic acid. In certain embodiments, the olefin is formed by reacting the feedstock in the presence of a metathesis catalyst under conditions sufficient to form a metathesized product comprising olefins and esters, separating the olefins from the esters in the metathesized product, and transesterifying the esters in the presence of an alcohol to form a transesterified product having unsaturated esters.

  11. RAFT Polymerization of Vinyl Esters: Synthesis and Applications

    OpenAIRE

    Simon Harrisson; Xuan Liu; Jean-Noël Ollagnier; Olivier Coutelier; Jean-Daniel Marty; Mathias Destarac

    2014-01-01

    This article is the first comprehensive review on the study and use of vinyl ester monomers in reversible addition fragmentation chain transfer (RAFT) polymerization. It covers all the synthetic aspects associated with the definition of precision polymers comprising poly(vinyl ester) building blocks, such as the choice of RAFT agent and reaction conditions in order to progress from simple to complex macromolecular architectures. Although vinyl acetate was by far the most studied monomer of th...

  12. A newly discovered xenobiotic metabolic pathway: Ethyl ester formation

    Energy Technology Data Exchange (ETDEWEB)

    Chou, R.C.; Wyss, R.; Huselton, C.A.; Wiegand, U.W. (F. Hoffmann-La Roche Ltd., Basel (Switzerland))

    1991-01-01

    Formation of etretinate, ethyl ester of acitretin, can be confirmed in vitro and in vivo using acitretin as the substrate. Etretinate was identified by LC/MS. The in vitro incubation was performed using rat and human liver 12000 g supernatant, and the in vivo experiment was conducted in rats after oral dosing of acitretin. The ethyl ester formation was greatly enhanced by addition of or dosing with ethanol.

  13. Rheology of silicon carbide/vinyl ester nanocomposites

    OpenAIRE

    Yong, Virginia; Hahn, H. Thomas

    2006-01-01

    Silicon carbide (SiC) nanoparticles with no surface treatment raise the viscosity of a vinyl ester resin much more intensely than micrometer-size SiC particles. An effective dispersant generally causes a reduction in the resin viscosity attributed to its surface-active properties and thereby increases the maximum fraction of particles that can be introduced. This article assesses the rheological behavior of SiC-nanoparticle-filled vinyl ester resin systems with the Bingham, power-law, Hersche...

  14. The enantioselective b-keto ester reductions by Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    HASSAN TAJIK

    2006-09-01

    Full Text Available The enantioselective yeast reduction of aromatic b-keto esters, by use of potassium dihydrogen phosphate, calcium phosphate (monobasic, magnesium sulfate and ammonium tartrate (diammonium salt (10:1:1:50 in water at pH 7 as a buffer for 72–120 h with 45–90 % conversion to the corresponding aromatic -hydroxy esters was achieved by means of Saccharomyces cerevisiae.

  15. Transport of glutathione diethyl ester into human cells.

    OpenAIRE

    Levy, E J; Anderson, M E; Meister, A.

    1993-01-01

    Glutathione monoesters in which the carboxyl group of the glycine residue is esterified were previously found, in contrast to glutathione itself, to be effectively transported into various types of cells and to be converted intracellularly into glutathione. Glutathione monoesters are thus useful for prevention of oxidative stress, certain toxicities, and for treatment of glutathione deficiency. Glutathione diethyl ester is rapidly split to the glutathione monoethyl ester by mouse plasma gluta...

  16. Solid state crystallisation of oligosaccharide ester derivatives

    CERN Document Server

    Wright, E A

    2002-01-01

    An investigation of the solid state properties of oligosaccharide ester derivatives (OEDs) with potential applications in drug delivery has been carried out. The amorphous form of two OEDs, trehalose octa-acetate (TOAC) and 6:6'-di-(beta-tetraacetyl glucuronyl)-hexaacetyl trehalose (TR153), was investigated as a matrix for the sustained release of active ingredients. The matrices showed a tendency to crystallise and so polymorph screens were performed to provide crystalline samples for structural analysis. The crystal structures of TOAC methanolate and TR153 acetonitrile solvate have been determined by single-crystal laboratory X-ray diffraction. TOAC methanolate crystallises in the orthorhombic space group P2 sub 1 2 sub 1 2 sub 1 with a = 15.429(18) A, b = 17.934(19) A and c = 13.518(4) A at 123 K. The structure is isomorphous with the previously reported structure of TOAC monohydrate form II. TR153 acetonitrile solvate crystallises in the monoclinic spacegroup C2 with a = 30:160(6) A, b = 11.878(3) A, c 20...

  17. Combustion characteristics of the mustard methyl esters

    International Nuclear Information System (INIS)

    Mustard Methyl Esters (further bio diesel) and regular diesel fuel were tested in direct injection diesel engine. Analysis of experimental data was supported by an analysis of fuel injection and combustion characteristics. Engine fuelled with bio diesel had increased brake specific fuel consumption, reduced nitrogen oxides emission and smoke opacity, moderate increase in carbon monoxide emission with essentially unchanged unburned hydrocarbons emission. Increase in fuel consumption was attributed to lesser heating value of bio diesel and partially to decreased fuel conversion efficiency. Analysis of combustion characteristics revealed earlier start of injection and shorter ignition delay period of bio diesel. Resulting decrease in maximum rate of heat release and cylinder pressure was the most probable reason for reduced emission of nitrogen oxides. Analysis of combustion characteristics also showed that cetane index determined by ASTM Method D976 is not a proper measure of ignition quality of bio diesel. Conclusion was made on applicability of mustard oil as a source for commercial production of bio diesel in Pakistan. Potentialities of on improving combustion and emissions characteristics of diesel engine by reformulating bio diesel were discussed. (author)

  18. Determination of Mass Spectrometric Sensitivity of Different Metalloporphyrin Esters Relative to Porphyrin Ester

    DEFF Research Database (Denmark)

    Larsen, Elfinn; Egsgaard, Helge; Møller, J.; With, T. K.

    1977-01-01

    Quantitative determination of metalloporphyrin contamination in preparations of biologically important porphyrins was achieved mass spectrometrically by application of the integrated ion current technique. For this purpose, the relative molecular ion sensitivities of the contaminating metal compl...... complexes were determined from the ratios of the integrated molecular ion currents of a series of calibration samples containing a porphyrin ester and one of its metal complexes in known molar ratio. Complexes formed with divalent ions of Cu, Zn, Fe, Co and Ni of copro- as well as uro...

  19. Strategies for the analysis of highly reactive pinacolboronate esters.

    Science.gov (United States)

    Zhong, Qiqing; Ngim, Kenley K; Sun, Megan; Li, Jane; Deese, Alan; Chetwyn, Nik P

    2012-03-16

    Pinacolboronate esters (or boronic acid, pinacol esters) are widely used in the Suzuki coupling reaction to connect organic building blocks for the total synthesis of complex molecules. The 2-aminopyrimidine-5-pinacolboronate ester was used as a starting material in the synthesis of a development compound, necessitating a chromatographic purity method to assess its quality. This aryl pinacolboronate ester posed unique analytical challenges due to its facile hydrolysis to the corresponding boronic acid, which is nonvolatile and poorly soluble in organic solvents. This made GC and normal-phase HPLC analysis unsuitable. In reversed-phase mode, typical sample preparation and analysis conditions promoted rapid sample degradation to the boronic acid. To overcome these challenges, unconventional approaches were necessary in order to stabilize 2-aminopyrimidine-5-pinacolboronate ester, adequately solubilize its boronic acid, and produce acceptable separation and retention. The final method employed non-aqueous and aprotic diluent, and a reversed-phase separation using highly basic mobile phases (pH 12.4) with an ion pairing reagent. These strategies were successfully applied to several other reactive pinacolboronate esters for purity analysis, demonstrating broad applicability to this unique class of compounds. PMID:22321949

  20. Ester Tuiksoo võitleb viina puhtuse eest / Ester Tuiksoo ; interv. Silja Lättemäe

    Index Scriptorium Estoniae

    Tuiksoo, Ester, 1965-

    2006-01-01

    Põllumajandusminister Ester Tuiksoo lubab Euroopa Liidu piiritusjookide määruse eelnõu arutusel kaitsta seisukohta, et viinaks tuleb pidada üksnes teraviljast või kartulist valmistatud piiritusjooki

  1. Lubricating and Waxy Esters. VI. Effect of Symmetry about Ester on Crystallization of Linear Monoester Isomers

    Directory of Open Access Journals (Sweden)

    Laziz Bouzidi

    2014-08-01

    Full Text Available The crystal structure development of jojoba-like esters incorporating either 1-decenoic acid and/or 1-decenol, namely octadec-9-enyl dec-9-enoate (JLE-281, and its isomer dec-9-enyl oleate (JLE-282 was investigated to reveal the effect of symmetry about the ester group on crystallization of aliphatic fatty monoesters. The phase transformation path was investigated with temperature-time resolved X-ray diffraction during stepped isothermal crystallization, and while cooling from the melt at a fixed rate. Startling differences in phase behavior were uncovered between the isomers. When stepped isothermals were used, selective extinctions occurred at a transition temperature for JLE-281 but not for JLE-282. The extinctions, which are due to dramatic changes in the electronic density of certain families of planes, indicate a phase transition attributed to a brusque rearrangement of the oxygen atoms in the crystal subcell. The phase transition did not occur when the JLEs were cooled continuously. The crucial role played by the position of the alkyl chain and its orientation relative to the easy rotation site of the C–O bond in the phase trajectories of the JLEs was particularly highlighted.

  2. Rape oil methyl ester (RME) and used cooking oil methyl ester (UOME) as alternative fuels

    Energy Technology Data Exchange (ETDEWEB)

    Hohl, G.H. [Military Technology Agency, Vienna (Austria)

    1995-12-31

    The author presents a review about the fleet tests carried out by the Austrian Armed Forces concerning the practical application of a vegetable oil, i.e Rape Oil Methyl Ester (RME) and Used Cooking Oil Methyl Ester (UOME) as alternative fuels for vehicles under military conditions, and reviews other research results carried out in Austria. As a result of over-production in Western European agriculture, the increase in crop yields has led to tremendous surpluses. Alternative agricultural products have been sought. One alternative can be seen in biological fuel production for tractors, whereby the farmer is able to produce his own fuel supply as was the case when he previously provided self-made feed for his horses. For the market introduction different activities were necessary. A considerable number of institutes and organizations including the Austrian Armed Forces have investigated, tested and developed these alternative fuels. The increasing disposal problems of used cooking oil have initiated considerations for its use. The recycling of this otherwise waste product, and its preparation for use as an alternative fuel to diesel oil, seems to be most promising.

  3. Studies on novel interpenetrating networks of urethane modified poly(ester-amide and vinyl ester of bisphenol-C

    Directory of Open Access Journals (Sweden)

    Pragnesh N. Dave

    2016-05-01

    Full Text Available Bisphthalamic acids were prepared by reaction of maleic anhydride and aromatic diamines. Novel poly(ester-amides (PEAs were prepared by reaction of DGEBF with bisphthalamic acids. Acrylation of PEAs was carried out using acryloyl chloride; products are called acrylated poly(ester-amides (APEAs. Epoxy resin based unsaturated poly(ester-amide resins (UPEAs can be prepared by many methods but here these were prepared by reported method. These UPEAs were then treated with acryloyl chloride to afford acrylated UPEAs resin (i.e. AUPEAs. Interpenetrating networks of equal proportional urethane modified poly(ester-amide and acrylated poly(ester-amide and vinyl ester of biaphenol c (VE resin were prepared. Urethane modified APEAs and AUPEAs were characterized by elemental analysis, molecular weight was determined by vapor pressure osmometer and by IR spectral study and by thermogravimetry. Based on DSC data in situ glass reinforced composites of the resultant blends have been prepared and characterized for mechanical, electrical and chemical properties. Unreinforced blends were characterized by thermogravimetry (TGA.

  4. Sorption of organophosphate esters by carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Wei; Yan, Li [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Duan, Jinming [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an 710055 (China); Jing, Chuanyong, E-mail: cyjing@rcees.ac.cn [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)

    2014-05-01

    Graphical abstract: The interfacial interactions between the OPE molecules and CNTs. - Highlights: • Oxygen-containing groups on CNTs change the sorption property for OPEs. • Molecular configuration of OPEs has insignificant impact on their sorption. • Hydrophobic, π–π EDA and Brønsted acid–base interaction occurred between the CNTs and OPEs. - Abstract: Insights from the molecular-level mechanism of sorption of organophosphate esters (OPEs) on carbon nanotubes (CNTs) can further our understanding of the fate and transport of OPEs in the environment. The motivation for our study was to explore the sorption process of OPEs on multi-walled CNTs (MWCNTs), single-walled CNTs (SWCNTs) and their oxidized counterparts (O-MWCNTs and O-SWCNTs), and its molecular mechanism over a wide concentration range. The sorption isotherm results revealed that the hydrophobicity of OPEs dominated their affinities on a given CNT and the π–π electron donor–acceptor (EDA) interaction also played an important role in the sorption of aromatic OPEs. This π–π EDA interaction, verified with Raman and FT-IR spectroscopy, could restrict the radial vibration of SWCNTs and affect the deformation vibration γ(CH) bands of OPE molecules. The OPE surface coverage on CNTs, estimated using the nonlinear Dubinin–Ashtakhov model, indicated that the oxygen-containing functional groups on CNTs could interact with water molecules by H-bonding, resulting in a decrease in effective sorption sites. In addition, FTIR analysis also confirmed the occurrence of Brønsted acid–base interactions between OPEs and surface OH groups of SWCNTs. Our results should provide mechanistic insights into the sorption mechanism of OPE contaminants on CNTs.

  5. Synthesis and properties of differently charged chemiluminescent acridinium ester labels.

    Science.gov (United States)

    Natrajan, Anand; Sharpe, David

    2013-02-14

    Chemiluminescent acridinium dimethylphenyl esters containing N-sulfopropyl groups in the acridinium ring are highly sensitive, hydrophilic labels that are used in automated immunoassays for clinical diagnostics. Light emission from these labels is triggered with alkaline peroxide in the presence of a cationic surfactant. At physiological pH, N-sulfopropyl acridinium esters exist as water adducts that are commonly referred to as pseudobases. Pseudobase formation, which results from addition of water to the zwitterionic N-sulfopropyl acridinium ring, neutralizes the positive charge on the acridinium nitrogen and imparts a net negative charge to the label due to the sulfonate moiety. As a consequence, N-sulfopropyl acridinium ester conjugates of small molecule haptens as well as large molecules such as proteins gain negative charges at neutral pH. In the current study, we describe the synthesis and properties of two new hydrophilic acridinium dimethylphenyl ester labels where the net charge in the labels was altered. In one label, the structure of the hydrophilic N-alkyl group attached to the acridinium ring was changed so that the pseudobase of the label contains no net charge. In the second acridinium ester, two additional negative charges in the form of sulfopropyl groups were added to the acridinium ring to make this label's pseudobase strongly anionic. Chemiluminescence measurements of these labels, as well as their conjugates of an antibody with a neutral pI, indicate that acridinium ester charge while having a modest effect on emission kinetics has little influence on light output. However, our results demonstrate that acridinium ester charge can affect protein pI, apparent chemiluminescence stability and non-specific binding of protein conjugates to microparticles. These results emphasize the need for careful consideration of acridinium ester charge in order to optimize reagent stability and performance in immunoassays. In the current study, we observed that

  6. Effect of temperature stress on protein methyl esters

    International Nuclear Information System (INIS)

    Protein methyl esters have been implicated in a number of physiological processes. They have measured the effect of temperature stress on the levels of protein methyl esters in the mesophilic fungus Penicillium chrysogenum (PCPS) and the thermophilic fungus P. duponti (PD). PD and PCPS were incubated with [methyl-3H]methionine. The mycelia were collected by filtration, frozen in liquid nitrogen and ground to a fine powder. The nitrogen powder was extracted with either phosphate buffer or with SDS, glycerol, phosphate, 2-mercaptoethanol. Insoluble material was removed by centrifugation. The supernatants were assayed for protein methyl esters. The released [3H]methanol was extracted into toluene:isoamyl alcohol (3:2) and quantitated by liquid scintillation. The production of volatile methanol was confirmed by use of Conway diffusion cells. Soluble proteins accounted for about one-fourth of the total protein methyl ester extracted by SDS. In PCPS, the SDS extracted proteins have about three times the level of esterification of the soluble proteins whereas in PD there is little difference between soluble and SDS extracted protein. The level of protein esterification in PD is about one-tenth that observed in PCPS. Temperature stress caused large changes in the level of protein esterification. The data suggest protein methyl esters may contribute to the adaptation to environmental stress

  7. RELEASE PAPER: CAN PHOSPHATE ESTERS BE AN ALTERNATIVE TO SILICONE?

    Directory of Open Access Journals (Sweden)

    Dan Belosinschi,

    2012-01-01

    Full Text Available Release paper is a special paper grade with one or both sides coated with non-sticking materials. Silicone is currently the only material used to produce release paper at the industrial level. Its remarkable properties and availability ensure product quality and sustainability of the industrial production. Meanwhile, the stability of silicone polymers raises serious environmental problems in terms of paper substrate recyclability. Studies are currently under way to evaluate the ability of phosphate esters as a new class of compounds capable of developing non-adhesive surface properties. This paper presents initial attempts to coat the paper with phosphate esters and to assess phosphate ester / fibrous substrate and phosphate ester / adhesive interactions. The results show that this class of compounds exhibits non-adhesive properties and, when coated on paper under certain conditions, can lead to a non-sticking surface. Despite the fact that there is a long way to achieve ester anchoring to surface fibers and to control the peeling force from an adhesive tape, preliminary results are encouraging.

  8. Chemiluminescence from alkoxy-substituted acridinium dimethylphenyl ester labels.

    Science.gov (United States)

    Natrajan, Anand; Sharpe, David; Wen, David

    2012-05-01

    Chemiluminescent acridinium dimethylphenyl ester labels are used in automated immunoassays for clinical diagnostics. Light emission from these labels is triggered by alkaline peroxide in the presence of the cationic surfactant cetyltrimethylammonium chloride (CTAC). The surfactant plays a critical role in the chemiluminescence process of these labels by both accelerating their emission kinetics and increasing total light output enabling high throughout and improved assay sensitivity in automated immunoassays. Despite the surfactant's crucial role in the chemiluminescent reaction, no study has investigated how structural perturbations in the acridinium ring could impact the influence of the surfactant. We describe herein the synthesis and properties of three new alkoxy-substituted, acridinium dimethylphenyl esters where the nature of the alkoxy group in the acridinium ring was varied (hydrophobic or hydrophilic). Chemiluminescence measurements of these alkoxy-substituted labels indicate that hydrophilic functional groups in the acridinium ring, in particular sulfobetaine zwitterions, disrupt surfactant-mediated compression of emission times but not enhancement of light yield. These results support the hypothesis that surfactant-mediated effects require the binding of two different reaction intermediates to surfactant aggregates and, that surfactants influence light emission from acridinium esters by two separate mechanisms. Our studies also indicate that preservation of both surfactant effects on acridinium ester chemiluminescence and low non-specific binding of the label can be achieved with a relatively hydrophobic acridinium ring coupled to a hydrophilic phenolic ester leaving group. PMID:22441905

  9. Solid state crystallisation of oligosaccharide ester derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Elaine Ann

    2002-07-01

    An investigation of the solid state properties of oligosaccharide ester derivatives (OEDs) with potential applications in drug delivery has been carried out. The amorphous form of two OEDs, trehalose octa-acetate (TOAC) and 6:6'-di-({beta}-tetraacetyl glucuronyl)-hexaacetyl trehalose (TR153), was investigated as a matrix for the sustained release of active ingredients. The matrices showed a tendency to crystallise and so polymorph screens were performed to provide crystalline samples for structural analysis. The crystal structures of TOAC methanolate and TR153 acetonitrile solvate have been determined by single-crystal laboratory X-ray diffraction. TOAC methanolate crystallises in the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1} with a = 15.429(18) A, b = 17.934(19) A and c = 13.518(4) A at 123 K. The structure is isomorphous with the previously reported structure of TOAC monohydrate form II. TR153 acetonitrile solvate crystallises in the monoclinic spacegroup C2 with a = 30:160(6) A, b = 11.878(3) A, c 20.6645(5) A and {beta} = 115.027 (10) deg at 123 K. The crystal structures of both TOAC methanolate and TR153 acetonitrile solvate are stabilised by complex networks of intermolecular C--H...O contacts. Two model compounds were selected for dissolution studies: diltiazem hydrochloride, as a water- soluble organic salt, and ketoprofen as a poorly water-soluble organic compound. Dissolution of both compounds from amorphous TOAC and TR153 matrices was investigated. The release of both drugs was more rapid and complete from TOAC matrices than from TR153 matrices, with both matrices showing a tendency to crystallise (devitrify) during the course of the dissolution experiments. This tendency was greater for the TOAC matrix, which transformed to the extent of ca. 100% within 48 hours. The available evidence suggests that devitrification of the matrix in contact with water produces a polycrystalline, non-monolithic structure rich in microscopic cracks and pores

  10. Solid state crystallisation of oligosaccharide ester derivatives

    International Nuclear Information System (INIS)

    An investigation of the solid state properties of oligosaccharide ester derivatives (OEDs) with potential applications in drug delivery has been carried out. The amorphous form of two OEDs, trehalose octa-acetate (TOAC) and 6:6'-di-(β-tetraacetyl glucuronyl)-hexaacetyl trehalose (TR153), was investigated as a matrix for the sustained release of active ingredients. The matrices showed a tendency to crystallise and so polymorph screens were performed to provide crystalline samples for structural analysis. The crystal structures of TOAC methanolate and TR153 acetonitrile solvate have been determined by single-crystal laboratory X-ray diffraction. TOAC methanolate crystallises in the orthorhombic space group P212121 with a = 15.429(18) A, b = 17.934(19) A and c = 13.518(4) A at 123 K. The structure is isomorphous with the previously reported structure of TOAC monohydrate form II. TR153 acetonitrile solvate crystallises in the monoclinic spacegroup C2 with a = 30:160(6) A, b = 11.878(3) A, c 20.6645(5) A and β = 115.027 (10) deg at 123 K. The crystal structures of both TOAC methanolate and TR153 acetonitrile solvate are stabilised by complex networks of intermolecular C--H...O contacts. Two model compounds were selected for dissolution studies: diltiazem hydrochloride, as a water- soluble organic salt, and ketoprofen as a poorly water-soluble organic compound. Dissolution of both compounds from amorphous TOAC and TR153 matrices was investigated. The release of both drugs was more rapid and complete from TOAC matrices than from TR153 matrices, with both matrices showing a tendency to crystallise (devitrify) during the course of the dissolution experiments. This tendency was greater for the TOAC matrix, which transformed to the extent of ca. 100% within 48 hours. The available evidence suggests that devitrification of the matrix in contact with water produces a polycrystalline, non-monolithic structure rich in microscopic cracks and pores which allows diffusion of the

  11. Saliva-catalyzed hydrolysis of a ketobemidone ester prodrug

    DEFF Research Database (Denmark)

    Hansen, L.B.; Christrup, Lona Louring; Bundgaard, H.

    Saliva enzyme-catalysed hydrolysis of ester prodrugs or drugs containing sensitive ester groups may be a limiting factor for the buccal absorption of such compounds. Using the isopropyl carbonate ester of ketobemidone as a model substance of a hydrolysis-sensitive prodrug the esterase activity of...... human saliva has been characterized as a function of various factors. The esterase activity was found to decrease rapidly upon storage of the saliva at 37°C. The activity increased with increasing pH in the range 4.5-7.4 and with increasing salivation flow rate up to a rate of 0.9 ml min. Under resting...... conditions, the flow rate was about 0.2 ml min which implied a greatly decreased esterase activity. The activity was highest after fasting and decreased after intake of a meal. The intraindividual variation in the saliva esterase activity was small whereas a larger interindividual variation was found....

  12. Isolation and pharmacological activity of phenylpropanoid esters from Marrubium vulgare.

    Science.gov (United States)

    Sahpaz, Sevser; Garbacki, Nancy; Tits, Monique; Bailleul, Francois

    2002-03-01

    The isolation and identification of major phenylpropanoid esters from Marrubium vulgare: (+) (E)-caffeoyl-L-malic acid 1, acteoside 2, forsythoside B 3, arenarioside 4, ballotetroside 5, as well as their anti-inflammatory activity are reported for the first time. We evaluated the inhibitory effects of these five compounds on cyclooxygenase (Cox) catalysed prostaglandin biosynthesis activity. Only the glycosidic phenylpropanoid esters showed an inhibitory activity towards the Cox-2 enzyme and three of them: acteoside 2, forsythoside B 3, arenarioside 4, exhibited higher inhibitory potencies on Cox-2 than on Cox-1. These results are of interest, as Cox-2 is mainly associated with inflammation and the Cox-1 inhibition with adverse side effects often observed with non-steroidal anti-inflammatory drugs. The occurrence of these phenylpropanoid esters could also explain some other pharmacological properties of M. vulgare. PMID:11849848

  13. Maximization of fructose esters synthesis by response surface methodology.

    Science.gov (United States)

    Neta, Nair Sampaio; Peres, António M; Teixeira, José A; Rodrigues, Ligia R

    2011-07-01

    Enzymatic synthesis of fructose fatty acid ester was performed in organic solvent media, using a purified lipase from Candida antartica B immobilized in acrylic resin. Response surface methodology with a central composite rotatable design based on five levels was implemented to optimize three experimental operating conditions (temperature, agitation and reaction time). A statistical significant cubic model was established. Temperature and reaction time were found to be the most significant parameters. The optimum operational conditions for maximizing the synthesis of fructose esters were 57.1°C, 100 rpm and 37.8 h. The model was validated in the identified optimal conditions to check its adequacy and accuracy, and an experimental esterification percentage of 88.4% (±0.3%) was obtained. These results showed that an improvement of the enzymatic synthesis of fructose esters was obtained under the optimized conditions. PMID:21356336

  14. Boric Ester-Type Molten Salt via Dehydrocoupling Reaction

    Directory of Open Access Journals (Sweden)

    Noriyoshi Matsumi

    2014-11-01

    Full Text Available Novel boric ester-type molten salt was prepared using 1-(2-hydroxyethyl-3-methylimidazolium chloride as a key starting material. After an ion exchange reaction of 1-(2-hydroxyethyl-3-methylimidazolium chloride with lithium (bis-(trifluoromethanesulfonyl imide (LiNTf2, the resulting 1-(2-hydroxyethyl-3-methylimidazolium NTf2 was reacted with 9-borabicyclo[3.3.1]nonane (9-BBN to give the desired boric ester-type molten salt in a moderate yield. The structure of the boric ester-type molten salt was supported by 1H-, 13C-, 11B- and 19F-NMR spectra. In the presence of two different kinds of lithium salts, the matrices showed an ionic conductivity in the range of 1.1 × 10−4–1.6 × 10−5 S cm−1 at 51 °C. This was higher than other organoboron molten salts ever reported.

  15. A Comparison Study: The New Extended Shelf Life Isopropyl Ester PMR Technology versus The Traditional Methyl Ester PMR Approach

    Science.gov (United States)

    Alston, William B.; Scheiman, Daniel A.; Sivko, Gloria S.

    2005-01-01

    Polymerization of Monomeric Reactants (PMR) monomer solutions and carbon cloth prepregs of PMR II-50 and VCAP-75 were prepared using both the traditional limited shelf life methanol based PMR approach and a novel extended shelf life isopropanol based PMR approach. The methyl ester and isopropyl ester based PMR monomer solutions and PMR prepregs were aged for up to four years at freezer and room temperatures. The aging products formed were monitored using high pressure liquid chromatography (HPLC). The composite processing flow characteristics and volatile contents of the aged prepregs were also correlated versus room temperature storage time. Composite processing cycles were developed and six ply cloth laminates were fabricated with prepregs after various extended room temperature storage times. The composites were then evaluated for glass transition temperature (Tg), thermal decomposition temperature (Td), initial flexural strength (FS) and modulus (FM), long term (1000 hours at 316 C) thermal oxidative stability (TOS), and retention of FS and FM after 1000 hours aging at 316 C. The results for each ester system were comparable. Freezer storage was found to prevent the formation of aging products for both ester systems. Room temperature storage of the novel isopropyl ester system increased PMR monomer solution and PMR prepreg shelf life by at least an order of magnitude while maintaining composite properties.

  16. Raman spectroscopic analysis of isomers of biliverdin dimethyl ester.

    Science.gov (United States)

    Matysik, J; Hildebrandt, P; Smit, K; Mark, F; Gärtner, W; Braslavsky, S E; Schaffner, K; Schrader, B

    1997-06-01

    The constitutional isomers of biliverdin dimethyl ester, IX alpha and XIII alpha, were studied by resonance Raman spectroscopy. The far-reaching spectral similarities suggest that despite the different substitution patterns, the compositions of the normal modes are closely related. This conclusion does not hold only for the parent state (ZZZ, sss configuration) but also for the configurational isomers which were obtained upon double-bond photoisomerization. Based on a comparison of the resonance Raman spectra, a EZZ configuration is proposed for one of the two photoisomers of biliverdin dimethyl ester IX alpha, while a ZZE, ssa configuration has been assigned previously to the second isomer. PMID:9226559

  17. Sodium borohydride reduction of aromatic carboxylic acids via methyl esters

    Indian Academy of Sciences (India)

    Aamer Saeed; Zaman Ashraf

    2006-09-01

    A number of important aromatic carboxylic acids precursors, or intermediates in the syntheses of natural products, are converted into methyl esters and reduced to the corresponding primary alcohols using a sodium borohydride-THF-methanol system. The alcohols are obtained in 70-92% yields in 2-5 hours, in a pure state. This two-step procedure not only provides a better alternative to aluminum hydride reduction of acids but also allows the selective reduction of esters in presence of acids, amides, nitriles or nitro functions which are not affected under these conditions.

  18. Solvent effects on hydrogen bonding between primary alcohols and esters

    Institute of Scientific and Technical Information of China (English)

    DHARMALINGAM K.; RAMACHANDRAN K.; SIVAGURUNATHAN P.

    2006-01-01

    The interaction by hydrogen bond formation of some primary alcohols (1-heptanol, 1-octanol and 1-decanol) with esters (methyl methacrylate, ethyl methacrylate and butyl methacrylate) was investigated in non-polar solvents viz., n-heptane,CCh and benzene by means of FTIR spectroscopy. Formation constants and free energy changes of complex formation were determined. The dependence of the equilibrium constants and free energy changes of complex formation on the alkyl chain length of both the alcohols and esters are discussed. The solvent effect on the hydrogen bond formation is discussed in terms of specific interaction between the solute and solvent.

  19. 40 CFR 721.3800 - Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, condensated... Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. (a... generically as formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol,...

  20. N-[11C]methylpiperidine esters as acetylcholinesterase substrates: an in vivo structure-reactivity study

    International Nuclear Information System (INIS)

    A series of simple esters incorporating the N-[11C]methylpiperidine structure were examined as in vivo substrates for acetylcholinesterase in mouse brain. 4-N-[11C]Methylpiperidinyl esters, including the acetate, propionate and isobutyrate esters, are good in vivo substrates for mammalian cholinesterases. Introduction of a methyl group at the 4-position of the 4-piperidinol esters, to form the ester of a teritary alcohol, effectively blocks enzymatic action. Methylation of 4- N-[11C]methylpiperidinyl propionate at the 3-position gives a derivative with increased in vivo reactivity toward acetylcholinesterase. Esters of piperidinecarboxylic acids (nipecotic, isonipecotic and pipecolinic acid ethyl esters) are not hydrolyzed by acetylcholinesterase in vivo, nor do they act as in vivo inhibitors of the enzyme. This study has identified simple methods to both increase and decrease the in vivo reactivity of piperidinyl esters toward acetylcholinesterase

  1. EXPERIMENTAL INVESTIGATION OF LINSEED AND NEEM METHYL ESTERS AS BIODIESEL ON CI ENGINE

    OpenAIRE

    V.DHANA RAJU; P.RAVINDRA KUMAR

    2012-01-01

    An experimental investigations were carried out on C.I.engine with Bio Diesel blends of Linseed Methyl Esters and Neem Oil Methyl Esters .The engine used for the experiments was single cylinder Four Stroke water cooled, constant speed diesel engine . Linseed Methyl ester (LSOME) and Neem oil methyl ester (NOME) are derived through transesterification process and parameters of transesterification were optimized. The blends of various proportions of the LSOME & NOME with diesel were prepared, a...

  2. Preconcentration procedures for phthalate esters combined with chromatographic analysis.

    Science.gov (United States)

    Lv, Xueju; Hao, Yi; Jia, Qiong

    2013-08-01

    Phthalate esters are endocrine disrupters or mutagens. They are widely used as plasticizers and can be usually found in environmental samples, such as food, soil and polluted air. However, it is difficult to directly determine phthalate esters owing to their relatively low concentration and complex matrices. Therefore, preconcentration and separation have become increasingly important. In recent years, many preconcentration methods have been successfully developed and widely used, such as liquid-liquid extraction, dispersive liquid-liquid microextraction and solid-phase extraction. These preconcentration methods for phthalate esters can be applied to various real samples, water, soil, air, food and cosmetics. The aim of this paper is to review recent literature studies (primarily from the last five years) about preconcentration techniques for phthalate esters coupled with chromatographic analysis. The following text describes several preconcentration approaches, including liquid-liquid extraction, dispersive liquid-liquid microextraction, cloud point extraction, solid-phase extraction, solid-phase microextraction and stir bar sorptive extraction. Their advantages and disadvantages are also summarized. PMID:23696389

  3. A New Jatrophane Diterpenoid Ester from Euphorbia turczaninowii

    Institute of Scientific and Technical Information of China (English)

    Li Gen LIU; Ren Xiang TAN; You Ming GONG

    2006-01-01

    A new jatrophane diterpenoid ester (2S, 3S, 4R, 5R, 7S, 8R, 13R, 15R) - 3, 5, 7, 8, 15-pentaacetoxy-9, 14-dioxojatropha-6(17), 11E-diene was isolated from the whole plant of Euphorbia turczaninowii Kar. & Kir.. Its structure was characterized by spectral analysis and confirmed by X-ray crystallographic analysis.

  4. New triterpene esters from flowerheads of Arnica lonchophylla.

    Science.gov (United States)

    Schmidt, Thomas J; von Raison, Jeanette; Willuhn, Günter

    2004-10-01

    From the flowerheads of Arnica lonchophylla Greene ssp. lonchophylla Maguire (Asteraceae), a variety of mono-, di- and trihydroxytriterpenes of the oleanane, ursane, lupane and dammarane types were isolated and their structures elucidated by EI and CI mass spectrometry and extensive NMR spectroscopic analysis. Most of the compounds are esterified at position 3 with lauric, myristic, palmitic and stearic acids. Several ester derivatives of known triterpenes represent new natural products. The triterpenetriols 20(30)-taraxasten-3beta,16beta,21alpha-triol (arnitriol A) and lupane-3beta,16beta,20-triol, both isolated in the form of their C3-fatty acid ester derivatives, possess hydroxylation patterns which have not been described previously. Besides small amounts of triterpenetriol esters, the lauric, myristic, palmitic and stearic acid esters of arnidiol, faradiol, maniladiol and calenduladiol were also identified in the flowerheads of A. montana (Arnicae flos Ph. Eur.), A. chamissonis ssp. foliosa and A. angustifolia ssp. attenuata. A search for sesquiterpene lactones in the flowers of A. lonchophylla resulted in the identification of small amounts of helenalin and 11alpha,13-dihydrohelenalin. PMID:15490326

  5. RAFT Polymerization of Vinyl Esters: Synthesis and Applications

    Directory of Open Access Journals (Sweden)

    Simon Harrisson

    2014-05-01

    Full Text Available This article is the first comprehensive review on the study and use of vinyl ester monomers in reversible addition fragmentation chain transfer (RAFT polymerization. It covers all the synthetic aspects associated with the definition of precision polymers comprising poly(vinyl ester building blocks, such as the choice of RAFT agent and reaction conditions in order to progress from simple to complex macromolecular architectures. Although vinyl acetate was by far the most studied monomer of the range, many vinyl esters have been considered in order to tune various polymer properties, in particular, solubility in supercritical carbon dioxide (scCO2. A special emphasis is given to novel poly(vinyl alkylates with enhanced solubilities in scCO2, with applications as reactive stabilizers for dispersion polymerization and macromolecular surfactants for CO2 media. Other miscellaneous uses of poly(vinyl esters synthesized by RAFT, for instance as a means to produce poly(vinyl alcohol with controlled characteristics for use in the biomedical area, are also covered.

  6. Polyfluorinated alkyl phosphate ester surfactants - current knowledge and knowledge gaps

    DEFF Research Database (Denmark)

    Taxvig, Camilla; Rosenmai, Anna Kjerstine; Vinggaard, Anne Marie

    2014-01-01

    information on fluorochemicals. Polyfluorinated alkyl phosphate ester surfactants (PAPs) belong to the group of polyfluorinated alkyl surfactants. They have been detected in indoor dust and are widely used in food-contact materials, from which they have the ability to migrate into food. Toxicological data on...

  7. Characteristics of polyglycerol ester and its different fractions.

    Science.gov (United States)

    Curschellas, Corina; Nagy, Kornél; Windhab, Erich; Limbach, Hans Jörg

    2013-03-01

    Polyglycerol esters obtained from edible oils are commonly used surfactants in the food industry. Despite their widespread application, the composition and properties of these surfactants are still not well characterized. This study reveals the presence of so far unknown tetra-, penta-antennary constituents in polyglycerol esters, which exhibit very strong sodium affinity. The implications of these new insights on surfactant activity were investigated. Liquid-liquid extraction was used to fractionate a polyglycerol ester ingredient in order to link physicochemical behavior to the polarity of the fractions. The most polar fraction showed faster adsorption kinetics and higher elastic moduli than the full mixture, whereas the least polar fraction showed slower adsorption kinetics and lower elastic moduli as compared to the complex mixture. The addition of Na(+) was shown to accelerate the agglomeration of surfactant self-assemblies in bulk solutions and also to increase the elastic modulus at the air-water interface. These observations suggest that the composition of natural polyglycerol esters is more diverse than so far assumed and the overall behavior of these mixtures is determined not only by the amphyphilic interactions between mono- and penta-antennary forms, but also by the endogenous salt content of the ingredient. PMID:23207050

  8. Enzymatic synthesis of oligo- and polysaccharide fatty acid esters

    NARCIS (Netherlands)

    Broek, van den L.A.M.; Boeriu, C.G.

    2013-01-01

    Amphiphilic oligo- and polysaccharides (e.g. polysaccharide alkyl or alkyl-aryl esters) form a new class of polymers with exceptional properties. They function as polymeric surfactants, whilst maintaining most of the properties of the starting polymeric material such as emulsifying, gelling, and fil

  9. SYNTHESIS OF ACRYLIC ESTERS IN PTC: KINETICS AND ECOLOGICAL ASPECTS

    Directory of Open Access Journals (Sweden)

    G.Torosyan

    2013-06-01

    Full Text Available The synthesis of esters of acrylic acids, which are applied for synthesis of polymeric materials by phase transfer catalysis were discussed (PTC, which is very useful for reduction of reaction consumption of materials and power.This method has substantial advantages including high speed of the process, soft condition of reaction and reduced pollution.

  10. Separation of isomeric xylenes by pervaporation through cellulose ester membranes

    NARCIS (Netherlands)

    Mulder, M.H.V.; Kruitz, F.; Smolders, C.A.

    1982-01-01

    The interaction between the isomeric xylenes and different cellulose esters was investigated using solubility parameter considerations and through measurements of swelling values. p]Hansen's three-dimensional solubility parameters δd, δp, δh of all the components have been calculated. These values h

  11. Radical Mechanism in the Elimination of 2-Arylsulfinyl Esters

    OpenAIRE

    LaTorre, Antonio; López Martín, Irakusne; Ramírez, Victoria; Rodríguez Pastor, Santiago; Izquierdo Ferrer, Javier; González Adelantado, Florenci Vicent; Vicent Barrera, Cristian

    2012-01-01

    The mechanism of the dehydrosulfenylation of 2-arylsulfinyl esters was investigated. The reaction was found to follow a homolytic cleavage mechanism as verified by electrospray ionization tandem mass spectrometry and experimental work. Rearranged sulfoxides are obtained as byproduct during the elimination reaction.

  12. Comparative assay of antioxidant packages for dimer of estolide esters

    Science.gov (United States)

    A series of 26 different antioxidants and commercial antioxidant packages, containing both natural and synthetic-based materials, were evaluated with dimeric coconut-oleic estolide 2-ethylhexyl ester. The different antioxidants were broken down into different classes of materials: phenolic, aminic, ...

  13. 21 CFR 172.735 - Glycerol ester of rosin.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Glycerol ester of rosin. 172.735 Section 172.735 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD..., gum rosin, or tall oil rosin may be safely used in food in accordance with the following...

  14. Steric effect of ortho subsituents on ester reactivity towards nucleophiles

    International Nuclear Information System (INIS)

    Reactivities of ortho- and para-substituted phenyl acetates in isotopic acyl exchange and in aminolysis were compared. In aminolysis the ortho-substituted esters reacted more rapidly than their para isomers. The increased reactivity is attributed to the proton acceptor ortho substituents. These substituents act as general base catalytic functions in aminolysis but they act differently in isotopic acyl exchange. (author)

  15. Synthesis, Characterization, Antibacterial and Antifungal Evaluation of Novel Monosaccharide Esters

    Directory of Open Access Journals (Sweden)

    Yong Deng

    2012-07-01

    Full Text Available A novel series of 3-(2-furylacrylate monosaccharide esters Iaf and menthyloxycarbonyl monosaccharide esters IIaf were designed and synthesized. The chemical structures of the target compounds were confirmed by IR, 1H- and 13C-NMR and ESI-MS, and the target compounds were investigated for their in vitro antibacterial and antifungal activities. The antibacterial screening results showed that the 3-(2-furylacrylate monosaccharide ester derivatives Iaf were either inactive or only weakly active against the three Gram-positive bacterial strains tested, whereas the menthyloxycarbonyl monosaccharide ester derivatives IIaf exhibited higher levels of activity, with compound IIe being especially potent. The results of the antifungal screening revealed that compounds Ib, Ie, IIb and IIc displayed potent in vitro activities, whereas If and IIf showed promising activities against all of the microorganisms tested, with If exhibiting levels of activity deserving of further investigation.

  16. Improving Biodiesel Fuel Properties by Modifying Fatty Ester Composition

    Science.gov (United States)

    Biodiesel is an alternative to petroleum-derived diesel fuel composed of alkyl esters of vegetable oils, animal fats or other feedstocks such as used cooking oils. The fatty acid profile of biodiesel corresponds to that of its feedstock. Most feedstocks possess fatty acid profiles consisting mainl...

  17. Preparation of Jojoba Oil Ester Derivatives for Biodiesel Evaluation

    Science.gov (United States)

    As a result of the increase in commodity vegetable oil prices, it is imperative that non-food oils should be considered as alternative feedstocks for biodiesel production. Jojoba oil is unusual in that it is comprised of wax esters as opposed to the triglycerides found in typical vegetable oils. A...

  18. A Convenient Synthesis of Amino Acid Methyl Esters

    Directory of Open Access Journals (Sweden)

    Yaowu Sha

    2008-05-01

    Full Text Available A series of amino acid methyl ester hydrochlorides were prepared in good toexcellent yields by the room temperature reaction of amino acids with methanol in thepresence of trimethylchlorosilane. This method is not only compatible with natural aminoacids, but also with other aromatic and aliphatic amino acids.

  19. Activities of the Environmental Protection Agency concerning phthalate esters

    OpenAIRE

    Newburg-Rinn, Steven D.

    1982-01-01

    EPA's activities concerning phthalate esters have been in four general areas, namely: (1) their status as toxic pollutants under the Clean Water Act; (2) their status as “new chemicals” under Section 5 of TSCA; (3) the potential risk to human beings posed by DEHP; and (4) finally, the need for testing phthalates with respect to their health and environmental effects.

  20. Chemistry for Kids. Ester, What's in My Food?

    Science.gov (United States)

    Clarke, Michele; And Others

    1986-01-01

    Describes three teaching activities used in the Chemistry for Kids program which focus on how esters are chemicals partially responsible for the flavor of foods. Includes a discussion of a demonstration involving role-playing, a set of taste tests, and an activity using chewing gum to investigate odors in food. (TW)

  1. 4-Dimenthylaminopyridine or Acid-Catalyzed Synthesis of Esters: A Comparison

    Science.gov (United States)

    van den Berg, Annemieke W. C.; Hanefeld, Ulf

    2006-01-01

    A set of highly atom-economic experiments was developed to highlight the differences between acid- and base-catalyzed ester syntheses and to introduce the principles of atom economy. The hydrochloric acid-catalyzed formation of an ester was compared with the 4-dimethylaminopyradine-catalyzed ester synthesis.

  2. Two-generation reproductive toxicity study of plant stanol esters in rats

    NARCIS (Netherlands)

    Whittaker, M.H.; Frankos, V.H.; Wolterbeek, A.P.M.; Waalkens-Berendsen, D.H.

    1999-01-01

    Plant stanol esters are intended for use as an ingredient in food to reduce the absorption of cholesterol from the gastrointestinal tract. Consumption of plant stanol esters has a demonstrated diet-derived public health benefit, as shown by numerous clinical studies. Plant stanol esters are ring-sat

  3. 21 CFR 172.816 - Methyl glucoside-coconut oil ester.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Methyl glucoside-coconut oil ester. 172.816 Section... HUMAN CONSUMPTION Multipurpose Additives § 172.816 Methyl glucoside-coconut oil ester. Methyl glucoside-coconut oil ester may be safely used in food in accordance with the following conditions: (a) It is...

  4. 21 CFR 178.3600 - Methyl glucoside-coconut oil ester.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Methyl glucoside-coconut oil ester. 178.3600... SANITIZERS Certain Adjuvants and Production Aids § 178.3600 Methyl glucoside-coconut oil ester. Methyl glucoside-coconut oil ester identified in § 172.816(a) of this chapter may be safely used as a...

  5. 21 CFR 175.260 - Partial phosphoric acid esters of polyester resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Partial phosphoric acid esters of polyester resins... of polyester resins. Partial phosphoric acid esters of polyester resins identified in this section... prescribed conditions: (a) For the purpose of this section, partial phosphoric acid esters of...

  6. Skin permeation of testosterone and its ester derivatives in rats.

    Science.gov (United States)

    Kim, M K; Lee, C H; Kim, D D

    2000-04-01

    To establish the optimum conditions for improving the transdermal delivery of testosterone, we studied the relationship between the lipophilicity of testosterone ester derivatives and the rat skin permeation rate of testosterone. We performed a rat skin permeation study of testosterone and its commercially available ester derivatives, testosterone hemisuccinate, testosterone propionate and testosterone-17beta-cypionate, using an ethanol/water co-solvent system. The aqueous solubility and rat skin permeation rate of each drug, saturated in various compositions of an ethanol/water system, was determined at 37 degrees C. The aqueous solubility of testosterone and its ester derivatives increased exponentially as the volume fraction of ethanol increased up to 100% (v/v). The stability of testosterone propionate in both the skin homogenate and the extract was investigated to observe the enzymatic degradation during the skin permeation process. Testosterone propionate was found to be stable in the isotonic buffer solution and in the epidermis-side extract for 10h at 37 degrees C. However, in the skin homogenate and the dermis-side extract testosterone propionate rapidly degraded producing testosterone, implying that testosterone propionate rapidly degraded to testosterone during the skin permeation process. The steady-state permeation rates of testosterone in the ethanol/water systems increased exponentially as the volume fraction of ethanol increased, reaching the maximum value (2.69+/-0.69 microg cm(-2)h(-1)) at 70% (v/v) ethanol in water, and then decreasing with further increases in the ethanol volume fraction. However, in the skin permeation study with testosterone esters saturated in 70% (v/v) ethanol in water system, testosterone esters were hardly detected in the receptor solution, probably due to the rapid degradation to testosterone during the skin permeation process. Moreover, a parabolic relationship was observed between the permeation rate of testosterone and

  7. Encapsulating fatty acid esters of bioactive compounds in starch

    Science.gov (United States)

    Lay Ma, Ursula Vanesa

    Interest in the use of many bioactive compounds in foods is growing in large part because of the apparent health benefits of these molecules. However, many of these compounds can be easily degraded during processing, storage, or their passage through the gastrointestinal tract before reaching the target site. In addition, they can be bitter, acrid, or astringent, which may negatively affect the sensory properties of the product. Encapsulation of these molecules may increase their stability during processing, storage, and in the gastrointestinal tract, while providing controlled release properties. The ability of amylose to form inclusion complexes and spherulites while entrapping certain compounds has been suggested as a potential method for encapsulation of certain molecules. However, complex formation and spherulitic crystallization are greatly affected by the type of inclusion molecules, type of starch, and processing conditions. The objectives of the present investigation were to: (a) study the effect of amylose, amylopectin, and intermediate material on spherulite formation and its microstructure; (b) investigate the formation of amylose and high amylose starch inclusion complexes with ascorbyl palmitate, retinyl palmitate, and phytosterol esters; (c) evaluate the ability of spherulites to form in the presence of fatty acid esters and to entrap ascorbyl palmitate, retinyl palmitate, and phytosterol esters; and (d) evaluate the effect of processing conditions on spherulite formation and fatty acid ester entrapment. Higher ratios of linear to branched molecules resulted in the formation of more and rounder spherulites with higher heat stability. In addition to the presence of branches, it appears that spherulitic crystallization is also affected by other factors, such as degree of branching, chain length, and chain length distribution. Amylose and Hylon VII starch formed inclusion complexes with fatty acid esters of ascorbic acid, retinol, or phytosterols

  8. Synthesis of thermoplastic poly(ester-olefin elastomers

    Directory of Open Access Journals (Sweden)

    Tanasijević Branka

    2004-01-01

    Full Text Available A series of thermoplastic poly(ester-olefin elastomers, based on poly(ethylene-stat-butylene, HO-PEB-OH, as the soft segment and poly (butylene terephthalate, PBT, as the hard segment, were synthesized by a catalyzed transesterification reaction in solution. The incorporation of soft hydrogenated poly(butadiene segments into the copolyester backbone was accomplished by the polycondensation of α, ω-dihydroxyl telechelic HO-PEB-OH, (PEB Mn = 3092 g/mol with 1,4-butanediol (BD and dimethyl terephthalate (DMT in the presence of a 50 wt-% high boiling solvent i.e., 1,2,4-trichlorobenzene. The molar ratio of the starting comonomers was selected to result in a constant hard to soft weight ratio of 60:40. The synthesis was optimized in terms of both the concentration of catalyst, tetra-n-butyl-titanate (Ti(OBu4, and stabilizer, N,N'-diphenyl-p-phenylenediamine (DPPD, as well as the reaction time. It was found that the optimal catalyst concentration (Ti(OBu4 for the synthesis of these thermoplastic elastomers was 1.0 mmol/mol ester and the optimal DPPD concentration was 1.0 wt-%. The extent of the reaction was followed by measuring the inherent viscosity of the reaction mixture. The effectiveness of the incorporation of the soft segments into the copolymer chains was proved by Soxhlet extraction with chloroform. The molecular structures, composition and the size of the synthesized poly(ester-butylenes were verified by 1H NMR spectroscopy, viscometry of dilute solutions and the complex dynamic melt viscosity. The thermal properties of poly(ester-olefins were investigated by differential scanning calorimetry (DSC. The degree of crystallinity was also determined by DSC. The thermal and thermo-oxidative stability were investigated by thermogravimetric analysis (TGA. The rheological properties of poly(ester-olefins were investigated by dynamic mechanical spectroscopy in the melt and solid state.

  9. Valimiskaotuse haavu raviva Rahvaliidu ajutine juht Ester Tuiksoo : "Meil on tugev küünarnukitunne" / Ester Tuiksoo

    Index Scriptorium Estoniae

    Tuiksoo, Ester, 1965-

    2007-01-01

    Ilmunud ka: Severnoje Poberezhje, 28. märts 2007, lk. 2. Delfi lugejate küsimustele vastab Rahvaliidu ajutine juht ja lahkuva valitsuse põllumajandusminister Ester Tuiksoo, kellelt päriti nii erakonna maine taastamise, eesti toidu kui ka jopede jagamise kohta

  10. Lipase catalyzed ester synthesis for food processing industries

    Directory of Open Access Journals (Sweden)

    Aravindan Rajendran

    2009-02-01

    Full Text Available Lipases are one of the most important industrial biocatalyst which catalyzes the hydrolysis of lipids. It can also reverse the reaction at minimum water activity. Because of this pliable nature, it is widely exploited to catalyze the diverse bioconversion reactions, such as hydrolysis, esterification, interesterification, alcoholysis, acidolysis and aminolysis. The property to synthesize the esters from the fatty acids and glycerol promotes its use in various ester synthesis. The esters synthesized by lipase finds applications in numerous fields such as biodiesel production, resolution of the recemic drugs, fat and lipid modification, flavour synthesis, synthesis of enantiopure pharmaceuticals and nutraceuticals. It plays a crucial role in the food processing industries since the process is unaffected by the unwanted side products. Lipase modifications such as the surfactant coating, molecular imprinting to suit for the non-aqueous ester synthesis have also been reported. This review deals with lipase catalyzed ester synthesis, esterification strategies, optimum conditions and their applications in food processing industries.Lipases são catalizadores industriais dos mais importantes, os quais catalizam a hidrólise de lipídeos. Também podem reverter a reação a um mínimo de atividade de água. Devido sua natureza flexível, é amplamente explorada para catalizar uma diversidade de reações de bioconversão como hidrólise, esterificação, interesterificação, alcoólise, acidólise e aminólise. A propriedade de síntese de esteres a partir de ácidos graxos e glicerol promoveu seu uso em várias sínteses de esteres. Os esteres sintetizados por lipases encontram aplicação em numerosos campos como a produção de biodiesel, resolução de drogas racêmicas, modificação de gorduras e lipídios, sintese de aromas, síntese de produtos farmacêuticos enantiopuro e nutracêuticos. As lipases possuem um papel crucial nas indústrias de

  11. Occurrence of fatty acid esters of 3-MCPD, 2-MCPD and glycidol in infant formula.

    Science.gov (United States)

    Wöhrlin, Friederike; Fry, Hildburg; Lahrssen-Wiederholt, Monika; Preiß-Weigert, Angelika

    2015-01-01

    The discovery of fatty acid esters of monochloropropanediol (MCPD) and glycidol generated during the refinement process in vegetable fats and oils caused concerns about possible adverse health effects. As these fats are components of infant formula, the current investigation of the MCPD and glycidyl ester contents in infant formula was necessary to update the data for risk assessment purposes. For the analysis of 3-MCPD, 2-MCPD and glycidyl esters in infant formula, an existing method for fats and oils had to be modified and validated. The fat fraction containing MCPD and glycidyl esters was extracted from infant formula by accelerated solvent extraction (ASE). The extracted fat was then analysed according to an established method for fats and oils. Glycidyl esters are converted to monobrompropanediol (3-MBPD) esters, MCPD and 3-MBPD esters hydrolysed subsequently and after derivatisation detected by GC-MS. Seven different products of infant formula, covering two types and five lots each, altogether 70 samples, were bought in retail markets and analysed. In all samples, 3-MCPD and glycidyl esters could be detected. Both 3-MCPD and glycidyl esters' concentration levels were found to be lower in comparison with earlier investigations described in the literature. The occurrence of 2-MCPD esters in infant formula was investigated for the first time and revealed concentrations about half of 3-MCPD ester concentrations. PMID:26179516

  12. Fragmentation Mechanism of Trans-α-Aryl-β-enamino Esters

    Institute of Scientific and Technical Information of China (English)

    JIANG,Nan(蒋楠); WANG,Jian-Bo(王剑波); HE,Mei-Yu(何美玉)

    2002-01-01

    Electron impact-induced fragmentation mechanisms of trans-α-aryl-β-enamino esters were investigated using mass-analyzed ion kindetic energy (MIKE) spectrometry and high resolution accurate mass data. It was found that the main characteristic fragmentations of compounds studied were: an odd electron ion M+. - EtOH was formed by losing a neutral molecule of ethanol; and the skeletal rearrangements took place; and the ring opening reaction happened after losing a carbon monoxide;and the typical McLafferty rearrangement underwent in ester group. The cyclization reaction caused by losing neutral molecule of TsNH2 due to the ortho-effects of substituted group of aromatic ring was also observed.

  13. Organising pneumonia associated with fumaric acid ester treatment for psoriasis.

    LENUS (Irish Health Repository)

    Deegan, Alexander Paul

    2012-02-01

    INTRODUCTION: We present the case of a 49-year old male who presented with dyspnoea, cough, weight loss, night sweats and general malaise. He had been on treatment with oral fumaric acid esters (FAE, Fumaderm(R); Biogen Idec GmbH, Ismaning, Germany) for 6 months. METHODS: Report of a case. RESULTS: His chest X-ray showed patchy infiltrates in the left upper lobe which failed to resolve under empiric antibiotic therapy. A computed tomography of thorax revealed bilateral, mostly peripheral foci of consolidation with air bronchograms. Transbronchial biopsies showed a pattern of organising pneumonia (OP). CONCLUSIONS: Therapy with oral prednisolone (40 mg\\/day) resulted in a rapid clinical and radiological improvement. An association of FAE and OP has not previously been reported. Please cite this paper as: Deegan AP, Kirby B, Rogers S, Crotty TB and McDonnell TJ. Organising pneumonia associated with fumaric acid ester treatment for psoriasis.

  14. Processing and properties of SiC/vinyl ester nanocomposites

    Science.gov (United States)

    Yong, Virginia; Hahn, H. Thomas

    2004-09-01

    The feasibility of improving polymer composites was investigated using 30 nm SiC nanoparticles in a vinyl ester resin. Even when the particle loading was less than 4% by weight, the viscosity of the nanoparticle suspension was found to increase much higher than that of microparticle suspension. This phenomenon may be the result of association between nanoparticles and polymer molecules, effectively making the nanoparticles larger. The resulting reduction in the mobility of polymer molecules also led to delayed curing. Ultrasonic mixing did not fully disperse the particles. As a result, the composite strength did not improve although the modulus increased. The use of a dispersant, methacryloxy propyl trimethoxy silane (MPS), improved the dispersion quality and hence the composite strength. The paper discusses the issues involved with processing, characterization and properties of SiC/vinyl ester nanocomposites. Methods of improving the nanocomposite quality are proposed in the paper as well.

  15. Production and Characterization of Jatropha Oil Methyl Ester

    Directory of Open Access Journals (Sweden)

    P. Venkateswara Rao, G. Srinivasa Rao

    2013-04-01

    Full Text Available Biodiesel is emerging as a promising substitute of an alternative fuel and has gained significant attention due to the predicted depletion of conventional fuels availability in near future and environmental pollution concern. Utilization of biodiesel produced from Jatropha oil by transesterification process is one of the most promising options to replace conventional fossil diesel fuel. The physical properties such as density, Kinematic viscosity, flash point, carbon residue, Pour point and Cetane number were found out for diesel, Jatropha oil and Jatropha Oil Methyl Ester (JOME produced in the laboratory. Properties obtained for the Jatropha oil methyl ester are very closely matched with the values of conventional diesel fuel and can be used without any modification in the existing diesel engine.

  16. Fatty acid methyl esters production: chemical process variables

    Directory of Open Access Journals (Sweden)

    Paulo César Narváez Rincón

    2010-06-01

    Full Text Available The advantages of fatty acid methyl esters as basic oleochemicals over fatty acids, the seventies world energy crisis and the use of those oleochemicals as fuels, have increased research interest on fats and oils trans-esterification. In this document, a review about basic aspects, uses, process variables and problems associated to the production process of fatty acid methyl esters is presented. A global view of recent researches, most of them focused in finding a new catalyst with same activity as the alcohol-soluble hydroxides (NaOH, KOH, and suitable to be used in transforming fats and oils with high levels of free fatty acids and water avoiding separation problems and reducing process costs, is also discussed.

  17. Hydrogels Formed by Oxo-ester Mediated Native Chemical Ligation

    OpenAIRE

    Strehin, Iossif; Gourevitch, Dmitri; Zhang, Yong; Heber-Katz, Ellen; Messersmith, Phillip B.

    2013-01-01

    Oxo-ester mediated native chemical ligation (OMNCL) is a variation of the more general native chemical ligation (NCL) reaction that is widely employed for chemoselective ligation of peptide fragments. While OMNCL has been used for a variety of peptide ligations and for biomolecular modification of surfaces, it is typically practiced under harsh conditions that are unsuitable for use in a biological context. In this report we describe the use of OMNCL for polymer hydrogel formation, in-vitro c...

  18. Study on the Novel Dicyanate Ester Resin Containing Naphthalene Unit

    Institute of Scientific and Technical Information of China (English)

    Hong Qiang YAN; Hong Yun PENG; Li JI; Guo Rong QI

    2004-01-01

    The novel dicyanate ester resin containing naphthalene unit (DNCY) was synthesized, and characterized by FT-IR, 1H-NMR, 13C-NMR and elemental analysis (EA).The thermal properties of DNCY resin was studied by thermal degradation analysis at a heating rate of 10 (C /min-1 in N2 and air. The DNCY resin exhibited better thermal and thermal-oxidative stability than bisphenol A dicyanate (BACY) resin.

  19. Synthesis of new radiotracers based of Ethyl Ester

    International Nuclear Information System (INIS)

    The in vivo study of a biochemical or physiological process requires the synthesis of specific radiotracers but also the targeting of these compounds so that they can reach their target tissue. Methodologies original synthesis associated with radioisotopes used, the quantities and chemical forms often have to be available developed. The chemistry of metal complexes booming, we were able to use the ethyl ester combined with technetium, forming a stable radiotracer. Finally, a counting of radioactivity in different rat's organs completed our study. (Author)

  20. Rapid Enzymatic Method for Pectin Methyl Esters Determination

    OpenAIRE

    Lucyna Łękawska-Andrinopoulou; Vasiliou, Efstathios G.; Georgakopoulos, Dimitrios G.; Yialouris, Constantinos P.; Georgiou, Constantinos A.

    2013-01-01

    Pectin is a natural polysaccharide used in food and pharma industries. Pectin degree of methylation is an important parameter having significant influence on pectin applications. A rapid, fully automated, kinetic flow method for determination of pectin methyl esters has been developed. The method is based on a lab-made analyzer using the reverse flow-injection/stopped flow principle. Methanol is released from pectin by pectin methylesterase in the first mixing coil. Enzyme working solution is...

  1. Rheological behavior of castor oil mixed with different pyromellitic esters

    OpenAIRE

    Boran Sorina; Tamas Andra

    2014-01-01

    The paper presents the rheological behavior study of castor oil mixed with different pyromellitic esters. The pyromellitic tetraesters used were obtained through the esterification of pyromellitic anhydride with a special alcohol of a complex alkyl-aryl structure (2-phenoxy-ethanol) in conjunction with a linear aliphatic alcohol with variable length (n-butanol, n-decanol). The influence of pyromellitic esters’ structure and concentration was determined, as ...

  2. DNA-Catalyzed Hydrolysis of Esters and Aromatic Amides

    OpenAIRE

    Brandsen, Benjamin M.; Hesser, Anthony R.; Castner, Marissa A.; Chandra, Madhavaiah; Silverman, Scott K.

    2013-01-01

    We previously reported that DNA catalysts (deoxyribozymes) can hydrolyze DNA phosphodiester linkages, but DNA-catalyzed amide bond hydrolysis has been elusive. Here we used in vitro selection to identify DNA catalysts that hydrolyze ester linkages as well as DNA catalysts that hydrolyze aromatic amides, for which the leaving group is an aniline moiety. The aromatic amide-hydrolyzing deoxyribozymes were examined using linear free energy relationship analysis. The hydrolysis reaction is unaffec...

  3. Perfluorooxasulphonates of metals – the catalysts of esters manufacture

    OpenAIRE

    Melnyk, Stepan

    2013-01-01

    The process of obtaining of aliphatic dibasic esters from dicarboxylic acids and C4-C5 alcohols in the presence of perfluoro(4–methyl–3,6–dioxaoctane)sulphonates of different metals has been researched. For the comparative estimation of catalysts their concentration was chosen identical and of such value that the rate of the process was limited exactly by the rate of chemical reaction. The dependences of technological characteristics of esterification process on catalyst nature and c...

  4. Antiwear and antioxidant studies of cardanol phosphate ester additives

    OpenAIRE

    S. E. Mazzetto; L. D. M. Oliveira; D. Lomonaco; P. A. Veloso

    2012-01-01

    In the search for new applications and products derived from Cashew Nut Shell Liquid (CNSL), we report herein the synthesis and characterization (GC/MS and ¹H, 13C, and 31P NMR) of four phosphate esters derived from hydrogenated cardanol, including their applications as antiwear additives for diesel (S500) and as antioxidant additives for mineral oils, evaluated through the HFRR test and oxidative stability analyses, respectively. The results obtained showed very good to excellent performance...

  5. Processing and properties of SiC/vinyl ester nanocomposites

    OpenAIRE

    Yong, V.; Hahn, H T

    2004-01-01

    The feasibility of improving polymer composites was investigated using 30 nm SiC nanoparticles in a vinyl ester resin. Even when the particle loading was less than 4% by weight, the viscosity of the nanoparticle suspension was found to increase much higher than that of microparticle suspension. This phenomenon may be the result of association between nanoparticles and polymer molecules, effectively making the nanoparticles larger. The resulting reduction in the mobility of polymer molecules a...

  6. Characterization and Process Development of Cyanate Ester Resin and Composite

    Energy Technology Data Exchange (ETDEWEB)

    Frame, B.J.

    1998-03-01

    Cyanate ester (or polycyanate) resins offer advantages as composite matrices because of their high thermal stability, low outgassing, low water absorption and radiation resistance. This report describes the results of a processing study to develop high-strength hoop-wound composite by the wet-filament winding method using Toray T1000G carbon fiber and YLA RS-14A polycyanate resin as the constituent materials. Process trials, tests and analyses were conducted in order to gain insight into factors that can affect final properties of the cured cyanate ester resin and its composites. The study shows that the cyanate ester resin has a broad process envelope but that an inert-atmosphere cure is essential for obtaining optimum resin and composite properties. Minimizing moisture exposure prior to cure is also crucial as it affects the T{sub g} of the resin and composite. Recommendations for reducing moisture contact with the resin during wet-winding are presented. High fiber volume fraction ({approximately}80%) composites wound and cured with these methods yielded excellent hoop tensile strengths (660 to 670 ksi average with individual rings failing above 700 ksi), which are believed to be the highest recorded strengths for this class of materials. The measured transverse properties were also exceptional for these high fiber fraction composites. Based on the available data, this cyanate ester resin system and its composites are recommended for space and vacuum applications only. Further testing is required before these materials can be recommended for long term use at elevated temperatures in an ambient air environment. The results of all analyses and tests performed as part of this study are presented as well as baseline process for fabricating thick, stage-cured composites. The manufacture of a 1 in. thick composite cylinder made with this process is also described.

  7. Synthesis of stearic acid triethanolamine ester over solid acid catalysts

    Institute of Scientific and Technical Information of China (English)

    Tao Geng; Qiu Xiao Li; Ya Jie Jiang; Wei Wang

    2010-01-01

    The synthesis of stearic acid triethanolamine ester over solid acid catalysts was investigated.The results showed that the catalytic activity and selectivity of zirconium sulfate supported on SBA-15(6)(pore diameter 6 nm)is better than that of commonly used hypophosphorous acid,zirconium sulfate supported on MCM-41 and zirconium sulfate supported on SBA-15(9)(pore diameter 9 nm).

  8. Enzymatic synthesis and application of fatty acid ascorbyl esters

    Directory of Open Access Journals (Sweden)

    Stojanović Marija M.

    2013-01-01

    Full Text Available Fatty acid ascorbyl esters are liposoluble substances that possess good antioxidative properties. These compounds could be synthesized by using various acyl donors for acylation of vitamin C in reaction catalyzed by chemical means or lipases. Enzymatic process is preferred since it is regioselective, performed under mild reaction conditions, with the obtained product being environmentally friendly. Polar organic solvents, ionic liquids, and supercritical fluids has been successfully used as a reaction medium, since commonly used solvents with high Log P values are inapplicable due to ascorbic acid high polarity. Acylation of vitamin C using fatty acids, their methyl-, ethyl-, and vinyl esters, as well as triglycerides has been performed, whereas application of the activated acyl donors enabled higher molar conversions. In each case, majority of authors reported that using excessive amount of the acyl donor had positive effect on yield of product. Furthermore, several strategies have been employed for shifting the equilibrium towards the product by water content control. These include adjusting the initial water activity by pre-equilibration of reaction mixture, enzyme preparation with water vapor of saturated salt solutions, and the removal of formed water by the addition of molecular sieves or salt hydrate pairs. The aim of this article is to provide a brief overview of the procedures described so far for the lipase-catalyzed synthesis of fatty acid ascorbyl esters with emphasis on the potential application in food, cosmetics, and pharmaceutics. Furthermore, it has been pointed out that the main obstacles for process commercialization are long reaction times, lack of adequate purification methods, and high costs of lipases. Thus, future challenges in this area are testing new catalysts, developing continuous processes for esters production, finding cheaper acyl donors and reaction mediums, as well as identifying standard procedures for

  9. Enzymatic synthesis and application of fatty acid ascorbyl esters

    OpenAIRE

    Stojanović Marija M.; Carević Milica B.; Mihailović Mladen D.; Knežević-Jugović Zorica D.; Petrović Slobodan D.; Bezbradica Dejan I.

    2013-01-01

    Fatty acid ascorbyl esters are liposoluble substances that possess good antioxidative properties. These compounds could be synthesized by using various acyl donors for acylation of vitamin C in reaction catalyzed by chemical means or lipases. Enzymatic process is preferred since it is regioselective, performed under mild reaction conditions, with the obtained product being environmentally friendly. Polar organic solvents, ionic liquids, and supercritical fluids has been successfully use...

  10. Cellulose Ester / Polyolefin Binary Blends : Rheology, Morphology and Impact Properties

    OpenAIRE

    Besson, François; Vanhille, Aurélie; Budtova, Tatiana

    2012-01-01

    Due to depletion of fossil resources and global environmental respect awareness, interest in biobased plastic materials is tremendously growing. Direct extraction of vegetal polymers like cellulose followed by a chemical modification to bring new properties is one of the paths to produce a bioplastic. Progressively replaced by oil-based polymers in the sixties, thermoplastic cellulose esters are now reconsidered for various materials applications. To improve mechanical weaknesses of cellulose...

  11. Synthesis and Pharmacology of Ester Modified (+/-)-threo-Methylphenidate Analogs

    OpenAIRE

    Deutsch, Howard M.; Ye, Xiaocong Michael; Schweri, Margaret M.

    2014-01-01

    As part of a program to develop compounds with potential to treat cocaine abuse, eleven (+/-)-threo-methylphenidate (TMP; Ritalin) derivatives were synthesized and tested in rat striatal tissue preparations for inhibitory potency against [3H]WIN 35,428 binding (WIN) to the dopamine (DA) transporter, [3H]citalopram binding (CIT) to the serotonin transporter, and [3H]DA uptake. The ester function was replaced by other functional groups in all of the compounds; some also contained substituents o...

  12. L-Valine Ester of Cyclopropavir - a New Antiviral Prodrug

    OpenAIRE

    Wu, Zhimeng; Drach, John C.; Prichard, Mark N.; Yanachkova, Milka; Yanachkov, Ivan; Bowlin, Terry L.; Zemlicka, Jiri

    2009-01-01

    The L-Valine ester of antiviral agent cyclopropavir, valcyclopropavir (6), was synthesized and evaluated for antiviral properties. Prodrug (6) inhibited replication of HCMV virus (Towne and AD169 strain) in HFF cells to approximately the same extent as the parent drug cyclopropavir (5). Stability of 6 toward hydrolysis at pH 7.0 roughly corresponds to that of valganciclovir (2). Pharmacokinetic studies in mice established that the oral bioavailability of valcyclopropavir (6) was 95%.

  13. Characterization and Process Development of Cyanate Ester Resin Composites

    Energy Technology Data Exchange (ETDEWEB)

    Frame, B.J.

    1999-05-23

    Cyanate ester resins offer advantages as composite matrices because of their high thermal stability, low outgassing, low water absorption, and radiation resistance. This paper describes the results of a processing study to develop a high-strength hoop-wound composite by the wet-filament winding method using Toray TI 000G carbon fiber and YLA RS- 14A cyanate ester resin as the constituent materials. The study shows that the cyanate ester resin has a broad process envelope but that an inert-atmosphere cure is essential for obtaining optimum resin and composite properties. Minimizing moisture exposure prior to and during cure is also crucial as it affects the glass transition temperature of the resin and composite. Composite cylinders wound and cured with these methods yielded excellent ring tensile strengths both at room and elevated temperature. A summary of the measured mechanical and thermal property data for these composites is presented. Potential applications for these materials include flywheeI energy storage systems for space and satellite structures.

  14. Boric ester-type molten salt via dehydrocoupling reaction.

    Science.gov (United States)

    Matsumi, Noriyoshi; Toyota, Yoshiyuki; Joshi, Prerna; Puneet, Puhup; Vedarajan, Raman; Takekawa, Toshihiro

    2014-01-01

    Novel boric ester-type molten salt was prepared using 1-(2-hydroxyethyl)-3-methylimidazolium chloride as a key starting material. After an ion exchange reaction of 1-(2-hydroxyethyl)-3-methylimidazolium chloride with lithium (bis-(trifluoromethanesulfonyl) imide) (LiNTf2), the resulting 1-(2-hydroxyethyl)-3-methylimidazolium NTf2 was reacted with 9-borabicyclo[3.3.1]nonane (9-BBN) to give the desired boric ester-type molten salt in a moderate yield. The structure of the boric ester-type molten salt was supported by 1H-, 13C-, 11B- and 19F-NMR spectra. In the presence of two different kinds of lithium salts, the matrices showed an ionic conductivity in the range of 1.1 × 10⁻⁴-1.6 × 10⁻⁵ S cm⁻¹ at 51 °C. This was higher than other organoboron molten salts ever reported. PMID:25405738

  15. Cyanate Ester and Phthalonitrile Impregnated Carbon Ablative TPS

    Science.gov (United States)

    Boghozian, Tane; Stackpoole, Margaret M.; Gasch, Matt

    2016-01-01

    Phenolic resin has extensive heritage as a TPS (Thermal Protection Systems) material, however, alternative resin systems such as Cyanate Ester and Phthalonitrile may offer improved performance compared to state-of-the-art phenolic resin. These alternative resin systems may have higher char yield, higher char strength, lower thermal conductivity and improved mechanical properties. In current work at NASA Ames alternative resin systems were uniformly infused into fibrous substrates and preliminary properties characterized. The density of the cyanate ester infused in fibrous substrate ranged from 0.25-0.3 grams per cubic centimeter compared to PICA (Phenolic resin impregnated carbon ablative) having a density of approximately 0.25 grams per cubic centimeter. The density of Phthalonitrile varies from 0.22-0.25 grams per cubic centimeter. Initial formulations of these new resin systems were recently tested at the LARC HyMETs (Hypersonic Materials Environmental Test System) facility to evaluate their performance and data such as back face temperature, char yield, and recession are compared to PICA. Cyanate Ester and Phthalonitrile impregnated carbon ablative samples showed comparable performance to phenolic resin impregnated carbon ablative samples.

  16. MORPHOLOGY AND PROPERTIES OF SEGMENTED BLOCK COPOLY (ETHER ESTER)S FIBERS MADE BY GEL-DRAWING

    Institute of Scientific and Technical Information of China (English)

    CHEN Shouxi; G.Wegner

    1988-01-01

    The segmented block copoly(ether ester)s were swollen by tetrahydrofuran (THF) at 60℃ and formed-fibers by gel-drawing. The morphology and properties of these fibers were investigated by optical and electron microscopes, X-ray diffraction, DSC and an Instron test machine. The band structure morphology was observed in the gel-drawing fibers. The molecular chains were highly oriented as proved by X-ray diffraction data. The results indicated that the gel-drawing fibers have much better mechanical properties than those obtained otherwise. The tensile strength and elastic modulus were found to be 280 MPa and 802 MPa, repsectively. The mechanism of the gel-drawing process was also discussed.

  17. Synthesis and Characteristics of an Aspartame Analogue, L-Asparaginyl L-3-Phenyllactic Acid Methyl Ester

    Institute of Scientific and Technical Information of China (English)

    Hu TAO; Da-Fu CUI; You-Shang ZHANG

    2004-01-01

    An aspartame analogue,L-asparaginyl L-3-phenyllactic acid methyl ester was synthesized with aspartic acid replaced by asparagine and peptide bond replaced by ester bond.The aspartic acid of aspartame could be replaced by asparagine as reported in the literature.In this analogue,the hydrogen ofamide group could still form a hydrogen bond with the oxygen of ester bond and the ester bond was isosteric with peptide bond.However,the product was not sweet,showing that the peptide bond could not be replaced by ester bond.The peptide C-N bond behaves as a double bond that is not free to rotate and the C,O,N and H atoms are in the same plane.The replacement of peptide bond by ester bond destroyed the unique conformation of peptide bond,resulting in the loss of sweet taste.

  18. Lubricity of bio-based lubricant derived from chemically modified jatropha methyl ester

    Directory of Open Access Journals (Sweden)

    N.W.M. Zulkifli

    2014-06-01

    Full Text Available Many studies have been undertaken with a view to using chemically modified vegetable oil as a bio-based lubricant. This research focused on tribological properties of trimethylolpropane (TMP ester, which is derived from renewable resource. This TMP ester was produced from jatropha methyl ester; it is biodegradable and has high lubricity properties. Two different conditions of lubrication are being investigated: extreme pressure and anti-wear. It was found that the TMP ester (Jatropha has better lubricity in terms of wear and friction compared to paraffin oil under extreme pressure conditions. TMP ester (Jatropha has similar characteristics to fully formulated lubricant (FFL, in terms of the coefficient of friction (CoF. In terms of the anti-wear condition, TMP ester (Jatropha has the lowest CoF; however it also has the high wear scar diameter. This is due to corrosion and chemical attack.

  19. Improved synthesis of amino acid and dipeptide chloromethyl esters using bromochloromethane

    OpenAIRE

    Gomes, P; Santos, MI; Trigo, MJ; Castanheiro, R.; Moreira, R.

    2003-01-01

    Peptide chloromethyl esters are important compounds in prodrug synthesis. A simple, mild and efficient method for the synthesis of chloromethyl esters of N-blocked amino acids and dipeptides using exclusively bromochloromethane is reported. These N-blocked amino acid and dipeptide chloromethyl esters react readily with the carboxylic acid group of aspirin and with the sulfonamido group of the antimalarial sulfamethazine, to give the corresponding prodrugs.

  20. Characterization of structural stability of palm oil esters-based nanocosmeceuticals loaded with tocotrienol

    OpenAIRE

    Ng, Sook Han; Woi, Pei Meng; Basri, Mahiran; Ismail, Zahariah

    2013-01-01

    Background Palm oil esters (POEs) are esters derived from palm oil and oleyl alcohol have great potential in the cosmetic and pharmaceutical industries due to the excellent wetting behavior of the esters without the oily feel. The role of oil-in-water nanoemulsions loaded with tocotrienol sedimentation behavior was studied. LUMiFuge® 116 particle separation analyzer was used to investigate the sedimentation behavior of POEs/tocotrienol/xanthan gum nanoemulsion system during centrifugation. An...

  1. Regioselective transesterifications of cyclohexanone derivatives containing beta-keto and malonic ester moieties

    OpenAIRE

    Makarević, Janja; Žinić, Mladen

    1998-01-01

    The cyclohexanone derivatives 1–6 containing β-ketoester and α-disubstituted malonic ester moieties in the same molecule were found to undergo regioselective transesterifications with benzyl alcohol giving exclusively β-keto benzyl esters. On the contrary, the acyclic derivatives 9, 10 containing β-ketoester and α-monosubstituted malonic ester groups gave mixtures of transesterified products under the same reaction conditions.

  2. Phorbol ester effects on neurotransmission: interaction with neurotransmitters and calcium in smooth muscle.

    OpenAIRE

    Baraban, J M; Gould, R J; Peroutka, S J; Snyder, S. H.

    1985-01-01

    Stimulation of the phosphatidylinositol cycle by neurotransmitters generates diacylglycerol, an activator of protein kinase C, which may regulate some forms of neurotransmission. Phorbol esters, potent inflammatory and tumor-promoting compounds, also activate protein kinase C. We demonstrate potent and selective effects of phorbol esters on smooth muscle, indicating a role for protein kinase C in neurotransmission. In rat vas deferens and dog basilar artery, phorbol esters synergize with calc...

  3. Formation and occurrence of dimer esters of pinene oxidation products in atmospheric aerosols

    DEFF Research Database (Denmark)

    Kristensen, Kasper; Enggrob, Kirsten L.; King, S. M.;

    2013-01-01

    and at low NOx concentrations demonstrated formation of two dimer esters, pinyl-diaterpenyl (MW 358) and pinonyl-pinyl dimer ester (MW 368), under both low- and high-temperature conditions. Concentration levels of the pinyl-diaterpenyl dimer ester were lower than the assumed first-generation oxidation...... valuable information on pinene oxidation processes and should be included in studies of formation and photochemical aging of biogenic secondary organic aerosols, especially at high temperatures....

  4. Quasi-Static and Fatigue Evaluation of Pultruded Vinyl Ester/E-Glass Composites

    OpenAIRE

    Phifer, Stephan Paul

    1998-01-01

    QUASI-STATIC AND FATIGUE EVALUATION OF PULTRUDED VINYL ESTER/E-GLASS COMPOSITES Stephan P. Phifer (ABSTRACT) The quasi-static strength, stiffness, and fatigue properties of cross-ply, angle-ply, and quasi-isotropic vinyl ester/E-glass non-woven tricot stitched fabric composite laminates fabricated from the Continuous Resin Transfer Molding (CRTM) pultrusion process were the focus of this research. The tricot stitch and the 6% vinyl ester matrix cure shrinkage were found to play ...

  5. Preparation and characterization of aliphatic diphenyl esters intended as precursors for polyesters

    DEFF Research Database (Denmark)

    Hvilsted, S.; Andruzzi, F.; Cerrai, P.; Tricoli, M.

    1991-01-01

    An extensive number of aliphatic diphenyl esters, C6H5OOC(CH2)nCOOC6H5 (n = O,...,8,10,11,12,14), have been prepared in pure form. The crystalline melting points these esters exhibit an odd-even temperature behaviour, with the higher-melting even series (n even) displaying a minimum for n = 8 whi...... chloroform points to specific phenyl ester-solvent interactions, which obscure a potential s.e.c. conformational analysis of the diphenyl esters....

  6. Chromatographic, Spectrometric and NMR Characterization of a New Set of Glucuronic Acid Esters Synthesized by Lipase

    Directory of Open Access Journals (Sweden)

    Michel Marlier

    2007-01-01

    Full Text Available An enzymatic synthesis was developed on a new set of D-glucuronic acid esters and particularly the tetradecyl-D-glucopyranosiduronate also named tetradecyl D-glucuronate. Chromatographic analyses revealed the presence of the ester as a mixture of anomeric forms for carbon chain lengths superior to 12. TOF/MS and MS/MS studies confirmed the synthesis of glucuronic acid ester. The NMR study also confirmed the structure of glucuronic acid esters and clearly revealed an anomeric (α/β ratio equivalent to 3/2

  7. Experimental and Modeling Studies on the Synthesis and Properties of Higher Fatty Esters of Corn Starch

    OpenAIRE

    Junistia, Laura; Sugih, Asaf K.; Manurung, Robert; Picchioni, Francesco; Janssen, Leon P.B.M.; 068883455; Heeres, Hero J.

    2009-01-01

    This paper describes a systematic study on the synthesis of higher fatty esters of corn starch (starch laurate and starch stearate) by using the corresponding vinyl esters. The reactions were carried out in DMSO using basic catalysts (Na(2)HPO(4), K(2)CO(3), and Na-acetate). The effect of the process variables (vinyl ester to starch ratio, catalyst intake, reaction temperature and type of the catalyst) on the degree of substitution (DS) of the starch laurate and starch stearate esters was det...

  8. Conformational analysis of acetylcholine and related choline esters

    DEFF Research Database (Denmark)

    Frydenvang, Karla Andrea; Jensen, B

    1996-01-01

    ,2'-[(1,4-dioxo-1,4-butanediyl)bis(oxy)]bis(N,N,N-trimethylet hanaminium)¿ iodide have been redetermined at 105 K in order to obtain detailed and accurate information on the geometry of choline esters and to elucidate the conformationally dependent changes of geometry. The conformational flexibility and the...... preferred conformations are elucidated based on results obtained from X-ray crystallographic studies and molecular mechanics (MM2) calculations. The usefulness of molecular mechanics calculations for quaternary ammonium ions is discussed....

  9. Diastereoselective Ugi reaction for the synthesis of unnatural amino esters

    Directory of Open Access Journals (Sweden)

    Rafael Oliveira Rocha

    2012-06-01

    Full Text Available Multicomponent Reactions (MCR are useful reactions to obtain complex products by the simple mixture of 3 or more reactants. The classic Ugi reaction (4-UCR involves a mixture of an amine, aldehyde, isocyanide and a carboxylic acid, giving peptoides as products. Some modifications of this reaction have been reported, among which the use of amino acids and Lewis acids, such as titanium (IV chloride, to induce stereoselectivity in good ratio. In this work we demonstrate the efficiency of different Lewis acids in the modified Ugi reaction and good levels of diastereoselectivity and yields in the synthesis of unnatural secondary amino esters.

  10. Pharmaceutical potential of phorbol esters from Jatropha curcas oil.

    Science.gov (United States)

    Devappa, Rakshit K; Malakar, Chandi C; Makkar, Harinder P S; Becker, Klaus

    2013-01-01

    Phorbol esters (PEs) are diterpenes present in Jatropha curcas L. seeds and have a myriad of biological activities. Since PEs are toxic, they are considered to be futile in Jatropha-based biodiesel production chain. In the present study, the extracted PEs from Jatropha oil were used as a starting material to synthesise pharmacologically important compound, prostratin. The prostratin synthesised from Jatropha showed identical mass with that of the reference standard prostratin, as determined by Nano-LC-ESI-MS/MS. Considering the rapid growth in Jatropha biodiesel industry, potential exists to harness large amount of PEs which can be further utilised to synthesise prostratin as a value added product. PMID:22913490

  11. A New Insecticidal Sesquiterpene Ester from Celastrus Angulatus

    Directory of Open Access Journals (Sweden)

    Shao-peng Wei

    2009-03-01

    Full Text Available A new sesquiterpene polyol ester with a β-dihydroagarofuran skeleton, NW37 (1, and three known compounds NW13 (2, NW16 (3 and NW35 (4 were isolated by bioassay-guided fractionation from the highly polar MeOH extracts of the root bark of Celastrus angulatus. Their chemical structures were elucidated mainly by analyses of MS and NMR spectral data. The insecticidal activity of compound 1 against 4th instar Mythimna separata larvae with a KD50 value of 252.3 μg·g-1 was demonstrated.

  12. Ester Prodrugs of Ketoprofen: Synthesis, Hydrolysis Kinetics and Pharmacological Evaluation.

    Science.gov (United States)

    Dhokchawle, B V; Tauro, S J; Bhandari, A B

    2016-01-01

    The ester prodrugs of ketoprofen with various naturally available antioxidants; menthol, thymol, eugenol, guiacol, vanillin and sesamol have been synthesized by the dicyclohexyl carbodiimide (DCC) coupling method, purified and characterized by spectral data. Further, their, partition coefficients have been determined as well as, hydrolytic studies performed. The synthesized compounds are more lipophilic compared to the parent moieties and are stable in acidic environment, which is a prerequisite for their oral absorption. Under gastric as well as intestinal pH conditions these prodrugs showed variable susceptibility towards hydrolysis. The title compounds when evaluated for anti-inflammatory, analgesic activities and ulcerogenicity, showed improvement over the parent drug. PMID:25894087

  13. Carboxylic ester hydrolases in mitochondria from rat skeletal muscle

    DEFF Research Database (Denmark)

    Kirkeby, S; Moe, D; Zelander, T

    1990-01-01

    organophosphate and organomercury. The activity of the indoxyl acetate esterases was enhanced by the non-ionic detergents Tween-40 and Lubrol. After freezing, thawing and high speed centrifugation most of the alpha-naphthyl acetate splitting enzymes were found in the supernatant, indicating that the enzymes are......A mitochondrial pellet, prepared from rat skeletal muscle, contained a number of carboxylic ester hydrolase isoenzymes. The esterases which split alpha-naphthyl acetate were organophosphate sensitive, whereas two out of three indoxyl acetate hydrolysing enzymes were resistant to both...

  14. Phthalic acid esters found in municipal organic waste

    DEFF Research Database (Denmark)

    Hartmann, Hinrich; Ahring, Birgitte Kiær

    2003-01-01

    Contamination of the organic fraction of municipal solid waste (OFMSW) with xenobiotic compounds and their fate during anaerobic digestion was investigated. The phthalic acid ester di-(2- ethylhexyl)phthalate (DEHP) was identified as the main contaminant in OFMSW in concentrations more than half of...... bioavailability, which is enhanced at higher temperature and higher degradation of solid organic matter, to which the highly hydrophobic DEHP is adsorbed. The investigated reactor configuration with a thermophilic and a hyper-thermophilic treatment is, therefore, a good option for CD combining high rate...

  15. Synthesis of oleyl oleate wax esters in Arabidopsis thaliana and Camelina sativa seed oil.

    Science.gov (United States)

    Iven, Tim; Hornung, Ellen; Heilmann, Mareike; Feussner, Ivo

    2016-01-01

    Seed oil composed of wax esters with long-chain monoenoic acyl moieties represents a high-value commodity for industry. Such plant-derived sperm oil-like liquid wax esters are biodegradable and can have excellent properties for lubrication. In addition, wax ester oil may represent a superior substrate for biodiesel production. In this study, we demonstrate that the low-input oil seed crop Camelina sativa can serve as a biotechnological platform for environmentally benign wax ester production. Two biosynthetic steps catalysed by a fatty alcohol-forming acyl-CoA reductase (FAR) and a wax ester synthase (WS) are sufficient to achieve wax ester accumulation from acyl-CoA substrates. To produce plant-derived sperm oil-like liquid wax esters, the WS from Mus musculus (MmWS) or Simmondsia chinensis (ScWS) were expressed in combination with the FAR from Mus musculus (MmFAR1) or Marinobacter aquaeolei (MaFAR) in seeds of Arabidopsis thaliana and Camelina sativa. The three analysed enzyme combinations Oleo3:mCherry:MmFAR1∆c/Oleo3:EYFP:MmWS, Oleo3:mCherry:MmFAR1∆c/ScWS and MaFAR/ScWS showed differences in the wax ester molecular species profiles and overall biosynthetic performance. By expressing MaFAR/ScWS in Arabidopsis or Camelina up to 59% or 21% of the seed oil TAGs were replaced by wax esters, respectively. This combination also yielded wax ester molecular species with highest content of monounsaturated acyl moieties. Expression of the enzyme combinations in the Arabidopsis fae1 fad2 mutant background high in oleic acid resulted in wax ester accumulation enriched in oleyl oleate (18:1/18:1 > 60%), suggesting that similar values may be obtained with a Camelina high oleic acid line. PMID:25912558

  16. Uptake and Metabolism of Phthalate Esters by Edible Plants.

    Science.gov (United States)

    Sun, Jianqiang; Wu, Xiaoqin; Gan, Jay

    2015-07-21

    Phthalate esters (PAEs) are large-volume chemicals and are found ubiquitously in soil as a result of widespread plasticulture and waste disposal. Food plants such as vegetables may take up and accumulate PAEs from soil, potentially imposing human health risks through dietary intake. In this study, we carried out a cultivation study using lettuce, strawberry, and carrot plants to determine the potential of plant uptake, translocation, and metabolism of di-n-butyl phthalate (DnBP) and di(2-ethylhexyl) phthalate (DEHP) and their primary metabolites mono-n-butyl phthalate (MnBP) and mono(2-ethylhexyl) phthalate (MEHP). All four compounds were detected in the plant tissues, with the bioconcentration factors (BCFs) ranging from 0.16 ± 0.01 to 4.78 ± 0.59. However, the test compounds were poorly translocated from roots to leaves, with a translocation factor below 1. Further, PAEs were readily transformed to their monoesters following uptake. Incubation of PAEs and monoalkyl phthalate esters (MPEs) in carrot cell culture showed that DnBP was hydrolyzed more rapidly than DEHP, while the monoesters were transformed more quickly than their parent precursors. Given the extensive metabolism of PAEs to monoesters in both whole plants and plant cells, metabolism intermediates such as MPEs should be considered when assessing human exposure via dietary intake of food produced from PAE-contaminated soils. PMID:26090545

  17. Microreactors-A Powerful Tool to Synthesize Peroxycarboxylic Esters.

    Science.gov (United States)

    Illg, Tobias; Knorr, Annett; Fritzsche, Lutz

    2015-01-01

    The synthesis of peroxycarboxylic esters, as one subgroup of organic peroxides, is characterized by a high thermal hazard potential regarding process safety. In case of failure in the production process, e.g., if the heat of reaction cannot be removed sufficiently fast, decomposition reactions can be triggered, and as a result, remarkable amounts of heat and gas can be released and can cause a high extent of damage. Multifarious technical and organizational measures are necessary to ensure the safe industrial production of peroxides. With the introduction of microreaction technology plenty of possibilities have been opened to carry out highly exothermic reactions in smaller volumes and with more efficient heat removal. In this paper we report the application of three different microstructured reactors, representing different mixing strategies, to synthesize two peroxymonocarboxylic esters, namely tert-butyl peroxypivalate and tert-butyl peroxy-2-ethylhexanoate. The following reactor types were considered: an orifice microreactor, a split and recombine microreactor and a capillary tube reactor in combination with ultrasonication. The efficiency of the two phase liquid/liquid reaction is expressed in comparison of conversion and selectivity. With microreaction technology a remarkable increase in space-time-yield, ranging from 12,500 kg·m(-3)·h(-1) to 414,000 kg·m(-3)·h(-1), is achieved. PMID:26703553

  18. Solvent-free enzymatic production of high quality cetyl esters.

    Science.gov (United States)

    Serrano-Arnaldos, Mar; Máximo-Martín, María Fuensanta; Montiel-Morte, María Claudia; Ortega-Requena, Salvadora; Gómez-Gómez, Elisa; Bastida-Rodríguez, Josefa

    2016-04-01

    A solvent-free biocatalytic process for the synthesis of high quality cetyl laurate, myristate, palmitate and stearate has been optimized. This enzymatic procedure follows the fundamental principles of the Green Chemistry and lead to sustainable products, which can be labeled as natural and conform to the principal requirements for its use in high value-added goods. The four esters selected are the main components of spermaceti, a mixture of waxes very appreciated in cosmetic and pharmacy because of its physical properties and emolliency, which was formerly extracted from the head of the sperm whales. In this paper, the influence of the amount of biocatalyst, the commercially available Novozym(®) 435, and the temperature were studied in an open-air batch reactor before carrying out the synthesis in a high performance vacuum reactor with dry nitrogen input to shift the equilibrium towards product formation. Under optimal conditions, conversion was higher than 98.5 %. The characterization of the enzymatic cetyl esters puts in evidence that these are ultra-pure compounds, which have similar properties to the ones obtained through the conventional industrial processes with the extra benefit of being environmentally friendly. PMID:26801670

  19. N-hydroxysuccinimide-hippuran ester: application for radiolabeling of macromolecules

    International Nuclear Information System (INIS)

    A method for synthesis of N-hydroxysuccinimide ester of radioactive orthoiodohippurric acid (OIH-OSU) is developed in order to label macromolecules including antibodies. The OIH-OSU is prepared in 87% yield by reacting molar equivalents of o-iodohippuric acid, N:N-di-succinimidyl carbonate and pyridine in DMF overnight. The active labeled ester is obtained using high specific activity OIH in a similar synthetic protocol. Conjugation of OIH-OSU to human serum albumin is effected by incubating the reactants for half an hour at room temperature followed by purification of the labeled protein on a Sephadex G-100 column with activity yield of 44.3%. Organ distribution for the labeled albumin preparation and the commercial iodinated human serum albumin (RISA) in mice and rats is similar. As expected urinary excretion of radioactivity for the labeled preparation is greater than that of RISA reflecting the rapid urinary clearance of the OIH moiety released into the bloodstream. Hippuran labeling method offers a mild and rapid protocol for radioiodine labeling of proteins and antibodies for application in diagnostic nuclear medicine procedures

  20. New horizons for cholesterol ester transfer protein inhibitors.

    Science.gov (United States)

    Schwartz, Gregory G

    2012-02-01

    High-density lipoprotein (HDL) cholesterol levels bear an inverse relationship to cardiovascular risk. To date, however, no intervention specifically targeting HDL has been demonstrated to reduce cardiovascular risk. Cholesterol ester transfer protein (CETP) mediates transfer of cholesterol ester from HDL to apolipoprotein B-containing particles. Most, but not all observational cohort studies indicate that genetic polymorphisms of CETP associated with reduced activity and higher HDL cholesterol levels are also associated with reduced cardiovascular risk. Some, but not all studies indicate that CETP inhibition in rabbits retards atherosclerosis, whereas transgenic CETP expression in mice promotes atherosclerosis. Torcetrapib, the first CETP inhibitor to reach phase III clinical development, was abandoned due to excess mortality associated with increases in aldosterone and blood pressure. Two other CETP inhibitors have entered phase III clinical development. Anacetrapib is a potent inhibitor of CETP that produces very large increases in HDL cholesterol and large reductions in low-density lipoprotein (LDL) cholesterol, beyond those achieved with statins. Dalcetrapib is a less potent CETP inhibitor that produces smaller increases in HDL cholesterol with minimal effect on LDL cholesterol. Both agents appear to allow efflux of cholesterol from macrophages to HDL in vitro, and neither agent affects blood pressure or aldosterone in vivo. Two large cardiovascular outcomes trials, one with anacetrapib and one with dalcetrapib, should provide a conclusive test of the hypothesis that inhibition of CETP decreases cardiovascular risk. PMID:22083134

  1. Microreactors—A Powerful Tool to Synthesize Peroxycarboxylic Esters

    Directory of Open Access Journals (Sweden)

    Tobias Illg

    2015-12-01

    Full Text Available The synthesis of peroxycarboxylic esters, as one subgroup of organic peroxides, is characterized by a high thermal hazard potential regarding process safety. In case of failure in the production process, e.g., if the heat of reaction cannot be removed sufficiently fast, decomposition reactions can be triggered, and as a result, remarkable amounts of heat and gas can be released and can cause a high extent of damage. Multifarious technical and organizational measures are necessary to ensure the safe industrial production of peroxides. With the introduction of microreaction technology plenty of possibilities have been opened to carry out highly exothermic reactions in smaller volumes and with more efficient heat removal. In this paper we report the application of three different microstructured reactors, representing different mixing strategies, to synthesize two peroxymonocarboxylic esters, namely tert-butyl peroxypivalate and tert-butyl peroxy-2-ethylhexanoate. The following reactor types were considered: an orifice microreactor, a split and recombine microreactor and a capillary tube reactor in combination with ultrasonication. The efficiency of the two phase liquid/liquid reaction is expressed in comparison of conversion and selectivity. With microreaction technology a remarkable increase in space-time-yield, ranging from 12,500 kg·m−3·h−1 to 414,000 kg·m−3·h−1, is achieved.

  2. Synthesis and thermal behavior of new liquid crystals arylaldoxime esters

    Energy Technology Data Exchange (ETDEWEB)

    Tavares, Aline; Arruda, Barbara C.; Boes, Elvis S.; Stefani, Valter; Stassen, Hubert K.; Campo, Leandra F.; Merlo, Aloir A., E-mail: aloir@iq.ufrgs.br [Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Porto Alegre-RS (Brazil); Bechtold, Ivan H. [Departamento de Fisica, Universidade Federal de Santa Catarina, Florianopolis-SC (Brazil)

    2012-05-15

    We report the synthesis of a series of liquid-crystalline materials based on arylaldoxime esters and the characterization of these materials by {sup 1}H, {sup 13}C NMR, ATR/FT-IR spectroscopy and elemental analysis. The chemical stability and liquid-crystalline as well as photophysical properties of the compounds are described being dependent on the heating/cooling cycles. The changes in chemical stability and the liquid crystals properties of arylaldoxime esters were observed during these thermal cycles by IR analysis. All samples underwent a thermal degradation yielding the corresponding nitriles and carboxylic acid as evidenced by IR and {sup 1}H NMR spectra. Due to the decomposition process, information about the mesomorphic behaviour is lost. The UV-Vis absorption spectra in solution display three absorption bands between 230 and 340 nm. The fluorescence spectra exhibit a broad and structureless emission band located at 430 nm. Ab initio calculations were performed to obtain information on the molecular structure and properties of the title compounds. (author)

  3. Ester-based solutions for rechargeable lithium cells

    International Nuclear Information System (INIS)

    In recent years, considerable progress has been made in rechargeable lithium technology. Current state-of-the-art secondary lithium cells generally employ solutions based on propylene carbonate or 2-methyl tetrahydrofuran, with 2-methyl tetrahydrofuran being the preferred solvent. Good cycle life has been achieved with these solutions at ambient temperature. However, poor low temperature performance and limited rate capabilities have prevented widespread use of these cells in DoD applications. These limitations are due, primarily, to the low conductivity of the electrolyte solutions employed. To extend the performance capabilities of rechargeable lithium cells, we have investigated the use of high conductivity ester-based electrolyte solutions utilizing methyl formate and methyl acetate as solvents. This paper discusses the initial results achieved with these solutions including electrochemical stability, lithium cyclability, and compatibility and cell performance with V/sub 2/O/sub 5/ and V/sub 6/O/sub 13/ cathode materials. These initial investigations with ester-based solutions have shown that LiAsF/sub 6/ + LiBF/sub 4//MF solutions offer all of the properties needed to meet the demanding performance requirements for DoD rechargeable lithium battery applications including high solution conductivities, electrochemical stability, and compatibility with cathode materials

  4. Subchronic organophosphorus ester-induced delayed neurotoxicity in mallards

    Science.gov (United States)

    Hoffman, D.J.; Sileo, L.; Murray, H.C.

    1984-01-01

    Eighteen-week-old mallard hens received 0, 10, 30, 90, or 270 ppm technical grade EPN (phenylphosphonothioic acid O-ethyl-O-4-nitrophenyl ester) in the diet for 90 days. Ataxia was first observed in the 270-ppm group after 16 days, in the 90-ppm group after 20 days, in the 30-ppm group after 38 days; 10 ppm failed to produce ataxia. By the end of 90 days all 6 birds in the 270-ppm group exhibited ataxia or paralysis whereas 5 of 6 birds in the 90-ppm group and 2 of 6 birds in the 30-ppm group were visibly affected. Treatment with 30 ppm or more resulted in a significant reduction in body weight. Brain neurotoxic esterase activity was inhibited by averages of 16, 69, 73, and 74% in the 10-, 30-, 90-, and 270-ppm groups, respectively. Brain acetylcholinesterase, plasma cholinesterase, and plasma alkaline phosphatase were significantly inhibited as well. Distinct histopathological effects were seen in the 30-, 90-, and 270-ppm groups which included demyelination and degeneration of axons of the spinal cord. Additional ducks were exposed in a similar manner to 60-, 270-, or 540-ppm leptophos (phosphonothioic acid O-4-bromo-2,5-dichlorophenyl-O-methylphenyl ester) which resulted in similar behavioral, biochemical, and histopathological alterations. These findings indicate that adult mallards are probably somewhat less sensitive than chickens to subchronic dietary exposure to organophosphorus insecticides that induce delayed neurotoxicity.

  5. QSAR for cholinesterase inhibition by organophosphorus esters and CNDO/2 calculations for organophosphorus ester hydrolysis. [quantitative structure-activity relationship, complete neglect of differential overlap

    Science.gov (United States)

    Johnson, H.; Kenley, R. A.; Rynard, C.; Golub, M. A.

    1985-01-01

    Quantitative structure-activity relationships were derived for acetyl- and butyrylcholinesterase inhibition by various organophosphorus esters. Bimolecular inhibition rate constants correlate well with hydrophobic substituent constants, and with the presence or absence of cationic groups on the inhibitor, but not with steric substituent constants. CNDO/2 calculations were performed on a separate set of organophosphorus esters, RR-primeP(O)X, where R and R-prime are alkyl and/or alkoxy groups and X is fluorine, chlorine or a phenoxy group. For each subset with the same X, the CNDO-derived net atomic charge at the central phosphorus atom in the ester correlates well with the alkaline hydrolysis rate constant. For the whole set of esters with different X, two equations were derived that relate either charge and leaving group steric bulk, or orbital energy and bond order to the hydrolysis rate constant.

  6. KARAKTERISTIK EMULSI SANTAN DAN MINYAK KEDELAI YANG DITAMBAH GUM ARAB DAN SUKROSA ESTER [Emulsion Characteristics of Coconut Milk and Soybean Oil Added with Gum Arabic and Sucrose Ester

    Directory of Open Access Journals (Sweden)

    Laksmi Hartayanie

    2015-07-01

    Full Text Available High saturated fatty acid content in coconut milk can be reduced by adding unsaturated fat. Pretreatment such as pasteurisation, homogenization or stabilizer and emulsifier addition are essential to prevent emulsion deterioration that could happen in few hours. This study aimed to determine the most appropriate combination of gum arabic and sucrose ester to produce good emulsion stability based on its physical and chemical characteristics. Furthermore this study also aimed to determine correlation between creaming index and other characteristics of coconut milk emulsion. Emulsion stability of mixed coconut milk in sterile glass bottles was observed for 7 days under 23-24°C. Stabilizer and emulsifier added were gum arabic and sucrose ester in five combinations, i.e. 6% gum arabic, 0.3% sucrose ester, 6% gum arabic + 0.3% sucrose ester, 3% gum arabic + 0.15% sucrose ester and 4.5% gum arabic + 0.225% sucrose ester. The physical characteristics evaluated were creaming index, total color change, viscosity and droplet distribution, while the chemical characteristics observed included pH, TBA value, and protein content. Data were analyzed by One Way Anova at 95% significant level to determine the differences among treatments. Bivariate Pearson Correlation was used in order to determine the interaction among sample characteristics. The data showed that, gum arabic and sucrose ester can maintain the emulsion stability. A combination of 4.5% gum arabic and 0.225% sucrose ester provided the best physicochemical characteristics with the lowest creaming index and decreased viscosit, and uniform droplet distribution.

  7. Potential grape-derived contributions to volatile ester concentrations in wine.

    Science.gov (United States)

    Boss, Paul K; Pearce, Anthony D; Zhao, Yanjia; Nicholson, Emily L; Dennis, Eric G; Jeffery, David W

    2015-01-01

    Grape composition affects wine flavour and aroma not only through varietal compounds, but also by influencing the production of volatile compounds by yeast. C9 and C12 compounds that potentially influence ethyl ester synthesis during fermentation were studied using a model grape juice medium. It was shown that the addition of free fatty acids, their methyl esters or acyl-carnitine and acyl-amino acid conjugates can increase ethyl ester production in fermentations. The stimulation of ethyl ester production above that of the control was apparent when lower concentrations of the C9 compounds were added to the model musts compared to the C12 compounds. Four amino acids, which are involved in CoA biosynthesis, were also added to model grape juice medium in the absence of pantothenate to test their ability to influence ethyl and acetate ester production. β-Alanine was the only one shown to increase the production of ethyl esters, free fatty acids and acetate esters. The addition of 1 mg∙L(-1) β-alanine was enough to stimulate production of these compounds and addition of up to 100 mg∙L(-1) β-alanine had no greater effect. The endogenous concentrations of β-alanine in fifty Cabernet Sauvignon grape samples exceeded the 1 mg∙L(-1) required for the stimulatory effect on ethyl and acetate ester production observed in this study. PMID:25939071

  8. L-leucine methyl ester stimulates insulin secretion and islet glutamate dehydrogenase

    DEFF Research Database (Denmark)

    Knudsen, P; Kofod, Hans; Lernmark, A;

    1983-01-01

    Column perifusion of collagenase-isolated mouse pancreatic islets was used to study the dynamics of insulin release in experiments lasting for several hours. The methyl esters of L-leucine and L-arginine were synthesized. Whereas L-arginine methyl ester (L-arginine OMe) had no effect, L-leucine O...

  9. Combined approaches using sex pheromone and pear ester for behavioral disruption of codling moth (Lepidoptera: Tortricidae)

    Science.gov (United States)

    Studies utilized the attractive properties of pear ester, ethyl (E,Z)-2,4-decadienoate, and codlemone, (E,E)-8,10-dodecadien-1-ol, the sex pheromone of codling moth, Cydia pomonella (L)., for behavioural disruption. Standard dispensers loaded with codlemone alone or in combination with pear ester (c...

  10. Syntheses of carbon-11 labeled piperidine esters as potential in vivo substrates for acetylcholinesterase

    International Nuclear Information System (INIS)

    A series of carbon-11 labeled N-methylpiperidinyl esters were prepared as potential in vivo substrates for acetylcholinesterase (AChE). Target compounds were designed based on the structure of N-[11C]methylpiperidin-4-yl propionate, an ester currently used to measure AChE enzymatic activity in the human brain, to examine the structure-activity relationship for in vivo enzymatic hydrolysis. Changes in steric bulk and in the ester order ('reverse' esters) were made. Addition of methyl groups was made to both the acid side chain (synthesis of N-[11C]methylmethylpiperidin-4-yl isobutyrate) and to the piperidine ring (syntheses of N-[11C]methyl-4-methylpiperidin-4-yl propionate, N-[11C]methyl-4-methylpiperidin-4-yl acetate, and N-[11C]methyl-3-methylpiperidin-4-yl propionate). Alterations of the order of the ester heteroatoms was accomplished through syntheses of the N-[11C]methyl-2,3- and 4-piperidinecarboxylic acid ethyl esters. Finally, an additional piperidine-based ester (N-[11C]methylpiperidin-2-yl)methyl propionate was also prepared. All carbon-11-labeled esters were prepared by N-[11C]methylation reactions, using the desmethyl precursors and no-carrier-added [11C]methyltriflate, and were obtained in decay-corrected yields (not optimized) of 10-40% and high specific activities

  11. Enhanced delivery of ketobemidone through porcine buccal mucosa in vitro via more lipophilic ester prodrugs

    DEFF Research Database (Denmark)

    Hansen, L.B.; Christrup, Lona Louring; Bundgaard, H.

    1992-01-01

    The in vitro penetration of ketobemidone and various ester prodrugs through porcine buccal mucosa in a modified Ussing chamber was investigated in order to support the selection of a prodrug derivative with optimal buccal absorption. The nine esters studied included carboxylic acid and carbonate...

  12. Analysis of Polyadipate Ester Content in PVC Plastics by Means of FT-Raman Spectroscopy

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    2006-01-01

    Plasticizers are needed in flexible PVC (PolyVinylChloride) products. There is serious concern that commonly used phthalate esters may harm life reproduction systems. To avoid the problems, instead adipate di-esters (AEs) of C8 to C10 alcohols are used as higher prized alternatives; e.g. di-2...

  13. Preparation and characterization of aliphatic diphenyl esters intended as precursors for polyesters

    DEFF Research Database (Denmark)

    Hvilsted, S.; Andruzzi, F.; Cerrai, P.; Tricoli, M.

    1991-01-01

    An extensive number of aliphatic diphenyl esters, C6H5OOC(CH2)nCOOC6H5 (n = O,...,8,10,11,12,14), have been prepared in pure form. The crystalline melting points these esters exhibit an odd-even temperature behaviour, with the higher-melting even series (n even) displaying a minimum for n = 8 whi...

  14. Synthesis and physical properties of new coco-oleic dimer and trimer plus estolide branched esters

    Science.gov (United States)

    Estolides are a class of esters based on vegetable oils that are formed when the carboxylic acid functionality of one fatty acid reacts at the site of unsaturation of another fatty acid to form an ester linkage. The objective of this preliminary study was to separate coco-oleic estolide into two com...

  15. Rapid ester biosynthesis screening reveals a high activity alcohol-O-acyltransferase (AATase) from tomato fruit.

    Science.gov (United States)

    Lin, Jyun-Liang; Zhu, Jie; Wheeldon, Ian

    2016-05-01

    Ethyl and acetate esters are naturally produced in various yeasts, plants, and bacteria. The biosynthetic pathways that produce these esters share a common reaction step, the condensation of acetyl/acyl-CoA with an alcohol by alcohol-O-acetyl/acyltransferase (AATase). Recent metabolic engineering efforts exploit AATase activity to produce fatty acid ethyl esters as potential diesel fuel replacements as well as short- and medium-chain volatile esters as fragrance and flavor compounds. These efforts have been limited by the lack of a rapid screen to quantify ester biosynthesis. Enzyme engineering efforts have also been limited by the lack of a high throughput screen for AATase activity. Here, we developed a high throughput assay for AATase activity and used this assay to discover a high activity AATase from tomato fruit, Solanum lycopersicum (Atf-S.l). Atf1-S.l exhibited broad specificity towards acyl-CoAs with chain length from C4 to C10 and was specific towards 1-pentanol. The AATase screen also revealed new acyl-CoA substrate specificities for Atf1, Atf2, Eht1, and Eeb1 from Saccharomyces cerevisiae, and Atf-C.m from melon fruit, Cucumis melo, thus increasing the pool of characterized AATases that can be used in ester biosynthesis of ester-based fragrance and flavor compounds as well as fatty acid ethyl ester biofuels. PMID:26814045

  16. An electron spin resonance investigation of ester cation radicals at low temperatures

    International Nuclear Information System (INIS)

    The cation radicals of a series of esters have been produced by γ-irradiation of CFCl3 matrices containing the ester at 77 K. In previous work cations of methyl and ethyl esters were investigated. In this work we report results for larger esters. The cations of these esters are found to undergo immediate internal proton-transfer reactions involving specific sites on one of the alkyl substituents. For example, deuteration studies show that proton transfer occurs from the terminal methyl group in propyl formate to produce -OCH2CH2CH2; whereas in propyl acetate -OCH2CHCH3 is produced. The proton lost from these groups is assumed to add to an oxygen on the ester functional group. In the case of propyl acetate and esters with branched side chains we find that fragmentation reactions follow the proton transfer. In the cases of t-butyl acetate and isobutyl formate the fragmentation process occurs at 77 K and results in the isobutylene cation. Neopentyl formate gives evidence for the cation radical, an RCH2 radical and the fragmentation radical cation as the sample is annealed. These results show that ester cation radicals are highly reactive even at low temperatures where proton-transfer and fragmentation reactions are found. (author)

  17. Diarrhetic shellfish poisoning toxin esters in Danish blue mussels and surf clams

    DEFF Research Database (Denmark)

    Jørgensen, Kevin; Scanlon, Sine Hedegaard; Jensen, L.B.

    2005-01-01

    Until recently, little focus was given to the presence of diarrhetic shellfish poisoning ( DSP) toxin esters in seafood products. However, during the last few years, the occurrence of a high percentage of esters of the total amount of DSP toxins present in some seafood products has been observed...

  18. Analysis of Phthalate Ester Content in PVC Plastics by means of FT-Raman Spectroscopy

    DEFF Research Database (Denmark)

    Nørbygaard, Thomas; Berg, Rolf W.

    2004-01-01

    -phenyl group, and as the relative intensities of the six bands vary only slightly from one phthalate ester to the next one we have obtained an identifiable, characteristic fingerprint of the phthalate ester group as a whole. By use of the set of six bands, which are common to all the measured Raman spectra, we...

  19. 40 CFR 721.6180 - Polyalkylene glycol polyamide ester phosphate (generic).

    Science.gov (United States)

    2010-07-01

    ... phosphate (generic). 721.6180 Section 721.6180 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.6180 Polyalkylene glycol polyamide ester phosphate (generic). (a... generically as polyalkylene glycol polyamide ester phosphate (PMN P-98-0903) is subject to reporting...

  20. 21 CFR 573.660 - Methyl glucoside-coconut oil ester.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Methyl glucoside-coconut oil ester. 573.660 Section 573.660 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... ANIMALS Food Additive Listing § 573.660 Methyl glucoside-coconut oil ester. Methyl glucoside-coconut...

  1. Enantioseparation of Racemic Naproxen Esters on Cellulose Tris (4-methylbenzoate) Chiral Stationary Phase

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Several kinds of racemic naproxen ester were successfully separated on CTMB chiral stationary phase with hexane-ethanol (98:2, vol./vol.) as the mobile phase. The influence of mobile phase composition and structure of racemic naproxen ester on chiral separation was studied and the chiral recognition mechanism of CTMB was discussed.

  2. Enantioseparation of Racemic Naproxen Esters on Cellulose Tris(4—methylbenzoate) Chiral Stationary Phase

    Institute of Scientific and Technical Information of China (English)

    BaoHaiSHAO; XiuZhuXU; 等

    2002-01-01

    Several kinds of racemic naproxen ester were successfully separated on CTMB chiral stationary phase with hexane-ethanol(98:2,vol./vol.) as the mobile phase. The influence of mobile phase composition and structure of racemic naproxen ester on chiral separation was studied and the chiral recognition mechanism of CTMB was discussed.

  3. Selective enzymatic hydrolysis of C-terminal tert-butyl esters of peptides

    OpenAIRE

    Eggen, I.F.; Boeriu, C.G.

    2007-01-01

    The present invention relates to a process for the selective enzymatic hydrolysis of C-terminal esters of peptide substrates in the synthesis of peptides, comprising hydrolysing C-terminal tert-butyl esters using the protease subtilisin. This process is useful in the production of protected or unprotected peptides.

  4. Selective enzymatic hydrolysis of C-terminal tert-butyl esters of peptides

    NARCIS (Netherlands)

    Eggen, I.F.; Boeriu, C.G.

    2007-01-01

    The present invention relates to a process for the selective enzymatic hydrolysis of C-terminal esters of peptide substrates in the synthesis of peptides, comprising hydrolysing C-terminal tert-butyl esters using the protease subtilisin. This process is useful in the production of protected or unpro

  5. Experimental and Modeling Studies on the Synthesis and Properties of Higher Fatty Esters of Corn Starch

    NARCIS (Netherlands)

    Junistia, Laura; Sugih, Asaf K.; Manurung, Robert; Picchioni, Francesco; Janssen, Leon P. B. M.; Heeres, Hero J.

    2009-01-01

    This paper describes a systematic study on the synthesis of higher fatty esters of corn starch (starch laurate and starch stearate) by using the corresponding vinyl esters. The reactions were carried out in DMSO using basic catalysts (Na(2)HPO(4), K(2)CO(3), and Na-acetate). The effect of the proces

  6. Synthesis of Higher Fatty Acid Starch Esters using Vinyl Laurate and Stearate as Reactants

    NARCIS (Netherlands)

    Junistia, Laura; Sugih, Asaf K.; Manurung, Robert; Picchioni, Francesco; Janssen, Leon P. B. M.; Heeres, Hero J.

    2008-01-01

    This paper describes the synthesis of long-chain fatty esters of corn starch (starch laurate and starch stearate) with a broad range in degree of substitution (DS = 0.24-2.96). The fatty esters were prepared by reacting the starch with vinyl laurate or vinyl stearate in the presence of basic catalys

  7. 77 FR 27126 - [alpha]-(p-Nonylphenol)-[omega]-hydroxypoly(oxyethylene) Sulfate and Phosphate Esters; Exemption...

    Science.gov (United States)

    2012-05-09

    ... phosphate esters and the corresponding ammonium, calcium, magnesium, potassium, sodium, and zinc salts of... phosphate esters and the corresponding ammonium, calcium, magnesium, potassium, sodium, and zinc salts of..., ammonium, calcium, magnesium, potassium, sodium, and zinc salts when used as inert ingredients at...

  8. Synthesis of α-amino-β-keto-esters (β-oxodipeptides)

    Institute of Scientific and Technical Information of China (English)

    Yanjie XU; Ligong CHEN

    2008-01-01

    The synthesis of α-amino-β-keto-esters (β-oxo dipeptides) was studied. Corresponding α-amino-β-keto-esters were prepared from BOC-(L)-Valine and BOC-(L)-isoleucine by coupling with (D,L)-threonine hydro-chloride and oxidation with Dess-Martin periodinane (DMP) with a total yield of 48% and 38%, respectively.

  9. Study of intermolecular interactions in the system of equilibrium catalytic transesterification of esters. 4. Fourier IR studies of the interaction of alcohols with esters

    International Nuclear Information System (INIS)

    Interaction of alcohols ROH with esters PhCOOR (R = Me, n-Bu, n-C7H15) in binary mixtures and in solutions in non-polar solvents was studies over a wide temperature range by means of Fourier IR spectroscopy. Even with alcohol taken in a great excess, two bands are observed in the region of ΝCO vibrations. The low-frequency band, correspond to the ester molecules bonded by hydrogen bonds of the C=O...HO type. The high-frequence band is shifted by 3-5 cm-1 with respect to the ester ΝCO band. The discreteness of the shift, indicates that an H-complex of one more type is formed between the alcohol and the ester. The analysis of data available allows one to conclude that the complex formation involves the alkoxyl oxygen atom of the ester. The formation enthalpies were determined for H-bond of n-BuOH with the esters and with transesterification catalysts B(OBu)3

  10. Myo-inositol esters of indole-3-acetic acid are endogenous components of Zea mays L. shoot tissue

    Science.gov (United States)

    Chisnell, J. R.

    1984-01-01

    Indole-3-acetyl-myo-inositol esters have been demonstrated to be endogenous components of etiolated Zea mays shoots tissue. This was accomplished by comparison of the putative compounds with authentic, synthetic esters. The properties compared were liquid and gas-liquid chromatographic retention times and the 70-ev mass spectral fragmentation pattern of the pentaacetyl derivative. The amount of indole-3-acetyl-myo-inositol esters in the shoots was determined to be 74 nanomoles per kilogram fresh weight as measured by isotope dilution, accounting for 19% of the ester indole-3-acetic acid of the shoot. This work is the first characterization of an ester conjugate of indole-3-acetate acid from vegetative shoot tissue using multiple chromatographic properties and mass spectral identification. The kernel and the seedling shoot both contain indole-3-acetyl-myo-inositol esters, and these esters comprise approximately the same percentage of the total ester content of the kernel and of the shoot.

  11. Sinapate esters provide greater UV-B attenuation than flavonoids in Arabidopsis thaliana (Brassicaceae)

    International Nuclear Information System (INIS)

    Mutants affected in flavonoid (tt4) or sinapate ester (fah1) biosynthesis were used to assess the relative importance of these phenolic UV photoprotectants in Arabidopsis. Flavonoid and sinapate ester absorption was more specific for UV-B than major nonphenolic chromophores in crude extracts. A new method of evaluating phenolic UV-B attenuation was developed using fluorescence analysis. When excited by UV-B, sinapate ester containing leaves and cotyledons had enhanced sinapate ester fluorescence and reduced chlorophyll fluorescence relative to those without sinapate esters. Although fluorescence analysis gave no evidence of UV-B attenuation by flavonoids, enhanced chlorophyll and protein loss were observed upon UV-B exposure in flavonoid-deficient leaves, suggesting they have another mechanism of UV-B protection. The hydroxycinnamates have been largely ignored as UV-B attenuating pigments. and the results indicate that greater attention should be paid to their role in attenuating UV-B

  12. A preliminary study on anti-radiation effects of two cinnamic paeonol ester compounds

    International Nuclear Information System (INIS)

    Objective: To study the anti-radiation effect of two cinnamic paeonol ester compounds. Method: The index like white blood cell count, platelet count,bone marrow nucleated cells count, DNA and other organ index on ICR mice were observed to investigate the anti-radiation effect of the two compounds in high, medial and low dosages. Results: Compared to the control group, the increase of DNA content in marrow,the number of splenic nodules, splenic index and thymus index have been observed in group of 4-methyl cinnamic acid paeonol ester and 4-fluoro cinnamic acid paeonol ester. Conclusion: 4-methyl cinnamic acid paeonol ester and 4-fluoro cinnamic acid paeonol ester both have the protection effect against radiation damage. (authors)

  13. Synthesis and application of glycolic esters in methanol-gasoline as bifunctional additives

    International Nuclear Information System (INIS)

    To explore new and multifunctional additives for methanol-gasoline, glycolic esters were synthesized and screened as phase stabilizer and saturation vapor pressure depressor. The effect of the esters structure on the efficiency was discussed. It was found that the stability of the blends depend on the length of the glycolic esters' alkoxy group, and hexyl glycolic and octyl glycolic were found to be the most effective in various gasoline-methanol blends. Additionally, the glycolic esters can depress the saturation vapor pressure of methanol-gasoline effectively as well, and decyl glycolic is the most effective one. With these data, it can be concluded that the glycolic esters have the great potential to be used as bifunctional gasoline-methanol additives. (author)

  14. Acid esterification-alkaline transesterification process for methyl ester production from crude rubber seed oil.

    Science.gov (United States)

    Thaiyasuit, Prachasanti; Pianthong, Kulachate; Worapun, Ittipon

    2012-01-01

    This study aims to examine methods and the most suitable conditions for producing methyl ester from crude rubber seed oil. An acid esterification-alkaline transesterification process is proposed. In the experiment, the 20% FFA of crude rubber seed oil could be reduced to 3% FFA by acid esterification. The product after esterified was then tranesterified by alkaline transesterification process. By this method, the maximum yield of methyl ester was 90% by mass. The overall consumption of methanol was 10.5:1 by molar ratio. The yielded methyl ester was tested for its fuel properties and met required standards. The major fatty acid methyl ester compositions were analyzed and constituted of methyl linoleate 41.57%, methyl oleate 24.87%, and methyl lonolenate 15.16%. Therefore, the cetane number of methyl ester could be estimated as 47.85, while the tested result of motor cetane number was 51.20. PMID:22277892

  15. Technical performance of vegetable oil methyl esters with a high iodine number

    Energy Technology Data Exchange (ETDEWEB)

    Prankl, H.; Woergetter, M.; Rathbauer, J. [Federal Institute of Agricultural Engineering, Wieselburg (Austria)

    1999-07-01

    The Federal Institute of Agricultural Engineering in Austria has been gaining more experience about the technical performance of biodiesel with a high iodine number. Long-term bench tests evaluated rape seed oil methyl ester, sunflower oil methyl ester and camelina oil methyl ester with an iodine number of 107 to 150. The oil viscosity was observed and the engine parts were inspected after each run. To demonstrate the suitability of a methyl ester with a high iodine number, a fleet of nine vehicles and one stationary engine was tested for one to three engine oil drain intervals. Camelina oil methyl ester, with a content of 37% linolenic acid (C18:3), was used. No unusual deposits were observed after dismantling the engines. (author)

  16. Regioselective Nitration of Nα,N1-Bis(trifluoroacetyl)-L-Tryptophan Methyl Ester: Efficient Synthesis of 2-Nitro and 6-Nitro-N-Trifluoroacetyl-L-Tryptophan Methyl Ester

    OpenAIRE

    Osborne, Andrew S.; Som, Phanneth; Metcalf, Jessica L.; Phillips, Robert S.

    2008-01-01

    Nitration of Nα,N1-bis(trifluoroacetyl)-L-tryptophan methyl ester with HNO3 in acetic anhydride at 0° C provides Nα-trifluoroacetyl-2-nitro-L-tryptophan methyl ester in 67% yield, whereas nitration in trifluoroacetic acid at 0° C gives Nα-trifluoroacetyl-6-nitro-L-tryptophan methyl ester in 69% yield.

  17. A comparative estimation of C.I. engine fuelled with methyl esters of punnai, neem and waste cooking oil

    OpenAIRE

    D. Subramaniam, A. Murugesan, A. Avinashy

    2013-01-01

    In this experimental study, performance, emission, and combustion characteristics of methyl esters of Punnai, Neem, Waste Cooking Oil and their diesel blends in a C.I. engine was experimentally examined. For the study, Punnai oil methyl esters (POME), neem oil methyl esters (NOME), and Waste Cooking Oil Methyl Esters (WCOME) were prepared by tranesterification process. The Bio diesel-diesel blends were prepared by mixing 10%, 30%, 50%, and 70% of bio diesel with diesel. The effects of three m...

  18. 40 CFR 417.140 - Applicability; description of the neutralization of sulfuric acid esters and sulfonic acids...

    Science.gov (United States)

    2010-07-01

    ... neutralization of sulfuric acid esters and sulfonic acids subcategory. 417.140 Section 417.140 Protection of... MANUFACTURING POINT SOURCE CATEGORY Neutralization of Sulfuric Acid Esters and Sulfonic Acids Subcategory § 417.140 Applicability; description of the neutralization of sulfuric acid esters and sulfonic...

  19. Determination of 4-Chloroindole-3-Acetic Acid Methyl Ester in Lathyrus Vicia and Pisum by Gas Chromatography - Mass Spectrometry

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen; Egsgaard, Helge; Larsen, Elfinn

    1980-01-01

    methyl ester isomers. The quantitative determination of 4-chloroindole-3-acetic acid methyl ester in immature seeds of these three species was performed by gas chromatography – mass spectrometry using deuterium labelled 4-chloro-indole-3-acetic acid methyl ester as an internal standard. P. sativum...

  20. Effects of prolonged administration of phthalate ester on the liver

    International Nuclear Information System (INIS)

    Di(2-ethylhexyl)phthalate (DEHP) was administered to male rats in the diet at concentrations of 2.0, 0.2, and 0.02% for up to 102 weeks. Low doses resulted in moderate increases in certain hepatic enzymes during the initial phase of exposure and in a continuous increase in the activities of these same enzymes throughout the treatment period. An increased level of dolichol and decreased concentration of dolichyl-P were observed. Furthermore, the rate of protein glycosylation diminished. Liver biopsies from patients subjected to hemodialysis demonstrated an increased number of peroxisomes. Phthalate ester seems to interfere with protein turnover, so that the half-life of total mitochondrial and microsomal protein is considerably increased

  1. Use of calcium oxide in palm oil methyl ester production

    Directory of Open Access Journals (Sweden)

    Kulchanat Prasertsit

    2014-04-01

    Full Text Available Introducing an untreated calcium oxide (CaO as a solid heterogeneous catalyst for biodiesel production from palm oil by transesterification was studied in this work. The four studied parameters were methanol to oil molar ratio, CaO catalyst concentration, reaction time, and water content. The results for palm oil show that when the water content is higher than 3%wt and the amount of CaO greater than 7%wt soap formation from saponification occurs. A higher methanol to oil molar ratio requires a higher amount of CaO catalyst to provide the higher product purity. The appropriate methanol to CaO catalyst ratio is about 1.56. Commercial grade CaO gives almost the same results as AR grade CaO. In addition, reusing commercial grade CaO for about 5 to 10 repetitions without catalyst regeneration drops the percentage of methyl ester purity approximately 5 to 10%, respectively.

  2. Antiwear and antioxidant studies of cardanol phosphate ester additives

    Energy Technology Data Exchange (ETDEWEB)

    Mazzetto, S.E.; Oliveira, L.D.M.; Lomonaco, D.; Veloso, P.A., E-mail: selma@ufc.br [Lab. de Produtos e Tecnologia em Processos (LPT), Dept. de Quimica Organica e Inorganica, Universidade Federal do Ceara, Fortaleza, CE (Brazil)

    2012-07-15

    In the search for new applications and products derived from Cashew Nut Shell Liquid (CNSL), we report herein the synthesis and characterization (GC/MS and {sup 1}H, {sup 13}C, and {sup 31}P NMR) of four phosphate esters derived from hydrogenated cardanol, including their applications as antiwear additives for diesel (S500) and as antioxidant additives for mineral oils, evaluated through the HFRR test and oxidative stability analyses, respectively. The results obtained showed very good to excellent performances promoted by the bioadditives evaluated, especially for the thiophosphorylated derivative, which notably reduced the sludge residue and the acidity index of the oxidized oil (0.52 mg NaOH/g sample) and also improved the diesel lubricity, reducing the wear of metal parts by more than 50% (330 {Mu}m). Keywords: Cardanol; Antiwear; Antioxidant; Diesel; Mineral oil. (author)

  3. Starch fatty esters for potential use in petroleum industry

    OpenAIRE

    Dias, Fernanda; de Souza, Roberta; Lucas, Elizabete

    2013-01-01

    The aim of this study was to obtain and characterize starch fatty esters with variations in the hydrophilic/lipophilic balance and to assess whether these samples have potential application in oil-based drilling fluids. The variation in the hydrophobicity of the samples was verified by means of viscosity tests, which suggested that the products had varied solubility parameters, near the value of the solvent n-paraffin. Отримано і охарактеризовано жирні естери крохмалю при зміні гідрофільно/л...

  4. Antiwear and antioxidant studies of cardanol phosphate ester additives

    International Nuclear Information System (INIS)

    In the search for new applications and products derived from Cashew Nut Shell Liquid (CNSL), we report herein the synthesis and characterization (GC/MS and 1H, 13C, and 31P NMR) of four phosphate esters derived from hydrogenated cardanol, including their applications as antiwear additives for diesel (S500) and as antioxidant additives for mineral oils, evaluated through the HFRR test and oxidative stability analyses, respectively. The results obtained showed very good to excellent performances promoted by the bioadditives evaluated, especially for the thiophosphorylated derivative, which notably reduced the sludge residue and the acidity index of the oxidized oil (0.52 mg NaOH/g sample) and also improved the diesel lubricity, reducing the wear of metal parts by more than 50% (330 Μm). Keywords: Cardanol; Antiwear; Antioxidant; Diesel; Mineral oil. (author)

  5. Antiwear and antioxidant studies of cardanol phosphate ester additives

    Directory of Open Access Journals (Sweden)

    S. E. Mazzetto

    2012-09-01

    Full Text Available In the search for new applications and products derived from Cashew Nut Shell Liquid (CNSL, we report herein the synthesis and characterization (GC/MS and ¹H, 13C, and 31P NMR of four phosphate esters derived from hydrogenated cardanol, including their applications as antiwear additives for diesel (S500 and as antioxidant additives for mineral oils, evaluated through the HFRR test and oxidative stability analyses, respectively. The results obtained showed very good to excellent performances promoted by the bio-additives evaluated, especially for the thiophosphorylated derivative, which notably reduced the sludge residue and the acidity index of the oxidized oil (0.52 mg NaOH/g sample and also improved the diesel lubricity, reducing the wear of metal parts by more than 50% (330 μm.

  6. Acceleration effect of ionic liquids on polycyclotrimerization of dicyanate esters

    Directory of Open Access Journals (Sweden)

    A. Fainleib

    2016-09-01

    Full Text Available The polycyclotrimerization reaction of dicyanate ester of bisphenol E (DCBE in the presence of varying amounts (from 0.5 to 5 wt% of 1-octyl-3-methylimidazolium tetrafluoroborate ([OMIm][BF4] ionic liquid has been investigated using differential scanning calorimetry (DSC and Fourier transform infrared spectroscopy (FTIR techniques, after a curing stage at 150 °C for 6 h. It is noteworthy that an amount of [OMIm][BF4] as low as 0.5 wt% accelerates dramatically the thermal curing process leading to the formation of a polycyanurate network. The conversion of DCBE increased with increasing [OMIm][BF4] content in the temperature range studied. A reaction mechanism associated with the ionic liquid-catalyzed DCBE polycyclotrimerization is newly proposed via the involvement of a [CN]δ+–[OMIm]δ– complex as a key intermediate.

  7. Improved preparation of halopropyl bridged carboxylic ortho esters

    Directory of Open Access Journals (Sweden)

    Richard J. Petroski

    2008-10-01

    Full Text Available Bridged ortho esters of 3-halopropyl carboxylic acids were prepared by esterification of 3-methyl-3-hydroxymethyloxetane with 3-bromopropionyl chloride and pyridine in dry THF, followed by rearrangement with boron trifluoroetherate, to afford 1-(2-bromoethyl-4-methyl-2,6,7-trioxabicyclo[2,2,2]-octane. The 1-(2-iodoethyl-4-methyl-2,6,7-trioxabicyclo[2,2,2]-octane analogue could not be prepared directly by halogen exchange of 1-(2-bromoethyl-4-methyl-2,6,7-trioxabicyclo[2,2,2]-octane but could be prepared by halogen exchange of the (3-methyloxetan-3-ylmethyl 3-bromopropanoate with a mixture of sodium iodide and anhydrous sodium sulfate in acetone, followed by rearrangement with boron trifluoroetherate.

  8. Three New Triterpene Esters from Pumpkin (Cucurbita maxima Seeds

    Directory of Open Access Journals (Sweden)

    Takashi Kikuchi

    2014-04-01

    Full Text Available Three new multiflorane-type triterpene esters, i.e. 7α-hydroxymultiflor-8-ene-3α,29-diol 3-acetate-29-benzoate (1, 7α-methoxymultiflor-8-ene-3α,29-diol 3,29-dibenzoate (2, and 7β-methoxymultiflor-8-ene-3α,29-diol 3,29-dibenzoate (3, were isolated from seeds of Cucurbita maxima, along with the known compound, multiflora-7,9(11-diene-3α,29-diol 3,29-dibenzoate (4. Compound 1 exhibited melanogenesis inhibitory activities comparable with those of arbutin. In cytotoxicity assays, compounds 1 and 3 exhibited weak cytotoxicity, with IC50 values of 34.5–93.7 μM against HL-60 and P388 cells.

  9. Three new triterpene esters from pumpkin (Cucurbita maxima) seeds.

    Science.gov (United States)

    Kikuchi, Takashi; Ueda, Shinsuke; Kanazawa, Jokaku; Naoe, Hiroki; Yamada, Takeshi; Tanaka, Reiko

    2014-01-01

    Three new multiflorane-type triterpene esters, i.e. 7α-hydroxymultiflor-8-ene-3α,29-diol 3-acetate-29-benzoate (1), 7α-methoxymultiflor-8-ene-3α,29-diol 3,29-dibenzoate (2), and 7β-methoxymultiflor-8-ene-3α,29-diol 3,29-dibenzoate (3), were isolated from seeds of Cucurbita maxima, along with the known compound, multiflora-7,9(11)-diene-3α,29-diol 3,29-dibenzoate (4). Compound 1 exhibited melanogenesis inhibitory activities comparable with those of arbutin. In cytotoxicity assays, compounds 1 and 3 exhibited weak cytotoxicity, with IC50 values of 34.5-93.7 μM against HL-60 and P388 cells. PMID:24743937

  10. Interaction between Lubricants Containing Phosphate Ester Additives and Stainless Steels

    Directory of Open Access Journals (Sweden)

    David W. Johnson

    2013-05-01

    Full Text Available One way to improve fuel efficiency in today’s jet aircraft engines is to create an environment for higher operating temperatures and speeds. New and improved lubricants and bearing materials must be developed to remain stable in these elevated operating temperatures. Three lubricants, with varying amounts of tricresyl phosphate added as an anti-wear/extreme pressure additive were tested on two different stainless steels at varying temperatures ranging from 300 °C to 350 °C in vacuum. Significant decomposition of the lubricant base-stocks and the phosphate ester additive did occur in most of the trials resulting in the formation of carboxylic acids and phenols. In these cases a film containing phosphorus was deposited onto the stainless steel substrate.

  11. Reaction of gallocyanine methyl ester with uranyl ions

    International Nuclear Information System (INIS)

    The reaction of gallocyanine methyl ester with uranyl ions was studied spectrophotometrically in slightly acid or neutral solutions of 40% (m/m) ethanol. A violet complex of UO2L2 is formed at pH>5. The conditional stability constants of the complex in the pH range 6-7.4 and the equilibrium constants of the coordination reaction were derived from the concentration curves and the continuous variations curves. The optimum conditions were sought for the spectrophotometric determination of uranium based on the occurrence of the UO2L2 complex. The relative standard deviation obtained for a uranium concentration of 106 μg.l-1 was ssub(r)=2.13%. (author)

  12. Reaction of gallocyanine methyl ester with uranyl ions

    Energy Technology Data Exchange (ETDEWEB)

    Kotoucek, M.; Hrbkova, M. (Palackeho Univ., Olomouc (Czechoslovakia). Prirodovedecka Fakulta)

    1984-09-01

    The reaction of gallocyanine methyl ester with uranyl ions was studied spectrophotometrically in slightly acid or neutral solutions of 40% (m/m) ethanol. A violet complex of UO/sub 2/L/sub 2/ is formed at pH>5. The conditional stability constants of the complex in the pH range 6-7.4 and the equilibrium constants of the coordination reaction were derived from the concentration curves and the continuous variations curves. The optimum conditions were sought for the spectrophotometric determination of uranium based on the occurrence of the UO/sub 2/L/sub 2/ complex. The relative standard deviation obtained for a uranium concentration of 106 ..mu..g.l/sup -1/ was ssub(r)=2.13%.

  13. Effects of phthalic acid esters on the liver and thyroid

    International Nuclear Information System (INIS)

    The effects, over periods from 3 days to 9 months of administration, of diets containing di-2-ethylhexyl phthalate are very similar to those observed in rats administered diets containing hypolipidemic drugs such as clofibrate. Changes occur in a characteristic order commencing with alterations in the distribution of lipid within the liver, quickly followed by proliferation of hepatic peroxisomes and induction of the specialized P-450 isoenzyme(s) catalyzing omega oxidation of fatty acids. There follows a phase of mild liver damage indicated by changes in incorporation of 3H-thymidine into DNA, by induction of glucose-6-phosphatase activity and a loss of glycogen, eventually leading to the formation of enlarged lysosomes through autophagy and the accumulation of lipofuscin. Associated changes are found in the kidney and thyroid. The renal changes are limited to the proximal convoluted tubules and are generally similar to changes found in the liver. The effects on the thyroid are more marked. Although the levels of thyroxine in plasma fall to about half normal values, serum triiodothyronine remains close to normal values while the appearance of the thyroid varies, very marked hyperactivity being noted 7 days after commencement of treatment, this is less marked at 14 days, but even after 9 months treatment there is clear cut evidence for hyperactivity with colloid changes which indicate this has persisted for some time. The short-term in vivo hepatic effects of the three phthalate esters can be reproduced in hepatocytes in tissue culture. All three phthalate esters, as well as clofibrate, have early marked effects on the metabolism of fatty acids in isolated hepatocytes. A hypothesis is presented to explain the progress from these initial metabolic effects to the final formation of liver tumors

  14. Effects of phthalic acid esters on the liver and thyroid

    Energy Technology Data Exchange (ETDEWEB)

    Hinton, R.H.; Mitchell, F.E.; Mann, A.; Chescoe, D.; Price, S.C.; Nunn, A.; Grasso, P.; Bridges, J.W.

    1986-12-01

    The effects, over periods from 3 days to 9 months of administration, of diets containing di-2-ethylhexyl phthalate are very similar to those observed in rats administered diets containing hypolipidemic drugs such as clofibrate. Changes occur in a characteristic order commencing with alterations in the distribution of lipid within the liver, quickly followed by proliferation of hepatic peroxisomes and induction of the specialized P-450 isoenzyme(s) catalyzing omega oxidation of fatty acids. There follows a phase of mild liver damage indicated by changes in incorporation of /sup 3/H-thymidine into DNA, by induction of glucose-6-phosphatase activity and a loss of glycogen, eventually leading to the formation of enlarged lysosomes through autophagy and the accumulation of lipofuscin. Associated changes are found in the kidney and thyroid. The renal changes are limited to the proximal convoluted tubules and are generally similar to changes found in the liver. The effects on the thyroid are more marked. Although the levels of thyroxine in plasma fall to about half normal values, serum triiodothyronine remains close to normal values while the appearance of the thyroid varies, very marked hyperactivity being noted 7 days after commencement of treatment, this is less marked at 14 days, but even after 9 months treatment there is clear cut evidence for hyperactivity with colloid changes which indicate this has persisted for some time. The short-term in vivo hepatic effects of the three phthalate esters can be reproduced in hepatocytes in tissue culture. All three phthalate esters, as well as clofibrate, have early marked effects on the metabolism of fatty acids in isolated hepatocytes. A hypothesis is presented to explain the progress from these initial metabolic effects to the final formation of liver tumors.

  15. Optimal Use of Plant Stanol Ester in the Management of Hypercholesterolemia

    Directory of Open Access Journals (Sweden)

    Susanna Rosin

    2015-01-01

    Full Text Available Plant stanol ester is a natural compound which is used as a cholesterol-lowering ingredient in functional foods and food supplements. The safety and efficacy of plant stanol ester have been confirmed in more than 70 published clinical studies and the ingredient is a well-established and widely recommended dietary measure to reduce serum cholesterol. Daily intake of 2 g plant stanols as plant stanol ester lowers LDL-cholesterol by 10%, on average. In Europe, foods with added plant stanol ester have been on the market for 20 years, and today such products are also available in many Asian and American countries. Despite the well-documented efficacy, the full potential in cholesterol reduction may not be reached if plant stanol ester is not used according to recommendations. This review therefore concentrates on the optimal use of plant stanol ester as part of dietary management of hypercholesterolemia. For optimal cholesterol lowering aiming at a lower risk of cardiovascular disease, plant stanol ester should be used daily, in sufficient amounts, with a meal and in combination with other recommended dietary changes.

  16. Synthesis and Properties of Dendritic Long-Chain Esters as Crude Oil Flow Improver Additives

    Institute of Scientific and Technical Information of China (English)

    Li Cuiqin; Sun Peng; Shi Weiguang; Wang Jun

    2016-01-01

    The efifciencies of 6 kinds of macromolecules with dendritic structure in improving the lfow properties of crude oil were investigated. The dendritic additives were synthesized using low-generation dendritic poly(amidoamine) and alkyl long-chain acrylic esters as starting materials, and their structures were characterized by the Fourier transform infrared spectroscopy, 1H-nuclear magnetic resonance and elemental analysis. The effects on the pour point and rheological properties of crude oil samples were studied. Efifciencies of dendritic long-chain esters were not only inlfuenced by the alky chain length, but also by the generation of dendrimer. The longer the alkyl chain of dendritic long-chain ester was, the better the effect in the reduction of pour point and apparent viscosity was. Efifciencies of 1.5 generation dendritic long-chain ester with 8 branched chains for the reduction of pour point and apparent viscosity were superior to those of 0.5 generation dendritic long-chain ester with 4 branched chains. Under the same conditions, efifciencies of 1.5 generation dendritic eighteen ester were superior to those of other 1.5 generation dendritic long-chain esters for the reduction of pour point and viscosity of crude oil.

  17. Synthesis and properties of chemiluminescent acridinium ester labels with fluorous tags.

    Science.gov (United States)

    Natrajan, Anand; Wen, David; Sharpe, David

    2014-06-21

    Acridinium dimethylphenyl esters are highly sensitive chemiluminescent labels that are used in clinical diagnostics. Light emission from these labels is triggered with alkaline peroxide in the presence of the cationic surfactant cetyltrimethylammonium chloride (CTAC). CTAC compresses emission times of these labels to fluorous tags of varying fluorine content and their chemiluminescence in the presence of cationic micelles of CTAC, anionic micelles of sodium perfluorooctanoate (SPFO) as well as mixed micelles of CTAC and SPFO. These studies indicate that in the presence of the mixed micelle system of CTAC and SPFO and at low mole fractions of SPFO, polarity of the mixed micelle interface is lower than that of CTAC leading to a greater enhancement of chemiluminescence for both fluorinated acridinium esters as well as a structurally analogous but non-fluorinated acridinium ester. Chemiluminescence stability of the fluorinated acridinium esters was either comparable to or better than the stability of the non-fluorinated acridinium ester. Non-specific binding to paramagnetic microparticles was higher for fluorinated acridinium esters requiring a surfactant wash to reduce their non-specific binding to the same extent as that observed for the non-fluorinated acridinium ester. PMID:24788381

  18. Analysis of alcohols, as dimethylglycine esters, by electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Johnson, D W

    2001-03-01

    Dimethylglycine (DMG) esters are new derivatives for the rapid, sensitive and selective analysis of primary and secondary alcohols, in complex mixtures, by electrospray ionization tandem mass spectrometry (ESI-MS/MS). Their development was inspired by the use of the complementary dimethylaminoethyl esters for the trace, rapid analysis of fatty acids. DMG esters are simply prepared by heating a dichloromethane solution of the imidazolide of dimethylglycine, containing triethylamine, and an alcohol. DMG esters of long-chain fatty alcohols, isoprenoidal alcohols and hydroxy-acids are analysed by electrospray ionization tandem mass spectrometry with a precursor ion of m/z 104 scan. Diols, glyceryl esters, glyceryl ethers and some sterols are analysed by a neutral loss of 103 Da scan. Trimethylglycine (TMG) ester iodides, prepared by alkylation of DMG esters with methyl iodide, are more sensitive derivatives for molecules containing secondary alcohol groups, such as cholesterol and gibberellic acid. They are analysed by a precursor ion of m/z 118 scan. DMG or TMG derivatives were shown to be at least comparable and sometimes an order of magnitude more sensitive than N-methylpyridyl ether derivatives for ESI-MS/MS analysis of the different classes of alcohols. Applications of these derivatives for the diagnosis of inherited disorders and the analysis of natural products are presented. PMID:11312519

  19. Synthesis of novel naphthoquinone aliphatic amides and esters and their anticancer evaluation.

    Science.gov (United States)

    Kongkathip, Boonsong; Akkarasamiyo, Sunisa; Hasitapan, Komkrit; Sittikul, Pichamon; Boonyalai, Nonlawat; Kongkathip, Ngampong

    2013-02-01

    Fourteen new naphthoquinone aliphatic amides and seventeen naphthoquinone aliphatic esters were synthesized in nine to ten steps from 1-hydroxy-2-naphthoic acid with 9-25% overall yield for the amides, and 16-21% overall yield for the esters. The key step of the amide synthesis is a coupling reaction between amine and various aliphatic acids using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) as a coupling agent while for the ester synthesis, DCC/DMAP or CDI was used as the coupling reagent between aliphatic acids and naphthoquinone alcohol. Both naphthoquinone amides and esters were evaluated for their anticancer activity against KB cells. It was found that naphthoquinone aliphatic amides showed stronger anticancer activity than those of the esters when the chains are longer than 7-carbon atoms. The optimum chain of amides is expected to be 16-carbon atoms. In addition, naphthoquinone aliphatic esters with α-methyl on the ester moiety possessed much stronger anticancer activity than the straight chains. Decatenation assay revealed that naphthoquinone amide with 16-carbon atoms chain at 15 μM and 20 μM can completely inhibit hTopoIIα activity while at 10 μM the enzyme activity was moderately inhibited. Molecular docking result also showed the same trend as the cytotoxicity and decatenation assay. PMID:23313636

  20. Protective effects of glutathione isopropyl ester on the sensitivity of cultured cells to UVB irradiation

    International Nuclear Information System (INIS)

    The effect of glutathione (GSH) isopropyl ester on cellular sensitivity to UVB irradiation was investigated in HeLaS3 cells. Pretreatment with 0.1-0.5 mM GSH isopropyl ester for 4h significantly inhibited the decrease of thymidine (TdR) incorporation caused by UVB irradiation at a dose of 500 J/m2, whereas pretreatment with a high dose (1 mM) had no effect. The colony formation ability of the pretreated cells (0.3 mM) was significantly better than that of cells that received irradiation only. When the cells were treated with GSH isopropyl ester, their intracellular GSH level increased dose-dependently over a 4h period, suggesting that GSH isopropyl ester was transported into the cells and there converted to GSH. Within 2 min of exposure, the intracellular GSH level depleted rapidly to about 75% of that in non-irradiated normal cells. In contrast, the GSH level in cells pretreated with 0.3 mM GSH isopropyl ester was maintained at the same level as that in normal cells, indicating that the maintenance of intracellular GSH level is due to converted GSH from GSH isopropyl ester. These results clearly show that intracellular GSH is involved in cell protection against photodamage, and that GSH isopropyl ester is a useful antioxidant for protection against photooxidative injury. (author)

  1. A comparison of chemiluminescent acridinium dimethylphenyl ester labels with different conjugation sites.

    Science.gov (United States)

    Natrajan, Anand; Wen, David

    2015-03-01

    Chemiluminescent acridinium dimethylphenyl esters are highly sensitive labels that are used in automated assays for clinical diagnosis. Light emission from these labels and their conjugates is triggered by treatment with alkaline peroxide. Conjugation of acridinium ester labels is normally done at the phenol. During the chemiluminescent reaction of these acridinium esters, the phenolic ester is cleaved and the light emitting acridone moiety is liberated from its conjugate partner. In the current study, we report the synthesis of three new acridinium esters with conjugation sites at the acridinium nitrogen and compare their properties with that of a conventional acridinium ester with a conjugation site at the phenol. Our study is the first that provides a direct comparison of the emissive properties of acridinium dimethylphenyl esters (free labels and protein conjugates) with different conjugation sites, one where the light emitting acridone remains attached to its conjugate partner versus conventional labeling which results in cleavage of the acridone from the conjugate. Our results indicate that the conjugation at the acridinium nitrogen, which also alters how the acridinium ring and phenol are oriented with respect to the protein surface, has a minimal impact on emission kinetics and emission spectra. However, this mode of conjugation to three different proteins led to a significant increase in light yield which should be useful for improving the assay sensitivity. PMID:25581208

  2. Synthesis and characterization of vegetable oil derived esters: evaluation for their diesel additive properties.

    Science.gov (United States)

    Dmytryshyn, S L; Dalai, A K; Chaudhari, S T; Mishra, H K; Reaney, M J

    2004-03-01

    Trans-esterification of four vegetable oils; canola oil, greenseed canola oil from heat-damaged seeds, processed waste fryer grease and unprocessed waste fryer grease, was carried out using methanol, and KOH as catalyst. The methyl esters of the corresponding oils were separated from the crude glycerol, purified, and characterized by various methods to evaluate their densities, viscosities, iodine values, acid numbers, cloud points, pour points and gross heat of combustion, fatty acid and lipid compositions, lubricity properties, and thermal properties. The fatty acid composition suggests that 80-85% of the ester was from unsaturated acids. Substantial decrease in density and viscosity of the methyl esters compared to their corresponding oils suggested that the oils were in their mono or di glyceride form. The lubricity of the methyl esters, when blended at 1 vol% treat rate with ISOPAR M reference fuel, showed that the canola methyl ester enhanced the fuel's lubricity number. From the analyses performed, it was determined that the ester with the most potential for being an additive or a substitute for diesel fuel is the canola methyl ester, whose physical and chemical characteristics are similar to diesel fuel. PMID:14643986

  3. Analysis of phthalate ester content in poly(vinyl chloride) plastics by means of Fourier transform Raman spectroscopy

    DEFF Research Database (Denmark)

    Nørbygaard, Thomas; Berg, Rolf W.

    2004-01-01

    Fourier transform (FT) Raman spectroscopy is applied to a range of phthalate ester plasticizers in pure form as well as in poly(vinyl chloride) (PVC) samples. It is found that phthalate esters as a group can be identified by a set of six characteristic Raman bands. FT-Raman spectra of 22 phthalat...... esters are given. It is demonstrated that the presence of phthalate esters in PVC products is readily detectable by FT-Raman spectroscopy. By use of proper ref. samples quant. detn. of the phthalate ester content becomes possible as well....

  4. Synthesis and cytotoxicity of boronated fatty esters for BNCT of cervix cancer

    International Nuclear Information System (INIS)

    Esterification reactions of o-carboranic acid with six fatty alcohols, palmitoleyl, stearyl, oleyl, elaidyl, linoleyl and linoelaidyl alcohols, proceeded smoothly under nitrogen atmosphere with dimethylamino pyrimidine as a catalyst. The reaction gave the corresponding esters in moderate yields. Most of the synthetic esters are stable at room temperature except the linoleyl carboranate and linoelaidyl carboranate which decomposed within two weeks. The in vitro studies on Hela cells showed relatively low cytotoxic. The IC50 of boronated esters were in range of 36-83 micrograms/cm3. (author)

  5. Effects of Low-Ester Pectin on Wheat Dough's Physical Properties Detected by Rheological Method

    OpenAIRE

    Peilong Xu; Na Na; Qing Lin

    2013-01-01

    The study examined the influence of low-ester pectin on the rheological property of wheat dough through capillary rheological method. The experimental results showed that the more the content of low-ester pectin in wheat dough, the less viscosity of the dough, meanwhile, the higher of the dough strength, the weaker the maximum drawing force endured by the dough. Therefore, the content of low-ester pectin had a direct impact on gluten index of the dough, namely, the stability and stirring resi...

  6. Diarrhetic shellfish poisoning toxin esters in Danish blue mussels and surf clams

    DEFF Research Database (Denmark)

    Jørgensen, Kevin; Scanlon, Sine Hedegaard; Jensen, L.B.

    2005-01-01

    . Samples of Danish surf clams ( Spisola spp.) and blue mussels ( Mytilus edulis) from 1999 - 2004 were analysed by liquid chromatography coupled with tandem mass spectrometry ( LC/ MS/ MS) for the presence of DSP toxin esters. The samples contained only okadaic acid and esters of okadaic acid. The level of...... total okadaic acid equivalents ranged from 224 to 2516 mu g kg (-1) in surf clams. The percentage of okadaic acid esters of the total okadaic acid equivalents ranged from 83 to 98%, mean 95%. The level of total okadaic acid equivalents ranged from 43 to 1631 mu g kg (-1) in blue mussels. The percentage...

  7. Synthesis and Structural Characterization of 1- and 2-Substituted Indazoles: Ester and Carboxylic Acid Derivatives

    OpenAIRE

    Isabel Bento; Teresa Duarte, M.; M. João M. Curto; Inês F. Antunes; Hélène Ramos; Fátima C. Teixeira

    2006-01-01

    A series of indazoles substituted at the N-1 and N-2 positions with ester-containing side chains -(CH2)nCO2R of different lengths (n = 0-6, 9, 10) are described.Nucleophilic substitution reactions on halo esters (X(CH2)nCO2R) by 1H-indazole inalkaline solution lead to mixtures of N-1 and N-2 isomers, in which the N-1 isomerpredominates. Basic hydrolysis of the ester derivatives allowed the synthesis of thecorresponding indazole carboxylic acids. All compounds were fully characterised bymultin...

  8. Study on extraction mechanism of scandium (III) with alkylphosphonic acid monoalkyl ester

    International Nuclear Information System (INIS)

    The extraction mechanism of Sc(III)from hydrochloric acid solutions with s-octylphosphonic acid mono-iso-octyl ester (PT-19), iso-propylphosphonic acid mono-(1-hexyl-4-ethyl) octyl ester(PT-2) and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester(P507)in heptane is investigated. The extraction reaction of Sc(III) expressed by the equations of chemical reactions are given. The equilibrium constants and thermodynamic functions of extraction reactions are calculated. The IR and NMR spectra of the extraction complexes of Sc(III) are discussed as well

  9. [Synthesis and bronchodilator action of 4-(methoxycarbonylalkylsulfinyl)-4-pyrrol carboxylic esters].

    Science.gov (United States)

    Eiden, F; Grusdt, U

    1989-11-01

    The dihydro-dimethoxyfuran carboxylic ester 3 reacts with different mercaptoalkyl carboxylates to give the carbomethoxyalkylthio-tetrahydrofuran carboxylic esters 4. Methanol elimination of 4 yields the dihydrofuran derivatives 5. 4 and 5 can be oxidized to afford the sulfoxides 6 and the sulfones 7, respectively. 4 reacts with primary amines to give the title compounds 8. Derivatives of 8 can be cyclized to afford the thienopyrroles 11 and 12 as well as the thienopyranopyrrole 14. The mercaptopyrrole carboxylic ester 10 is obtained from 8f by elimination of propenic acid. 8e shows bronchodilatoric activity in low concentration. PMID:2624526

  10. Application of Factorial Design of Experiments for the Continuous Hydrogenation of Enriched Castor Oil Methyl Esters

    OpenAIRE

    Tulasi Sri Venkata Ramana Neeharika; Karna Narayana Prasanna Rani; Kasturi Venkata Sesha Adinarayana Rao; Thella Prathap Kumar; Rachapudi Badari Narayana Prasad

    2013-01-01

    Castor oil methyl esters contains nearly 90% ricinoleic acid (12-hydroxy-cis-9-octadecenoic acid). Hydrogen-ated castor oil methyl esters finds several applications in coating, lubricants formulations and pharmaceu-tical areas. The present study reports a fast, simple, efficient and continuous hydrogenation of enriched castor oil methyl ester (ECME) using 10% Pd/C catalyst at different pressures and temperatures. The range of process conditions for this study varied from 30-60 °C, 5-15 bar wi...

  11. Statistical Evaluation of HTS Assays for Enzymatic Hydrolysis of β-Keto Esters

    OpenAIRE

    Buß, O.; Jager, S.; S-M Dold; S. Zimmermann; Hamacher, K.; Schmitz, K.; J Rudat

    2016-01-01

    β-keto esters are used as precursors for the synthesis of β-amino acids, which are building blocks for some classes of pharmaceuticals. Here we describe the comparison of screening procedures for hydrolases to be used for the hydrolysis of β-keto esters, the first step in the preparation of β-amino acids. Two of the tested high throughput screening (HTS) assays depend on coupled enzymatic reactions which detect the alcohol released during ester hydrolysis by luminescence or absorption. The th...

  12. Synthesis and Biological Activity of New Pyrethroid Acid Oxime-esters Containing Pyrazole Ring

    Institute of Scientific and Technical Information of China (English)

    MA Jun-an; HUANG Run-qiu; FENG Lei; SONG Jian; QIU De-wen

    2003-01-01

    A series of compounds containing oxime-ester linkage and pyrazole ring(in place of the ester linkage and the alcohol moiety in pyrethroid ester) was designed and synthesized. The structures of all the compounds prepared were confirmed by 1H NMR and MS spectroscopy as well as elemental analyses. The bioassay data of those compounds against tobacco mosaic virus(TMV), cucumber mosaic virus(CMV), potato virus X(PVX) and potato virus Y(PVY) were presented. Among them compound 6i was found to possess significant plant antiviral activities. But all the compounds showed low insecticidal and acaricidal activities.

  13. Molecular Dynamics Simulation of Palmitate Ester Self-Assembly with Diclofenac

    Directory of Open Access Journals (Sweden)

    Abu Bakar Salleh

    2012-07-01

    Full Text Available Palm oil-based esters (POEs are unsaturated and non-ionic esters with a great potential to act as chemical penetration enhancers and drug carriers for transdermal drug nano-delivery. A ratio of palmitate ester and nonionic Tween80 with and without diclofenac acid was chosen from an experimentally determined phase diagram. Molecular dynamics simulations were performed for selected compositions over a period of 15 ns. Both micelles showed a prolate-like shape, while adding the drug produced a more compact micellar structure. Our results proposed that the drug could behave as a co-surfactant in our simulated model.

  14. Correlation Research and Molecular Regulation Mechanism of Cholesteryl Ester Transfer Protein Gene rs708272 Polymorphism with Exercise Induced Serum Lipid Changes in Obese Adolescents%CETP基因rs708272与肥胖青少年运动调节血脂效果的关联性及分子调控机制

    Institute of Scientific and Technical Information of China (English)

    瞿贤和; 胡扬; 许春艳; 李燕春; 张泽亚; 陈思韵; 黄亚茹; 毛小云

    2015-01-01

    探讨CETP基因rs708272多态位点与肥胖青少年运动调节血脂效果的关联性,并通过双荧光素酶报告系统研究其分子调控机制.对象和方法:50名(男23,女27;平均年龄14.9±3.35岁)中国北方肥胖青少年进行1个月的运动减脂,以有氧运动为主辅以力量和拉伸训练,统一饮食.减脂前后取空腹静脉血测定血清TC、TG、HDL-C、LDL-C水平,PCR-RFLP法进行CETP基因rs708272分型,观察rs708272与肥胖青少年运动调节血脂效果的关联性;通过构建重组质粒,利用双荧光素酶报告系统检测重组质粒中荧光素酶报告基因的相对表达活性.结果:(1)训练后,B1B2基因型组血清TC(0.64±0.51mmol/L)、LDL-C(0.51±0.41 mmol/L)的降低程度显著大于B1B1基因型组(TC:0.20±0.53 mmol/L;LDL-C:0.24±0.35 mmol/L);B2B2基因型组(0.10±0.15 mmol/L)和B1B1基因型组(0.18±0.26mmol/L)血清HDL-C的升高程度显著大于B1B2基因型组(-0.03±0.16mmol/L).(2)含B1等位基因的重组载体中报告基因的相对活性(11.40士0.26)显著低于B2等位基因(31.19±1.50),但两者均显著高于对照组(3.78±0.11).结论:(1)rs708272位点多态性与运动减脂后血清TC、HDL-C、LDL-C浓度的变化程度存在一定的关联,可作为运动降血脂效果敏感性的分子遗传学标记;(2) rs708272位点处由B1→B2的突变是功能性突变,能显著提高CETP基因的表达活性.

  15. Catalytic synthesis of butyric esters with TiSiW12O40/TiO2

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The catalytic activities of TiSiW12O40/TiO2 in synthesizing ethyl ester, propyl ester, n-butyl ester, and amyl esterwere reported. It was demonstrated that TiSiW12O40/TiO2is an excellent catalyst. Various factors concemed with esterifica-tion were investigated. The optimum conditions were found: the mole ratio of alcohol to acid is 1.3:1, the mass ratio ofcatalyst to reactants is 1.5%, and the reaction time is 1.0 h. Under the optimum conditions, the yields are 88.0% for ethylester, 94.5% for propyl ester, 98.6% for n-butyl ester, 99.1% for n-amyl ester, and 96.7% for iso-amyl ester, respectively.

  16. Coupling of activated esters to gramines in the presence of ethyl propiolate under mild conditions

    OpenAIRE

    Jones, David T.; Artman, Gerald D.; Williams, Robert M.

    2007-01-01

    The coupling of activated esters to gramine derivatives is described using ethyl propiolate. A series of substrates have been prepared using these mild conditions to provide a scope and limitations for this methodology.

  17. Enantiospecific sp2-sp3 coupling of secondary and tertiary boronic esters

    Science.gov (United States)

    Bonet, Amadeu; Odachowski, Marcin; Leonori, Daniele; Essafi, Stephanie; Aggarwal, Varinder K.

    2014-07-01

    The cross-coupling of boronic acids and related derivatives with sp2 electrophiles (the Suzuki-Miyaura reaction) is one of the most powerful C-C bond formation reactions in synthesis, with applications that span pharmaceuticals, agrochemicals and high-tech materials. Despite the breadth of its utility, the scope of this Nobel prize-winning reaction is rather limited when applied to aliphatic boronic esters. Primary organoboron reagents work well, but secondary and tertiary boronic esters do not (apart from a few specific and isolated examples). Through an alternative strategy, which does not involve using transition metals, we have discovered that enantioenriched secondary and tertiary boronic esters can be coupled to electron-rich aromatics with essentially complete enantiospecificity. As the enantioenriched boronic esters are easily accessible, this reaction should find considerable application, particularly in the pharmaceutical industry where there is growing awareness of the importance of, and greater clinical success in, creating biomolecules with three-dimensional architectures.

  18. Phthalate Esters and Reproductive Toxicity** Presentation requested by State of Mass Use Reductions Committee-TURI

    Science.gov (United States)

    Phthalate esters and reproductive toxicity the presentation described the uses of phthalates, the toxicity to mammals with a focus on reproductive toxicity and the potency of these chemicals to disrupt mammalian reproductive development in utero

  19. Lutein and lutein esters in marigold flowers by high performance chromatography

    Institute of Scientific and Technical Information of China (English)

    JIANG Xin-yu; CHEN Long-sheng; ZHOU Chun-shan

    2005-01-01

    Lutein and lutein esters in marigold flowers was quantitatively determined by high performance chromatography (HPLC) with ODS-C18 column. A mixture of CH3CN - CH3OH - CH3COOCH2CH3 with volume ratio of 55: 1: 44 was used as mobile phase at a flow rate of 1.0 mL/min and detection was carried out at 460 nm. The column temperature was about 20 ℃. The contents of lutein and lutein esters were determined by analytical curve of lutein since lutein and lutein esters have the same spectral characteristics. Determination results of hexane extracts and saponified samples of lutein show that the saponification transforms the esters into free lutein. The increase of the content of dipalmitate and palmitate stearate reveals that the reaction includes transesterifications.

  20. Ester Tuiksoo : Saksamaa on Eestile biomassi ja GMO vallas eeskujuks / Ain Lember

    Index Scriptorium Estoniae

    Lember, Ain

    2006-01-01

    Põllumajandusminister Ester Tuiksoo ja abiminister Rain Vändre kohtusid Kielis Schleswig-Holsteini liidumaa ministri dr. Christian von Boetticheriga, peateemadeks abi biomassi ja geneetiliselt muundatud kultuurtaimede kooseksisteerimise vallas

  1. Efficient Syntheses of 2-Substituted Benzimidazoles and Benzoxazoles from β-Keto Esters

    Institute of Scientific and Technical Information of China (English)

    XIAO Li-wei; ZHANG Min; SUN Wen-hua

    2011-01-01

    An efficient synthetic method was developed to synthesize 2-substituted benzimidazoles and benzoxazoles withβ-keto esters as starting materials under mild reaction conditions, during which other functional groups are bearable from reactants to products.

  2. RELATIONSHIP OF NEUROPATHY TARGET ESTERASE INHIBITION TO NEUROPATHOLOGY AND ATAXIA IN HENS GIVEN ORGANOPHOSPHORUS ESTERS

    Science.gov (United States)

    Adult WhiteLeghorn hens were acutely exposed to 3 dosages of the following organophosphorus esters: mipafox, tri-ortho-tolyl phosphate (TOTP), penyl saligenin phosphate, diisppropylophosphoro-fluoridate (DFP), malathion and dichlorvos. europathy target esterase (NTE) activity was...

  3. Radiosensitivity and hydroxyl radical reactivity of phosphate esters as measured by radiation-induced dephosphorylation

    International Nuclear Information System (INIS)

    The yields of inorganic phosphate from irradiated phosphate esters of biological interest have been measured in the presence of various free-radical scavengers. These studies indicated that hydroxyl radical attack on the phosphate esters accounts for most of this damage. Competition kinetics using different hydroxyl radical scavengers whose reactivities are known to have been used to estimate the rate-constants for the overall hydroxyl radical reactivities of the phosphate esters. The extent of hydroxyl-radical-induced dephosphorylation was very low for nucleotide derivatives, but high for some sugar and glycerol phosphates, reflecting the probability of hydroxyl radical abstraction at the α or β carbon atoms adjacent to the phosphate ester linkage. The hydroxyl radical reactivities of nucleotides, coenzymes, sugar phosphates and phospholipid components were all high (1 to 10x109M-1sec-1), indicating the importance of hydroxyl radical attack in the inactivation of these components in living cells, although not necessarily by dephosphorylation. (author)

  4. Synthesis and evaluation of thalidomide and phthalimide esters as antitumor agents

    DEFF Research Database (Denmark)

    Zahran, Magdy A H; Abdin, Yasmin G.; Osman, Amany M A;

    2014-01-01

    A series of thalidomide and phthalimide ester analogs were efficiently synthesized from N-chloromethylthalidomide, N-chloromethylphthalimide, and N-(2-bromoethyl)phthalimide derivatives with various biologically important carboxylic acids. The synthesized compounds were purified and characterized...

  5. The oxidative stability of rapeseed oil methyl and ethyl esters - environment friendly alternative fuel

    International Nuclear Information System (INIS)

    The oxidative stability of rapeseed oil and bio diesel fuel RME and REE, produced from it, has been determined. The addition of antioxidant BHT essentially prolongs the utility term of oil and its esters. (authors)

  6. Nooruslikud juubilarid: fotokelder Lee 20 ja fotomuuseum 30 / Mall Parmas, Betty Ester-Väljaots

    Index Scriptorium Estoniae

    Parmas, Mall

    2013-01-01

    Peeter Toominga algatusel 1992. aastal asutatud Lee fotokeldrist. Loetletud fotomuuseumis oma töid eksponeerinud fotograafid. Ülevaatenäitus "Lee fotokelder 20" 17. jaanuarist 20. märtsini, koostaja Betty Ester-Väljaots

  7. New composites of betulin esters with arabinogalactan as highly potent anti-cancer agents.

    Science.gov (United States)

    Shakhtshneider, T P; Kuznetsova, S A; Zamay, A S; Zamay, T N; Spivak, E A; Mikhailenko, M A; Malyar, Yu N; Kuznetsov, B N; Chesnokov, N V; Boldyrev, V V

    2016-06-01

    Betulin and its esters are the natural compounds with high in vitro cytotoxicity toward many cancer cells. However, the poor water solubility of these compounds has limited their applications. We prepared new composites of betulin esters using two methods, namely ball-milling of the mixtures of betulin esters with arabinogalactan and preparation of thin films of these mixtures by evaporating the aqueous solutions. These composites revealed higher water solubility as compared with the initial substances without losing the structural integrity and functionality. As a result, the new composites have shown much higher inhibitory effects against different cancer cell lines such as Ehrlich ascites carcinoma cells and lung carcinoma cells (A549) in comparison with the initial substances. The cell viability studies based on Annexin V and Propidium iodide probes have confirmed the high proapoptotic effect of betulin ester derivatives against cancer cells. PMID:26165861

  8. Experimental investigation on a DI diesel engine fuelled with Madhuca Indica ester and diesel blend

    Energy Technology Data Exchange (ETDEWEB)

    Saravanan, N. [ERC Engines, Hall 11A, Tata Motors, Pimpri, Pune 411019, Maharashtra (India); Nagarajan, G. [Department of Mechanical Engineering, College of Engineering, Guindy, Anna University, Chennai (India); Puhan, Sukumar [Department of Mechanical Engineering, Veltech Engineering College, Avadi, Chennai (India)

    2010-06-15

    Biodiesel is a fatty acid alkyl ester, which is renewable, biodegradable and non-toxic fuel which can be derived from any vegetable oil by transesterification. One of the popularly used biodiesel in India is Mahua oil (Madhuca Indica). In the present investigation Mahua oil was transesterified using methanol in the presence of alkali catalyst and was used to study the performance and emission characteristics. The biodiesel was tested on a single cylinder, four stroke compression ignition engine. Engine performance tests showed that power loss was around 13% combined with 20% increase in fuel consumption with Mahua oil methyl ester at full load. Emissions such as carbon monoxide, hydrocarbon were lesser for Mahua ester compared to diesel by 26% and 20% respectively. Oxides of nitrogen were lesser by 4% for the ester compared to diesel. (author)

  9. Identification of rapeseed oil fatty acid esters in transesterification reactions by gas chromatography - mass spectrometry method

    International Nuclear Information System (INIS)

    Rapeseed oil transesterification with different alcohols - methyl, ethyl, n-propyl and isopropyl alcohol - has been carried out. Yields of fatty acid alkyl esters obtained from rapeseed oil were determined using the internal standard method. Results of interpretation of the obtained ester mass spectra are reported. The specimen of Latvian rape oil contains: 57.6% of oleic acid, 18.2% of linoleic acid, 8.2% linolenic acid, 3.3% palmitic acid, 2% of stearic acid and less than 1% of arachidic acid. Values of Kovats retention indices of the rapeseed oil fatty acid esters on the capillary columns DB-5 MS and DB-17 MS have been compared. More selective separation of fatty acid alkyl esters has been achieved on the stationary phase with higher content of phenyl groups (DB-17 MS). (authors)

  10. Unsaturated Fatty Acid Esters Metathesis Catalyzed by Silica Supported WMe5

    KAUST Repository

    Riache, Nassima

    2015-11-14

    Metathesis of unsaturated fatty acid esters (FAEs) by silica supported multifunctional W-based catalyst is disclosed. This transformation represents a novel route towards unsaturated di-esters. Especially, the self-metathesis of ethyl undecylenate results almost exclusively on the homo-coupling product whereas with such catalyst, 1-decene gives ISOMET (isomerization and metathesis olefin) products. The olefin metathesis in the presence of esters is very selective without any secondary cross-metathesis products demonstrating that a high selective olefin metathesis could operate at 150 °C. Additionally, a cross-metathesis of unsaturated FAEs and α-olefins allowed the synthesis of the corresponding ester with longer hydrocarbon skeleton without isomerisation.

  11. Investigation on the lubrication properties of biodiesel made of Camelina Sativa and Lard esters

    Energy Technology Data Exchange (ETDEWEB)

    Kreivaitis, Raimondas; Padgurskas, Juozas [Aleksandras Stulginskis Univ., Kaunas (Lithuania). Inst. of Power and Transport Machinery; Gumbyte, Milda [Aleksandras Stulginskis Univ., Kaunas (Lithuania). Inst. of Environment and Ecology

    2013-06-01

    The ethyl esters can be produced from renewable resources while methyl esters have petroleum based methyl part. Camelina Sativa is the potential source of oilseeds. The oil has similar properties as that of rapeseed oil. Animal fats are cheap raw material and there esters were suggested as a fuel for diesel engine by many authors. The objective of this study would be the lubrication properties of ethyl esters made of Camelina Sativa and Lard. The lubrication properties investigated using High-Frequency Reciprocating Rig (HFRR) method. The wear scar diameter represents the lubrication properties. The observed lubrication results are compared with lubrication properties of conventional diesel fuel obtained from manufacturer ''ORLEN Lietuva'' Lithuania. The results show that mixtures of diesel and biodiesel improve the lubrication properties. (orig.)

  12. One-pot synthesis of thermoplastic mixed paramylon esters using trifluoroacetic anhydride.

    Science.gov (United States)

    Shibakami, Motonari; Tsubouchi, Gen; Sohma, Mitsugu; Hayashi, Masahiro

    2015-03-30

    Mixed paramylon esters prepared from paramylon (a storage polysaccharide of Euglena), acetic acid, and a long-chain fatty acid by one-pot synthesis using trifluoroacetic anhydride as a promoter and solvent were shown to have thermoplasticity. Size exclusion chromatography indicated that the mixed paramylon esters had a weight average molecular weight of approximately 4.9-6.7×10(5). Thermal analysis showed that these esters were stable in terms of the glass transition temperature (>90°C) and 5% weight loss temperature (>320°C). The degree of substitution of the long alkyl chain group, a dominant factor determining thermoplasticity, was controlled by tuning the feed molar ratio of acetic acid and long-chain fatty acid to paramylon. These results implied that the one-pot synthesis is useful for preparing structurally-well defined thermoplastic mixed paramylon esters with high molecular weight. PMID:25563938

  13. Chiral Borated Esters in Asymmetric Synthesis:1.The First Asymmetric Reaction Catalyzed by Chiral Spiroborated Esters with an O3BN Framework

    Institute of Scientific and Technical Information of China (English)

    LIU, De-Jun(刘德军); SHAN, Zi-Xing(单自兴); QIN, Jin-Gui(秦金贵)

    2004-01-01

    The first asymmetric reaction catalyzed by chiral spiroborated esters with an O3BN framework was reported. In the presence of 0.1 equivalent of (R,S)-1 or (S,S)-1, acetophenone was reduced by 0.6 equivalent of borane in THF at 0-5 ℃ for 2 h to give (R)-1-phenylethanol of up to 76% ee and 73% isolated yield. Influence of reaction conditions on the stereoselectivity of the reduction was investigated and a possible catalytic mechanism of the chiral spiroborated esters toward the reduction was also suggested.

  14. Briareolate Esters from the Gorgonian Briareum asbestinum

    Directory of Open Access Journals (Sweden)

    Lyndon M. West

    2012-08-01

    Full Text Available Two new briarane diterpenoids briareolate esters J (1 and K (2 were isolated from the methanolic extract of the octocoral Briareum asbestinum collected off the coast of Boca Raton, Florida. The structures of briaranes 1 and 2 were elucidated by interpretation of spectroscopic data. Briareolate ester K (2 showed weak growth inhibition activity against human embryonic stem cells (BG02.

  15. Fatty Acid Methyl Esters as Biosolvents of Epoxy Resins: A Physicochemical Study

    OpenAIRE

    Medina-González, Yaocihuatl; De Caro, Pascale; Thiebaud-Roux, Sophie; Lacaze-Dufaure, Corinne

    2007-01-01

    The C8 to C18 fatty acid methyl esters (FAME) have been compared as solvents for two epoxy resin pre-polymers, bisphenol A diglycidyl ether (DGEBA) and triglycidyl paminophenol ether (TGPA). It was found that the solubilization limits vary according to the ester and that methyl caprylate is the best solvent of both resins. To explain these solubility performances, physical and chemical properties of FAME were studied, such as the Hansen parameters, viscosity, binary diffusion coefficient and ...

  16. Temperature Distribution in Fibre-glass Composite Impregnated with Epoxy-Cyanate ester Blend

    OpenAIRE

    Priyanka Brahmbhatt; Moni Banaudha; Subrata Pradhan

    2014-01-01

    Cyanate ester and epoxy blends have been identified as an attractive insulating material for fusion grade magnet winding packs. An insulation system comprising of fibre glass composites and cyanate ester and blend has been analyzed during its vacuum pressure impregnation and curing. The transient one dimensional distribution of temperature and extent of cure has been evaluated both analytically and experimentally in this paper. The one dimensional transient (1-D) heat transfer cha...

  17. Enzymatic synthesis of polyol esters in aqueous-organic two-phase systems.

    OpenAIRE

    Janssen, A.E.M.

    1993-01-01

    The last decade increasingly attention is paid to lipases as catalysts for synthesis of components, such as fatty acid-based surfactants, flavors, edible oil equivalents, monomers and polymers, and amides. In this thesis, the lipase-catalyzed esterification of polyols and fatty acids is described. These esters consist of a nonpolar part (fatty acid) and a polar part (polyol). Therefore, polyol esters have surface-active properties and are used as emulsifier in food, pharmaceutics; and cosmeti...

  18. Zeolite-catalysed preparation of alpha-hydroxy carboxylic acids and esters thereof

    DEFF Research Database (Denmark)

    2010-01-01

    A process for the production of lactic acid and 2-hydroxy-3-butenoic acid or esters thereof by conversion of glucose, fructose, sucrose, xylose and glycolaldehyde dissolved in a solvent in presence of a solid Lewis acidic catalyst.......A process for the production of lactic acid and 2-hydroxy-3-butenoic acid or esters thereof by conversion of glucose, fructose, sucrose, xylose and glycolaldehyde dissolved in a solvent in presence of a solid Lewis acidic catalyst....

  19. Copper-Mediated Fluorination of Arylboronate Esters. Identification of a Copper(III) Fluoride Complex

    OpenAIRE

    Fier, Patrick S.; Luo, Jingwei; Hartwig, John F.

    2013-01-01

    A method for the direct conversion of arylboronate esters to aryl fluorides under mild conditions with readily available reagents is reported. Tandem reactions have also been developed for the fluorination of arenes and aryl bromides through aryl-boronate ester intermediates. Mechanistic studies suggest that this fluorination reaction occurs through facile oxidation of Cu(I) to Cu(III) followed by rate-limiting transmetallation of a bound arylboronate to Cu(III). Fast C-F reductive eliminatio...

  20. Antioxidant phenolic esters with potential anticancer activity: A Raman spectroscopy study

    OpenAIRE

    Calheiros, R.; Machado, N. F. L.; Fiuza, S. M.; Gaspar, A.; Garrido, J.; Milhazes, N.; Borges, F.; Marques, M.P.M.

    2008-01-01

    A Raman study of hydroxycinnamic and hydroxybenzoic esters (caffeates, ferulates and gallates) displaying antioxidant and anticancer properties was undertaken, with particular emphasis on the analysis of the effect of the ring substituents and the nature of the ester alkyl chain on their spectroscopic features. A complete assignment of the spectra was carried out for all the compounds investigated, in the light of the corresponding calculated wavenumbers (at the density functional theory leve...

  1. Clean synthesis of biolubricant range esters using novel liquid lipase enzyme in solvent free medium

    OpenAIRE

    Trivedi, Jayati; Aila, Mounika; Sharma, Chandra Dutt; Gupta, Piyush; Kaul, Savita

    2015-01-01

    In view of the rising global problems of environment pollution and degradation, the present process provides a ‘green solution’ to the synthesis of higher esters of lubricant range, more specifically in the range C12-C36, using different combinations of acids and alcohols, in a single step reaction. The esters produced are biodegradable in nature and have a plethora of uses, such as in additives, as lubricating oils and other hydraulic fluids. The enzymatic esterification was performed using ...

  2. Synthesis and Crystal Structure of a Novel Calix [8] arene Ester Derivative

    Institute of Scientific and Technical Information of China (English)

    DaQiangYUAN; RuJiWANG; 等

    2002-01-01

    The synthesis and crystal structure of a novel calix[8] arene ester are reported herein. The calix [8] arene ester derivative has been characterized by IR,NMR and X-ray crystal analysis. The X-ray structure analysis revealed that the 8 phenolic hydroxy groups of the calix [8] arene have been substituted by 4 diethyl dibromomalonate molecules with each two adjacent hydroxy oxygen atoms attached to a bridge diethyl malonate.

  3. Synthesis of chlorine - containing ethylene glycol esters in the presence of nano-heterogeneous catalyst

    International Nuclear Information System (INIS)

    The esterification reactions on the basis of ethylene glycol and monotrichloroacetic acid in the presence of catalyst nano-titanium dioxide (TiO2) of anatase modification have been carried out. The significant advantages of nano - catalyst uses have been shown in comparison with traditional proton acid catalysts. The main esters have been obtained with high yield for comparatively short time. The constitution of the esters obtained has been confirmed by IR - spectroscopy and chemical methods of analysis

  4. SYNTHESIS AND CHARACTERIZATION O F SODIUM METHYL ESTER SULFONATE FOR CHEMICALLY-ENHANCED OIL RECOVERY

    OpenAIRE

    Babu, K.; N. K. Maurya; Mandal, A.; Saxena, V. K.

    2015-01-01

    AbstractAttention has been given to reduce the cost of surfactant by using castor oil as an alternative natural source of feedstock. A new surfactant, sodium methyl ester sulfonate (SMES) was synthesised using ricinoleic acid methyl ester, which is obtained from castor oil, for enhanced oil recovery in petroleum industries. The performance of SMES was studied by measuring the surface tension with and without sodium chloride and its thermal stability at reservoir temperature. SMES exhibited go...

  5. Ester-linked Glycopeptides as Tools for Studies of Biological Phenomena

    OpenAIRE

    Horvat, Štefica; Jerić, Ivanka; Varga-Defterdarović, Lidija; Roščić, Maja; Horvat, Jaroslav

    2001-01-01

    Modifications of plasma proteins, structural proteins and other macromolecules by glycation (the Maillard reaction) contribute to the development of accelerated atherosclerosis and other complications in diabetes and are also involved in the pathogenesis of aging. Monosaccharide esters, which mimic the reactivity of sugar 6-phosphate esters in nonenzymatic glycations, were prepared from endogenous opioid peptide leucine-enkephalin (Tyr-Gly-Gly-Phe-Leu), smaller peptides of different lengths (...

  6. Tricarballylic ester formation during biosynthesis of fumonisin mycotoxins in Fusarium verticillioides

    OpenAIRE

    Lia, Yaoyao; Lou, Lili; Cerny, Ronald L.; Butchko, Robert A.E.; Proctor, Robert H.; Shen, Yuemao; Du, Liangcheng

    2014-01-01

    Fumonisins are agriculturally important mycotoxins produced by the maize pathogen Fusarium verticillioides. The chemical structure of fumonisins contains two tricarballylic esters, which are rare structural moieties and important for toxicity. The mechanism for the tricarballylic ester formation is not well understood. FUM7 gene of F. verticillioides was predicted to encode a dehydrogenase/reductase, and when it was deleted, the mutant produced tetradehydro fumonisins (DH4–FB). MS and NMR ana...

  7. Review of glycol ether and glycol ether ester solvents used in the coating industry.

    OpenAIRE

    Smith, R.L.

    1984-01-01

    Ethylene oxide-based glycol ether and glycol ether ester solvents have been used in the coatings industry for the past fifty years. Because of their excellent performance properties (evaporation rate, blush resistance, flow-out and leveling properties, solubility for coating resins, solvent activity, mild odor, good coupling ability, good solvent release) a complete line of ethylene oxide-based solvents of various molecular weights has been developed. These glycol ether and glycol ether ester...

  8. A simple synthesis of kaurenoic esters and other derivatives and evaluation of their antifungal activity

    International Nuclear Information System (INIS)

    Representative esters derived from kaurenoic acid were prepared in order to evaluate their antifungal properties. Alkyl and substituted benzyl esters were obtained in good yield under mild conditions by esterification of kaurenoic acid with the corresponding alkyl halide in KOH-acetone. All synthesized compounds were tested for antifungal properties against pathogenic yeasts, hialohyphomycetes and dermatophytes. Kaurenoic acid and derivatives containing a free carboxyl group were moderately active against dermatophytes. (author)

  9. Reptilian chemistry: Characterization of a family of dianeackerone-related steroidal esters from a crocodile secretion

    OpenAIRE

    Yang, Zhicai; Whyte, Authrine; Attygalle, Athula B.; Weldon, Paul J.; Eisner, Thomas; Meinwald, Jerrold

    1999-01-01

    The African dwarf crocodile, Osteolaemus tetraspis (Crocodilidae, Reptilia), possesses a pair of skin glands, the paracloacal glands, the secretion of which is thought to be used to mark nest sites or attract mates. Ten aromatic steroidal esters were isolated from this secretion and characterized on the basis of NMR spectroscopic investigations, electrospray ionization-MS analyses, and chemical degradation. These esters, which account for more than 90% of the paracloacal glandular secretion, ...

  10. Synthesis and characterization of new biodegradable thermosensitive polyphosphazenes with lactic acid ester and methoxyethoxyethoxy side groups

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Two novel biodegradable thermosensitive polyphosphazenes with lactic acid ester and methoxyethoxyethoxy side groups were synthesized via the macromolecular substitution reactions of poly(dichlorophosphazene) with the sodium salt of lactic acid ester and sodium methoxyethoxyethoxide.Their structures were confirmed by ~(31)p NMR,~1H NMR,~(13)C NMR,IR,DSC,and elemental analysis.The lower critical solution temperature(LCST) behavior in water and in vitro degradation property of the polymers was investigated....

  11. Spectroscopic Characterization of Molecular Interdiffusion at a Poly(Vinyl Pyrrolidone) / Vinyl Ester Interface

    OpenAIRE

    Laot, Christelle Marie III

    1997-01-01

    Mechanical properties of (woven carbon fiber / vinyl ester matrix) composites can be greatly improved if the interphase between the reinforcing high-strength low-weight fiber and the thermoset resin is made more compliant. In order to improve the adhesion of the vinyl ester matrix to the carbon fiber, a thermoplastic coating such as poly(vinyl pyrrolidone) (PVP) can be used as an intermediate between the matrix and the fiber. The extent of mutual diffusion at the (sizing material / polymer ma...

  12. Antifungal chalcones and new caffeic acid esters from Zuccagnia punctata acting against soybean infecting fungi.

    Science.gov (United States)

    Svetaz, Laura; Tapia, Alejandro; López, Silvia N; Furlán, Ricardo L E; Petenatti, Elisa; Pioli, Rosanna; Schmeda-Hirschmann, Guillermo; Zacchino, Susana A

    2004-06-01

    The crude methanolic extract of Zuccagnia punctata was active toward the fungal pathogens of soybean Phomopsis longicolla and Colletotrichum truncatum. Assay guided fractionation led to the isolation of two chalcones, one flavanone and a new caffeoyl ester derivative as the compounds responsible for the antifungal activity. Another new caffeoyl ester derivative was isolated from the antifungal chloroform extract but proved to be inactive against the soybean infecting fungi up to 50 microg/mL PMID:15161186

  13. Synthesis of Isocoumarins via Silver(I)-Mediated Annulation of Enol Esters.

    Science.gov (United States)

    Panda, Niranjan; Mishra, Priyadarshini; Mattan, Irshad

    2016-02-01

    Silver-mediated annulation of 2-iodo enol esters leading to 4- and 3,4-substituted isocoumarins was accomplished selectively at room temperature. Coupling of 2-iodo benzoic acids with enolates that were produced in situ from the simple esters was also performed to produce isocoumarins under analogous reaction conditions. Owing to the mildness of the current protocol, 4-acyl 3-substituted isocoumarins were efficiently produced without any deacylation. PMID:26745524

  14. Transesterification of Vegetable Oils with Ethanol and Characterization of the Key Fuel Properties of Ethyl Esters

    Directory of Open Access Journals (Sweden)

    Stamoulis Stournas

    2009-06-01

    Full Text Available The transesterification reactions of four different vegetable oils (sunflower, rapeseed, olive oil and used frying oil with ethanol, using sodium hydroxide as catalyst, were studied. The ester preparation involved a two-step transesterification reaction, followed by purification. The effects of the mass ratio of catalyst to oil (0.25 – 1.5%, the molar ratio of ethanol to oil (6:1 – 12:1, and the reaction temperature (35 – 90 °C were studied for the conversion of sunflower oil to optimize the reaction conditions in both stages. The rest of the vegetable oils were converted to ethyl esters under optimum reaction parameters. The optimal conditions for first stage transesterification were an ethanol/oil molar ratio of 12:1, NaOH amount (1% wt/wt, and 80 °C temperature, whereas the maximum yield of ethyl esters reached 81.4% wt/wt. In the second stage, the yield of ethyl esters was improved by 16% in relation with the one-stage transesterification, which was obtained under the following optimal conditions: catalyst concentration 0.75% and ethanol/oil molar ratio 6:1. The fuel properties of the esters were measured according to EN test methods. Based on the experimental results one can see that the ethyl esters do not differ significantly from methyl esters. Moreover, the results showed that the values of density, viscosity, and higher heating value of ethyl esters were similar to those of automotive and heavy duty engine diesel fuel. However, the CFPP values were higher, which may contribute to potential difficulties in cold starts. On the other hand, the flash points, which were higher than those of diesel fuel constituted a safety guarantee from the point of view of handling and storage.

  15. Biodegradable polyoxyethylenated pentaerythritol quaternary esters as oil spill dispersants

    Energy Technology Data Exchange (ETDEWEB)

    El-Sayed Abdel-Raouf, Manar [Egyptian Petroleum Research Institute, Cairo (Egypt). Petroleum Application Dept.

    2012-03-15

    Four polyoxyethylenated pentaerythritol (PE) ester surfactants have been synthesized. The molecular weights of these surfactants were calculated and evaluated experimentally by GPC and confirmed by calculations based on {sup 1}H-NMR. Also, their HLB values were calculated by Griffin formula. The surface tension and thermodynamic properties of the surfactants were obtained from surface tension measurements at different temperatures (298-318 K). It was found that the minimum area/surfactant molecule (A{sub min}) for the investigated surfactants increased with increasing the molecular weight of the incorporated ethylene oxide. The thermodynamic parameters of micellization ({delta}G{sub mic,} {delta}H{sub mic} and {delta}S{sub mic}) and that for adsorption ({delta}G{sub ad,} {delta}H{sub ad} and {delta}S{sub ad}) were also calculated. The more negative Gibbs free energy of adsorption values than those of micellization suggest that these surfactants favor adsorption than micellization. This finding is utilized for monitoring their dispersancy power. It was found that the water solubility of the prepared surfactants is correlated to their HLB values. Furthermore, the biodegradability of the prepared compounds was studied at different conditions in order to investigate their usability as oil spill dispersants. The data revealed that PE200-C12 had maximum dispersion efficiency and it was completely biodegraded after 8 days. (orig.)

  16. Aspects of the testicular toxicity of phthalate esters

    International Nuclear Information System (INIS)

    Di(2-ethylhexyl) phthalate (DEHP) produced seminiferous tubular atrophy and reductions in seminal vesicle and prostate weight in 4-week-old, but not in 15 -week-old rats. Di-n-pentyl phthalate (DPP) did produce atrophy in the older rats but this developed more slowly than in young animals. Coadministration of testosterone or gonadotrophins did not protect against phthalate-induced testicular toxicity but did partly reverse the depression of seminal vesicle and prostate weight. Secretion of seminiferous tubule fluid and androgen binding protein by the Sertoli cells was markedly suppressed within 1 hr of a dose of DPP or mono-2-ethylhexyl phthalate (MEHP) in immature rats. This occurred less rapidly in mature rats. [14C]mono-n-pentyl phthalate and [14C]MEHP penetrated the blood testis barrier only to a very limited extent. These findings and the early morphological changes in the Sertoli cells produced by DPP suggest that phthalate esters may act initially to cause Sertoli cell injury, the subsequent loss of germ cells occurring as a consequence of this

  17. Carboxyfluorescein Diacetate Succinimidyl Ester Fluorescent Dye for Cell Labeling

    Institute of Scientific and Technical Information of China (English)

    Xiao-Qi WANG; Xiu-Mei DUAN; Li-Hua LIU; Yan-Qiu FANG; Yan TAN

    2005-01-01

    Our objective was to study the properties of the carboxyfluorescein diacetate succinimidyl ester (CFDA-SE) and the methodology of cell labeling using CFDA-SE fluorescent dye. First, we analyzed the kinetics of CFDA-SE fluorescent dye intensity over time. Second, we determined the optimal concentration of CFDA-SE fluorescent dye for cell labeling. Third, we tested the toxicity of CFDA-SE fluorescent dye on labeled cells. Finally, we determined the optimal staining time of CFDA-SE fluorescent dye for cell labeling.The results show that the optimal concentration of CFDA-SE fluorescent dye for cell labeling varies according to different cell types. CFDA-SE fluorescent dye is non-toxic to cells as the cell death rate caused by CFDASE labeling is below 5%. The optimal cell labeling time was determined to be 8 min of incubation with CFDA-SE fluorescent dye. We concluded that the advantages of using CFDA-SE fluorescent dye for cell labeling are as follows: (1) the binding of CFDA-SE fluorescent dye to cells is stable; (2) CFDA-SE fluorescent dye is not toxic and does not modify the viability of labeled cells; and (3) CFDA-SE fluorescent dye is a suitable fluorochrome for cell labeling.

  18. Impact of ester promoieties on transdermal delivery of ketorolac.

    Science.gov (United States)

    Liu, Kuo-Sheng; Hsieh, Pei-Wen; Aljuffali, Ibrahim A; Lin, Yin-Ku; Chang, Shu-Hao; Wang, Jhi-Joung; Fang, Jia-You

    2014-03-01

    Different types of ketorolac ester prodrugs incorporating tert-butyl (KT), benzyl (KB), heptyl (KH), and diketorolac heptyl (DKH) promoieties were synthesized for the comparison of percutaneous penetration. The prodrugs were characterized according to their melting point, capacity factor, lipophilicity, solubility in 30% ethanol/buffer, enzymatic hydrolysis, in vitro skin permeation, hair follicle accumulation, and in vivo skin tolerance. Interactions between the prodrugs and esterases were predicted by molecular docking. Both equimolar suspensions and saturated solutions in 30% ethanol/pH 7.4 buffer were employed as the applied dose. All of the prodrugs exhibited a lower melting point than ketorolac. The lipophilicity increased in the following order: ketorolac absorption into follicles and a threefold greater follicular uptake compared with ketorolac. KB, KH, and DKH slightly but significantly increased transepidermal water loss (TEWL) after consecutive administration for 7 days, whereas ketorolac and KT exhibited no influence on TEWL. According to the experimental results, it can be concluded that an optimal balance between lipophilicity and aqueous solubility is important in the design of a successful prodrug. The acceptable skin tolerance for safe application is also an important consideration. PMID:24481782

  19. Synthesis of calixarenes and their extraction performance for ester catechins

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A series of extractants (tert-butylcalix[6]arene, tert-butylcalix[8]arene and octeacetate of tert-butylcalix[8]arene) were synthesized, and their structures were identified by IR and 1H-NMR. The distribution behavior of ester catechins monomer in the aqueous and chloroform two-phase system containing one of calixarene was studied. The influences of different extractants,concentration of tert-butylcalix[8]arene and extraction temperature on the partition coefficients and the separation factors were investigated. The experiment results show that tert-butylcalix[8]arene is the best extractant that forms a more stable supramolecular compound with gallocatechin gallate (GCG) than with epigallocathechin gallate (EGCG) or epicatechin gallate (ECG). When the concentration ofp-tert-butylcalix[8]arene is 3.79 mmol/L, the extraction temperature is 4 ℃C, the partition coefficients of KGG cG, KECG,KEGG cG are 0.987, 0.629, 0.449, the separation factors ofα1 and α2 are 1.450 and 1.596, respectively. The important factors influencing the extraction properties of calixarene are discovered to be its cavity size and hydrogen bonding.

  20. Successful treatment of recalcitrant cutaneous sarcoidosis with fumaric acid esters

    Directory of Open Access Journals (Sweden)

    Hanefeld Christoph

    2002-12-01

    Full Text Available Abstract Background Sarcoidosis is a multisystem disease of unknown origin characterized by the formation of noncaseating granulomas, in particular in the lungs, lymph nodes, eyes, and skin. Systemic treatment for cutaneous sarcoidosis can be used for large disfiguring lesions, generalized involvement, or recalcitrant lesions that did not respond to topical therapy. Case presentations We report three patients with recalcitrant cutaneous sarcoidosis who were treated with oral fumaric acid esters (FAE. Three female patients presented with cutaneous sarcoidosis that have proved to be refractory to various therapies, including corticosteroids and chloroquine. We treated the patients with FAE in tablet form using two formulations differing in strength (Fumaderm® initial, Fumaderm®. Dosage of FAE was performed according to the standard therapy regimen for psoriasis patients. After treatment with FAE (4–12 months, a complete clearance of skin lesions was achieved in the three patients. The side effects observed in this trial correspond to the well-known spectrum of adverse effects of FAE (flush, minor gastrointestinal complaints, lymphopenia. Conclusions On the basis of our findings FAE therapy seems to be a safe and effective regimen for patients with recalcitrant cutaneous sarcoidosis. Nevertheless further investigations are necessary to confirm our preliminary results.

  1. Occular and dermal toxicity of Jatropha curcas phorbol esters.

    Science.gov (United States)

    Devappa, Rakshit K; Roach, Joy S; Makkar, Harinder P S; Becker, Klaus

    2013-08-01

    Jatropha curcas seeds are a promising feedstock for biodiesel production. However, Jatropha seed oil and other plant parts are toxic due to the presence of phorbol esters (PEs). The ever-increasing cultivation of toxic genotype of J. curcas runs the risk of increased human exposure to Jatropha products. In the present study, effects of J. curcas oil (from both toxic and nontoxic genotypes), purified PEs-rich extract and purified PEs (factors C1, C2, C(3mixture), (C4+C5)) on reconstituted human epithelium (RHE) and human corneal epithelium (HCE) were evaluated in vitro. The PEs were purified from toxic Jatropha oil. In both RHE and HCE, the topical application of PEs containing samples produced severe cellular alterations such as marked oedema, presence of less viable cell layers, necrosis and/or partial tissue disintegration in epithelium and increased inflammatory response (interleukin-1α and prostaglandin E2). When compared to toxic oil, histological alterations and inflammatory response were less evident (PJatropha PEs are toxic towards RHE and HCE models, which represents dermal and occular toxicity respectively. Data obtained from this study would aid in the development of safety procedures for Jatropha biodiesel industries. It is advised to use protective gloves and glasses when handling PEs containing Jatropha products. PMID:23706600

  2. Phorbol esters induce multidrug resistance in human breast cancer cells

    International Nuclear Information System (INIS)

    Mechanisms responsible for broad-based resistance to antitumor drugs derived from natural products (multidrug resistance) are incompletely understood. Agents known to reverse the multidrug-resistant phenotype (verapamil and trifluoperazine) can also inhibit the activity of protein kinase C. When the authors assayed human breast cancer cell lines for protein kinase C activity, they found that enzyme activity was 7-fold higher in the multidrug-resistance cancer cells compared with the control, sensitive parent cells. Exposure of drug-sensitive cells to the phorbol ester phorbol 12,13-dibutyate [P(BtO)2] led to an increase in protein kinase C activity and induced a drug-resistance phenotype, whereas exposure of drug-resistant cells to P(BtO)2 further increased drug resistance. In sensitive cells, this increased resistance was accomplished by a 3.5-fold increased phosphorylation of a 20-kDa particulate protein and a 35-40% decreased intracellular accumulation of doxorubicin and vincristine. P(BtO)2 induced resistance to agents involved in the multidrug-resistant phenotype (doxorubicin and vincristine) but did not affect sensitivity to an unrelated alkylating agent (melphalan). The increased resistance was partially or fully reversible by the calcium channel blocker verapamil and by the calmodulin-antagonist trifluoperazine. These data suggest that stimulation of protein kinase C playus a role in the drug-transport changes in multidrug-resistant cells. This may occur through modulation of an efflux pump by protein phosphorylation

  3. Structural Interactions within Lithium Salt Solvates: Cyclic Carbonates and Esters

    Energy Technology Data Exchange (ETDEWEB)

    Seo, D. M.; Afroz, Taliman; Allen, Joshua L.; Boyle, Paul D.; Trulove, Paul C.; De Long, Hugh C.; Henderson, Wesley A.

    2014-11-13

    Only limited information is available regarding the manner in which cyclic carbonate and ester solvents coordinate Li+ cations in electrolyte solutions for lithium batteries. One approach to gleaning significant insight into these interactions is to examine crystalline solvate structures. To this end, eight new solvate structures are reported with ethylene carbonate, γ-butyrolactone and γ-valerolactone: (EC)3:LiClO4, (EC)2:LiClO4, (EC)2:LiBF4, (GBL)4:LiPF6, (GBL)1:LiClO4, (GVL)1:LiClO4, (GBL)1:LiBF4 and (GBL)1:LiCF3SO3. The crystal structure of (EC)1:LiCF3SO3 is also re-reported for comparison. These structures enable the factors which govern the manner in which the ions are coordinated and the ion/solvent packing—in the solid-state—to be scrutinized in detail.

  4. New Water-Soluble Carbamate Ester Derivatives of Resveratrol

    Directory of Open Access Journals (Sweden)

    Andrea Mattarei

    2014-10-01

    Full Text Available Low bioavailability severely hinders exploitation of the biomedical potential of resveratrol. Extensive phase-II metabolism and poor water solubility contribute to lowering the concentrations of resveratrol in the bloodstream after oral administration. Prodrugs may provide a solution—protection of the phenolic functions hinders conjugative metabolism and can be exploited to modulate the physicochemical properties of the compound. We report here the synthesis and characterization of carbamate ester derivatives of resveratrol bearing on each nitrogen atom a methyl group and either a methoxy-poly(ethylene glycol-350 (mPEG-350 or a butyl-glucosyl promoiety conferring high water solubility. Ex vivo absorption studies revealed that the butyl-glucosyl conjugate, unlike the mPEG-350 one, is able to permeate the intestinal wall. In vivo pharmacokinetics confirmed absorption after oral administration and showed that no hydrolysis of the carbamate groups takes place. Thus, sugar groups can be attached to resveratrol to obtain soluble derivatives maintaining to some degree the ability to permeate biomembranes, perhaps by facilitated or active transport.

  5. Effect of reaction temperature and time on neem methyl ester yield in a batch reactor

    International Nuclear Information System (INIS)

    Highlights: • Fatty acid profile and molecular mass of neem oil were determined. • Main effects of the factors and interaction were successfully quantified and compared. • Six (6) regression models were developed for methyl ester yield using NLREG software. • Results showed that the models can predict the methyl ester yield within 7% of experimental values. - Abstract: Experimental investigation of neem methyl ester yield in a batch reactor at different process conditions of temperature and reaction duration was carried out using a 2-factor, 5-level full factorial experimental design. Reaction temperature was varied between 40 °C and 60 °C, while reaction time was studied in the range of 30–120 min. The study, which was carried out using 1% w/w catalyst amount and alcohol to oil ratio of 6:1, showed that reaction temperature had a highly significant effect (p < 0.01) in comparison with reaction time, which had a significant effect (p < 0.05) on methyl ester yield. Six (6) empirical models were developed for the response variable of methyl ester yield using a non-linear regression analysis method, facilitated by NLREG version 6.3 software. Results showed that the mean predicted ester yield values and mean experimental values were not statistically different at the 95% confidence level, whereas the maximum deviation observed was 6.9%

  6. EXPERIMENTAL INVESTIGATION OF LINSEED AND NEEM METHYL ESTERS AS BIODIESEL ON CI ENGINE

    Directory of Open Access Journals (Sweden)

    V.DHANA RAJU

    2012-06-01

    Full Text Available An experimental investigations were carried out on C.I.engine with Bio Diesel blends of Linseed Methyl Esters and Neem Oil Methyl Esters .The engine used for the experiments was single cylinder Four Stroke water cooled, constant speed diesel engine . Linseed Methyl ester (LSOME and Neem oil methyl ester (NOME are derived through transesterification process and parameters of transesterification were optimized. The blends of various proportions of the LSOME & NOME with diesel were prepared, analyzed and compared with diesel fuel,and comparison was made to suggest the better option among the bio diesel. Various Tests have been carried out to examine properties, performance of different blends (B05, B10, B15, and B20 of LSOME and NOME in comparison to diesel. From the experimental Results it is indicated that B20 have closer performance to diesel. However, its diesel blends showed reasonable efficiencies. From the experimental results it is observed that Linseed methyl ester gives better performance compared to Neem methyl esters and also the emissions and smoke for these diesel blends are less as compare to the pure diesel.

  7. Antioxidants Inhibit Formation of 3-Monochloropropane-1,2-diol Esters in Model Reactions.

    Science.gov (United States)

    Li, Chang; Jia, Hanbing; Shen, Mingyue; Wang, Yuting; Nie, Shaoping; Chen, Yi; Zhou, Yongqiang; Wang, Yuanxing; Xie, Mingyong

    2015-11-11

    The capacities of six antioxidants to inhibit the formation of 3-monochloropropane-1,2 diol (3-MCPD) esters were examined in this study. Inhibitory capacities of the antioxidants were investigated both in chemical models containing the precursors (tripalmitoyl glycerol, 1,2-dipalmitoyl-sn-glycerol, monopalmitoyl glycerol, and sodium chloride) of 3-MCPD esters and in oil models (rapeseed oil and sodium chloride). Six antioxidants, butylated hydroxytoluene (BHT), butylated hydroxy anisole (BHA), tert-butyl hydroquinone (TBHQ), propyl gallate (PG), L-ascorbyl palmitate (AP), and α-tocopherol (VE), were found to exhibit inhibiting capacities on 3-MCPD ester formation both in chemical models and in oil models. TBHQ provided the highest inhibitory capacity both in chemical models and in oil models; 44% of 3-MCPD ester formation was inhibited in the presence of TBHQ (66 mg/kg of oil) after heating of rapeseed oil at 230 °C for 30 min, followed by PG and AP. BHT, BHA, and VE appeared to have weaker inhibitory abilities in both models. VE exhibited the lowest inhibition rate; 22% of 3-MCPD esters were inhibited in the presence of VE (172 mg/kg of oil) after heating of rapeseed oil at 230 °C for 30 min. In addition, the inhibition rates of PG and VE decreased dramatically with an increase in temperature or heating time. The results suggested that some antioxidants, such as TBHQ, PG, and AP, could be the potential inhibitors of 3-MCPD esters in practice. PMID:26478126

  8. Enzymatic synthesis of lipophilic rutin and vanillyl esters from fish byproducts.

    Science.gov (United States)

    Mbatia, Betty; Kaki, Shiva Shanker; Mattiasson, Bo; Mulaa, Francis; Adlercreutz, Patrick

    2011-07-13

    Lipase-catalyzed synthesis of lipophilic phenolic antioxidants was carried out with a concentrate of n-3 polyunsaturated fatty acids (PUFAs), recovered from oil extracted from salmon ( Salmon salar ) byproduct. Vanillyl alcohol and rutin were selected for the esterification reaction, and obtained esters yields were 60 and 30%, respectively. The antioxidant activities of the esters were compared with those of commercial butylated hydroxytoluene (BHT) and α-tocopherol using DPPH radical scavenging and thiobarbituric acid assays. In the DPPH assay, rutin esters showed better activity than vanillyl esters, and on the contrary in lipophilic medium, vanillyl esters were found to be superior to rutin esters. In bulk oil system, the antioxidant activities of rutin and vanillyl derivatives were lower than that of BHT and α-tocopherol, but in emulsion, they showed better activity than α-tocopherol. By attaching to natural phenolics, the PUFAs are protected against oxidation, and PUFA improves the hydrophobicity of the phenolic, which could enhance its function in lipid systems. PMID:21630661

  9. Interaction of ester functional groups with aluminum oxide surfaces studied using infrared reflection absorption spectroscopy.

    Science.gov (United States)

    van den Brand, J; Blajiev, O; Beentjes, P C J; Terryn, H; de Wit, J H W

    2004-07-20

    The bonding of two types of ester group-containing molecules with a set of different oxide layers on aluminum has been investigated using infrared reflection absorption spectroscopy. The different oxide layers were made by giving typical surface treatments to the aluminum substrate. The purpose of the investigation was to find out what type of ester-oxide bond is formed and whether this is influenced by changes in the composition and chemistry of the oxide. The extent by which these bonded ester molecules resisted disbondment in water or substitution by molecules capable of chemisorption was also investigated. The ester groups were found to show hydrogen bonding with hydroxyls on the oxide surfaces through their carbonyl oxygens. For all oxides, the ester groups showed the same nu(C = O) carbonyl stretching vibration after adsorption, indicating very similar bonding occurs. However, the oxides showed differences in the amount of molecules bonded to the oxide surface, and a clear relation was observed with the hydroxyl concentration present on the oxide surface, which was determined from XPS measurements. The two compounds showed differences in the free to bonded nu(C = O) infrared peak shift, indicating differences in bonding strength with the oxide surface between the two types of molecules. The bonding of the ester groups with the oxide surfaces was found to be not stable in the presence of water and also not in the presence of a compound capable of chemisorption with the aluminum oxide surface. PMID:15248718

  10. Study of vanadium (5) interaction with Meerwein ester in aqueous-ethanolic medium

    International Nuclear Information System (INIS)

    Interaction of V(5) aqueous solutions with Meerwein ester ethanolic solutions (tetramethyl ester of bicyclo[3.3.1]-nonane-2,6-dione-1,3,5,7-tetracarboxylic acid) has been studied. The investigation of the structure of Meerwein ester and the complex formed by this ester as a result of interaction has been carried out by the NMR spectroscopy. It is established that in solutions with the concentration of V(5)C-3 mol/l in the pH region from 0 to 3 the monomeric ions of VO2+ form with ester molecules a positively charged complex due to methoxycarboxylic groups in positions 1 or 5. In solutions with V(5) concentration c > 1x10-2 mol/l in the pH region from 0to 2 a polynuclear complex being extracted by nonpolar solvent is formed. The Meerwein ester is a polydentate bridge ligand and is coordinated by molecules of the decavanadic acid due to methoxycarbonyl groups in positions 3,7 and 1 or 5

  11. Tricarballylic ester formation during biosynthesis of fumonisin mycotoxins in Fusarium verticillioides.

    Science.gov (United States)

    Lia, Yaoyao; Lou, Lili; Cerny, Ronald L; Butchko, Robert A E; Proctor, Robert H; Shen, Yuemao; Du, Liangcheng

    2013-12-01

    Fumonisins are agriculturally important mycotoxins produced by the maize pathogen Fusarium verticillioides. The chemical structure of fumonisins contains two tricarballylic esters, which are rare structural moieties and important for toxicity. The mechanism for the tricarballylic ester formation is not well understood. FUM7 gene of F. verticillioides was predicted to encode a dehydrogenase/reductase, and when it was deleted, the mutant produced tetradehydro fumonisins (DH4-FB). MS and NMR analysis of DH4-FB1 indicated that the esters consist of aconitate with a 3'-alkene function, rather than a 2'-alkene function. Interestingly, the purified DH4-FB1 eventually yielded three chromatographic peaks in HPLC. However, MS revealed that the metabolites of the three peaks all had the same mass as the initial single-peak DH4-FB1. The results suggest that DH4-FB1 can undergo spontaneous isomerization, probably including both cis-trans stereoisomerization and 3'- to 2'-ene regioisomerization. In addition, when FUM7 was expressed in Escherichia coli and the resulting enzyme, Fum7p, was incubated with DH4-FB, no fumonisin with typical tricarballylic esters was formed. Instead, new fumonisin analogs that probably contained isocitrate and/or oxalosuccinate esters were formed, which reveals new insight into fumonisin biosynthesis. Together, the data provided both genetic and biochemical evidence for the mechanism of tricarballylic ester formation in fumonisin biosynthesis. PMID:24587959

  12. Glutathione isopropyl ester reduces UVB-induced skin damage in hairless mice

    International Nuclear Information System (INIS)

    The protective effect of administration of glutathione (GSH) isopropyl ester on photodamage, such as lipid peroxidation, inflammation and tumorigenesis induced by UV exposure (290-400 nm, max. 312 nm), was investigated using hairless mice. Pretreatment with 20 mg/kg GSH isopropyl ester prevented the increases of thiobarbituric acid-reactive substance (TBARS) formation in skin and serum sialic acid, indices of lipid peroxidation and inflammatory reaction, respectively, which were caused by a single dose (15kJ/m2) of UV irradiation. The level of epidermal GSH in skins of the GSH ester-treated mice was maintained within normal limits. When mice were exposed to UV at a dose of 2 kJ/m2, three times weekly, skin tumors developed in all of them after 25 weeks. The formation of skin tumors was significantly inhibited by administration of 10 mg/kg GSH ester prior to each UV irradiation for 25 weeks. Moreover, the increases of cutaneous TBARS and serum sialic acid in the tumor-bearing mice were also prevented by continuous pretreatment with GSH ester. Even after 24 weeks, the epidermal GSH content of the pretreated mice was mostly retained compared to nonirradiated mice. However, administration of GSH prior to acute or chronic UV irradiation had no effect on the UV-induced damage. The present results suggest that the protection from photodamage afforded by pretreatment with GSH ester is due to maintenance of a normal GSH level. (Author)

  13. Depigmenting Effect of Kojic Acid Esters in Hyperpigmented B16F1 Melanoma Cells

    Directory of Open Access Journals (Sweden)

    Ahmad Firdaus B. Lajis

    2012-01-01

    Full Text Available The depigmenting effect of kojic acid esters synthesized by the esterification of kojic acid using Rhizomucor miehei immobilized lipase was investigated in B16F1 melanoma cells. The depigmenting effect of kojic acid and kojic acid esters was evaluated by the inhibitory effect of melanin formation and tyrosinase activity on alpha-stimulating hormone- (α-MSH- induced melanin synthesis in B16F1 melanoma cells. The cellular tyrosinase inhibitory effect of kojic acid monooleate, kojic acid monolaurate, and kojic acid monopalmitate was found similar to kojic acid at nontoxic doses ranging from 1.95 to 62.5 μg/mL. However, kojic acid monopalmitate gave slightly higher inhibition to melanin formation compared to other inhibitors at doses ranging from 15.63 to 62.5 μg/mL. Kojic acid and kojic acid esters also show antioxidant activity that will enhance the depigmenting effect. The cytotoxicity of kojic acid esters in B16F1 melanoma cells was significantly lower than kojic acid at high doses, ranging from 125 and 500 μg/mL. Since kojic acid esters have lower cytotoxic effect than kojic acid, it is suggested that kojic acid esters can be used as alternatives for a safe skin whitening agent and potential depigmenting agents to treat hyperpigmentation.

  14. Synthesis and Biological Evaluation of Liguzinediol Mono- and Dual Ester Prodrugs as Promising Inotropic Agents

    Directory of Open Access Journals (Sweden)

    Jing Zhang

    2014-11-01

    Full Text Available The potent positive inotropic effect, together with the relatively low safety risk of liguzinediol (LZDO, relative to currently available inotropic drugs, has prompted us to intensively research and develop LZDO as a potent positive inotropic agent. In this study, to obtain LZDO alternatives for oral chronic administration, a series of long-chain fatty carboxylic mono- and dual-esters of LZDO were synthesized, and preliminarily evaluated for physicochemical properties and bioconversion. Enhanced lipophilic properties and decreased solubility of the prodrugs were observed as the side chain length increased. All esters showed conspicuous chemical stability in phosphate buffer (pH 7.4. Moreover, the enzymatic hydrolysis of esters in human plasma and human liver microsomes confirmed that the majority of esters were converted to LZDO, with release profiles that varied due to the size and structure of the side chain. In vivo pharmacokinetic studies following oral administration of monopivaloyl (M5, monodecyl (M10 and monododecyl (M12 esters demonstrated the evidently extended half-lives relative to LZDO dosed alone. In particular the monopivaloyl ester M5 exhibited an optimal pharmacokinetic profile with appropriate physiochemical characteristics.

  15. Thermal Decomposition of Methyl Esters in Biodiesel Fuel: Kinetics, Mechanisms and Products

    Science.gov (United States)

    Chai, Ming

    Biodiesel continues to enjoy increasing popularity. However, recent studies on carbonyl compounds emissions from biodiesel fuel are inconclusive. Emissions of carbonyl compounds from petroleum diesel fuels were compared to emissions from pure biodiesel fuels and petroleum-biodiesel blends used in a non-road diesel generator. The concentration of total carbonyl compounds was the highest when the engine was idling. The carbonyl emissions, as well as ozone formation potential, from biodiesel fuel blends were higher than those emitted from petroleum diesel fuel. The sulfur content of diesel fuel and the source of biodiesel fuel were not found to have a significant impact on emissions of carbonyl compounds. Mechanism parameters of the thermal decomposition of biodiesel-range methyl esters were obtained from the results of thermal gravimetric analysis (TGA). The overall reaction orders are between 0.49 and 0.71 and the energies of activation are between 59.9 and 101.3 kJ/mole. Methyl esters in air have lower activation energies than those in nitrogen. Methyl linoleate has the lowest activation energy, followed by methyl oleate, and methyl stearate. The pyrolysis and oxidation of the three methyl esters were investigated using a semi-isothermal tubular flow reactor. The profiles of major products versus reaction temperature are presented. In the pyrolysis of methyl stearate, the primary reaction pathway is the decarboxylic reaction at the methyl ester functional group. Methyl oleate's products indicate more reactions on its carbon-carbon double bond. Methyl linoleate shows highest reactivity among the three methyl esters, and 87 products were detected. The oxidation of three methyl esters resulted in more products in all compound classes, and 55, 114, and 127 products were detected, respectively. The oxidation of methyl esters includes decarboxylation on ester group. The methyl ester's carbon chain could be oxidized as a hydrocarbon compound and form oxidized esters and

  16. Phorbol ester stimulates calcium sequestration in saponized human platelets

    International Nuclear Information System (INIS)

    When platelets are activated by agonists, calcium (Ca2+) is released from an intracellular storage site. Recent studies using fura-2 show that, after thrombin stimulation, the rise in free calcium is transient and returns to base-line levels in 2-3 min, while the transient following ADP stimulation lasts only 15-20 s. We reported previously that the phorbol ester 12,13-phorbol myristate acetate (PMA), added at nanomolar levels after thrombin, immediately accelerated the rate of return of calcium to the base line severalfold. In the present study, we used both intact and saponized platelets to determine whether this is due to stimulation of calcium sequestration. Using fura-2 and intact platelets, we found 1) that PMA stimulated the restoration of free Ca2+ levels after ADP as well as after thrombin, and 2) that H-7, an inhibitor of protein kinase C (Ca2+/phospholipid-dependent enzyme), slowed the return of Ca2+ to baseline levels. Using saponized platelets, we also found 3) that pretreatment of platelets with PMA before saponin treatment increased the ATP-dependent 45Ca2+ uptake 2-fold, with a half-maximal effect at 5 nm; 4) that most of the Ca2+ released by ionomycin or by myoinositol 1,4,5-trisphosphate; and 5) that a GTP-binding protein inhibitor, guanosine 5'-O-(2-thiodiphosphate), decreased basal or PMA-stimulated 45Ca2+ uptake in saponin-treated platelets. Our data suggest that activation of protein kinase C stimulates the sequestration of Ca2+ independently of cAMP or myoinositol 1,4,5-trisphosphate

  17. Pemisahan dan Pemurnian Phthalic Acid Ester dari Minyak Nyamplung

    Directory of Open Access Journals (Sweden)

    William Ekaputra Taifan

    2013-09-01

    Full Text Available Minyak nyamplung dikenal sebagai minyak yang tidak dapat dikonsumsi. Oleh sebab itu, penelitian tentang minyak ini hanya fokus pada konversi minyak menjadi biodiesel. Pada penelitian ini, kami berusaha untuk memisahkan resin beracun dari fraksi metanol menggunakan ekstraksi pelarut diikuti kolom kromatografi. Resin beracun ini diidentifikasi sebagai phthalic acid ester (PAE. PAE ini biasanya digunakan sebagai zat aditif di industri polimer. Minyak nyamplung mengandung 1,8% PAE, yang masih jauh melebihi nilai ambang batas. Isolasi PAE dari minyak ini diharapkan dapt mengubah minyak yang tidak dapat dikonsumsi menjadi suplemen makanan yang bernilai. Proses isolasi PAE dimulai dengan memisahkan senyawa yang diinginkan dari lipid menggunakan ekstraksi pelarut bertingkat dengan metanol dan n-heksan. Analisa mass spectra dari fraksi pertama dan fraksi kedua metanol menunjukkan kandungan PAE sebesar 60% dan 6% pada tiap fraksi. Fraksi heksan tidak mengandung PAE. PAE yang terkandung pada fraksi metanol diisolasi lebih lanjut dari asam lemak menggunakan liquid column chromatography dengan n-heksan – etil asetat sebagai mobile phase. Bis- 2ethylhexyl phthalate diidentifikasi pada ketiga fraksi sesuai dengan hasil analisa GC-MS. Fraksi pertama diambil pada kondisi mobile phase 5% etil asetat, sedangkan fraksi kedua merupakan campuran 5% etil asetat dan 10% etil asetat. Fraksi ketiga diambil pada kondisi mobile phase 10% etil asetat mengandung PAE sebesar 98%. Fraksi keempat merupakan campuran 10% dan 15% mobile phase dan mengandung PAE sebesar 97%. Akhirnya, kandungan PAE pada fraksi metanol sebesar 58%. Dari hasil analisa, dapat disimpulkan bahwa mobile phase yang optimum untuk kromatografi adalah 10- 15% etil asetat dalam n-heksan.

  18. Phorbol ester stimulates calcium sequestration in saponized human platelets

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, K.; Nachmias, V.T.

    1987-11-25

    When platelets are activated by agonists, calcium (Ca2+) is released from an intracellular storage site. Recent studies using fura-2 show that, after thrombin stimulation, the rise in free calcium is transient and returns to base-line levels in 2-3 min, while the transient following ADP stimulation lasts only 15-20 s. We reported previously that the phorbol ester 12,13-phorbol myristate acetate (PMA), added at nanomolar levels after thrombin, immediately accelerated the rate of return of calcium to the base line severalfold. In the present study, we used both intact and saponized platelets to determine whether this is due to stimulation of calcium sequestration. Using fura-2 and intact platelets, we found 1) that PMA stimulated the restoration of free Ca2+ levels after ADP as well as after thrombin, and 2) that H-7, an inhibitor of protein kinase C (Ca2+/phospholipid-dependent enzyme), slowed the return of Ca2+ to baseline levels. Using saponized platelets, we also found 3) that pretreatment of platelets with PMA before saponin treatment increased the ATP-dependent /sup 45/Ca2+ uptake 2-fold, with a half-maximal effect at 5 nm; 4) that most of the Ca2+ released by ionomycin or by myoinositol 1,4,5-trisphosphate; and 5) that a GTP-binding protein inhibitor, guanosine 5'-O-(2-thiodiphosphate), decreased basal or PMA-stimulated /sup 45/Ca2+ uptake in saponin-treated platelets. Our data suggest that activation of protein kinase C stimulates the sequestration of Ca2+ independently of cAMP or myoinositol 1,4,5-trisphosphate.

  19. A comparative estimation of C.I. engine fuelled with methyl esters of punnai, neem and waste cooking oil

    Directory of Open Access Journals (Sweden)

    D. Subramaniam, A. Murugesan, A. Avinashy

    2013-01-01

    Full Text Available In this experimental study, performance, emission, and combustion characteristics of methyl esters of Punnai, Neem, Waste Cooking Oil and their diesel blends in a C.I. engine was experimentally examined. For the study, Punnai oil methyl esters (POME, neem oil methyl esters (NOME, and Waste Cooking Oil Methyl Esters (WCOME were prepared by tranesterification process. The Bio diesel-diesel blends were prepared by mixing 10%, 30%, 50%, and 70% of bio diesel with diesel. The effects of three methyl esters and their diesel blends on engine performance, combustion, and exhaust emissions were examined at different engine loads. Experimental results concluded that up to 30% of methyl esters did not affect the performance, combustion, and emissions characteristics. On the other hand, above B30 (30% Bio diesel with 70% diesel a reduction in performance, combustion, and emission characteristics were clear from the study.

  20. A comparative estimation of C.I. engine fuelled with methyl esters of punnai, neem and waste cooking oil

    Energy Technology Data Exchange (ETDEWEB)

    Subramaniam, D.; Avinash, A. [Department of Mechanical Engineering - K.S.Rangasamy College of Technology –Tiruchengode, 637215 Tamil Nadu (India); Murugesan, A. [Department of Mechatronics Engineering - K.S.Rangasamy College of Technology – Tiruchengode, 637215 Tamil Nadu (India)

    2013-07-01

    In this experimental study, performance, emission, and combustion characteristics of methyl esters of Punnai, Neem, Waste Cooking Oil and their diesel blends in a C.I. engine was experimentally examined. For the study, Punnai oil methyl esters (POME), neem oil methyl esters (NOME), and Waste Cooking Oil Methyl Esters (WCOME) were prepared by tranesterification process. The Bio diesel-diesel blends were prepared by mixing 10%, 30%, 50%, and 70% of bio diesel with diesel. The effects of three methyl esters and their diesel blends on engine performance, combustion, and exhaust emissions were examined at different engine loads. Experimental results concluded that up to 30% of methyl esters did not affect the performance, combustion, and emissions characteristics. On the other hand, above B30 (30% Bio diesel with 70% diesel) a reduction in performance, combustion, and emission characteristics were clear from the study.

  1. Method for the determination of natural ester-type gum bases used as food additives via direct analysis of their constituent wax esters using high-temperature GC/MS

    OpenAIRE

    Tada, Atsuko; Ishizuki, Kyoko; Yamazaki, Takeshi; Sugimoto, Naoki; Akiyama, Hiroshi

    2014-01-01

    Natural ester-type gum bases, which are used worldwide as food additives, mainly consist of wax esters composed of long-chain fatty acids and long-chain fatty alcohols. There are many varieties of ester-type gum bases, and thus a useful method for their discrimination is needed in order to establish official specifications and manage their quality control. Herein is reported a rapid and simple method for the analysis of different ester-type gum bases used as food additives by high-temperature...

  2. Method for the determination of natural ester-type gum bases used as food additives via direct analysis of their constituent wax esters using high-temperature GC/MS.

    Science.gov (United States)

    Tada, Atsuko; Ishizuki, Kyoko; Yamazaki, Takeshi; Sugimoto, Naoki; Akiyama, Hiroshi

    2014-07-01

    Natural ester-type gum bases, which are used worldwide as food additives, mainly consist of wax esters composed of long-chain fatty acids and long-chain fatty alcohols. There are many varieties of ester-type gum bases, and thus a useful method for their discrimination is needed in order to establish official specifications and manage their quality control. Herein is reported a rapid and simple method for the analysis of different ester-type gum bases used as food additives by high-temperature gas chromatography/mass spectrometry (GC/MS). With this method, the constituent wax esters in ester-type gum bases can be detected without hydrolysis and derivatization. The method was applied to the determination of 10 types of gum bases, including beeswax, carnauba wax, lanolin, and jojoba wax, and it was demonstrated that the gum bases derived from identical origins have specific and characteristic total ion chromatogram (TIC) patterns and ester compositions. Food additive gum bases were thus distinguished from one another based on their TIC patterns and then more clearly discriminated using simultaneous monitoring of the fragment ions corresponding to the fatty acid moieties of the individual molecular species of the wax esters. This direct high-temperature GC/MS method was shown to be very useful for the rapid and simple discrimination of varieties of ester-type gum bases used as food additives. PMID:25473499

  3. Phosphatidylinositol 4,5-bisphosphate competitively inhibits phorbol ester binding to protein kinase C

    International Nuclear Information System (INIS)

    Calcium phospholipid dependent protein kinase C (PKC) is activated by diacylglycerol (DG) and by phorbol esters and is recognized to be the phorbol ester receptor of cells; DG displaces phorbol ester competitively from PKC. A phospholipid, phosphatidylinositol 4,5-bisphosphate (PIP2), can also activate PKC in the presence of phosphatidylserine (PS) and Ca2+ with a KPIP2 of 0.04 mol %. Preliminary experiments have suggested a common binding site for PIP2 and DG on PKC. Here, the authors investigate the effect of PIP2 on phorbol ester binding to PKC in a mixed micellar assay. In the presence of 20 mol % PS, PIP2 inhibited specific binding of [3H]phorbol 12,13-dibutyrate (PDBu) in a dose-dependent fashion up to 85% at 1 mol %. Inhibition of binding was more pronounced with PIP2 than with DG. Scatchard analysis indicated that the decrease in binding of PDBu in the presence of PIP2 is the result of an altered affinity for the phorbol ester rather than of a change in maximal binding. The plot of apparent dissociation constants (Kd') against PIP2 concentration was linear over a range of 0.01-1 mol % with a Ki of 0.043 mol % and confirmed the competitive nature of inhibition between PDBu and PIP2. Competition between PIP2 and phorbol ester could be determined in a liposomal assay system also. These results indicate that PIP2, DG, and phorbol ester all compete for the same activator-receiving region on the regulatory moiety of protein kinase C, and they lend support to the suggestion that PIP2 is a primary activator of the enzyme

  4. Enzymatic Synthesis of Palm Alkyl Ester Using Dialkyl Carbonate as an Alkyl Donors

    Directory of Open Access Journals (Sweden)

    Roila Awang

    2010-01-01

    Full Text Available Problem statement: Though efficient in terms of reaction yield and time, the chemical approach to synthesizing alkyl ester has drawback such as difficulties in the recovery of glycerol and the need for removal of salt residue. On the other hand, biocatalyst allow for synthesis of specific alkyl esters and easy recovery of glycerol. However, the solvent-free alcoholysis, does not give high conversion. The same problem was also found when ethyl or methyl acetate was used as acyl acceptors. Approach: Lipase catalyzed transesterification of oil and dialkyl carbonate was predicted to give higher conversion in solvent free reaction system. Results: Alkyl esters were synthesized enzymatically to overcome the problems associated with chemical processes. In this study, dialkyl carbonates were used as an alkyl donor for the production of alkyl ester. Nine commercial lipases were tested for their suitability for the reaction system. Among the lipase tested, Novozym 435 was chosen for optimization study because of their higher activity. In a solvent-free reaction system, the ester formation using dialkyl carbonate was 6 times higher than using ethanol and methanol. The effect of various reaction parameters such as temperature, amount of enzyme, organic solvent and structure of substrates were studied to determine optimal condition. The optimal conditions of ester formation were reaction temperature at 60°C, reaction time at 8 h, enzyme amount of 10% (w/w of oil and 0.2% wt added water. Conclusion: Solvent-free lipase catalyzed transesterification of palm kernel oil and dialkyl carbonates gave higher conversion of ester compared to the reaction using short chain alcohol as an alkyl donors.

  5. Curing reaction of bisphenol-A based benzoxazine with cyanate ester resin and the properties of the cured thermosetting resin

    OpenAIRE

    Kimura, H.; Ohtsuka, K.; Matsumoto, A

    2011-01-01

    Curing reaction of bisphenol-A based benzoxazine with cyanate ester resin and the properties of the cured thermosetting resin were investigated. The cure behavior of benzoxazine with cyanate ester resin was monitored by model reaction using nuclear magnetic resonance (NMR). As a result of the model reaction, the ring opening reaction of benzoxazine ring and thermal self-cyclotrimerization of cyanate ester group occurred, and then the phenolic hydoroxyl group generated by the ring opening reac...

  6. Study of Pseudoternary Phase Diagram Behaviour and the Effect of Several Tweens and Spans on Palm Oil Esters Characteristics

    OpenAIRE

    Abdulkarim, Muthanna F; Ghassan Z Abdullah; M.H.F. Sakeena; Mallikarjun Chitneni; Mun F. Yam; Elrashid S. Mahdi; Salman, Ibrahim M.; Ameer, Omar Z.; Munavvar A. Sattar; Mahiran Basri; Azmin M. Noor

    2011-01-01

    Palm oil esters are high molecular weight esters oil that has been newly synthesized by University Putra Malaysia researchers. It has received a lot of attention for its pharmaceutical and chemical application. The aim of this study is to study the effects of the palm oil esters with different HLB surfactant mixture on the ternary diagrams behaviour and to confine the various systems resulted from these combinations. These systems include traditional emulsion, gel area, transpernat m...

  7. Study of Pseudoternary Phase Diagram Behaviour and the Effect of Several Tweens and Spans on Palm Oil Esters Characteristics

    OpenAIRE

    Abdulkarim, Muthanna F; Ghassan Z Abdullah; M.H.F. Sakeena; Mallikarjun Chitneni; Mun F. Yam; Elrashid S. Mahdi; Salman, Ibrahim M.; Ameer, Omar Z.; Munavvar A. Sattar; Mahiran Basri; Azmin M. Noor

    2011-01-01

    Palm oil esters are high molecular weight esters oil that has been newly synthesized by University Putra Malaysia researchers. It has received a lot of attention for its pharmaceutical and chemical application. The aim of this study is to study the effects of the palm oil esters with different HLB surfactant mixture on the ternary diagrams behaviour and to confine the various systems resulted from these combinations. These systems include traditional emulsion, gel area, transpernat micro-emul...

  8. Detectability of testosterone esters and estradiol benzoate in bovine hair and plasma following pour-on treatment

    OpenAIRE

    Stolker, A. A. M.; Groot, M.J.; Lasaroms, J. J. P.; Nijrolder, A.W.J.M.; Blokland, M.H.; Riedmaier, I.; Becker, C.; Meyer, H.H.D.; Nielen, M. W. F.

    2009-01-01

    The abuse of synthetic esters of natural steroids such as testosterone and estradiol in cattle fattening and sports is hard to detect via routine urine testing. The esters are rapidly hydrolysed in vivo into substances which are also endogenously present in urine. An interesting alternative can be provided by the analysis of the administered synthetic steroids themselves, i.e., the analysis of intact steroid esters in hair by liquid chromatography tandem mass spectrometry (LC/MS/MS). However,...

  9. Les esters de sucres : voies de synthèse et potentialités d'utilisation

    OpenAIRE

    Blecker C.; Deroanne C.; Piccicuto S.; Brohee J.C.; Mbampara A.; Lognay G.; Paquot M.; Marlier M.

    2001-01-01

    Sugar esters : ways of synthesis and potential applications [a review]. Sugar esters are nonionic surfactants and exhibit relevant properties as structural diversity and environmental and health safety. Their potential applications extend from human food to drugs formulation and biochemical studies. Some sugar esters also exhibit interesting biological activities. A lot of papers have been submitted during the last ten years. Those articles describe the various ways of synthesis of those comp...

  10. Examination of the Aging Properties of Novel Cyanate Ester Thermosets and the Subsequent Evaluation of the Material under Application Conditions

    OpenAIRE

    Hahn, Daniel Robert

    2004-01-01

    (ABSTRACT) Cyanate ester thermosetting resins are a novel family of materials for high technology and aerospace applications. The high glass transition temperatures available from cured cyanate ester networks and subsequently, their resistances to corrosive materials make these resins attractive for harsh environmental applications. These features of cyanate ester resins presented a threefold opportunity for investigation, namely: 1) establish a characterization technique for the long te...

  11. PREPARATION AND REACTIVITY OF FUNCTIONALISED BORONIC ESTERS FROM 4,4,6- TRIMETHYL-1,3,2-DIOXABORINANE

    OpenAIRE

    Praveenganesh, Nageswaran

    2008-01-01

    In the course of our studies on the vinylation of nitrones, we had found that vinylboronic esters, in the presence of dialkylzincs, could transfer their vinylic chain onto nitrones. We had developed this method with pinacol esters, since these reagents offer two important advantages: they are very easily accessible by hydroboration of 1-alkynes, and they are air- and water- stable, thus can be purified and stored.But we also found that these pinacolboronic esters were poorly reactive. We coul...

  12. Engineering of chromosomal wax ester synthase integrated Saccharomyces cerevisiae mutants for improved biosynthesis of fatty acid ethyl esters.

    Science.gov (United States)

    Shi, Shuobo; Valle-Rodríguez, Juan Octavio; Siewers, Verena; Nielsen, Jens

    2014-09-01

    In recent years, significant advances have been made to engineer robust microbes for overproducing biochemical products from renewable resources. These accomplishments have to a large extend been based on plasmid based methods. However, plasmid maintenance may cause a metabolic burden on the host cell and plasmid-based overexpression of genes can result in genetically unstable strains, which contributes to loss in productivity. Here, a chromosome engineering method based on delta integration was applied in Saccharomyces cerevisiae for the production of fatty acid ethyl esters (FAEEs), which can be directly used as biodiesel and would be a possible substitute for conventional petroleum-based diesel. An integration construct was designed and integrated into chromosomal delta sequences by repetitive transformation, which resulted in 1-6 copies of the integration construct per genome. The corresponding FAEE production increased up to 34 mg/L, which is an about sixfold increase compared to the equivalent plasmid-based producer. The integrated cassette in the yeast genome was stably maintained in nonselective medium after deletion of RAD52 which is essential for efficient homologous recombination. To obtain a further increase of FAEE production, genes encoding endogenous acyl-CoA binding protein (ACB1) and a bacterial NADP(+)-dependent glyceraldehyde-3-phosphate dehydrogenase (gapN) were overexpressed in the final integration strain, which resulted in another 40% percent increase in FAEE production. Our integration strategy enables easy engineering of strains with adjustable gene copy numbers integrated into the genome and this allows for an easy evaluation of the effect of the gene copy number on pathway flux. It therefore represents a valuable tool for introducing and expressing a heterologous pathway in yeast. PMID:24752598

  13. Determination of 4-Chloroindole-3-Acetic Acid Methyl Ester in Lathyrus Vicia and Pisum by Gas Chromatography - Mass Spectrometry

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen; Egsgaard, Helge; Larsen, Elfinn

    1980-01-01

    4-Chloroindole-3-acetic acid methyl ester was identified unequivocally in Lathyrus latifolius L., Vicia faba L. and Pisum sativum L. by thin layer chromatography, gas chromatography and mass spectrometry. The gas chromatographic system was able to separate underivatized chloroindole-3-acetic acid...... methyl ester isomers. The quantitative determination of 4-chloroindole-3-acetic acid methyl ester in immature seeds of these three species was performed by gas chromatography – mass spectrometry using deuterium labelled 4-chloro-indole-3-acetic acid methyl ester as an internal standard. P. sativum...

  14. Discovery of mass spectral characteristics and automatic identification of wax esters from gas chromatography mass spectrometry data.

    Science.gov (United States)

    Zhang, Liang-xiao; Yun, Yi-feng; Liang, Yi-zeng; Cao, Dong-sheng

    2010-06-01

    The mass spectral characteristics of wax esters were systemically summarized and interpreted through data mining of their standard mass spectra taken from NIST standard mass spectral library. Combining with the rules of retention indices described in the previous study, an automatic system was subsequently developed to identify the structural information for wax esters from GC/MS data. After tested and illustrated by both simulated and real GC/MS data, the results indicate that this system could identify wax esters except the polyunsaturated ones and the mass spectral characteristics are useful and effective information for identification of wax esters. PMID:20417935

  15. Lubricants on the basis of synthetic esters. Part 3 - Ester oils for carbon dioxide refrigerators and air conditioning systems; Schmierstoffe auf Basis synthetischer Ester. Teil 3 - Esteroele fuer CO{sub 2}-Kaelte- und Klimasysteme

    Energy Technology Data Exchange (ETDEWEB)

    Fahl, J. [FUCHS DEA Schmierstoffe GmbH und Co. KG (Germany). Betrieb Hamburg

    2000-11-01

    In carbon dioxide refrigerators, the lubricating oil is subject to extreme mechanical and thermal loads, especially in transcritical operation. Polyalcohol esters mix with carbon dioxide and have an extremely high stability. However, their high solubility will result in a dramatic reduction of viscosity, and technical problems may occur in the lubricating process. The investigation focused on the development of ester oils with certain physical and fluid-dynamic characteristics when mixed with carbon dioxide. [German] In Kaelteanlagen, die mit dem Arbeitsstoff Kohlendioxid betrieben werden, unterliegt das Schmieroel extrem mechanischen und thermischen Belastungen, dies gilt insbesondere fuer die transkritische Betriebsweise. Polyolesteroele sind mit CO{sub 2} mischbar und zeichnen sich durch ihre ausserordentlich hohe Stabilitaet aus. Aufgrund der starken Loeslichkeit kommt es jedoch zu einer drastischen Viskositaetsabsenkung und es koennen ausserdem schmierungstechnische Probleme auftreten. Ziel der Arbeit war, Esteroele zu entwickeln, die bestimmte physikalische und fluiddynamische Eigenschaften mit Kohlendioxid aufweisen. (orig.)

  16. Toxicokinetics, recovery, and metabolism of triclopyr butotyl (ACTP) ester in goats.

    Science.gov (United States)

    Sar, Tapas K; Bagchi, Biplab; Das, Shyamal K; Mandal, Tapan K; Chakraborty, Animesh K; Bhattacharyya, Anjan; Choudhury, Ashim

    2002-07-17

    Toxicokinetic behavior, recovery, and metabolism studies of ACTP ester and its effect on cytochrome P(450) content of liver microsomal pellet were carried out in black Bengal goat after a single intravenous administration of 11.88 mg kg(-1) and consecutive oral administration of 79.22 mg kg(-1) for 7 days. ACTP ester achieved a maximum blood concentration of 42.64 +/- 4.26 microg mL(-1) at 0.08 h after intravenous administration followed by a sharp decline until 0.5 h, and the minimum blood concentration was recorded at 36 h (1.93 +/- 0.14 microg mL(-1)) postdosing. The kinetic behavior of ACTP ester followed a "two-compartment open model". Comparatively shorter alpha (0.81 +/- 0.02 h(-1)) and greater t1/2 (alpha) (0.86 +/- 0.03 h) indicated a slower rate of distribution of ACTP ester in goat. The t1/2(beta)()) (14.83 +/- 1.49 h) and V(d(area)) (0.91 +/- 0.19 L kg(-1)) suggested a longer elimination phase with general distribution in all compartments of the body. The higher T/B and K12/K21 values associated with a lower f(c) value suggested longer persistence in the tissue compartment at higher concentration. The higher Cl(R) compared to Cl(H) indicated the major amount was eliminated by the kidney. Maximum concentration of ACTP ester including its metabolites, triclopyr acid and trichloropyridinol, was excreted through urine at 48 h. The recovery of ACTP ester including metabolites after repeated nontoxic oral dose administration was 70.09%, of which recovery from feces was 4.45%, suggesting the major portion of administered ACTP ester was absorbed through the gastrointestinal tract of the goat. All of the tissues contained ACTP ester and its metabolites. ACTP ester did not alter the cytochrome P(450) content of the liver tissue following repeated nontoxic oral dose administration for 7 days. PMID:12105946

  17. Synthesis and intrinsic blue fluorescence study of hyperbranched poly(ester-amide-ether)

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A series of hyperbranched poly(ester-amide-ether)s (H-PEAEs) were synthesized via the A2+CB3 approach by the self-transesterification of ethyl ester-amide-ethers end-capped with three hydroxyl groups and ethyl ester group at two terminals.The molecular structures were characterized with 1H NMR and FT-IR spectroscopy.The number average molecular weights were estimated by GPC analysis to possess bimodal wide distribution from 1.57 to 2.09.The strong inherent blue fluorescence was observed at 330 nm for excitation and 390 nm for emission.Moreover,the emission intensity and fluorescence quantum yield increased along with the incorporated ether chain length,as well as almost linearly with the H-PEAE concentration in an aqueous solution.For comparing the fluorescence performance,the linear poly(ester-amide-ether) (L-PEAE) and hyperbranched poly(ester-amide) (H-PEA) were synthesized.The results showed that the coexistence of ether bond and carboxyl group in the molecular chain was essential for generating the strong fluorescence.However,the compact backbone of H-PEAE would be propitious to the enhancement of fluorescence properties.

  18. Gamma irradiation effects on cyanate ester/epoxy insulation materials for superconducting magnets

    International Nuclear Information System (INIS)

    Highlights: • Irradiation resistance of glass fiber reinforced cyanate ester/epoxy composite was investigated. • The cyanate ester/epoxy resin system has a low viscosity and long pot life. • The Tg of the matrix resin decreased slightly with the increase of irradiation dose. • The ILSS of GFRP composite increased slightly when exposed to 10 MGy of gamma irradiation. - Abstract: Cyanate ester/epoxy resin was used as a cryogenic-grade polymer matrix and glass fiber reinforced polymer (GFRP) composite was manufactured. The processing properties of matrix resin in terms of the isothermal viscosity at 45 °C were investigated. The specimens were exposed with gamma irradiation of 1 MGy, 5 MGy and 10 MGy, respectively. The effect of gamma irradiation on thermal properties and structure of cyanate ester/epoxy matrix was investigated. The interlaminar shear strength (ILSS) of the composites before and after irradiation were investigated at room temperature, 77 K and 4.2 K. Results showed that cyanate ester/epoxy system had a low viscosity and a long pot life at 45 °C. The glass transition temperature of the matrix resin decreased with the increasing irradiation dose. Moreover, the ILSS of GFRP composite slightly increases after irradiation and toughening mechanism was also discussed

  19. Gamma irradiation effects on cyanate ester/epoxy insulation materials for superconducting magnets

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jingwen [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wu, Zhixiong, E-mail: zxwu@mail.ipc.ac.cn [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Huang, Chuanjun [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Li, Laifeng, E-mail: laifengli@mail.ipc.ac.cn [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-12-15

    Highlights: • Irradiation resistance of glass fiber reinforced cyanate ester/epoxy composite was investigated. • The cyanate ester/epoxy resin system has a low viscosity and long pot life. • The T{sub g} of the matrix resin decreased slightly with the increase of irradiation dose. • The ILSS of GFRP composite increased slightly when exposed to 10 MGy of gamma irradiation. - Abstract: Cyanate ester/epoxy resin was used as a cryogenic-grade polymer matrix and glass fiber reinforced polymer (GFRP) composite was manufactured. The processing properties of matrix resin in terms of the isothermal viscosity at 45 °C were investigated. The specimens were exposed with gamma irradiation of 1 MGy, 5 MGy and 10 MGy, respectively. The effect of gamma irradiation on thermal properties and structure of cyanate ester/epoxy matrix was investigated. The interlaminar shear strength (ILSS) of the composites before and after irradiation were investigated at room temperature, 77 K and 4.2 K. Results showed that cyanate ester/epoxy system had a low viscosity and a long pot life at 45 °C. The glass transition temperature of the matrix resin decreased with the increasing irradiation dose. Moreover, the ILSS of GFRP composite slightly increases after irradiation and toughening mechanism was also discussed.

  20. Composición Esterólica de la Esponja Marina Xestospongia Muta

    Directory of Open Access Journals (Sweden)

    Carmenza Duque

    2009-10-01

    Full Text Available De la esponja marina Xestospongia muta recolectada en la bahía de Santa Marta, Caribe Colombiano, se aislaron por Cromatografía en Columna (CC sobre Silica gel, eluyendo con Benceno: Acetato de Etilo 10:2, dos fracciones esteróiicas; XMl (Rf = 0,28,Si02/Benceno; AcOEt 10:2 y XM2 (Rf = 0,24,SiO2/Benceno : AcOEt 10:2, Los esteróles presentes en estas dos fracciones fueron sometidos a Cromatografía Liquida de Alta Eficiencia (CLAE preparativa y analizados por Cromatografía de Gases (CG y Cromatografía de Gases acoplada en Espectometrla de Masas (CG-EM, Catorce esteróles fueron separados y 13 idenficados. La mayoría de ellos fueron 3n-0H-A^-Esteróles (Aproximadamente el 87% de los esteróles totales incluyendo al (24R + 24S-5,28-Estigmastadien-3i3-24-diol, mezclaepimérica por primera vez asi reportada en la naturaleza. El porcentaje restante correspondió a Estañóles y a un 6,2% de compuestos sin identificar.

  1. Process optimization for methyl ester production from waste cooking oil using activated carbon supported potassium fluoride

    Energy Technology Data Exchange (ETDEWEB)

    Hameed, B.H.; Goh, C.S.; Chin, L.H. [School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

    2009-12-15

    This paper presents the transesterification of waste cooking palm oil (WCO) using activated carbon supported potassium fluoride catalyst. A central composite rotatable design was used to optimize the effect of molar ratio of methanol to oil, reaction period, catalyst loading and reaction temperature on the transesterification process. The reactor was pressurized up to 10 bar using nitrogen gas. All the variables were found to affect significantly the methyl ester yield where the most effective factors being the amount of catalyst and reaction temperature, followed by methanol to oil ratio. A quadratic polynomial equation was obtained for methyl ester yield by multiple regression analysis using response surface methodology (RSM). The optimum condition for transesterification of WCO to methyl ester was obtained at 3 wt.% amount of catalyst, 175 C temperature, 8.85 methanol to oil molar ratio and 1 h reaction time. At the optimum condition, the predicted methyl ester yield was 83.00 wt.%. The experimental value was well within the estimated value of the model. The catalyst showed good performance with a high yield of methyl ester and the separation of the catalyst from the liquid mixture is easy. (author)

  2. A study on emission of phthalate esters from plastic materials using a passive flux sampler

    Science.gov (United States)

    Fujii, M.; Shinohara, N.; Lim, A.; Otake, T.; Kumagai, K.; Yanagisawa, Y.

    Phthalate esters are used as plasticizer in many plastics, and several studies have shown their toxicity. Phthalate esters are gradually emitted over time, and so it is conceivable that they pose a significant health risk. This study aims to investigate the temperature dependence of the emissions of various phthalate esters and to estimate the health risks of these emissions at various temperatures. A passive-type sampler was developed to measure the flux of phthalate esters from the surface of plastic materials. With this sampler, we examined three widely used plastic materials: synthetic leather, wallpaper and vinyl flooring. The observed maximum emissions of diethyl phthalate, dibutyl phthalate, and diethylhexyl phthalate (DEHP) from these materials at 20°C were 0.89, 0.77, and 14 μg m -2 h -1, respectively. Emissions at 80°C were 2.8, 4.5×10 2, and 1.5×10 3 μg m -2 h -1, respectively. The results showed this temperature dependence is determined primarily by the type of phthalate ester and less so by the type of material. The estimation from the results of temperature dependence indicated the concentration of DEHP in a vehicle left out in the sunshine during the day can exceed the recommended levels of Japan Ministry of Health, Labour and Welfare.

  3. Aerobic biotransformation of polyfluoroalkyl phosphate esters (PAPs) in soil.

    Science.gov (United States)

    Liu, Chen; Liu, Jinxia

    2016-05-01

    Microbial transformation of polyfluoroalkyl phosphate esters (PAPs) into perfluorocarboxylic acids (PFCAs) has recently been confirmed to occur in activated sludge and soil. However, there lacks quantitative information about the half-lives of the PAPs and their significance as the precursors to PFCAs. In the present study, the biotransformation of 6:2 and 8:2 diPAP in aerobic soil was investigated in semi-dynamics reactors using improved sample preparation methods. To develop an efficient extraction method for PAPs, six different extraction solvents were compared, and the phenomenon of solvent-enhanced hydrolysis was investigated. It was found that adding acetic acid could enhance the recoveries of the diPAPs and inhibit undesirable hydrolysis during solvent extraction of soil. However 6:2 and 8:2 monoPAPs, which are the first breakdown products from diPAPs, were found to be unstable in the six solvents tested and quickly hydrolyzed to form fluorotelomer alcohols. Therefore reliable measurement of the monoPAPs from a live soil was not achievable. The apparent DT50 values of 6:2 diPAP and 8:2 diPAP biotransformation were estimated to be 12 and > 1000 days, respectively, using a double first-order in parallel model. At the end of incubation of day 112, the major degradation products of 6:2 diPAP were 5:3 fluorotelomer carboxylic acid (5:3 acid, 9.3% by mole), perfluoropentanoic acid (PFPeA, 6.4%) and perfluorohexanoic acid (PFHxA, 6.0%). The primary product of 8:2 diPAP was perfluorooctanoic acid (PFOA, 2.1%). The approximately linear relationship between the half-lives of eleven polyfluoroalkyl and perfluoroalkyl substances (PFASs, including 6:2 and 8:2 diPAPs) that biotransform in aerobic soils and their molecular weights suggested that the molecular weight is a good indicator of the general stability of low-molecular-weight PFAS-based compounds in aerobic soils. PMID:26849529

  4. Viscosity of aqueous and cyanate ester suspensions containing alumina nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lawler, Katherine [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    The viscosities of both aqueous and cyanate ester monomer (BECy) based suspensions of alumina nanoparticle were studied. The applications for these suspensions are different: aqueous suspensions of alumina nanoparticles are used in the production of technical ceramics made by slip casting or tape casting, and the BECy based suspensions are being developed for use in an injection-type composite repair resin. In the case of aqueous suspensions, it is advantageous to achieve a high solids content with low viscosity in order to produce a high quality product. The addition of a dispersant is useful so that higher solids content suspensions can be used with lower viscosities. For BECy suspensions, the addition of nanoparticles to the BECy resin is expected to enhance the mechanical properties of the cured composite. The addition of saccharides to aqueous suspensions leads to viscosity reduction. Through DSC measurements it was found that the saccharide molecules formed a solution with water and this resulted in lowering the melting temperature of the free water according to classic freezing point depression. Saccharides also lowered the melting temperature of the bound water, but this followed a different rule. The shear thinning and melting behaviors of the suspensions were used to develop a model based on fractal-type agglomeration. It is believed that the structure of the particle flocs in these suspensions changes with the addition of saccharides which leads to the resultant viscosity decrease. The viscosity of the BECy suspensions increased with solids content, and the viscosity increase was greater than predicted by the classical Einstein equation for dilute suspensions. Instead, the Mooney equation fits the viscosity behavior well from 0-20 vol% solids. The viscosity reduction achieved at high particle loadings by the addition of benzoic acid was also investigated by NMR. It appears that the benzoic acid interacts with the surface of the alumina particle which may

  5. Papain-Catalyzed Chemoenzymatic Synthesis of Telechelic Polypeptides Using Bis(Leucine Ethyl Ester) Initiator.

    Science.gov (United States)

    Tsuchiya, Kousuke; Numata, Keiji

    2016-07-01

    In order to construct unique polypeptide architectures, a novel telechelic-type initiator with two leucine ethyl ester units is designed for chemoenzymatic polymerization. Glycine or alanine ethyl ester is chemoenzymatically polymerized using papain in the presence of the initiator, and the propagation occurs at each leucine ethyl ester unit to produce the telechelic polypeptide. The formation of the telechelic polypeptides is confirmed by (1) H NMR and MALDI-TOF mass spectroscopies. It is revealed by AFM observation that long nanofibrils are formed from the telechelic polyalanine, whereas a conventional linear polyalanine with a similar degree of polymerization shows granule-like structures. The telechelic polyglycine and polyalanine show the crystalline structures of Polyglycine II and antiparallel β-sheet, respectively. It is demonstrated that this method to synthesize telechelic-type polypeptides potentially opens up a pathway to construct novel hierarchical structures by self-assembly. PMID:26947148

  6. Batch Production of Trimetylolpropane Ester from Palm Oil as Lubricant Base Stock

    Science.gov (United States)

    Zubaidah Sulaiman, Siti; Luqman Chuah, A.; Fakhru`L-Razi, A.

    A batch process for the ransesterification of Palm Oil Methyl Ester (POME) with trimethylolpropane (TMP) to TMP ester was investigated in a mini pilot reactor. The process was equipped with a high vacuum pump. The experimental studies explored effects of vacuum pressure, temperature, molar ratio, catalyst amount and agitator speed on the overall conversion. Five liters of TMP esters containing 83 to 87 w/w % triesterss (TE) were successfully synthesized after 2 h of reaction time Application of vacuum pump enhanced conversion of TE (w/w %) for the process. High catalyst amount resulted in higher conversion of TE (w/w %) but increased in solid content of the product. This has reduced the product yield due to inefficient separation by gravity settling.

  7. Optimization of the production of ethyl esters by ultrasound assisted reaction of soybean oil and ethanol

    Directory of Open Access Journals (Sweden)

    S. Rodrigues

    2009-06-01

    Full Text Available Biodiesel is a renewable liquid fuel that can be produced by a transesterification reaction between a vegetable oil and an alcohol. This paper evaluates and optimizes the production of ethyl esters (biodiesel from soybean oil and ethanol. The reaction was carried out by applying ultrasound under atmospheric pressure and ambient temperature. Response surface methodology was used to evaluate the influence of alcohol to oil molar ratio and catalyst concentration on the yield of conversion of soybean oil into ethyl esters. The process resulted in a maximum yield of 91.8% after 30 minutes of reaction. The process variables alcohol to oil ratio and catalyst to oil ratio were statistically significant regarding the yield of ethyl esters. The optimal operating condition was obtained applying an alcohol to oil molar ratio of 10.2 and a catalyst to oil weight ratio of 0.0035.

  8. The possible participation of esters as well as amides in prebiotic polymers.

    Science.gov (United States)

    Rich, A.

    1971-01-01

    Demonstration that alpha-hydroxy acids may have participated in the formation of prebiological polymers in a manner similar to the participation of alpha-amino acids. Ex periments are described which indicate that the system for forming peptide bonds in present-day biological organisms is equally competent in forming ester and polyester bonds. In particular, the experiments described are directed toward answering questions regarding the action of peptidyl transferase in ester formation. Also, an attempt is made to determine whether a complete protein synthetic system can operate with transfer RNA molecules which have alpha-hydroxyl acids attached to them instead of alpha-amino acids, using both synthetic and natural mRNA. The ability of ribosomal peptidyl transferase to catalyze the formation of an ester bond as well as its normal product, the peptide bond, is demonstrated.

  9. Studi Penggunaan Metil Ester Minyak Sawit sebagai Minyak Isolasi Peralatan Listrik

    Directory of Open Access Journals (Sweden)

    Abdul Rajab

    2014-03-01

    Full Text Available This paper discusses experimental results on some parameters of palm methyl ester as insulating oil. Destillations are firstly made to obtained the composition of oil that provide the optimal compromise among measured parameters. Breakdown voltage, dissipation factor, dielectric constant, viscosity and oxidation stability were then tested on original, destilled, and destillation residual oils. The results showed that the dissipation factor and viscosity of destilled palm methyl ester comply with the standard spesification for natural ester to be used as insulating oil. Sadly, the breakdown voltage and oxidation stability of oils do not fulfill the standard. However, the lower breakdown voltage of oils seem to be tolerable as their value are still higher then that of mineral oil. Dielectric constant of oils which were higher then that of mineral oil is an advantage when the oils will be used in combination with solid insulation for more uniformly field reason.

  10. Esteróles libres monohidroxilados de la esponja marina agelas schmidti (wilson, 1902)

    OpenAIRE

    Carmenza Duque; Germán Castillo; Sandra Buitrago; Oscar Osorno; Sven Zea

    2010-01-01

    De la esponja marina Ágelas schmidti recolectada en la bahía de Santa Marta (Caribe Colombiano), se aisló por cromatografía en columna sobre silica gel la fracción esterólica. Los esteróles presentes en esta fracción fueron sometidos a Cromatografía Líquida de Alta Eficiencia preparativa en fase reversa y analizados por Cromatografía de Gases de Alta Resolución y Cromatografía de Gases de Alta Resolución acoplada a Espectrometría de Masas. De dieciocho esteróles separados, diecisiete fu...

  11. Density of Jatropha curcas Seed Oil and its Methyl Esters: Measurement and Estimations

    Science.gov (United States)

    Veny, Harumi; Baroutian, Saeid; Aroua, Mohamed Kheireddine; Hasan, Masitah; Raman, Abdul Aziz; Sulaiman, Nik Meriam Nik

    2009-04-01

    Density data as a function of temperature have been measured for Jatropha curcas seed oil, as well as biodiesel jatropha methyl esters at temperatures from above their melting points to 90 ° C. The data obtained were used to validate the method proposed by Spencer and Danner using a modified Rackett equation. The experimental and estimated density values using the modified Rackett equation gave almost identical values with average absolute percent deviations less than 0.03% for the jatropha oil and 0.04% for the jatropha methyl esters. The Janarthanan empirical equation was also employed to predict jatropha biodiesel densities. This equation performed equally well with average absolute percent deviations within 0.05%. Two simple linear equations for densities of jatropha oil and its methyl esters are also proposed in this study.

  12. Synthesis and Structural Characterization of 1- and 2-Substituted Indazoles: Ester and Carboxylic Acid Derivatives

    Directory of Open Access Journals (Sweden)

    Isabel Bento

    2006-11-01

    Full Text Available A series of indazoles substituted at the N-1 and N-2 positions with ester-containing side chains -(CH2nCO2R of different lengths (n = 0-6, 9, 10 are described.Nucleophilic substitution reactions on halo esters (X(CH2nCO2R by 1H-indazole inalkaline solution lead to mixtures of N-1 and N-2 isomers, in which the N-1 isomerpredominates. Basic hydrolysis of the ester derivatives allowed the synthesis of thecorresponding indazole carboxylic acids. All compounds were fully characterised bymultinuclear NMR and IR spectroscopies, MS spectrometry and elemental analysis; theNMR spectroscopic data were used for structural assignment of the N-1 and N-2 isomers.The molecular structure of indazol-2-yl-acetic acid (5b was determined by X-raydiffraction, which shows a supramolecular architecture involving O2-H...N1intermolecular hydrogen bonds.

  13. Pinosylvin-Based Polymers: Biodegradable Poly(Anhydride-Esters) for Extended Release of Antibacterial Pinosylvin.

    Science.gov (United States)

    Bien-Aime, Stephan; Yu, Weiling; Uhrich, Kathryn E

    2016-07-01

    Pinosylvin is a natural stilbenoid known to exhibit antibacterial bioactivity against foodborne bacteria. In this work, pinosylvin is chemically incorporated into a poly(anhydride-ester) (PAE) backbone via melt-condensation polymerization, and characterized with respect to its physicochemical and thermal properties. In vitro release studies demonstrate that pinosylvin-based PAEs hydrolytically degrade over 40 d to release pinosylvin. Pseudo-first order kinetic experiments on model compounds, butyric anhydride and 3-butylstilbene ester, indicate that the anhydride linkages hydrolyze first, followed by the ester bonds to ultimately release pinosylvin. An antibacterial assay shows that the released pinosylvin exhibit bioactivity, while in vitro cytocompatibility studies demonstrate that the polymer is noncytotoxic toward fibroblasts. These preliminary findings suggest that the pinosylvin-based PAEs can serve as food preservatives in food packaging materials by safely providing antibacterial bioactivity over extended time periods. PMID:27071713

  14. Malleable and Self-Healing Covalent Polymer Networks through Tunable Dynamic Boronic Ester Bonds.

    Science.gov (United States)

    Cromwell, Olivia R; Chung, Jaeyoon; Guan, Zhibin

    2015-05-27

    Despite numerous strategies involving dynamic covalent bond exchange for dynamic and self-healing materials, it remains a challenge to be able to tune the malleability and self-healing properties of bulk materials through simple small molecule perturbations. Here we describe the use of tunable rates of boronic ester transesterification to tune the malleability and self-healing efficiencies of bulk materials. Specifically, we used two telechelic diboronic ester small molecules with variable transesterification kinetics to dynamically cross-link 1,2-diol-containing polymer backbones. The sample cross-linked with fast-exchanging diboronic ester showed enhanced malleability and accelerated healing compared to the slow-exchanging variant under the same conditions. Our report demonstrates the possibility of transferring small molecule kinetics to dynamic properties of bulk solid material and may serve as a guide for the rational design of tunable dynamic materials. PMID:25945818

  15. Identification and dosage by HRGC of minor alcohol and esters in Brazilian sugar-cane spirit

    Energy Technology Data Exchange (ETDEWEB)

    Boscolo, Mauricio; Bezerra, Cicero W.B.; Cardoso, Daniel R.; Lima Neto, Benedito S.; Franco, Douglas W. [Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. de Quimica

    2000-02-01

    The presence of 51 volatile compounds, among alcohols and esters in Brazilian sugar-cane spirit (cachaca), were investigated by high-resolution gas chromatography (HRGC). The following alcohols and esters were identified and quantified: methanol, 1,4-butanodiol, 2-phenylethyl alcohol, amyl alcohol, cetyl alcohol, cynamic alcohol, n-decanol, geraniol, isoamyl alcohol, isobutanol, menthol, n-butanol, n-dodecanol, n-propanol, n-tetradecanol, amyl propionate, ethyl acetate, ethyl benzoate, ethyl heptanoate, isoamyl valerate, methyl propionate, propyl butyrate. The average higher alcohols content (262 mg/100 mL in anhydrous alcohol a.a) and total esters content (24 mg/100 mL a.a) in cachacas, are smaller than in other spirits. The average methanol content in cachacas (6 mg/100 mL a.a) is the same as in rum, but smaller than in wine spirit. No qualitative differences of chemical profile among cachacas have been observed. (author)

  16. Long-acting contraceptive agents: structure activity relationships in a series of norethisterone and levonorgestrel esters.

    Science.gov (United States)

    Bialy, G; Blye, R P; Enever, R P; Naqvi, R H; Lindberg, M C

    1983-03-01

    A large number of esters of norethisterone (17 alpha-ethynyl-17 beta-hydroxyestr-4-en-3-one) and levonorgestrel (D-(-)-13 beta-ethyl-17 alpha-ethynyl-17 beta-hydroxygon-4-en-3-one) were synthesized and tested for biological activity. The test employed in these studies was the duration of estrus suppression in cycling mature rats. In the norethisterone series several esters exhibited duration of activity comparable to that of norethisterone enanthate. In the levonorgestrel series the butanoic, cyclobutylcarboxylic and cyclopropylcarboxylic esters were longer acting than medroxyprogesterone acetate (17 alpha-acetoxy-6 alpha-methylpregn-4-ene-3,20-dione) when prepared as aqueous microcrystalline suspensions. PMID:6419411

  17. Synthesis and biological evaluation of arctigenin ester and ether derivatives as activators of AMPK.

    Science.gov (United States)

    Shen, Sida; Zhuang, Jingjing; Chen, Yijia; Lei, Min; Chen, Jing; Shen, Xu; Hu, Lihong

    2013-07-01

    A series of new arctigenin and 9-deoxy-arctigenin derivatives bearing different ester and ether side chains at the phenolic hydroxyl positions are designed, synthesized, and evaluated for activating AMPK potency in L6 myoblasts. Initial biological evaluation indicates that some alkyl ester and phenethyl ether arctigenin derivatives display potential activities in AMPK phosphorylation improvement. Further structure-activity relationship analysis shows that arctigenin ester derivatives 3a, 3h and 9-deoxy-arctigenin phenethyl ether derivatives 6a, 6c, 6d activate AMPK more potently than arctigenin. Moreover, the 2-(3,4-dimethoxyphenyl)ethyl ether moiety of 6c has been demonstrated as a potential functional group to improve the effect of AMPK phosphorylation. The structural optimization of arctigenin leads to the identification of 6c as a promising lead compound that exhibits excellent activity in AMPK activation. PMID:23673223

  18. [Analysis of constituents of ester-type gum bases used as natural food additives].

    Science.gov (United States)

    Tada, Atsuko; Masuda, Aino; Sugimoto, Naoki; Yamagata, Kazuo; Yamazaki, Takeshi; Tanamoto, Kenichi

    2007-12-01

    The differences in the constituents of ten ester-type gum bases used as natural food additives in Japan (urushi wax, carnauba wax, candelilla wax, rice bran wax, shellac wax, jojoba wax, bees wax, Japan wax, montan wax, and lanolin) were investigated. Several kinds of gum bases showed characteristic TLC patterns of lipids. In addition, compositions of fatty acid and alcohol moieties of esters in the gum bases were analyzed by GC/MS after methanolysis and hydrolysis, respectively. The results indicated that the varieties of fatty acids and alcohols and their compositions were characteristic for each gum base. These results will be useful for identification and discrimination of the ester-type gum bases. PMID:18203503

  19. Identification and dosage by HRGC of minor alcohol and esters in Brazilian sugar-cane spirit

    International Nuclear Information System (INIS)

    The presence of 51 volatile compounds, among alcohols and esters in Brazilian sugar-cane spirit (cachaca), were investigated by high-resolution gas chromatography (HRGC). The following alcohols and esters were identified and quantified: methanol, 1,4-butanodiol, 2-phenylethyl alcohol, amyl alcohol, cetyl alcohol, cynamic alcohol, n-decanol, geraniol, isoamyl alcohol, isobutanol, menthol, n-butanol, n-dodecanol, n-propanol, n-tetradecanol, amyl propionate, ethyl acetate, ethyl benzoate, ethyl heptanoate, isoamyl valerate, methyl propionate, propyl butyrate. The average higher alcohols content (262 mg/100 mL in anhydrous alcohol a.a) and total esters content (24 mg/100 mL a.a) in cachacas, are smaller than in other spirits. The average methanol content in cachacas (6 mg/100 mL a.a) is the same as in rum, but smaller than in wine spirit. No qualitative differences of chemical profile among cachacas have been observed. (author)

  20. Interfacial properties of Quillaja saponins and its use for micellisation of lutein esters.

    Science.gov (United States)

    Tippel, Janine; Lehmann, Maren; von Klitzing, Regine; Drusch, Stephan

    2016-12-01

    Natural food colourants, colouring foods and bioactive food ingredients need to be solubilised for their incorporation in food. Aim of the present study was to investigate the micelle-forming properties of saponins from Quillaja saponaria Mollina (QS) in order to solubilise a lutein ester extract for its incorporation in food matrices. QS showed a high surface activity and functionality with respect to micellisation as derived from interfacial tension measurements and subsequent data fitting to the classical Frumkin model. The composition of the aqueous phase affected the lutein ester incorporation as revealed by particle size, zeta potential and colour measurements. In terms of morphology of lutein ester loaded saponin micelles (LMS), cryo-TEM micrographs showed depending on the composition of the medium both, spherical and elongated branched micelles. PMID:27374503

  1. Rhodium-catalyzed acyloxy migration of propargylic esters in cycloadditions, inspiration from the recent "gold rush".

    Science.gov (United States)

    Shu, Xing-Zhong; Shu, Dongxu; Schienebeck, Casi M; Tang, Weiping

    2012-12-01

    Transition metal-catalyzed acyloxy migration of propargylic esters offers versatile entries to allene and vinyl carbene intermediates for various fascinating subsequent transformations. Most π-acidic metals (e.g. gold and platinum) are capable of facilitating these acyloxy migration events. However, very few of these processes involve redox chemistry, which are well-known for most other transition metals such as rhodium. The coupling of acyloxy migration of propargylic esters with oxidative addition, migratory insertion, and reductive elimination may lead to ample new opportunities for the design of new reactions. This tutorial review summarizes recent developments in Rh-catalyzed 1,3- and 1,2-acyloxy migration of propargylic esters in a number of cycloaddition reactions. Related Au- and Pt-catalyzed cycloadditions involving acyloxy migration are also discussed. PMID:22895533

  2. Evaluation of the Phthalate Esters in South Indian Women with Endometriosis

    Directory of Open Access Journals (Sweden)

    with Endometriosis

    2008-01-01

    Full Text Available Background: To evaluate the possible association between phthalate esters (PEs and the occurrenceof endometriosis. Blood samples were collected from 99 infertile women with endometriosis (studygroup; 135 age-matched women without endometriosis (control group but with infertility relatedto tubal defects, fibroids, polycystic ovaries, idiopathic infertility and pelvic inflammatory diseasesdiagnosed by laparoscopy with no evidence of endometriosis or other gynecological disordersduring laparoscopic sterilization.Materials and Methods: This is a prospective case-control study, which recruited womenundergoing infertility treatment at three collaborating centers (BMMHRC: Bhagwan MahavirMedical Hospital and Research Centre, MHRT: Maternal Health and Research Trust, and OwaisiHospital and Research Center of Reproductive Medicine Hyderabad, which receives cases fromall over the region of Andhra Pradesh, India. The concentrations of Phthalate Esters were measuredby using the High Performance Liquid Chromatography (HPLC.Evaluation of Phthalate Esters concentrations in women with endometriosis compared with womenwho are free from the disease.Results: Women with endometriosis showed significantly higher concentrations of Phthalate esters(Dimethyl phthalate (DMP, Diethyl phthalate (DEP, Di-n-butyl phthalate (DnBP, Butyl benzylphthalate (BBP and Bis (2-ethylhexyl phthalate (BEHP compared with control group. Wefound that (38% of the cases with endometriosis and (21% of the control group. The correlationbetween the concentrations of Phthalate esters and different severity of endometriosis was strongand statistically significant at p<0.05 for all five compounds (DMP: r=+0.57, p<0.0001; DnBPr=+0.39, p<0.0001; BBP: r=+0.89, p<0.0001; DnOP: r=+0.66, p<0.0001 and BEHP: r=+0.33,p<0.0014.Conclusion: This study for the first time from Indian subcontinent demonstrates that possiblyPhthalate Esters might have a role in etiology of endometriosis.

  3. Recovery of sterols as fatty acid steryl esters from waste material after purification of tocopherols.

    Science.gov (United States)

    Nagao, Toshihiro; Hirota, Yoshinori; Watanabe, Yomi; Kobayashi, Takashi; Kishimoto, Noriaki; Fujita, Tokio; Kitano, Motohiro; Shimada, Yuji

    2004-08-01

    Tocopherols are purified industrially from soybean oil deodorizer distillate by a process comprising distillation and ethanol fractionation. The waste material after ethanol fractionation (TC waste) contains 75% sterols, but a purification process has not yet been developed. We thus attempted to purify sterols by a process including a lipase-catalyzed reaction. Candida rugosa lipase efficiently esterified sterols in TC waste with oleic acid (OA). After studying several factors affecting esterification, the reaction conditions were determined as follows: ratio of TC waste/OA, 1:2 (wt/wt); water content, 30%; amount of lipase, 120 U/g-reaction mixture; temperature, 40 degrees C. Under these conditions, the degree of esterification reached 82.7% after 24 h. FA steryl esters (steryl esters) in the oil layer were purified successfully by short-path distillation (purity, 94.9%; recovery, 73.1%). When sterols in TC waste were esterified with FFA originating from olive, soybean, rapeseed, safflower, sunflower, and linseed oils, the FA compositions of the steryl esters differed somewhat from those of the original oils: The content of saturated FA was lower and that of unsaturated FA was higher. The m.p. of the steryl esters synthesized (21.7-36.5 degrees C) were remarkably low compared with those of the steryl esters purified from high-b.p. soybean oil deodorizer distillate substances (56.5 degrees C; JAOCS 80, 341-346, 2003). The low-m.p. steryl esters were soluble in rapeseed oil even at a final concentration of 10%. PMID:15638248

  4. Development of Enantiospecific Coupling of Secondary and Tertiary Boronic Esters with Aromatic Compounds.

    Science.gov (United States)

    Odachowski, Marcin; Bonet, Amadeu; Essafi, Stephanie; Conti-Ramsden, Philip; Harvey, Jeremy N; Leonori, Daniele; Aggarwal, Varinder K

    2016-08-01

    The stereospecific cross-coupling of secondary boronic esters with sp(2) electrophiles (Suzuki-Miyaura reaction) is a long-standing problem in synthesis, but progress has been achieved in specific cases using palladium catalysis. However, related couplings with tertiary boronic esters are not currently achievable. To address this general problem, we have focused on an alternative method exploiting the reactivity of a boronate complex formed between an aryl lithium and a boronic ester. We reasoned that subsequent addition of an oxidant or an electrophile would remove an electron from the aromatic ring or react in a Friedel-Crafts-type manner, respectively, generating a cationic species, which would trigger 1,2-migration of the boron substituent, creating the new C-C bond. Elimination (preceded by further oxidation in the former case) would result in rearomatization giving the coupled product stereospecifically. Initial work was examined with 2-furyllithium. Although the oxidants tested were unsuccessful, electrophiles, particularly NBS, enabled the coupling reaction to occur in good yield with a broad range of secondary and tertiary boronic esters, bearing different steric demands and functional groups (esters, azides, nitriles, alcohols, and ethers). The reaction also worked well with other electron-rich heteroaromatics and 6-membered ring aromatics provided they had donor groups in the meta position. Conditions were also found under which the B(pin)- moiety could be retained in the product, ortho to the boron substituent. This protocol, which created a new C(sp(2))-C(sp(3)) and an adjacent C-B bond, was again applicable to a range of secondary and tertiary boronic esters. In all cases, the coupling reaction occurred with complete stereospecificity. Computational studies verified the competing processes involved and were in close agreement with the experimental observations. PMID:27384259

  5. Proton Exchange Membrane from the Blend of Copolymers of Vinyl Acetate- Acrylic Ester and Styrene-Acrylic Ester for Power Generation Using Fuel Cell

    Directory of Open Access Journals (Sweden)

    Alvaro Realpe

    2014-10-01

    Full Text Available Proton exchange membranes for fuel cells were synthesized from the blend of copolymers of vinyl acetate-acrylic ester and styrene-acrylic ester, which were modified by sulfonation and addition of silica gel. Water uptake, ion exchange capacity, infrared spectroscopy and tensile tests were applied to characterize the prepared membranes. The results show that the prepared membranes with the processes of sulfonation and loaded with silica have the highest water uptake (92,7%. On the other hand, the sulfonation process lead to membranes with high ion exchange capacity and high mechanical strength (0,68 meq/g and 1,29 MPa, respectively. Therefore, the sulfonated membrane represents an alternative for the application as proton exchange membrane in fuel cells.

  6. Possible involvement of radical intermediates in the inhibition of cysteine proteases by allenyl esters and amides

    OpenAIRE

    Takeuchi, Yoshio; Fujiwara, Tomoya; Shimone, Yoshihito; Miyataka, Hideki; Satoh, Toshio; Kirk, Kenneth L.; Hori, Hitoshi

    2008-01-01

    In order to investigate crystallographically the mechanism of inhibition of cysteine protease by α-methyl-γ,γ-diphenylallenecarboxylic acid ethyl ester 3, a cysteine protease inhibitor having in vivo stability, we synthesized N-(α-methyl-γ,γ-diphenylallenecarbonyl)-l-phenylalanine ethyl ester 4. Reaction of 4 with thiophenol, the SH group of which has similar pKa value to that of cysteine protease, produced oxygen-mediated radical adducts 6 and 7 in ambient air but did not proceed under oxyge...

  7. Synthesis of new fatty acids amides from aminolysis of fatty acid methyl esters (FAMEs)

    International Nuclear Information System (INIS)

    Recent biochemical and pharmacological studies have led to the characterization of different fatty acid amides as a new family of biologically active lipids. Here, we describe the synthesis of new amides from C16:0, 18:0, 18:1 and 18:1, OH fatty acids (FFA) families with cyclic and acyclic amines and demonstrate for the first time that these compounds produce cytotoxic effects. Application of this method to the synthesis of fatty acid amides was performed using the esters aminolysis as a key step and various carboxylic amides were prepared in good yield from fatty acid methyl esters (FAMEs). (author)

  8. Preparation and Reactions of Amino Acid Ester Sulfones as New Remote Asymmetrical Induced Reagents

    Institute of Scientific and Technical Information of China (English)

    ZHOU,Cheng-He; BAI,Xue; LI,Tan-Qing; WU,Jun; Alfred Hassner

    2004-01-01

    @@ The development of chiral auxiliary-controlled asymmetric synthesis has been receiving increasing interest in recent yearsfi,2] Various chiral auxiliary reagents have been observed[3] and a lot of results showed that variation of the chiral auxiliary could influence asymmetric induction. Recently, it has been reported the reaction of the aminated sulfones as a remote chiral auxiliary with α,β-unsaturated carbonyl compounds.[4] Here we would like to report the preparation of amino acid ester sulfones as new remote asymmetrical induced reagents and their reactions with α,β-unsaturated esters.

  9. Deptermination of Partial Molar Volumes of EPA and DHA Ethyl Esters in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    MeiHUANG; XianDaWANG; 等

    2002-01-01

    The use of supercritical-fluid shromatogrphy for determining partial molar volumes of ethyl esters of cis-5,8,11,14,17-eicosapentaenoic acid (EPA) and cis-4,7,10,13,16,19-docosa-hexaenoic acid(DHA) in supercritical carbon dioxide is presented and discussed. Partial molar volumes of EPA and DHA esters are obtained from the variation of the retention properties with the density of mobile phase at 313.15K,323.15K,333.15K and in the pressure range from 9 MPa to 21 MPa.

  10. Determination of Partial Molar Volumes of EPA and DHA Ethyl Esters in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The use of supercritical-fluid chromatography for determining partial molar volumes of ethyl esters of cis-5,8,11,14,17-eicosapentaenoic acid (EPA) and cis -4,7,10,13,16,19- docosa-hexaenoic acid (DHA) in supercritical carbon dioxide is presented and discussed. Partial molar volumes of EPA and DHA esters are obtained from the variation of the retention properties with the density of mobile phase at 313.15 K, 323.15 K, 333.15 K and in the pressure range from 9 MPa to 21 MPa.

  11. Fatty acid methyl esters as reactive diluents in solvent-borne thermally cured coil-coatings

    OpenAIRE

    Johansson, Katarina

    2006-01-01

    This work describes how a fatty acid methyl ester (FAME) derived from a vegetable oil can be introduced as reactive diluent in a solvent-borne thermally cured coil-coating system. The evaluated reactive diluent, rape seed methyl ester (RME), has been evaluated both in a fully formulated clear coat system and via model studies. A reactive diluent is a compound that acts as a solvent in the liquid paint, lowering the viscosity, and chemically reacts into the final film during cure. Introduction...

  12. Synthesis and Stability Studies of α,α‐Difluoro Ester Phospholipids

    DEFF Research Database (Denmark)

    Pedersen, Palle Jacob; Andresen, Thomas Lars; Clausen, Mads Hartvig

    2012-01-01

    The synthesis of two new α,α‐difluoro ester phospholipid conjugates is described and the stability of their liposomal formulations in three different aqueous buffers (pH 4.5, 7.5 and 8.5) has been investigated. The studies confirmed that α,α‐difluoro esters are much more prone to hydrolysis when...... positioned close to the hydrophilic head group of phospholipids than when the functionality is placed in the lipophilic part of the bilayer in liposomes. This observation lends further support to the concept of protecting hydrolysable functionalities by formulation as part of the membrane of liposomes....

  13. Reptilian chemistry: Characterization of a family of dianeackerone-related steroidal esters from a crocodile secretion

    Science.gov (United States)

    Yang, Zhicai; Whyte, Authrine; Attygalle, Athula B.; Weldon, Paul J.; Eisner, Thomas; Meinwald, Jerrold

    1999-01-01

    The African dwarf crocodile, Osteolaemus tetraspis (Crocodilidae, Reptilia), possesses a pair of skin glands, the paracloacal glands, the secretion of which is thought to be used to mark nest sites or attract mates. Ten aromatic steroidal esters were isolated from this secretion and characterized on the basis of NMR spectroscopic investigations, electrospray ionization-MS analyses, and chemical degradation. These esters, which account for more than 90% of the paracloacal glandular secretion, are derived from either cholesterol or cholestanol, esterified with a C-20 or C-22 acid closely related to dianeackerone, the only significant volatile compound found in this secretion. PMID:10535907

  14. Synthesis of Chiral, Enantiopure Allylic Amines by the Julia Olefination of α-Amino Esters.

    Science.gov (United States)

    Benedetti, Fabio; Berti, Federico; Fanfoni, Lidia; Garbo, Michele; Regini, Giorgia; Felluga, Fulvia

    2016-01-01

    The four-step conversion of a series of N-Boc-protected l-amino acid methyl esters into enantiopure N-Boc allylamines by a modified Julia olefination is described. Key steps include the reaction of a lithiated phenylalkylsulfone with amino esters, giving chiral β-ketosulfones, and the reductive elimination of related α-acetoxysulfones. The overall transformation takes place under mild conditions, with good yields, and without loss of stereochemical integrity, being in this respect superior to the conventional Julia reaction of α-amino aldehydes. PMID:27338326

  15. Composición Esterólica de la Esponja Marina Xestospongia Muta

    OpenAIRE

    Carmenza Duque; Alejandro Martínez; Gustavo Peñuela

    2009-01-01

    De la esponja marina Xestospongia muta recolectada en la bahía de Santa Marta, Caribe Colombiano, se aislaron por Cromatografía en Columna (CC) sobre Silica gel, eluyendo con Benceno: Acetato de Etilo 10:2, dos fracciones esteróiicas; XMl (Rf = 0,28,Si02/Benceno; AcOEt 10:2) y XM2 (Rf = 0,24,SiO2/Benceno : AcOEt 10:2), Los esteróles presentes en estas dos fracciones fueron sometidos a Cromatografía Liquida de Alta Eficiencia (CLAE) preparativa y analizados por Cromatografía de Gases (CG) y Cr...

  16. Low-temperature side-chain cleavage and decarboxylation of polythiophene esters by acid catalysis

    DEFF Research Database (Denmark)

    Søndergaard, Roar; Norrman, Kion; Krebs, Frederik C

    2012-01-01

    substituents have been examined by TGA‐MS using different sulphonic acids. A substantial lowering of the cleavage temperature is observed, and the ester cleavage can even be performed in situ on roll‐to‐roll‐coated films on polyethylene terephthalate (PET). © 2011 Wiley Periodicals, Inc. J Polym Sci Part A......Solubility switching of polymers is very useful in thin layer processing of conjugated polymers, as it allows for multilayer processing and increases the stability of the polymer. Acid catalyzed thermocleavage of ester groups from thiophene polymers carrying primary, secondary, and tertiary......: Polym Chem, 2012...

  17. Theoretical study of cocaine and ecgonine methyl ester in gas phase and in aqueous solution

    Science.gov (United States)

    Rincón, David A.; Cordeiro, M. Natália D. S.; Mosquera, Ricardo A.; Borges, Fernanda

    2009-01-01

    The conformational preferences of cocaine and ecgonine methyl ester were determined through ab initio and density functional theory calculations. They share the same preferred orientation of the acetate group with a hydrogen bond between the amine and carbonyl groups, and s- cis conformation for the methoxyl group. The benzoyloxy group of cocaine defines a specific accessible conformational region. In solution the most stable conformers are stabilized by internal hydrogen bonds in contrast to the lesser stables, which are stabilized by solute/solvent interactions. Overall, these conformational features explain why ecgonine methyl ester is the principal metabolite of cocaine in a human environment.

  18. Baker's Yeast: improving the D-stereoselectivity in reduction of 3-oxo esters

    DEFF Research Database (Denmark)

    Madsen, Jørgen Øgaard

    1999-01-01

    The stereoselectivity of baker's yeast in the reduction of ethyl 3-oxopentanoate was shifted towards the corresponding (R)-hydroxy ester by sugar, heat treatment and allyl alcohol. The highest enantiomeric excesses obtained with baker's yeast with a good reduction capacity, 92-97%, were achieved by...... combining allyl alcohol and sugar; heat treatment did not increase the stereoselectivity further. With the use of this technique, ethyl (R)-3-hydroxyhexanoate, >99% ee, and ethyl (S)-4-chloro-3-hydroxybutanoate, 82-90% ee, were produced from the corresponding esters, and for the first time an excess of the...

  19. Evaluation of the Ser-His Dipeptide, a Putative Catalyst of Amide and Ester Hydrolysis.

    Science.gov (United States)

    MacDonald, Melissa J; Lavis, Luke D; Hilvert, Donald; Gellman, Samuel H

    2016-08-01

    Efficient hydrolysis of amide bonds has long been a reaction of interest for organic chemists. The rate constants of proteases are unmatched by those of any synthetic catalyst. It has been proposed that a dipeptide containing serine and histidine is an effective catalyst of amide hydrolysis, based on an apparent ability to degrade a protein. The capacity of the Ser-His dipeptide to catalyze the hydrolysis of several discrete ester and amide substrates is investigated using previously described conditions. This dipeptide does not catalyze the hydrolysis of amide or unactivated ester groups in any of the substrates under the conditions evaluated. PMID:27400366

  20. Stanol esters attenuate the aggravating effect of dietary cholesterol on atherosclerosis in homozygous Watanabe rabbits

    DEFF Research Database (Denmark)

    Schrøder, Malene; Husche, Constanze; Pilegaard, Kirsten; Lütjohann, Dieter; Mortensen, Alicja

    2009-01-01

    Plant stanols are marketed as natural means to lower blood cholesterol in humans; hence the effect on combined familial hyperlipidemia is not known. The objective was to investigate the effect of stanol esters on blood lipids and aortic atherosclerosis in homozygous WHHL rabbits challenged with...... dietary cholesterol. A total of 36 rabbits, 6 weeks of age, with initial plasma cholesterol of 22.5 mmol/L were assigned to two treatment groups fed a standard rabbit chow with 1 g/kg cholesterol or this diet added 34 g/kg stanol ester, respectively, for 16 weeks. Plasma cholesterol was measured initially...

  1. STUDY ON THE SYNTHESIS AND PROPERTIES OF POLY(ESTER-IMIDE-ETHER) MULTIBLOCK COPOLYMERS

    Institute of Scientific and Technical Information of China (English)

    Zu-yao Shan; Zhen-yi Li

    2000-01-01

    A new class of poly(ester-imide-ether) multiblock copolymers was synthesized by transes-terification and melt copolymerization of dimethyl terephthalate (DMT) and N-(4-carbomethoxyphenyl)-4-(carbomethoxy)-phthalimide with ethylene glycol (EG) and polytetramethylene glycol (PTMG). The structure of the above copolymers was characterized by 1H-NMR and IR spectroscopy. Some properties of the coplymers were also examined. It was found that their mechanical properties and heat stability, compared with poly(ether-ester) copolymers, were obviously improved.

  2. Novel Approach: Tungsten Oxide Nanoparticle as a Catalyst for Malonic Acid Ester Synthesis via Ozonolysis

    Directory of Open Access Journals (Sweden)

    Bilal A. Wasmi

    2014-01-01

    Full Text Available Malonic acid ester was synthesized via the one-step ozonolysis of palm olein. Malonic acid ester was spectroscopically characterized using gas chromatography mass spectroscopy (GC-MS. Tungsten oxide nanoparticles were used as the catalyst, which was characterized via X-ray powder diffraction (XRD and field emission scanning electron microscopy (FE-SEM. Tungsten oxide provided several advantages as a catalyst for the esterification malonic acid such as simple operation for a precise ozonation method, an excellent yield of approximately 10%, short reaction times of 2 h, and reusability due to its recyclability.

  3. Study of the formation, prevention, and recovery of plutonium from plutonium esters in the Purex process

    International Nuclear Information System (INIS)

    The Savannah River Plant uses the basic Purex process to separate 239Pu from 238U and fission products. Dark-brown, dense solids containing up to 30% Pu have previously occurred in rotameters in the plutonium finishing operations. The kinetics of formation of this mixture of DBP- and MBP-Pu esters suggest two methods to prevent the formation of the solids. A selective dissolution method using NaOH metathesis has been developed to separate the phosphate ester from the plutonium before dissolution of the residual plutonium hydroxide in a HNO3-HF medium

  4. Towards an identification of the pyrethroid pharmacophore. A molecular modelling study of some pyrethroid esters

    DEFF Research Database (Denmark)

    Byberg, J R; Jørgensen, Flemming Steen; Klemmensen, P D

    1987-01-01

    A molecular modelling and computer graphics study of a series of pyrethroid insecticides has been carried out. The three-dimensional arrangement of the groups essential for the biological activity (pharmacophore) has been identified for the acid and the alcohol moieties, respectively. These...... pharmacophores are based on the relationship between molecular structure and biological activity for a number of pyrethroid esters. The pharmacophores, which describe the relative location in space of the unsaturated systems, the dimethyl groups and the ester moiety, may be useful in the design of novel...

  5. Succinimidyl Ester Surface Chemistry: Implications of the Competition between Aminolysis and Hydrolysis on Covalent Protein Immobilization

    OpenAIRE

    Lim, China Y.; Owens, Nicholas A.; Wampler, Ronald D.; Ying, YiXin; Granger, Jennifer H.; Porter, Marc D.; Takahashi, Makoto; Shimazu, Katsuaki

    2014-01-01

    N-Hydroxysuccinimide (NHS) ester terminal groups are commonly used to covalently couple amine-containing biomolecules (e.g., proteins and peptides) to surfaces via amide linkages. This one-step aminolysis is often performed in buffered aqueous solutions near physiological pH (pH 6 to pH 9). Under these conditions, the hydrolysis of the ester group competes with the amidization process, potentially degrading the efficiency of the coupling chemistry. The work herein examines the efficiency of c...

  6. Synthesis of Fluoroalkoxy Substituted Arylboronic Esters by Iridium-Catalyzed Aromatic C–H Borylation

    KAUST Repository

    Batool, Farhat

    2015-08-17

    The preparation of fluoroalkoxy arylboronic esters by iridium-catalyzed aromatic C–H borylation is described. The fluoroalkoxy groups employed include trifluoromethoxy, difluoromethoxy, 1,1,2,2-tetrafluoroethoxy, and 2,2-difluoro-1,3-benzodioxole. The borylation reactions were carried out neat without the use of a glovebox or Schlenk line. The regioselectivities available through the iridium-catalyzed C–H borylation are complementary to those obtained by the electrophilic aromatic substitution reactions of fluoroalkoxy arenes. Fluoroalkoxy arylboronic esters can serve as versatile building blocks.

  7. The occurrence of 2-hydroxy-6-methoxybenzoic acid methyl ester in Securidaca longepedunculata Fresen root bark

    Directory of Open Access Journals (Sweden)

    Lognay G.

    2000-01-01

    Full Text Available As part of our ongoing search for natural fumigants from Senegalese plants, we have investigated Securicicidaca longepedunculata root barks and demonstrated that 2-hydroxy-benzoic acid methyl ester (methyl salicylate, I is responsible of their biocide effect against stored grain insects. A second unknown apparented product, II has been systematically observed in all analyzed samples. The present paper describes the identification of this molecule. The analytical investigations including GCMS, GLC and 1H-NMR. spectrometry led to the conclusion that II corresponds to the 2-hydroxy-6-methoxybenzoic acid methyl ester.

  8. Potentiation of insulin release in response to amino acid methyl esters correlates to activation of islet glutamate dehydrogenase activity

    DEFF Research Database (Denmark)

    Kofod, Hans; Lernmark, A; Hedeskov, C J

    1986-01-01

    Column perifusion of mouse pancreatic islets was used to study the ability of amino acids and their methyl esters to influence insulin release and activate islet glutamate dehydrogenase activity. In the absence of L-glutamine, L-serine and the methyl ester of L-phenylalanine, but neither L-phenyl...

  9. Direct analysis of intact glycidyl fatty acid esters in edible oils using gas chromatography-mass spectrometry

    NARCIS (Netherlands)

    H. van Steenbergen; K. Hrnčiřík; A. Ermacora; S. de Koning; H.-G. Janssen

    2013-01-01

    Glycidyl esters (GE), fatty acid esters of glycidol, are process contaminants formed during edible oil processing. A novel direct method for the determination of intact GE in oils and fats based on gas chromatography-mass spectrometry (GC-MS) is presented. The method consists of a simple extraction

  10. 40 CFR 721.4097 - 7-Oxabicyclo[4.1.0]heptane-3-carboxylic acid, methyl ester.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 7-Oxabicyclo heptane-3-carboxylic acid... Specific Chemical Substances § 721.4097 7-Oxabicyclo heptane-3-carboxylic acid, methyl ester. (a) Chemical...-oxabicyclo heptane-3-carboxylic acid, methyl ester (PMN P-98-101) is subject to reporting under this...

  11. ISOLATION AND CHARACTERIZATION OF AN ACID, BILE SALT-INDEPENDENT, RETINYL ESTER HYDROLASE FROM RAT LIVER MICROSOMES

    Science.gov (United States)

    Previous work in this laboratory has revealed the presence of both acidic and neutral bile-salt independent retinyl ester hydrolase activities in rat liver homogenates. Here we present the purification, identification and characterization of an acid retinyl ester hydrolase activity from solubilized ...

  12. 40 CFR 721.3130 - Sulfuric acid, mono-C9-11-alkyl esters, sodium salts.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Sulfuric acid, mono-C9-11-alkyl esters... Specific Chemical Substances § 721.3130 Sulfuric acid, mono-C9-11-alkyl esters, sodium salts. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as...

  13. Facile spectrophotometric assay of molar equivalents of N-hydroxysuccinimide esters of monomethoxyl poly-(ethylene glycol derivatives

    Directory of Open Access Journals (Sweden)

    Gao Ang

    2012-11-01

    Full Text Available Abstract Background A new method is developed to quantify molar equivalents of N-hydroxysuccinimide (NHS esters of derivatives of monomethoxyl poly-(ethylene glycol (mPEG in their preparations with NHS acetate ester as the reference. Results NHS ester of succinic monoester or carbonate of mPEG of 5,000 Da was synthesized and reacted with excessive ethanolamine in dimethylformamide at 25°C for 15 min. Residual ethanolamine was subsequently quantified by absorbance at 420 nm after reaction with 2,4,6-trinitrobenzenesulfonic acid (TNBS at pH 9.2 for 15 min at 55°C followed by cooling with tap water. Reaction products of ethanolamine and NHS esters of mPEG caused no interference with TNBS assay of residual ethanolamine. Reaction between ethanolamine and NHS acetate ester follows 1:1 stoichiometry. By the new method, molar equivalents of NHS esters of carbonate and succinic monoester of mPEG in their preparations were about 90% and 60% of their theoretical values, respectively. During storage at 37°C in humid air, the new method detected spontaneous hydrolyses of the two NHS esters of mPEG more sensitively than the classical spectrophotometric method based on absorbance at 260 nm of NHS released by reaction with ammonia in aqueous solution. Conclusion The new method is favorable to quantify molar equivalents of NHS esters of mPEG derivatives and thus control quality of their preparations.

  14. Effect of sample pre-treatment on the determination of steroid esters in hair of bovine calves

    NARCIS (Netherlands)

    Aqai, P.; Stolker, A.A.M.; Lasaroms, J.J.P.

    2009-01-01

    The effect of three sample pre-treatment steps, washing, cutting and grinding on the determination of steroid esters in hair is studied. The study is performed by using hair samples obtained after pour-on application of steroid esters to bovine calves. After sample pre-treatment the hair is treated

  15. A convenient enantioselective decarboxylative aldol reaction to access chiral α-hydroxy esters using β-keto acids

    Directory of Open Access Journals (Sweden)

    Zhiqiang Duan

    2014-04-01

    Full Text Available We show a convenient decarboxylative aldol process using a scandium catalyst and a PYBOX ligand to generate a series of highly functionalized chiral α-hydroxy esters. The protocol tolerates a broad range of β-keto acids with inactivated aromatic and aliphatic α-keto esters. The possible mechanism is rationalized.

  16. Pyridine-promoted dediazoniation of aryldiazonium tetrafluoroborates: Application to the synthesis of SF5-substituted phenylboronic esters and iodobenzenes.

    Science.gov (United States)

    Iakobson, George; Du, Junyi; Slawin, Alexandra M Z; Beier, Petr

    2015-01-01

    Pyridine promotes dediazoniation of aryldiazonium tetrafluoroborates. The formed aryl radicals were trapped with B2pin2, iodine, or tetrahydrofuran to afford boronic esters, iodobenzenes and benzenes, respectively. The application to the synthesis of (pentafluorosulfanyl)phenylboronic esters, iodo(pentafluorosulfanyl)benzenes and (pentafluorosulfanyl)benzene is shown. PMID:26425206

  17. 75 FR 20785 - Polyglyceryl Phthalate Ester of Coconut Oil Fatty Acids; Exemption from the Requirement of a...

    Science.gov (United States)

    2010-04-21

    ... . II. What Does this Correction Do? In the Federal Register of July 8, 2009, (74 FR 32456), EPA's... AGENCY 40 CFR Part 180 Polyglyceryl Phthalate Ester of Coconut Oil Fatty Acids; Exemption from the..., concerning polyglyceryl phthalate ester of coconut oil fatty acids; exemption from the requirement of...

  18. Multi residue screening of intact testosterone esters and boldenone undecylenate in bovine hair using liquid chromatography electrospray tandem mass spectrometry

    NARCIS (Netherlands)

    Nielen, M.W.F.; Lasaroms, J.J.P.; Mulder, P.P.J.; Hende, van J.; Rhijn, van J.A.; Groot, M.J.

    2006-01-01

    The abuse of esters of natural androgenic steroids in cattle fattening and sports is hard to control via routine urine testing. The esters are rapidly hydrolysed in vivo into substances which are also endogenously present in urine. In veterinary control strange findings of 17ß-testosterone and 17¿-t

  19. Detectability of testosterone esters and estradiol benzoate in bovine hair and plasma following pour-on treatment

    NARCIS (Netherlands)

    Stolker, A.A.M.; Groot, M.J.; Lasaroms, J.J.P.; Nijrolder, A.W.J.M.; Blokland, M.H.; Riedmaier, I.; Becker, C.; Meyer, H.H.D.; Nielen, M.W.F.

    2009-01-01

    The abuse of synthetic esters of natural steroids such as testosterone and estradiol in cattle fattening and sports is hard to detect via routine urine testing. The esters are rapidly hydrolysed in vivo into substances which are also endogenously present in urine. An interesting alternative can be p

  20. Intra- and Intermolecular Nickel-Catalyzed Reductive Cross-Electrophile Coupling Reactions of Benzylic Esters with Aryl Halides.

    Science.gov (United States)

    Konev, Mikhail O; Hanna, Luke E; Jarvo, Elizabeth R

    2016-06-01

    Nickel-catalyzed cross-electrophile coupling reactions of benzylic esters and aryl halides have been developed. Both inter- and intramolecular variants proceed under mild reaction conditions. A range of heterocycles and functional groups are tolerated under the reaction conditions. Additionally, the first example of a stereospecific cross-electrophile coupling of a secondary benzylic ester is described. PMID:27099968