bluuebunny/crossref_metadata_2025 huggingface dataset:
Sphingolipids in immature and mature soybeans
Authors: Ohnishi Masao , Fujino Yasuhiko
Published: December 2006

Ceramides and cerebrosides were isolated from immature and mature soybeans, and structures of the constituents were investigated. As component fatty acids, normal, 2‐hydroxy and 2,3‐dihydroxy acids were found in ceramides, whereas only normal and 2‐hydroxy acids were identified in cerebrosides. The principal fatty acid component was 2‐hydroxylignoceric acid in ceramides, and 2‐hydroxypalmitic acid in cerebrosides. Sphingoids in ceramides consisted mainly of trihydroxy bases, with 4‐hydroxy‐trans‐8‐sphingenine being predominant. In contrast, cerebrosides contained mainly dihydroxy bases, the principal constituent beingtrans‐4,trans‐8‐sphingadienine. The only sugar in cerebrosides was glucose. The constituents of the two sphingolipids were similar to each other in immature and mature seeds. Possible metabolic relations of plant sphingolipids, based on composition, are discussed.
Glass capillary gas chromatography‐mass spectrometry of wax esters, steryl esters and triacylglycerols
Authors: Wakeham Stuart G. , Frew Nelson M.
Published: December 2006

Complex mixtures of wax esters, steryl esters and triacylglycerols isolated from representative biological and geochemical samples have been analyzed using combined high resolution gas chromatography and electron impact and chemical ionization quadrupole mass spectrometry. These low volatility neutral lipids containing up to 65 carbons were chromatographed intact on 15–20 m high‐temperature (upper limit: 370 C) persilylated SE‐52 and SE‐30 glass capillary columns. Discrimination effects due to adsorptive losses and degradation were minimized using a nonvaporizing on‐column injector and a direct all‐glass capillary connection (370 C) to the quadrupole mass spectrometer. Structural information regarding the fatty acid and alcohol moieties was found to be maximal for methane‐CI spectra in the case of wax and steryl esters, whereas EI spectra were most useful in interpreting triacylglycerol structures. Principal features of the EI and CI fragmentation patterns are discussed. The molecular composition of complex mixtures of these lipids is reconstructed for selected samples.
Riboflavin deficiency and β‐oxidation systems in rat liver
Authors: Sakurai Takehiko , Miyazawa Shoko , Furuta Shuichi , Hashimoto Takashi
Published: December 2006

Weanling rats were fed a riboflavin‐deficient diet. The mitochondrial fatty acid oxidation in liver was depressed in riboflavin deficiency but restored after supplementation of riboflavin. Among the enzymes involved in this system, only the acyl‐CoA dehydrogenase (EC 1.3.99.2 and 1.3.99.3) activities varied with the change in fatty acid oxidation. An accumulation of the apoforms of acyl‐CoA dehydrogenases was found in riboflavin deficiency. The levels of electron transfer flavoprotein and other enzymes involved in the β‐oxidation system remained unchanged. The peroxisomal fatty acid oxidation and levels of individual enzymes of this system remained constant. No accumulation of the apoform of acyl‐CoA oxidase was observed under simple, riboflavin‐deficient conditions. However, accumulation of a large amount of apo‐acyl‐CoA oxidase was observed when the peroxisomal system was induced by administration of a peroxisome proliferator, di(2‐ethylhexyl)phthalate, under riboflavin‐deficient conditions.
Fecal steroids in diarrhea: IV. Cholera
Authors: Huang Charles T. L. , Levine Myron M. , Daoud Georgette S. , Nalin David R. , Nichols Buford L.
Published: December 2006

Fecal bile acid and neutral sterol patterns were studied in eight healthy adult volunteers who were challenged withVibrio cholerae classical Ogawa 395 strain in the course of vaccine development studies. Bacterial 7α‐dehydroxylation of cholic and chenodeoxycholic acids was not altered during experimentally induced cholera diarrhea, despite the fact that fecal weight in g/day (wet wt) was increased greatly during diarrhea (1913±390 vs 161±11 in controls, p<0.005). Consistent with the findings on bile acids, no significant changes in the production of coprostanol, epicoprostanol, or coprostanone were observed although the percentage of unmodified cholesterol was increased during the diarrheal episode (20.7±3.3% vs 11.9±2.3, p<0.02). Total concentrations of both bile acids and cholesterol in mg/g of feces (wet wt) were decreased considerably as a result of diarrhea). However, total bile acid and neutral steroid excretions in mg/kg/day in subjects with and without diarrhea do not appear to be different. Intestinal transit times, measured in eight subjects by the use of carmine red dye, were found to be shortened in diarrhea (5.8±1.1 hr vs 23.4±4.1 hr in controls, p<0.001). The results from this study are similar to those observed in experimentally induced travellers' diarrhea associated with toxigenicEscherichia coli, but they are in striking contrast to the changes in gastrointestinal steroid metabolism observed in acute shigello sis, an invasive intestinal infection.
Fatty acid patterns in iron‐deficient maternal and neonatal rats
Authors: Sherman Adria Rothman , Bartholmey Sandra J. , Perkins Edward G.
Published: December 2006

To determine the effects of maternal iron deficiency on lipid composition and fatty acid patterns in offspring, rats were fed ad libitum diets containing 5 ppm iron (deficient) (n=8) or 320 ppm iron (control) (n=7) and deionized water from day‐1 of gestation through day‐18 of lactation. On day‐2 of lactation, litters were standardized to three male and three female pups. On day‐18, pups were fasted for 4 hr before tissue and blood collection. Significant changes in serum and liver lipid concentrations and fatty acid patterns were observed in deficient pups. Serum triglycerides, cholesterol and phospholipids and liver triglycerides, cholesterol, and cholesteryl esters were increased. In deficient pups, percentage total fatty acids of 14∶0, 16∶1, 18∶1, 18∶2 from serum lipids were increased; in liver, 14∶0, 18∶2, 18∶3 were increased; 18∶0 and 20∶4 were decreased in both serum and liver. Dam serum lipid levels did not differ between groups. Lipid changes observed in iron‐deficient pups did not consistently reflect the milk, serum or liver lipid patterns observed in dams. Altered lipid composition and fatty acid patterns of iron‐deficient pups thus appear to be of endogenous origin.
Occurrence of octadecenoic fatty acid isomers from hydrogenated fats in human tissue lipid classes
Authors: Ohlrogge J. B. , Gulley R. M. , Emken E. A.
Published: December 2006

The level oftrans‐18∶1 isomers in several isolated lipid classes of human liver, heart, red blood cells and plasma was determined. Phospholipids contained substantially fewertrans‐18∶1 isomers than triglycerides. The double bond distribution of thecis andtrans octadecenoate fraction of triglycerides and phosphatidylcholines from human liver and heart was determined. Whereas the double bond distribution of the triglycerides correlated closely with the pattern found in dietary hydrogenated vegetable oils, the phosphatidylcholine fraction showed evidence of selective incorporation or metabolism of specifictrans positional isomers. In general, isomers with double bonds near the methyl terminus were present at levels higher than expected from their relative abundance in the diet. Refinements in methodology needed to analyze octadecenoate double bond configuration and location in human tissues are presented.
Synthesis of mixed‐acid phosphatidylcholines and high pressure liquid chromatographic analysis of isomeric lysophosphatidylcholines
Authors: Nicholas Allan W. , Khouri Liliane G. , Ellington Joe C. , Porter Ned A.
Published: December 2006

A new method for the synthesis of mixed‐chain phosphatidylcholines is reported. Silver ion catalyzed acylation of lysophosphatidylcholines by 2‐thiopyridyl esters occurs rapidly (10 min) at room temperature in organic solvents. Yields of isomerically pure mixed‐chain phosphatidylcholines (>98% isomeric purity) are generally greater than 80%. The reaction proceeds with only 1.5‐ to 2‐fold excess of thiopyridyl ester, thus offering some advantages over existing procedures when precious acylating agents are used. The major disadvantage of the procedure is its sensitivity to water. Phosphatidylcholines having hydroxy fatty acyl groups are prepared by protection of the hydroxyl as the levulinate ester, conversion to the 2‐thiopyridyl ester, acylation, and removal of the levulinate with hydrazine. For purification of lysophosphatidylcholines, a reverse‐phase high pressure liquid chromatographic method for separation of 1‐acylglycerophosphocholines from 2‐acylglycerophosphocholines was developed.
Sulfite‐induced lipid peroxidation
Authors: Lizada M. C. C. , Yang S. F.
Published: December 2006

Sulfite initiated the peroxidation of linoleic acid and linolenic acid emulsions via a free radical mechanism. Peroxidation of these fatty acids required oxygen and sulfite and occurred with concomitant oxidation of sulfite to sulfate. In reaction mixtures containing linoleic acid, the formation of conjugated diene equaled the formation of hydroperoxide. In reaction mixtures containing linolenic acid emulsions, thiobarbituric acid reactive materials were also formed. Peroxidation was pH‐dependent; peroxidation of linoleic acid proceeded between pH 4 and 7, but linolenic acid peroxidation was significant only if pH was below pH 6. The linoleic acid hydroperoxides thus formed were reduced and methylated to methyl hydroxystearate. Analysis of methyl hydroxystearate by gas chromatographymass spectrometry indicated that sulfite‐induced peroxidation gave rise to the 9‐ and 13‐hydroperoxy isomers. In addition to the hydroperoxides, sulfite adducts were detected. Hydroquinone, butylated hydroxytoluene and α‐tocopherol effectively inhibited both sulfite oxidation and hydroperoxide formation. Conjugated diene formation also was inhibited by 4‐thiouridine, suggesting that the reaction is mediated by the sulfite radical. No significant inhibition was observed with the addition of superoxide dismutase, catalase, or the hydroxyl radical scavengers, mannitol ort‐butanol. A possible mechanism is presented to account for sulfite‐induced peroxidation of linoleic acid.
Purification of surfactant from lung washings and washings contaminated with blood constituents
Authors: Shelley Sue A. , Paciga June E. , Balis John U.
Published: December 2006

A rapid and simple method capable of purifying surfactant from rabbit alveolar washings and from washings contaminated with serum has been developed. The sample, containing 16% NaBr, is placed beneath a two‐layer discontinuous gradient of NaBr. After centrifugation, the surfactant is found near the top of the gradient tube at a density of 1.085 at 4 C while the contaminating material remains near the bottom. The lipid composition of surfactant from lung washings of normal animals isolated by this method compares quite favorably with surfactant isolated by much more elaborate and time consuming methods. Surfactant purified from mixtures of3H‐palmitate labeled rabbit serum and lung washings (1.6 mg serum phospholipid: 1 mg washing phospholipid) contained less than 3% of the phospholipid radioactivity. The phospholipid composition of this band was quite similar to that of surfactant from normal lung washings, but the protein content was much higher. A second density gradient centrifugation removed 90% of this protein resulting in a surfactant fraction with a phospholipid to protein ratio similar to that of surfactant from normal lung washings. These findings demonstrate that this purification method is capable of removing a large proportion of both serum phospholipids and proteins from lung washings contaminated with serum, making this method uniquely suitable for evaluation of surfactant in pathologic conditions of the lung.
Chaulmoogric acid: Assimilation into the complex lipids of mycobacteria
Authors: Cabot Myles C. , Goucher Charles R.
Published: December 2006

Lipid analysis ofMycobacterium vaccae, grown in the presence of chaulmoogric acid, demonstrates that this cyclopentenyl fatty acid is taken up by the organism and incorporated into cellular phospholipids and triacylglycerols. As cell growth is retarded by the addition of chaulmoorgric acid to the growth medium, it is possible that the antimicrobial properties of this compound result from a perturbation of membrane processes.
Stimulation of bile acid synthesis by dibutyryl cyclic AMP in isolated rat hepatocytes
Authors: Sundaram G. S. , Rothman Vicki , Margolis Simeon
Published: December 2006

Freshly isolated rat hepatocytes were used to examine the effects of dibutyryl cyclic AMP on the incorporation of14C‐acetate and14C‐cholesterol into bile acids. After an initial lag period, both precursors were incorporated into cholic and chenodeoxycholic acids at a linear rate for the subsequent 60 min. An apparent stimulation of bile acid formation from14C‐acetate by dibutyryl cyclic AMP was complicated by the concomitant inhibition of cholesterol synthesis. In experiments with14C‐cholesterol, dibutyryl cyclic AMP (1 mM) increased the labeled cholic and chenodeoxycholic acids in the medium by 83 and 224%, respectively, but cellular levels of labeled bile acids were unchanged. As a result, the nucleotide stimulated the overall incorporation of14C‐cholesterol into cholic acid by 39% and into chenodeoxycholic acid by 123%. The mean ratio of labeled cholic to chenodeoxycholic acid declined from 55∶45 in control cells to 41∶59 in cells incubated with dibutyryl cyclic AMP. The results demonstrate that label incorporation can be used to study the regulation of bile acid synthesis in isolated hepatocytes. We propose that dibutyryl cyclic AMP enhances bile acid production by phosphorylating, and thus stimulating the activity of, cholesterol 7α‐hydroxylase, the rate‐limiting enzyme in bile acid synthesis.
Hypercholesterolemia in rats fed cholesterol in agar gel diets
Authors: Erdman John W. , O'Reilly Thomas C.
Published: December 2006

Female (Exp. I) or male (Exp. II) weanling rats were fed diets containing either 2% Solka‐Floc or 2% agar for 28‐day periods. Some groups received 1% cholesterol, either added in crystalline form or first dispersed in the oil portion of the diet, and some agar groups received their diet in a gelled form. Feces were collected for a 3‐day period after 2 weeks (Exp. II) or during the fourth week (Exp. I) of experimentation. Serum and liver cholesterol, total liver lipids, fecal lipids, and fecal sterols were determined. The results indicated that cholesterol feeding increased serum cholesterol, total liver, and fecal lipids, liver cholesterol, and fecal sterols. Substitution of agar for Solka‐Floc in dry (nongelled) diets further increased total liver lipids (Exp. I), but had no significant effect upon any other measured parameter. Gelling of 1% cholesterol agar diets, in contrast to the 1% cholesterol dry agar diet, resulted in reduced liver cholesterol in both experiments. Gelling significantly increased fecal sterols after 2 weeks feeding (Exp. II), but no significant differences were observed after 4 weeks feeding (Exp. I) when compared to 1% cholesterol‐fed groups. Small, nonsignificant increases of liver cholesterol and total liver lipids with similar reduction of fecal sterols resulted from dispersing the cholesterol in the oil portion of the diet prior to mixing. The results indicate that (a) inclusion of 2% agar in rat diets and (b) dispersing cholesterol in oil had little effect upon serum, liver, or fecal lipids in cholesterol‐fed rats. However, gelling the agar diets reduced liver cholesterol, possibly by initial reduction of dietary cholesterol absorption.
The transfer of free palmitic and linoleic acids across the ovine placenta
Authors: Noble R. C. , Shand J. H. , Bell A. W. , Thompson G. E. , Moore J. H.
Published: December 2006

Following the injection of3H‐16∶0 and14C‐18∶2 (n−6) into the jugular vein of the ewe, the rates of disappearance of these fatty acids from the maternal plasma and their rates of appearance in the fetal plasma have been studied. The rates of disappearance of both labeled acids from the maternal circulation were similar. The appearance of radioactivity in the fetal plasma was rapid and could be detected within 2.5 min after injection into the mother. In contrast to the similar rates of disappearance of the fatty acids from the maternal plasma, the rate of accumulation of3H‐16∶0 within the fetal plasma was appreciably greater than that of14C‐18∶2 (n−6). The absolute concentrations of the total lipid and unesterified fatty acid fractions within the fetal plasma were significantly lower than that of the maternal plasma. In comparison to that of maternal plasma, fetal plasma lipid contained an extremely low proportion of 18∶2 (n−6) accompanied by an appreciable accumulation of 20∶3 (n−9). On the other hand, the proportion of 20∶4 (n−6) within the fetal plasma was about twice that present within the maternal plasma. The obvious inability of the placenta to be as freely permeable to the passage of 18∶2 (n−6) as to 16∶0 is discussed in relation to these differences in fatty acid composition between the maternal and fetal plasmas and the known poor essential fatty acid status of the developing fetus.
Analysis of alpha tocopherol in blood plasma and platelets by gas liquid chromatography
Authors: Lehmann Joanna
Published: December 2006

A method is described for the analysis of α‐tocopherol by gas liquid chromatography (GLC) with 0.3% Apiezon L as liquid phase. Impurities that interfere with GLC are removed by saponification. Cholesterol and other nonsaponifiables are separated from α‐tocopherol by GLC.
17Z‐Tetracosenyl 1‐glycerol ether from the spongesCinachyra alloclada andUlosa ruetzleri
Authors: Cardellina John H. , Graden Clinton J. , Greer Bradley J. , Kern John R.
Published: December 2006

The 1‐glycerol ether of 17Z‐tetracosenol has been identified as a major constituent of the dichloromethanesoluble extracts of two marine sponges,Cinachyra alloclada andUlosa ruetzleri. Spectral analysis and chemical degradations led to the assigned structure. Batyl alcohol was also found, in lesser quantities, inU. ruetzleri, but not inC. alloclada.
Different fatty chain compositions of alkenylacyl, alkylacyl and diacyl phospholipids in rabbit alveolar macrophages: High amounts of arachidonic acid in ether phospholipids
Authors: Sugiura Takayuki , Nakajima Motoko , Sekiguchi Nobuyuki , Nakagawa Yasuhito , Waku Keizo
Published: December 2006

High levels of ether phospholipids were found in rabbit alveolar macrophages. Choline phosphoglycerides (CPG) contained a significant amount of alkylacyl compound (32.5%). On the other hand, ethanolamine phosphoglyceride (EPG) included a very large amount of alkenylacyl compounds (61.2%). Small amounts of alkenylacyl CPG and alkylacyl EPG were also observed. The occurrence of a high amount of alkylacyl CPG may be related to the synthesis or release of platelet‐activating factor (PAF) from macrophages. Fatty chains at the 1‐ and 2‐positions in each lipid class of CPG or CPG or alkenylacyl EPG were several other. Particularly, the levels of 20∶4 (arachidonic acid) in alkylacyl CPG or alkenylacyl EPG were several times higher than those in corresponding diacyl phospholipids. Large portions of 20∶4‐containing species have alkenyl or alkyl ether moieties at their 1‐position in both CPG (73.6%) and EPG (85.9%). These results suggest the importance of ether‐containing phospholipids in rabbit alveolar macrophages.
Cholesteryl ester transfer protein inhibition by PD 140195
Authors: Bisgaier Charles L. , Essenburg Arnold D. , Minton Laura L. , Homan Reynold , Blankley C. John , White Andrew
Published: December 2006

The presence of plasma cholesteryl ester transfer protein (CETP) activity may be atherogenic, and, therefore, strategies to inhibit its activity or production may result in a beneficial effect on lipoprotein profiles and the disease process. The current report describes 4‐phenyl‐5‐tridecyl‐4H‐1,2,4‐triazole‐3‐thiol (PD 140195), a novel CETP inhibitor. The concentration‐dependent inhibition of CETP by PD 140195 and the inhibitory monoclonal antibody (Mab) TP2 is demonstrated in a variety ofin vitro assay systems. Molecular models of PD140195 suggest a spatial mimicry of the cholesteryl ester structure. Despite the structural similarity, kinetic studies with a fluorescent cholesteryl ester analog suggest that the inhibition of transfer is not competitive. PD 140195 also selectively inhibited cholesteryl ester but not triglyceride transfer, while the Mab TP2 blocked CETP transfer of both. Studies were carried out to determine whether CETP inhibition observedin vitro could also be demonstratedin vivo. When PD 140195 was intravenously infused to anesthetized rabbits (up to 20 mg/kg), only transient CETP inhibition was observed.In vitro reconstitution studies in the presence of bovine serum albumin resulted in marked reduction of PD 140195 inhibitory activity. Thus, the low activity of PD 140195 in whole plasma probably results from binding to other plasma proteins.
The lipids of slugs and snails: Evolution, diet and biosynthesis
Authors: Zhu Ning , Dai Xiaonan , Lin Don S. , Connor William E.
Published: December 2006

There is a considerable gap in current knowledge of the lipid composition of snails and slugs, both of which belong to the phylum Mollusca. We have therefore analyzed the sterol and fatty acid compositions of three species of slugs and three species of snails. The sterols of slugs included eight different sterols: cholesterol contributed 76–85% of the total sterols, brassicasterol accounted for 4–13%; other sterols we identified were lathosterol, 24‐methylene cholesterol, campesterol, stigmasterol, sitosterol and sitostanol. In contrast, snails contained two additional sterols, desmosterol and cholestanol. Of the polyunsaturated fatty acids in slugs, linoleic (18∶2n−6) and arachidonic acids (20∶4n−6) were the major n−6 fatty acids, while linolenic (18∶3n−3) and eicosapentaenoic acids (20∶5n−3) were the predominant n−3 fatty acids. Docosahexaenoic acid (22∶6n−3), the end product in the n−3 fatty acid synthetic pathway and an important membrane fatty acid of mammals, fish and birds, was absent in both slugs and snails. However, the analogous product of n−6 fatty acid synthesis, 22∶5n−6, was found in both snails and slugs. This raises speculation about preference for n−6 fatty acid synthesis in these species. Our data show the unique sterol and fatty acid compositions of slugs and snails, as well as similarities and differences in sterol composition between the two. The results between the two land mollusks are contrasted with those of marine mollusks, such as oysters, clams and scallops.
A method of ultraviolet spectrophotometry of lipid monolayers on silica gel
Authors: Porter W. L. , Henick A. S. , Jeffers J. I. , Levasseur L. A.
Published: December 2006

A method has been developed for visible and UV spectrophotometry of lipid monolayers after preadsorption on silica gel from solution in hydrocarbon solvents. Lipid‐coated silica gel is made optically transparent in the desired spectral region by slurrying with an inert solvent mixture. Reproducible gels with nearly the same refractive index as the solvent are achieved by careful choice of mixed solvents and carefully timed settling periods. The gel is pipetted into a silica cuvette of 1 cm light path, and a 9 mm silica spacer bar is inserted between Teflon guide strips. Appropriate choice of solvent mixtures (mainly spectral grade cyclohexane and cyclooctane) permits quantitation of spectra down to 2250 Angstrom units, using a silica gel reference cell. Lipid elution from the monolayer into the solvent is usually less than 1% at the dry‐mixing dilutions used. Spectra of known unsaturated carbonyl compounds adsorbed on silica show red shifts as great as 240 Angstrom units, while blue shifts as great as 100 Angstrom units are observed for tocopherol derivatives with an intact aromatic ring. Very small shifts are observed for polyenes. The extent and direction of the shifts are indicative of adsorption and its orientation and are useful in the preliminary determination of the class of an unknown compound. The silica slurry spectra of the important tocopherol oxidation products, the quinone, dimer and trimer, have been examined. Peak wavelength shifts are consistent with structures elsewhere proposed for these compounds.
Inhibition of cholesterol and fatty acid biosynthesis in liver enzymes and chicken hepatocytes by polar fractions of garlic,
Authors: Qureshi Asaf A. , Abuirmeileh Naji , Din Zafeer Z. , Elson Charles E. , Burger Warren C.
Published: December 2006

Different concentrations of polar fractions, methanol‐soluble (MESF), or water‐soluble (WASF), of 1–8% equivalent to fresh garlic paste were added to yellow corn‐soybean based diets and fed to 5‐week‐old male broiler chickens for 3 weeks to measure the inhibition of hepatic β‐hydroxy‐β‐methylglutaryl coenzyme A (HMG‐CoA) reductase, cholesterol 7α‐hydroxylase (7α‐hydroxy) and fatty acid synthetase (FAS). Dose‐related decreases in the activities of these enzymes were obtained. Decreases in serum total cholesterol and in low density lipoprotein (LDL) levels were also observed. There was no effect on the level of cholesterol in high density lipoprotein (HDL). The most effective dose for these decreases was found 0.54% (MESF) and 1.2% (WASF) equivalent to 6% of the fresh garlic. The inhibition of HMG‐CoA reductase and FAS by 25–300 μm of MESF or WASF for 15 min was tested in vitro, in male and female chicken hepatocytes. Inhibitions of activity were dose‐dependent and the degree of inhibition increased with duration of incubation (150 μg of MESF or WASF 5 to 60 min). Dietary supplementation of odorless WASF of garlic was found to be very effective in lowering the total and LDL cholesterol levels compared to control chickens.
Analysis of autoxidized fats by gas chromatography‐mass spectrometry: VIII. Volatile thermal decomposition products of hydroperoxy cyclic peroxides
Authors: Frankel Edwin N. , Neff William E. , Selke Edward
Published: December 2006

Secondary oxidation products are important sources of volatiles because of their susceptibility to further decomposition. Volatiles from the thermal decomposition of hydroperoxy cyclic peroxides have been identified by capillary gas chromatography followed by mass spectrometry (GC‐MS). By using a saturated hydroperoxy cyclic peroxide as a synthetic model, the thermal decomposition pathways have been elucidated. Main cleavage occurs between the peroxide ring and the carbon‐bearing hydroperoxide group. Volatiles produced were generally similar to those from corresponding monohydroperoxides. New volatiles identified included methyl furan octanoate, methyl ketones, and conjugated diunsaturated aldehyde esters. The general fragmentation observed between the peroxide ring and the hydroperoxide‐bearing carbons is sufficiently predictable that it can be used as a tool for the structural characterization of hydroperoxy cyclic peroxides. Hydroperoxy cyclic peroxides from autoxidized and photosensitized oxidized methyl linolenate are suggested as important precursors of volatiles that may affect flavor quality of lipid‐containing foods.
Effects of dietaryTrans‐fat on biliary and fecal steroid excretion and serum lipoproteins in rats
Authors: Sugano Michihiro , Watanabe Midori , Kohno Mitsuko , Cho Young J. , Ide Takashi
Published: December 2006

Rats were fed cholesterol‐free or cholesterol‐enriched diets containing olive oil or partially hydrogenated corn oil at the 10% level for ca. 30 days (c‐18∶1, 77.0% in the former diet andc‐18∶1, 24.7% andt‐18∶1, 42.5% in the latter). The linoleic acid content of these fat diets was made equivalent (1.7 energy%). After feeding cholesterol‐free diets,trans fat compared tocis fat showed(a) no untoward effects on growth parameters, (b) a reduction of serum cholesterol levels without influencing concentrations of serum apolipoproteins A‐I, B and E, (c) no effects on the bile flow and the concentration of biliary cholesterol and bile acids, (d) an increasing trend of fecal excretion of neutral and acidic steroids, both in terms of mg/day and mg/g feces, and (e) rather equivocal change in the composition of fecal, but not biliary steroids. Similar response patterns were also observed when cholesterol‐enriched diets were fed except for a decrease in serum apo B and an ineffectiveness to increase fecal acidic steroids. Together with the results obtained from experiments simultaneously performed with safflower oil and completely hydrogenated corn oil, it seems that the steroid metabolism can be specificallymodified by the geometry of dietary fats.
The biosynthesis of cholesterol and other sterols by brain tissue: II. A comparison of in vitro and in vivo methods
Authors: Ramsey R. B. , Jones J. P. , Naqvi S. H. M. , Nicholas H. J.
Published: December 2006

When microsomal + soluble preparations of adult or 15‐day‐old rat brains were incubated with 2‐14C‐mevalonic acid,14C‐squalene accumulated. A metabolic block at the squalene to cholesterol stage was indicated. This prompted a comparison of all methods currently used to study cholesterol biosynthesis by brain tissue. Brain cell‐free preparations from newborn, 15‐day‐old or adult rats accumulated14C‐squalene in a similar manner, with either 2‐14C‐acetate or 2‐14C‐mevalonic acid as substrates. Homogenates and minced preparations from newborn or 15‐day‐old rats accumulated some 4,4‐dimethyl sterols, but considerable conversion to free 4‐desmethyl sterols (cholesterol) was evident. Sterol esters were also present in all the in vitro studies. In general, increased disruption of tissue resulted in decreased free 4‐desmethyl sterol formation in vitro. Intraperitoneal injection of labeled acetate or mevalonate to newborn or 15‐day‐old rats produced labeled brain 4‐desmethyl sterol with little accumulation of squalene or 4,4‐dimethyl sterols, but the yields in brain were small compared to total amount of labeled material administered. At all ages intracerebral injection produced the best yield of labeled cholesterol for the amount of nonsaponifiable material formed.
Detecting and managing an overgrazing‐drought synergism in the threatenedEcheveria longissima(Crassulaceae): the role of retrospective demographic analysis
Authors: Martorell Carlos
Published: December 2006

Echeveria longissima, a threatened herb whose habitat has been severely overgrazed and eroded, was studied for three years in a currently grazed and a fenced area. Matrix population models were used to assess if livestock elimination provides a proper management strategy. The merits of retrospective perturbation analyses in terms of management planning have been debated. Nevertheless, they may prove useful when applied in combination with exclosures because they may detect the effects of anthropogenic disturbance on population dynamics. Thus, the results of retrospective and prospective methods were compared. A rapid decrease in population size was projected in both areas, even though it was faster in the exposed one. The demographic processes that were favourable or detrimental in a given year were magnified outside of the fence, but buffered in the exclosure, showing a strong drought‐disturbance synergism. Thus, the largest difference in the population growth rateλbetween areas was observed in the driest year. Higher nurse‐plant density inside the fence seems to alleviate drought effects. The use of prospective analysis alone may lead to erroneous management decisions, since the highest elasticities corresponded to transitions that were favoured by human activities. While allowing for an increasedλin the short term, intervention aimed at increasing these transitions further without attending others that are lessened by disturbance may introduce large changes in the population dynamics, with negative long‐term consequences. Retrospective methods can detect which processes have been altered by disturbance and its synergisms, so we may more efficiently restore healthy population dynamics.
Paternal ages below or above 35 years old are associated with a different risk of schizophrenia in the offspring
Authors: Wohl M. , Gorwood P.
Published: December 2006

Background

A link between older age of fatherhood and an increased risk of schizophrenia was detected in 1958. Since then, 10 studies attempted to replicate this result with different methods, on samples with different origins, using different age classes. Defining a cut-off at which the risk is significantly increased in the offspring could have an important impact on public health.

Methods

A meta-analysis (Meta Win®) was performed, assessing the mean effect size for each age class, taking into account the difference in age class references, and the study design.

Results

An increased risk is detected when paternal age is below 20 (compared to 20–24), over 35 (compared to below 35), 39 (compared to less than 30), and 54 years old (compared to less than 25). Interestingly, 35 years appears nevertheless to be the lowest cut-off where the OR is always above 1, whatever the age class reference, and the smallest value where offspring of fathers below or above this age have a significantly different risk of schizophrenia.

Conclusion

No threshold can be precisely defined, but convergent elements indicate ages below or above 35 years. Using homogeneous age ranges in future studies could help to clarify a precise threshold.
hnRNP‐U enhances the expression of specific genes by stabilizing mRNA
Authors: Yugami Masato , Kabe Yasuaki , Yamaguchi Yuki , Wada Tadashi , Handa Hiroshi
Published: December 2006

Heterogeneous nuclear ribonucleoproteins (hnRNPs) are thought to be involved in pre‐mRNA processing. hnRNP‐U, also termed scaffold attachment factor A (SAF‐A), binds to pre‐mRNA and nuclear matrix/scaffold attachment region DNA elements. However, its role in the regulation of gene expression is as yet poorly understood. In the present study, we show that hnRNP‐U specifically enhances the expression of tumor necrosis factor α mRNA by increasing its stability, possibly through binding to the 3′ untranslated region. We also show that hnRNP‐U enhances the expression of several other genes as well, including GADD45A, HEXIM1, HOXA2, IER3, NHLH2, and ZFY, by binding to and stabilizing these mRNAs. These results suggest that hnRNP‐U enhances the expression of specific genes by regulating mRNA stability.
The solution structure of the PufX polypeptide from Rhodobacter sphaeroides
Authors: Tunnicliffe Richard B. , Ratcliffe Emma C. , Hunter C. Neil , Williamson Mike P.
Published: December 2006

PufX organises the photosynthetic reaction centre–light harvesting complex 1 (RC–LH1) core complex of Rhodobacter sphaeroides and facilitates quinol/quinone exchange between the RC and cytochrome bc
1 complexes. The structure of PufX in organic solvent reveals two hydrophobic helices flanked by unstructured termini and connected by a helical bend. The proposed location of basic residues and tryptophans at the membrane interface orients the C‐terminal helix along the membrane normal, with the GXXXG motifs in positions unsuitable as direct drivers of dimerisation of the RC–LH1 complex. The N‐terminal helix is predicted to extend ∼40 Å along the membrane interface.
Virulence determinants in a natural butterfly-parasite system
Authors: de ROODE J. C. , GOLD L. R. , ALTIZER S.
Published: December 2006

Much evolutionary theory assumes that parasite virulence (i.e. parasite-induced host mortality) is determined by within-host parasite reproduction and by the specific parasite genotypes causing infection. However, many other factors could influence the level of virulence experienced by hosts. We studied the protozoan parasite Ophryocystis elektroscirrha in its host, the monarch butterfly, Danaus plexippus. We exposed monarch larvae to wild-isolated parasites and assessed the effects of within-host replication and parasite genotype on host fitness measures, including pre-adult development time and adult weight and longevity. Per capita replication rates of parasites were high, and infection resulted in high parasite loads. Of all host fitness traits, adult longevity showed the clearest relationship with infection status, and decreased continuously with increasing parasite loads. Parasite genotypes differed in their virulence, and these differences were maintained across ecologically relevant variables, including inoculation dose, host sex and host age at infection. Thus, virulence appears to be a robust genetic parasite trait in this system. Although parasite loads and genotypes had strong effects on virulence, inoculation dose, host sex and age at infection were also important. These results have implications for virulence evolution and emphasize the need for a detailed understanding of specific host-parasite systems for addressing theory.
How experts reason: the acquisition of experts' knowledge structures
Authors: VAN GEENEN ERWIN W. , WITTEMAN CILIA L. M.
Published: December 2006

We were faced with a shelved knowledge system at a health insurance company. The system used Bayesian statistics. For correct computations such a system is of course well suited, but not for the people who use it: people do not easily formulate their expertise in numerical probabilities. We addressed the question of whether it is possible to find out in which format experts do represent their knowledge, and if so, what format that is. This representation might then replace the format of numerical probabilities in the knowledge system's interface, increasing its ease of use. We found one method that includes, apart from a technique to elicit knowledge contents, techniques to also acquire its format: Cognitive Structure Analysis. In this contribution we discuss this method, use it in two studies, and show that it yields valid results. It gives insight into the format of experts' knowledge structures; experts turn out to use mainly frame representations.
Towards an argument interchange format
Authors: CHESÑEVAR CARLOS , MCGINNIS  , MODGIL SANJAY , RAHWAN IYAD , REED CHRIS , SIMARI GUILLERMO , SOUTH MATTHEW , VREESWIJK GERARD , WILLMOTT STEVEN
Published: December 2006

The theory of argumentation is a rich, interdisciplinary area of research straddling the fields of artificial intelligence, philosophy, communication studies, linguistics and psychology. In the last few years, significant progress has been made in understanding the theoretical properties of different argumentation logics. However, one major barrier to the development and practical deployment of argumentation systems is the lack of a shared, agreed notation or ‘interchange format’ for argumentation and arguments. In this paper, we describe a draft specification for an argument interchange format (AIF) intended for representation and exchange of data between various argumentation tools and agent-based applications. It represents a consensus ‘abstract model’ established by researchers across fields of argumentation, artificial intelligence and multi-agent systems. In its current form, this specification is intended as a starting point for further discussion and elaboration by the community, rather than an attempt at a definitive, all-encompassing model. However, to demonstrate proof of concept, a use case scenario is briefly described. Moreover, three concrete realizations or ‘reifications’ of the abstract model are illustrated.
A synchronic perspective on the grammaticalization of Swedish Future constructions
Authors: Hilpert Martin
Published: December 2006

This paper is a corpus-based investigation of five Swedish constructions that are used to express futurity. The method of Collexeme Analysis (Stefanowitsch & Gries 2003) is applied to constructions with the auxiliaries ska ‘will’, skall ‘shall’, its past form skulle ‘should’, komma ‘come’, and tänka ‘think’. All of these are future markers that have grammaticalized to varying degrees. The aim of this paper is to investigate semantic differences between constructions with these auxiliaries. By analyzing the main verbs that co-occur with a given auxiliary, it can be statistically assessed what verbs are significantly attracted to the construction. It thus becomes possible to analyze the constructional semantics in terms of co-occurring lexical material. Conversely, it is also insightful to consider what verbs occur significantly less often than expected with a given auxiliary. These procedures allow a fine-grained semantic description in both positive and negative terms.
Demarcating degrammaticalization: the Swedish s-genitive revisited
Authors: Norde Muriel
Published: December 2006

Ever since its introduction by Christian Lehmann in 1982, the term ‘degrammaticalization’ has been the subject of much controversy. There has been considerable disagreement about what kind of phenomena the term refers to, and indeed if degrammaticalization exists at all. In this paper I will argue that degrammaticalization is not grammaticalization in reverse, but a separate kind of change worthy of study in its own right. The purpose of this paper will be to show how degrammaticalization changes are best identified, by using existing linguistic tests as diagnostics for establishing changes in the morphological status of certain degrammaticalization suspects, and for assessing the nature of the subchanges involved. One of the stock examples of degrammaticalization literature, i.e. the s-genitive in Swedish, will serve as a case study.
Casting the First Stone: Who Can, and Who Can’t, Condemn the Terrorists?
Authors: Cohen G.
Published: December 2006

‘No matter what the grievance, and I'm sure that the Palestinians have some legitimate grievances, nothing can justify the deliberate targeting of innocent civilians. If they were attacking our soldiers it would be a different matter.’ (Dr. Zvi Shtauber, Israeli Ambassador to the United Kingdom, BBC Radio 4, May 1, 2003).
Juggling with Fast and Slow Time: Some of the Challenges of Project Management
Authors: Allan Barbara
Published: December 2006

Paper presented by Barbara Allan at the 37th BIALL Annual Study Conference in Brighton, June 2006, covering the human resources aspects of project management; project life cycles and project planning and implementation.
“Don't Students Learn Anything About Research on the LPC?” Developing a Multimedia Research Tutorial at The College of Law.
Authors: Simmonds Tony
Published: December 2006

Paper presented by Tony Simmonds at the 37th BIALL Annual Study Conference in Brighton, June 2006, describing the design process for, and key features of, the i-Tutorial software introduced at the College.
Workplace Learning for Busy Information Professionals
Authors: Power Gerry
Published: December 2006

Paper presented by Gerry Power at the 37th BIALL Annual Study Conference in Brighton, June 2006, outlining the importance of lifelong learning; discussing the work of some prominent writers and suggesting how to surmount barriers to learning.
Microstructural and geochemical perspectives on planktic foraminiferal preservation: “Glassy” versus “Frosty”
Authors: Sexton Philip F. , Wilson Paul A. , Pearson Paul N.
Published: December 2006

In recent years it has become apparent that the “cool tropic paradox” of Paleogene and Cretaceous “greenhouse” climates arises because of the diagenetic alteration of tropical planktic foraminiferal calcite near the seafloor, yielding artificially high δ18O values. Because the Mg/Ca compositions of foraminiferal and inorganic calcite are thought to be quite different, Mg/Ca measurements should be a sensitive way of monitoring diagenetic alteration. Here we examine the extent of diagenetic alteration of Eocene planktic foraminiferal calcite using scanning electron microscope imaging of foraminiferal test microstructures and geochemical (δ18O and Mg/Ca) analyses. We compare microstructural and geochemical characteristics between given species exhibiting two contrasting states of preservation: those that appear “frosty” under reflected light and those that appear “glassy.” Microstructural evidence reveals extensive diagenetic alteration of frosty foraminiferal tests at the micron scale, while δ18O analyses document consistently higher δ18O (and therefore lower paleotemperatures) in this material. Yet we find that δ18O offsets between species in these frosty foraminiferal assemblages appear to be generally preserved, suggesting that frosty foraminifera remain valuable for generating relatively short (approximately ≤1 Myr) paleoceanographic time series that do not demand absolute estimates of paleotemperature. We also find that the observed increase in Mg/Ca for planktic foraminifera exhibiting diagenetic alteration (compared to glassy taphonomies) is far smaller than would be expected from the addition of inorganic calcite based on laboratory‐derived Mg2+ partition coefficients. Our findings imply that a much lower Mg2+ partition coefficient controls inorganic calcite formation in deep sea sedimentary sections, in accordance with the findings of Baker et al. (1982).
Evaluation of a planetary boundary layer subgrid‐scale model that accounts for near‐surface turbulence anisotropy
Authors: Drobinski Philippe , Redelsperger Jean‐Luc , Pietras Christophe
Published: December 2006

In numerical modelling, far from regions of large gradients, the resolved scales contain most of the energy of turbulent motion whilst on subgrid scales (SGS), motions are less energetic. However, SGS contribution becomes larger than the resolved part near the surface. Recent studies have shown that near‐surface turbulence anisotropy has a dramatic effect on the mixing length to be used in SGS models which are generally derived for free‐stream isotropic turbulence or use the standard Prandtl mixing length κz. Using the flux measurements collected at the SIRTA observatory located near Paris (France), this paper shows that a SGS model suitable for both the surface layer and free‐stream turbulence must discard the Prandtl mixing length and account for near‐surface turbulence anisotropy. It also shows that such an SGS scheme, which is suited for all numerical models of the atmosphere, improves the representation of planetary boundary layer processes in most stability conditions.
Impact of a priori zenith hydrostatic delay errors on GPS estimates of station heights and zenith total delays
Authors: Tregoning P. , Herring T. A.
Published: December 2006

Corrections to zenith atmospheric delays (including hydrostatic components) are estimated in geodetic analyses using partial derivatives that relate wet delays to the phase observations. At low‐elevation angles, partial derivatives of the hydrostatic and wet delays are sufficiently different as to cause errors in the estimates of station heights and zenith total delays unless accurate surface pressure values are used to model the hydrostatic delay. The associated errors are latitude dependent because sites at high latitudes have a higher percentage of low‐elevation observations. A priori zenith hydrostatic delay errors project into GPS height estimates with typical sensitivities of up to −0.2 mm/hPa, depending on the elevation angle cutoff and elevation angle dependent data weighting used in the analysis. This generates height errors of up to 10 mm and seasonal variations of up to 2 mm amplitude. The errors in zenith delay estimates are about half the magnitude of the height errors.