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1.
The formation and phase behavior of Jatropha curcas-based microemulsion systems, which could potentially be used in enhanced oil recovery applications, has been investigated. Winsor type III microemulsions were obtained by adding n-octane to Winsor type I microemulsion systems prepared using various concentrations of alkyl polyglucoside (APG). To optimize the formulation of type III microemulsion systems, five different types of co-surfactants, i.e. normal butyl alcohol (NBA), isobutyl alcohol, isopropyl alcohol, fatty acid alcohol C8 (FAC8) and fatty acid alcohol C8/C10 (FAC8/C10) were used. The microemulsion phase behavior was determined along with particle size distributions by dynamic light scattering measurements. Results show that the optimum Winston type III system can be achieved by mixing 3 wt% of NBA, 1 wt% APG and 3 wt% NaCl. At the optimum formulation, the IFT reached a minimum value (0.016 mN/m) and formed very small emulsion droplets with a narrow particle size distribution.  相似文献   

2.
Jatropha curcas seeds are rich in oil (28–32%), which can be converted to high quality biodiesel. The oil is non-edible due to the presence of toxic compounds, namely, phorbol esters (PEs). PEs have a number of agricultural/medicinal/pharmaceutical applications and hence their recovery generates a value added co-product towards the biodiesel production chain. This study aims to assess the effects of PE extraction on quality of both the residual oil and the biodiesel production from it. Two Approaches (1, use of an Ultra-turrax; and 2, use of a magnetic stirrer) were used with an effective treatment time of 2 and 5 min, resulting in 80 and 78% extraction of PEs, respectively. The phosphorus content was reduced by 70.2 and 75.8%, free fatty acids by 55.3 and 55.6%, and the fatty acid composition did not change in the residual oils. The peroxide value increased from 2.69 (untreated oil) to 3.01 and 3.49 mequiv O2/kg in the residual oils following Approach 1 and Approach 2, respectively. The biodiesel prepared from both residual oils met European (EN 14214:2008) and American biodiesel standard (ASTM D6751-09) specifications. Oxidative stability indices for both the biodiesels were well within the permitted limit. It is concluded that PEs could be isolated in active forms for various applications by either of the two methods with a high yield and the residual oil can be processed to produce high quality biodiesel.  相似文献   

3.
Phorbol esters present in Jatropha curcas oil are toxic when consumed and are co-carcinogens. These could be a potential constraint in the widespread acceptance of Jatropha oil as a source of biodiesel. Phorbol esters were quantified in the fractions obtained at different stages of oil pre-treatment and biodiesel production. During degumming some phorbol esters were removed in the acid gums and wash water. This implies that the use of these acid gums in animal feed is not possible and care should be taken when disposing the wash water into the environment. Silica treatment did not decrease the phorbol esters, while stripping/deodorization at 260 °C at 3 mbar pressure with 1% steam injection completely degraded phorbol esters. Phorbol esters were not detected in stripped oil, fatty acid distillate, transesterified oil (biodiesel) and glycerine. The presence of possibly toxic phorbol ester degradation products in these fractions could not be ruled out.  相似文献   

4.
Few studies report the individual effect of 9c,11t- and 10t,12c-CLA on human energy metabolism. We compared the postprandial oxidative metabolism of 9c,11t- and 10t,12c-CLA and oleic acid (9c-18:1) in 22 healthy moderately overweight volunteers. After 24 weeks supplementation with 9c,11t-, 10t,12c-CLA or 9c-18:1 (3 g/day), subjects consumed a single oral bolus of the appropriate [1-13C]-labeled fatty acid. 8 h post-dose, cumulative oxidation was similar for 9c-18:1 and 10t,12c (P = 0.66), but significantly higher for 9c,11t (P < 0.01).  相似文献   

5.
The autoxidation processes of the cis-9,trans-11 (c9,t11) and trans-10,cis-12 (t10,c12) isomers of CLA were separately observed at ca. 0% RH and different temperatures. The t10,c12 CLA oxidized faster than the c9,t11 isomer at all tested temperatures. The first half of the oxidation process of t10,c12 CLA obeyed an autocatalytic-type rate expression, but the latter half followed first-order kinetics. On the other hand, the entire oxidation process of c9,t11 CLA could be expressed by the autocatalytic-type rate expression. The apparent activation energies and frequency factors for the autoxidation of the isomers were estimated from the rate constants obtained at various temperatures based on the Arrhenius equation. The apparent activation energies for the CLA isomers were greater than those for the nonconjugated n−6 and n−3 PUFA or their esters. However, the enthalpyentropy compensation held during the autoxidation of both the CLA and PUFA. This suggested that the autoxidation mechanisms for the CLA and PUFA were essentially the same.  相似文献   

6.
Yellow-cedar, Callitropsis nootkatensis, is prevalent in coastal forests of southeast Alaska, western Canada, and inland forests along the Cascades to northern California, USA. These trees have few microbial or animal pests, attributable in part to the distinct groups of biologically active secondary metabolites their tissues store for chemical defense. Here we summarize the new yellow-cedar compounds identified and their biological activities, plus new or expanded activities for tissues, extracts, essential oils and previously known compounds since the last review more than 40 years ago. Monoterpene hydrocarbons are the most abundant compounds in foliage, while heartwood contains substantial quantities of oxygenated monoterpenes and oxygenated sesquiterpenes, with one or more tropolones. Diterpenes occur in foliage and bark, whereas condensed tannins have been isolated from inner bark. Biological activities expressed by one or more compounds in these groups include fungicide, bactericide, sporicide, acaricide, insecticide, general cytotoxicity, antioxidant and human anticancer. The diversity of organisms impacted by whole tissues, essential oils, extracts, or individual compounds now encompasses ticks, fleas, termites, ants, mosquitoes, bacteria, a water mold, fungi and browsing animals. Nootkatone, is a heartwood component with sufficient activity against arthropods to warrant research focused toward potential development as a commercial repellent and biopesticide for ticks, mosquitoes and possibly other arthropods that vector human and animal pathogens.  相似文献   

7.
Derivatives of 2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylic acid (chrysanthemic acid) are classic natural pyrethroids discovered in pyrethrum plants and show insecticidal activity. Chrysanthemic acid, with two asymmetric carbons, has four possible stereoisomers, and most natural pyrethroids have the (1R,3R)-trans configuration. Interestingly, chrysanthemic acid–related structures are also found in insect sex pheromones; carboxylic esters of (1R,3R)-trans-(2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropyl)methanol (chrysanthemyl alcohol) have been reported from two mealybug species. In the present study, another ester of chrysanthemyl alcohol was discovered from the striped mealybug, Ferrisia virgata (Cockerell), as its pheromone. By means of gas chromatography–mass spectrometry, nuclear magnetic resonance spectrometry, and high-performance liquid chromatography analyses using a chiral stationary phase column and authentic standards, the pheromone was identified as (1S,3R)-(?)-cis-chrysanthemyl tiglate. The (1S,3R)-enantiomer strongly attracted adult males in a greenhouse trapping bioassay, whereas the other enantiomers showed only weak activity. The cis configuration of the chrysanthemic acid–related structure appears to be relatively scarce in nature, and this is the first example reported from arthropods.  相似文献   

8.
We used a microwave heating system to increase Jatropha biodiesel yield, and to reduce both reaction time and energy consumption. The feasibility of converting natural and non-edible feedstocks including arcuate mussel shells and dolomitic rocks, into a novel high-performance, reusable, low-cost and heterogeneous catalyst for the synthesis of biodiesel was also explored. Arcuate mussel shells and dolomitic rocks were first ground and calcined at 900 °C for 2 h. After calcination, calcium oxide (CaO) or a mixed oxide of calcium and magnesium (CaO·MgO) was obtained as white powder, which was then chemically activated to improve the physical, chemical and surface properties, and catalytic activities of the catalysts. By heating CaO from waste shells in an excess dehydrated methanol under 65 °C at 8 h with nitrogen (N2) flow, calcium methoxide (Ca(OCH3)2) catalyst was prepared. The CaO from natural rocks was, however, turned into calcium glyceroxide complex, by combining with methanol and glycerol of the by-product. It was determined that calcium glyceroxide (Ca[O(OH)2C3H5]2) was formed during the transesterification and acted as the most active phase. Catalyst characterization was by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), and Brunauer-Emmett-Teller (BET) surface area and basic strength measurements. The reaction parameters, including reaction time, microwave power, methanol/oil molar ratio, catalyst dosage and catalyst reusability, were studied for fatty acid methyl esters (FAME) yield. The results indicated that Ca(OCH3)2 and Ca[O(OH)2C3H5]2 catalysts derived from waste shells and natural rocks showed good reusability, high energy efficient, environmental-friendly, low cost and facile route for the synthesis of biodiesel.  相似文献   

9.
The sandalwood kernels of Santalum insulare (Santalaceae) collected in French Polynesia give seed oils containing significant amounts of ximenynic acid, E-11-octadecen-9-oic acid (64–86%). Fatty acid (FA) identifications were performed by gas chromatography/mass spectrometry (GC/MS) of FA methyl esters. Among the other main eight identified fatty acids, oleic acid was found at a 7–28% level. The content in stearolic acid, octadec-9-ynoic acid, was low (0.7–3.0%). An inverse relationship was demonstrated between ximenynic acid and oleic acid using 20 seed oils. Results obtained have been compared to other previously published data on species belonging to the Santalum genus, using multivariate statistical analysis. The relative FA S. insulare composition, rich in ximenynic acid is in the same order of those given for S. album or S. obtusifolium. The other compared species (S. acuminatum, S. lanceolatum, S. spicatum and S. murrayanum) are richer in oleic acid (40–59%) with some little differences in linolenic content.  相似文献   

10.
In this study, we synthesized the new kinds of semiconducting polymeric gels having negative (n-type) and positive (p-type) counter ions as charge carriers. The polyacrylamide gel was doped with pyranine (8-hydroxypyrene-1,3,6-trisulfonic acid, trisodium salt), having \textSO3 - {\text{SO}}_{3}^{ - } ions as side groups and Na+ as counter ions, so-called p-type semiconducting gel. The doping process was performed during the polymerization where the pyranine binds to the polymer strands over OH group chemically via radical addition. In a similar way, N-isopropylacrylamide (NIPA) gel was doped with methacrylamidopropyltrimethyl ammonium chloride (MAPTAC), having Cl as counter ions, so-called n-type semiconducting gel. Here MAPTAC was embedded by copolymerization within the polymer network (NIPA). These semiconducting gels can show different electrical properties by changing the concentration of the doping agents, swelling ratio etc. We have shown that the pn junction, formed by combining p-type and n-type gels together in close contact, rectifies the current similar to the conventional Si and Ge diodes.  相似文献   

11.
The seeds of two Apiaceae species, Ligusticum hultenii and Lomatium californicum, were investigated. Preliminary bioassays indicated that methylene chloride extracts of seeds of both species contained selective phytotoxic activity against monocots and antifungal activity against Colletotrichum fragariae. Active constituents were isolated by bioassay-guided fractionation, and the structures were elucidated by NMR and GC-MS as apiol and Z-ligustilide, isolated from L. hultenii and L. californicum, respectively. Apiol and Z-ligustilide had I50 values of about 80 and 600 μM, respectively, for inhibition of the growth of Lemna paucicostata. The methylene chloride (CH2Cl2) extracts of the seeds and the isolated and purified compounds were tested against the 2-methylisoborneol-producing cyanobacterium (blue-green alga) Oscillatoria perornata, and the green alga Selenastrum capricornutum. The CH2Cl2 extracts of both Apiaceae species and apiol were weakly toxic to both species of phytoplankton, while Z-ligustilide was toxic to both with a lowest complete inhibitory concentration (LCIC) of 53 μM. Seeds of L. californicum and L. hultenii were found to be rich sources of Z-ligustilide (97 mg/g of dry seed) and apiol (40 mg/g of dry seed), respectively.  相似文献   

12.
Neotropical attine ants live in obligatory symbiosis with a fungus that they grow for food on a substrate of primarily plant material harvested by workers. Nestmate recognition is likely based on chemical cues as in most other social insects, but recent studies have indicated that both the ants and their mutualistic fungi may contribute to the recognition templates. To investigate the within-colony variation in chemical profiles, we extracted and identified compounds from the cuticle of workers, the postpharyngeal gland of workers, ant pupae and larvae, and the fungal symbiont of three species of higher attine ants: Atta colombica, Acromyrmex echinatior, and Sericomyrmex amabilis. The relative proportions of identified compounds were compared and represented 11 classes: n-alkanes, alkenes, branched methylalkanes, branched dimethylalkanes, trimethylalkanes, branched alkenes, aldehydes, alcohols, acetates, acids, and esters. The chemical profiles in all three species are likely to be sufficiently different to allow discrimination at the species and colony level and sufficiently similar within colonies to generate a relatively constant colony-specific chemical gestalt. The relative likelihood of individual compounds being derived from the ants, the ant brood, or the fungal symbiont are discussed. We hypothesize that hydrocarbons are particularly important as recognition cues because they appear to simultaneously allow the assessment of developmental stages and the identification of symbiont, colony, and species.  相似文献   

13.
Trail pheromones mediate communication among western subterranean termites, Reticulitermes hesperus Banks. Repetitive passages of ≥28 termites were required to establish a pheromone trail and trails needed to be reinforced because they lasted <48 hr. The minimal threshold concentration for inducing responses from termite workers and secondary reproductives was between 0.01 and 0.1 fg/cm of (3Z,6Z,8E)-dodecatrien-1-ol (henceforth, dodecatrienol). Workers showed optimal trail-following behavior to dodecatrienol at a concentration of 10 fg/cm. Trails with concentrations >10 pg/cm were repellent to workers. Workers did not detect pheromone gradients, responding equally to increasing or decreasing gradients of dodecatrienol, and termite workers were not able to differentiate between different concentrations of dodecatrienol. Termites preferred dodecatrienol trails to 2-phenoxyethanol trails. Antennae played a key role in trail pheromone perception. Dodecatrienol acted as an arrestant for worker termites (10 fg/cm2) and male alates (5 ng/cm2), whereas sternal gland extracts from females attracted male alates. Workers and alates, upon contact with filter paper disks treated with higher doses (10 fg/cm2 and 5 ng/cm2, respectively) of dodecatrienol, were highly excited (increased antennation and palpation) and repeatedly returned to the treated disks. Dodecatrienol did not act as a phagostimulant when offered on a paper towel disk. Reticulitermes hesperus is highly responsive to dodecatrienol, and it may play an important role in orientation of workers and alates.  相似文献   

14.
The chitosan Schiff bases were synthesised through the condensation reaction of chitosan with o-, m- and p-nitrobenzaldehyde (abbreviated as CSB-o, CSB-m and CSB-p) in the ratio 1:1 and were characterised by means of FTIR, UV, XRD and SEM. The thermal dehydration and degradation kinetics of all these Schiff bases were studied using different isoconversional and maximum rate (peak) methods, viz. Kissinger–Akahira–Sunose (KAS), Tang, Starink, Flynn–Wall–Ozawa (FWO) and Bosewell from DSC data and the thermal stability from TG. The activation energy values of thermal dehydration and degradation reactions obtained from isoconversional methods of FWO and Bosewell are slightly higher than that obtained from other methods. All the isoconversional and maximum rate (peak) methods yielded consistent values of E α for both the dehydration and degradation reactions and is in the order CSB-o < CSB-m < CSB-p. The Schiff bases observed (from TG) the same order of thermal stability.  相似文献   

15.
The objective of the present study was to compare the effects of cis-9,trans-11 + trans-8,cis-10 conjugated linoleic acid (CLA) mixture to those of cis-9,trans-11 + trans-10,cis-12 CLA mixture and linoleic acid (LA) on lipoprotein profile, hepatic lipids, body composition and digestibility of dietary fat in hamsters (n = 17) fed diets containing 2% of experimental fat (w/w) for 28 days. The cis-9,trans-11 + trans-10,cis-12 CLA mixture showed higher LDL cholesterol concentrations than LA and the cis-9,trans-11 + trans-8,cis-10 CLA mixture. The cis-9,trans-11 + trans-8,cis-10 CLA mixture induced similar plasma LDL cholesterol and hepatic lipid concentrations, and coefficient of digestibility as LA, indicating no effect of the trans-8,cis-10 CLA isomer on these lipid parameters. On the other hand, the cis-9,trans-11 + trans-8,cis-10 CLA mixture induced higher plasma VLDL cholesterol and triglycerides than LA and the cis-9,trans-11 + trans-10,cis-12 CLA mixture. The cis-9,trans-11 + trans-8,cis-10 CLA mixture also induced the highest plasma glucose concentrations compared with the two other groups, indicating an impairment of glycemic control. No differences in body composition were noted between the three groups. The present results thus show that the cis-9,trans-11 + trans-8,cis-10 CLA mixture can deteriorate plasma VLDL cholesterol and triglycerides in hamsters, possibly due to an increased flux of glucose.  相似文献   

16.
Ethanolic extract of aerial parts of Artemisia annua L. and artemisinin were evaluated as anti-insect products. In a feeding deterrence assay on Epilachna paenulata Germ (Coleoptera: Coccinellidae) larvae, complete feeding rejection was observed at an extract concentration of 1.5 mg/cm2 on pumpkin leaf tissue. The same concentration produced a feeding inhibition of 87% in Spodoptera eridania (Cramer) (Lepidoptera: Noctuidae). In a no-choice assay, both species ate less and gained less weight when fed on leaves treated with the extract. Complete mortality in E. paenulata and 50% mortality in S. eridania were observed with extract at 1.5 mg/cm2. Artemisinin exhibited a moderate antifeedant effect on E. paenulata and S. eridania at 0.03–0.375 mg/cm2. However, a strong effect on survival and body weight was observed when E. paenulata larvae were forced to feed on leaves treated at 0.03 and 0.075 mg/cm2. Artemisia annua ethanolic extract of aerial parts at 1.5 mg/cm2 showed no phytotoxic effect on pumpkin seedlings.  相似文献   

17.
Evidence suggests that minor isomers of conjugated linoleic acid (CLA), such as trans8, cis10 CLA, can elicit unique biological effects of their own. In order to determine the effect of a mixture of t8, c10+c9, t11 CLA isomers on selected aspects of lipid metabolism, 3T3-L1 preadipocytes were differentiated for 8 days in the presence of 100 μM linoleic acid (LA); t8, c10+c9, t11 CLA; t10, c12+c9, t11 CLA or purified c9, t11 CLA. Whereas supplementation with c9, t11 and t10, c12+c9, t11 CLA resulted in cellular triglyceride (TG) concentrations of 3.4 ± 0.26 and 1.3 ± 0.11 μg TG/μg protein, respectively (P < 0.05), TG accumulation following treatment with CLA mixture t8, c10+c9, t11 was significantly intermediate (2.5 ± 0.22 μg TG/μg protein, P < 0.05) between the two other CLA treatments. However, these effects were not attributable to an alteration of the Δ9 desaturation index. Adiponectin content of adipocytes treated with t8, c10+c9, t11 mixture was similar to the individual isomer c9, t11 CLA, and both the t8, c10+c9, t11 and c9, t11 CLA groups were greater (P < 0.05) than in the t10, c12+c9, t11 CLA group. Overall, these results suggest that t8, c10+c9, t11 CLA mixture affects TG accumulation in 3T3-L1 cells differently from the c9, t11 and t10, c12 isomers. Furthermore, the reductions in TG accumulation occur without adversely affecting the adiponectin content of these cells.  相似文献   

18.
E-2-ethyl-2-hexen-1-ol (1), mellein (4), and 4-hydroxymellein (5) were identified as the major volatile compounds in the head and/or thorax of Camponotus quadrisectus. Neither 1 nor 5 have been previously detected in insects. Also identified were small amounts of m-cresol (2) and 6-methyl salicylic acid (3). E-2-ethylhexenal (6) and small amounts of 3 were identified in heads of Camponotus irritibilis from Kuala Belalong, Brunei. Compounds 24 occur in other Bornean camponotines with hypertrophied mandibular glands, and 4 is widespread in the tribe. The possibility of semiochemical parsimony (multiple functions) for these mandibular gland compounds is reviewed in the context of existing data on mandibular gland products of other camponotines, reported biological activities of the compounds, and secondary loss of metapleural glands in this ant group.  相似文献   

19.
The hydrocarbons (3Z,6Z,9Z)-3,6,9-octadecatriene (3Z,6Z,9Z-18:H) and (3Z,6Z,9Z)-3,6,9-nonadecatriene (3Z,6Z,9Z-19:H) constitute the pheromone of the winter moth, Erannis bajaria. These compounds belong to a large group of lepidopteran pheromones which consist of unsaturated hydrocarbons and their corresponding oxygenated derivatives. The biosynthesis of such hydrocarbons with an odd number of carbons in the chain is well understood. In contrast, knowledge about the biosynthesis of even numbered derivatives is lacking. We investigated the biosynthesis of 3Z,6Z,9Z-18:H by applying deuterium-labeled precursors to females of E. bajaria followed by gas chromatography–mass spectrometry analysis of extracts of the pheromone gland. A mixture of deuterium-labeled [17,17,18,18-2H4]-3Z,6Z,9Z-18:H and the unlabeled 3Z,6Z,9Z-18:H was obtained after topical application and injection of (10Z,13Z,16Z)-[2,2,3,3-2H4]-10,13,16-nonadecatrienoic acid ([2,2,3,3-2H4]-10Z,13Z,16Z-19:acid) or (11Z,14Z,17Z)-[3,3,4,4-2H4]-11,14,17-icosatrienoic acid ([3,3,4,4-2H4]-11Z,14Z,17Z-20:acid). These results are consistent with a biosynthetic pathway that starts with α-linolenic acid (9Z,12Z,15Z-18:acid). Chain elongation leads to 11Z,14Z,17Z-20:acid, which is shortened by α-oxidation as the key step to yield 10Z,13Z,16Z-19:acid. This acid can be finally reduced to an aldehyde and decarbonylated or decarboxylated to furnish the pheromone component 3Z,6Z,9Z-18:H. A similar transformation of 11Z,14Z,17Z-20:acid yields the second pheromone component, 3Z,6Z,9Z-19:H.  相似文献   

20.
Hyalesthes obsoletus Signoret (Homoptera: Cixiidae) is a polyphagous planthopper that transmits stolbur phytoplasma (a causative agent of yellows disease) to various weeds, members of the Solanaceae, and wine grapes (Vitis vinifera L.) in Europe and the Middle East. Planthoppers were collected by hand vacuuming eight native plant species. Vitex agnus-castus L., a shrub in the Verbenaceae, hosted the largest number of H. obsoletus, although Olea europaea L. also served as a host for adults. Using a Y-olfactometer, we compared the planthoppers relative preference for V. agnus-castus, Convolvulus arvensis, and V. vinifera. V. agnus-castus was more attractive to both male and female H. obsoletus than the other plants. H. obsoletus antennal response was stronger to volatiles collected from V. agnus-castus than from Cabernet Sauvignon variety of V. vinifera. To determine if V. agnus-castus would serve as a reservoir for the pathogen, H. obsoletus were collected from leaf and stem samples of native V. agnus-castus, and were tested by polymerase chain reaction (PCR) for the presence of phytoplasma DNA. While 14% and 25% (2003 and 2004, respectively) of the insects tested positive for phytoplasma DNA, none of the plant samples tested positive. To determine if V. agnus-castus could serve as a host plant for the development of the planthopper, we placed emergence cages beneath field shrubs and enclosed wild-caught H. obsoletus in a cage with a potted young shrub. We found adult H. obsoletus in the emergence cases and planthopper nymphs in the soil of the potted plant. We concluded that V. agnus-castus is attractive to H. obsoletus, which seems to be refractory to phytoplasma infections and warrants further testing as a trap plant near vineyards.  相似文献   

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