bluuebunny/crossref_metadata_2025 huggingface dataset:
The uptake of surfactants into wheat
Authors: Anderson Nicholas H. , Girling Jeanne
Published: November 2006

The time course of uptake has been determined for seven poly(oxyethylene) surfactants, and one anionic surfactant (sodium dodecyl sulphate), into the leaves of wheat plants grown in a phytotron. Uptake was relatively rapid during an initial period of 24 h for six of the eight surfactants; after this period, the uptake rate was lower, and total uptake after 48 h was in the range 80‐91% for those six surfactants. The other two compounds, sodium dodecyl sulphate and cetostearyl alcohol‐22EO condensate (hexadecan‐1‐ol/octadecan‐1‐ol ethylene oxide condensate; average number of ethylene oxide units 22) were barely taken up at all. The observed time course for uptake was consistent with a complex process based on more than one rate‐determining process. The physical properties of the surfactants are discussed in relation to their observed uptake behaviour. The surfactant deposit areas, measured by microscopy, were concluded to be not particularly relevant in interpreting the uptake results. Uptake was not related to surfactant chain length, but the physical form of the hydrated surfactant on a leaf surface appeared to influence uptake behaviour.
Malathion toxicity: Skeletal deformities in zebrafish (Brachydanio rerio, cyprinidae)
Authors: Kumar Kaushal , Ansari Badre A.
Published: November 2006

Toxicity tests reveal that the zebrafish (Brachydanio rerio) is very sensitive to malathion, an organophosphorus insecticide, and 24 to 96‐h LC50 values showed a gradual decrease as the exposure time was increased. Zebrafish exposed to long‐term sublethal concentrations failed to spawn and invariably exhibited skeletal deformities. Possible causes of the reduced gonadosomatic index and skeletal deformities are discussed.
Diastereoisomers and enantiomers of paclobutrazol: Their preparation and biological activity
Authors: Sugavanam Balasubramanyan
Published: November 2006

Paclobutrazol is a highly active plant growth regulator with very good fungicidal activity. Aspects of the synthesis of paclobutrazol and its diastereoisomer are discussed, the resolution of paclobutrazol into its two enantiomers is described. It has been shown for the first time that it is possible to separate the plant growth regulatory activity from the fungicidal activity by resolution. Computer graphic studies are also included.
Increasing the sample size during clinical trials with t‐distributed test statistics without inflating the type I error rate
Authors: Timmesfeld Nina , Schäfer Helmut , Müller Hans‐Helge
Published: November 2006

In clinical trials with t‐distributed test statistics the required sample size depends on the unknown variance. Taking estimates from previous studies often leads to a misspecification of the true value of the variance. Hence, re‐estimation of the variance based on the collected data and re‐calculation of the required sample size is attractive. We present a flexible method for extensions of fixed sample or group‐sequential trials with t‐distributed test statistics. The method can be applied at any time during the course of the trial and does not require the necessity to pre‐specify a sample size re‐calculation rule. All available information can be used to determine the new sample size. The advantage of our method when compared with other adaptive methods is maintenance of the efficient t‐test design when no extensions are actually made. We show that the type I error rate is preserved. Copyright © 2006 John Wiley & Sons, Ltd.
The effect of docosahexaenoic acid on the electroretinogram of the guinea pig
Authors: Weisinger Harrison S. , Vingrys Algis J. , Sinclair Andrew J.
Published: November 2006

Docosahexaenoic acid (DHA), an n‐3 polyunsaturated fatty acid, is found in consistently high concentrations in the retinae of mammals, yet its role in vision remains unclear. In this study, a mammalian model of variable retinal DHA concentration has been developed, such that the retinal phospholipids of guinea pigs contained between 2.5 and 30.8% DHA. Visual function was assessed using full‐field flash electroretinography, over a range of exposure levels spanning six log units. Trend analysis indicated that retinal function was altered by the tissue DHA level, and was described by a second‐order polynomial “inverted U‐shaped” function. The results suggested that although some amount of DHA is essential for normal retinal function increases in the DHA level past an optimal amount, found to be 19%, provided diminishing returns. In this study, manipulation of the retinal DHA level accounted for 21–35% of the electroretinographic variability.
Visual acuity and erythrocyte docosahexaenoic acid status in breast‐fed and formula‐fed term infants during the first four months of life
Authors: Hørby Jørgensen M. , Hernell O. , Lund P. , Hølmer G. , Fleischer Michaelsen K.
Published: November 2006

It has been recognized that preterm infants have a more rapid development of visual acuity if fed human milk or a formula enriched with the long‐chain polyunsaturated fatty acid (LCPUFA) docosahexaenoic acid (DHA) compared to a standard formula devoid of LCPUFA. Few studies have addressed whether the same is also true in term infants. The aim of the present study was to follow visual acuity and fatty acid composition in red blood cells (RBC) for the first 4 mon of life in 17 breast‐fed and 16 formula‐fed term infants. The formula used did not contain LCPUFA, but contained 1.7 wt% α‐linolenic acid, and the linoleic/α‐linolenic acid ratio was 8.5. The increase in visual acuity measured by Teller acuity cards developed more rapidly in breast‐fed infants compared to formula‐fed infants (P<0.001). This was parallelled by a decrease in DHA of RBC in formulafed infants, and with a significantly lower level at two and four months as compared to breast‐fed infants. The content of DHA in milk from the breast‐feeding mothers was high compared to other Western countries. The difference in visual acuity between the two feeding groups could be due to differences in DHA status as reflected by the RBC levels, but other explanations are possible. Intervention studies are required to verify if development of visual acuity in term formula‐fed infants is dependent on the DHA level of formula.
Effects of membrane charges and hydroperoxides on Fe(II)‐supported lipid peroxidation in liposomes
Authors: Tampo Yoshiko , Yonaha Masanori
Published: November 2006

The processes in producing a lag phase in Fe2+‐supported lipid peroxidation in liposomes were investigated. Incorporation of phosphatidylserine (PS) or dicetyl phosphate (DCP) into phosphatidylcholine [PC(A)] liposomes, which have arachidonic acid, produced a marked lag phase in Fe2+‐supported peroxidation, where PS was more effective than DCP. Phosphatidylcholine dipalmitoyl [PC(DP)] with a net‐neutral charge was still effective in producing a lag phase, though weak. Increasing concentrations of PS, DCP, and PC(DP) prolonged the lag period. Initially after adding Fe2+, slight oxygen consumption occurred in PC(A)/PS liposomes including hydroperoxides, followed by a lag phase. An increase in the hydroperoxide resulted in a shortening of the lag period. The initial events of Fe2+ oxidation accompanied by oxygen consumption were dependent on the hydroperoxide content, but significant changes in diene conjugation and hydroperoxide levels at this stage were not found. The molar ratios of both dis‐appeared Fe2+ and consumed O2 to preformed hydroperoxide in liposomes with or withouttert‐butylhydroxytoluene were constant, regardless of the different amounts of lipid hydroper‐oxides. The antioxidant completely inhibited the propagation of lipid peroxidation in the lipid phase, following a lag phase. In a model system containing 2,2′‐azobis (2‐amidinopropane) dihydrochloride, Fe2+ were consumed. We suggest that Fe2+ retained at a high level on membrane surfaces play a role in producing a lag phase following the terminating behavior of a sequence of free radical reactions initiated by hydroperoxide decompositin, probably by intercepting peroxyl radicals.
Regulation of platelet‐activating factor receptor expression in human B cells and B cell lines
Authors: Nguer Cheikh M. , Treton Dominique , Rola‐Pleszczynski Marek , Mishal Zohair , Thomas Yolène , Galanaud Pierce , Richard Yolande
Published: November 2006

We extended our previous data regarding the modulation of human platelet‐activating factor receptor (hPAF‐R) expression on human B cell lines as well as normal B cells. First, we showed that hPAF‐R, but was absent from cell lines devoid of hPAF‐R. Second, enhanced hPAF‐R membrane expression induced in IM9 line by IL9 line by IL4 was preceeded by hPAF‐R mRNA accumulation that was detectable by 8 h and which peaked at 24 h. Similar results were observed for 10 nM platelet‐activating factor treatment, which increased hPAF‐R mRNA content up to 120% at 48 h, whereas hPAF‐R membrane expression was up‐regulated by 130%. Third, our data indicate that functional hPAF‐R are expressed on resting, as well as on activated, B cells and that B cell activation is required for maintaining hPAF‐R membrane and mRNA expression. Thus, in normal B cells, as well as in B cell lines, transcriptional regulation and/or messager stability control hPAF‐R expression.
Influence of a subinhibitory dose of antifungal atty acids fromSporothrix flocculosa on cellular lipid composition in fungi
Authors: Benyagoub M. , Willemot C. , Bélanger R. R.
Published: November 2006

Abstracts

Antifungal fatty acids produced by the biocontrol fungusSporothrix flocculosa were studied on the basis of their effect on growth and cellular lipid composition of three fungi,Cladosporium cucumerinum, Fusarium oxysporum, andS. flocculosa, whose growth was decreased by 51, 33, and 5% respectively, when exposed to 0.4 mg fatty acid per ml. The sensitivity to fatty acid antibiotics fromS. flocculosa was related to a high degree of unsaturation of phospholipid fatty acids and a low proportion of sterols. The major responses of sensitive fungi to sublethal doses of antifungal fatty acids from liquid culture ofS. flocculosa were: (i) a decrease in total lipid; (ii) an increase in the degree of fatty acid unsaturation (18∶1>18∶2 > 18∶3); (iii) an increase in free fatty acids and phosphatidic acid and a decrease in total phospholipids; and (iv) an increase in sterol/phospholipid ratio. These modifications in lipid composition led to an increase in membrane fluidity in sensitive fungi, as demonstrated by assessment of fluorescence anisotropy using liposomes and 1,6‐diphenyl‐1,3,5‐hexatriene probe. This alteration in the physical state of lipids appears to be responsible for the previously demonstrated alteration of membrane structure and function in fungi confronted toS. flocculosa.
An unusual fatty acid pattern inEranthis seed oil
Authors: Aitzetmüller K.
Published: November 2006

The current discussion on “renewable resources”, and the possibility of gene transfer into rapeseed, has led to many investigations into the biosynthetic pathways leading to industrially useful fatty acids. The various tribes and genera of the plant familyRanunculaceae contain a large variety of unusual fatty acids. Seed fatty acid patterns differ considerably from genus to genus and are chemotaxonomically significant indicators.Eranthis seed oil has now been found to contain a fatty acid pattern that deviates significantly from the eleven different fatty acid patterns that had been described in this plant family. The main fatty acid (up to 57%) is 13‐cis, 16‐cis‐docosadienoic acid. Other, minor fatty acids found are Δ5‐cis‐monoenoic,‐dienoic, and‐trienoic fatty acids that had already been reported to be constituents of the genus‐specific seed oil fatty acid patterns of various genera from this plant family. Capillary gas‐liquid chromatographic retention data indicate that 22:3Δ5cis, 13cis, 16cis is probably also present. Seed fatty acid chemotaxonomic evidence thus points to a different position ofEranthis within the tribes of this plant family. These findings again indicate that the plant familyRanunculaceae would be an ideal object to study fatty acid biosynthesis and phylogenetic evolution, because in other genera of this family other types of desaturation and chain elongation mechanisms predominate.
Quantitative high‐performance liquid chromatography analysis of plant phospholipids and glycolipids using light‐scattering detection
Authors: Picchioni G. A. , Watada A. E. , Whitaker B. D.
Published: November 2006

Application of the evaporative light‐scattering principle to quantitative high‐performance liquid chromatography (HPLC) analyses of plant membrane lipids has received little study. Light‐scattering detection response curves were generated for nine classes of plant membrane phospholipid and glycolipids. Quantitative results obtained by HPLC/light‐scattering detection and conventional lipid analytical methods (thin‐layer chromatography and lipid‐P assay) were in close agreement, confirming the reliability of HPLC/evaporative light‐scattering detection (ELSD) analyses. Only three of the nine plant lipid classes gave linear detector response functions above 10 μg injected lipid mass. This finding contradicts earlier precepts involving light‐scattering detection of lipids. At a given mass, appreciable variation in ELSD signal intensity and detection limit was found to exist among the various plant membrane lipid classes. The variation in detector response among plant lipid classes is an important consideration in achieving accurate quantitative results in plant lipid analyses.
Phosphatidylglycerol molecular species of photosynthetic membranes analyzed by high‐performance liquid chromatography: Theoretical considerations
Authors: Xu Yinong , Siegenthaler Paul‐André
Published: November 2006

A reversed‐phase high‐performance liquid chromatography technique was developed to separate, identify, and quantify individual phsphatidylglycerol (PG) molecular species in thylakoid membranes isolated from higher plant leaves. PG was first separated by thin‐layer chromatography; then the dinitrobenzoyl derivatives of diacylglycerols produced after phospholipase C hydrolysis of PG were separated by a C18 reversed‐phase column and detected at 254 nm. A linear response of the detector was observed in the range of 0.025 to 12 nmol of PG molecular species. It was established that there was an excellent correlation (r=0.996) between the carbon and double‐bond number in the aliphatic residues and the relative retention time of dinitrobenzoyl derivatives. A new equivalent carbon number value (ECN*) which takes into consideration the number ofcis‐(nc) andtrans‐(nt) double bonds per molecular species was defined as ECN*=CN‐2nc‐nt′ where CN is the number of carbon atoms in the aliphatic residues. The logarithm of the retention time increased linearily as a function of ECN* value. However, in this type of correlation, it may happen that two molecular species of PG having distinct relative retention times has the same ECN* value. In this case, the two molecular species can be identified by the linear correlation (r=1) existing between the reciprocal of the relative retention time and the number of double bonds (0≤n≤3) in the separate 18:n/Δ3‐trans‐hexadecenoic acid [16:1(3t) and 18:n/16:0 molecular species series. The advantages of this method are good separation, short elution time, quantitative precision, and predictable retention times of PG molecular species from chloroplast membranes. The method has been used routinely to identify the ten PG molecular species of thylakoid membranes in squash, potato, lettuce, and spinach leaf: 18:3/16:1(3t), 18:3/16:0, 18:2/16:1(3t), 18:2/16:0, 18:1/16:1(3t), 18:1/16:0, 18:0/16:1(3t), 18:0/16:0, 16:0/16:1(3t), and 16:0/16:0.
Acyl‐CoA binding proteins: Multiplicity and function
Authors: Gossett Ruanna E. , Frolov Andrey A. , Roths John B. , Behnke W. David , Kier Ann B. , Schroeder Friedhelm
Published: November 2006

The physiological role of long‐chain fatty acyl‐CoA is thought to be primarily in intermediary metabolism of fatty acids. However, recent data show that nM to μM levels of these lipophilic molecules are potent regulators of cell functionsin vitro. Although long‐chain fatty acyl‐CoA are present at several hundred μM concentration in the cell, very little long‐chain fatty acyl‐CoA actually exists as free or unbound molecules, but rather is bound with high affinity to membrane lipids and/or proteins. Recently, there is growing awareness that cytosol contains nonenzymatic proteins also capable of binding long‐chain fatty acyl‐CoA with high affinity. Although the identity of the cytosolic long‐chain fatty acyl‐CoA binding protein(s) has been the subject of some controversy, there is growing evidence that several diverse nonenzymatic cytosolic proteins will bind long‐chain fatty acyl‐CoA. Not only does acyl‐CoA binding protein specifically bind medium and long‐chain fatty acyl‐CoA (LCFA‐CoA), but ubiquitous proteins with multiple ligand specificities such as the fatty acid binding proteins and sterol carrier protein‐2 also bind LCFA‐CoA with high affinity. The potential of these acyl‐CoA binding proteins to influence the level of free LCFA‐CoA and thereby the amount of LCFA‐CoA bound to regulatory sites in proteins and enzymes is only now being examined in detail. The purpose of this article is to explore the identity, nature, function, and pathobiology of these fascinating newly discovered long‐chain fatty acyl‐CoA binding proteins. The relative contributions of these three different protein families to LCFA‐CoA utilization and/or regulation of cellular activities are the focus of new directions in this field.
Effect of Castration and hormonal supplementation on cholesterol cholelithiasis in the male hamster
Authors: Ohshima Akira , Cohen Bertram I. , Ayyad Nariman , Mosbach Erwin H.
Published: November 2006

This study examined the effect of castration and dietary hormonal supplementation on cholesterol cholelithiasis in male hamsters. Animals fed a standard lithogenic diet developed cholesterol gallstones (17%) after 6 wk, while castrated hamsters did not form any stones. Addition of a synthetic androgen, methyltestosterone, to the lithogenic diet induced cholelithiasis in castrated animals (50%). The biles of normal and castrated‐hormone supplemented hamsters had cholesterol saturation indices of 1.0 and 1.1, respectively, while the bile of the castrated animals remained unsaturated (0.6). The ratio of cholic acid/chenodeoxycholic acid in bile increased after castration, but returned to normal levels following hormonal supplementation. Biliary cholesterol carriers were separated by ultracentrifugation. Animals in the stone‐forming groups (normal and castrated‐hormone treated) had a significant proportion of their biliary cholesterol in vesicles (44 and 46%, respectively); castrated hamsters had less cholesterol in vesicle form (9%). The molar ratio of cholesterol/phospholipid in vesicles was reduced after castration (0.93 vs. 0.42) and increased by hormonal supplementation (1.89). In conclusion, when compared to normal male hamsters fed a standard lithogenic diet, castration reduced the cholesterol saturation of bile, lowered the vesicular/micellar ratio in bile, and inhibited cholesterol cholelithiasis. Dietary androgen supplementation increased the lithogenicity of bile, resulting in stone formation in castrated animals.
Polyunsaturated fatty acids exert antiarrhythmic actions as free acids rather than in phospholipids
Authors: Weylandt Karsten H. , Kang Jing X. , Leaf Alexander
Published: November 2006

Previous studies have shown that exogenous free n‐3 polyunsaturated fatty acids (PUFA) can prevent tachyarrhythmias caused by specific agents in isolated cardiac myocytes. However, the question as to whether incorporation of the n‐3 PUFA into membrane phospholipids has the same immediate protective effects remained to be answered. To answer this question, we increased the content of n‐3 PUFA in the phospholipids of cultured neonatal rat myocytes by growing them 2–3 d in a culture to which eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) in 15 μM concentration was added. Analysis of the fatty acid composition of membrane phospholipids revealed a significantly higher level of EPA and DHA (from 0.2 to 7.6% and from 1.2 to 6.5%) in cells supplemented with EPA or DHA, respectively. The responses of the myocytes grown in normal media or in media enriched with the PUFA to arrhythmogenic agents were examined after free fatty acids were removed from the medium and the cells. The arrhythmogenic agents used were the β‐adrenergic agonist isoproterenol or an elevated extracellular concentration of calcium. The results showed that there was no significant difference in the induction of tachyarrhythmias by isoproterenol or by elevated [Ca2+]o in cells grown in media enriched with PUFA, as compared with cells grown in normal media in the absence of the free PUFA. Under the conditions of this study, only the unesterified PUFA were able to protect the cardiomyocytes against induced arrhythmias. There was no antiarrhythmic effect due to an increased fraction of EPA or DHA in membrane phospholipids.
The ratio of n‐6 to n‐3 polyunsaturated fatty acids in the rat diet alters serum lipid levels and lymphocyte functions
Authors: Jeffery N. M. , Sanderson P. , Sherrington E. J. , Newsholme E. A. , Calder P. C.
Published: November 2006

Previous studies have reported that feeding rats diets rich in fish oils, which contain high proportions of the n‐3 polyunsaturated fatty acids (PUFA) eicosapentaenoic and docosahexaenoic acids, results in lowering of blood lipid levels and suppression of lymphocyte functions testedex vivo andin vivo. The effects of other n‐3 PUFA, such as α‐linolenic acid, which is found in high proportions in linseed oil, are not as well documented. Therefore, in the present study, weanling male rats were fed for six weeks on one of five high‐fat (20% by weight) diets made by mixing together sunflower and linseed oils; the resulting blends had n‐6/n‐3 PUFA ratios of 112.5:1 (pure sunflower oil), 14.8:1, 6.5:1, 0.8:1, and 0.33:1 (pure linseed oil); the levels of all other components in the diet were identical. The final body weight and total dissectable fat were lowest in rats fed the pure linseed oil diet. Serum cholesterol, triacylglycerol and nonesterified fatty acid concentrations decreased as the n‐6/n‐3 PUFA ratio of the diet decreased. The fatty acid composition of the serum and of spleen lymphocytes was influenced by the diet fed‐there was a progressive decrease in the proportions of linoleic and arachidonic acids and a progressive increase in the proportion of α‐linolenic acid as the n‐6/n‐3 PUFA ratio of the diet decreased. Eicosapentaenoic and docosahexaenoic acids were detected in the serum but not in spleen lymphocytes. Inclusion of α‐linolenic acid in the diet resulted in significant suppression of spleen lymphocyte proliferation in response to the T‐cell mitogen concanavalin A and in spleen lymphocyte natural killer cell activity, both measuredex vivo. The localized graft vs. host response, a measure of cellmediated immunityin vivo, progressively decreased as the n‐6/n‐3 PUFA ratio of the diet decreased. Thus, this study shows that dietary α‐linolenic acid results in lowered blood lipid levels and suppressed lymphocyte functionsex vivo andin vivo. With respect to these effects, α‐linolenic acid is as potent as dietary fish oil.
Intestinal lymph absorption of butter, corn oil, cod liver oil, menhaden oil, and eicosapentaenoic and docosahexaenoic acid ethyl esters in rats
Authors: Degrace P. , Caselli C. , Rayo J. M. , Bernard A.
Published: November 2006

Adult male rats were surgically given a drainage catheter in the main mesenteric lymph duct. After an overnight fast, five groups of rats received intragastrically, in one bolus, butter, corn oil (CO), cod liver oil (CLO), menhaden oil (MO), or ethyl esters of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids (K80). Intestinal lymph was collected in these conscious animals, each hour during the first 6 h and in a single sample for the next 18 h. The absorption peak appeared earlier after MO and CO than after CLO administration. The quantities of triglycerides recovered during the first 6 h were significantly lower after butter (91 mg) and K80 (54 mg) administration than for the other three oils. No difference was observed between the vegetable oil and the two marine oils (CO=173 mg, CLO=148 mg, MO=180 mg). The total triglyceride recovered in 24 h was highest after CLO (410 mg) and lowest with K80 (146 mg). An increase in the weight percentage of some characteristic fatty acids of the lipid mixtures was observed: oleic acid for butter, oleic and linoleic acids for CO, EPA and DHA for CLO, MO, and K80. Chylomicrons were the largest with CO, more numerous and smaller with CLO, and the smallest with K80. Results obtained illustrated the relation between gastrointestinal hydrolysis, enterocyte biochemical events, and lymph triglyceride absorption profiles as related to the composition and distribution of triglyceride fatty acids.
Alterations in cell cholesterol content modulate Ca2+‐induced tight junction assembly by MDCK cells
Authors: Stankewich Michael C. , Francis Stacy A. , Vu Quynh U. , Schneeberger Eveline E. , Lynch Robert D.
Published: November 2006

Transepithelial electrical resistance (TER), a measure of tight junction (TJ) barrier function, develops more rapidly and reaches higher values after preincubation of MDCK cells for 24 h with 2 μM Lovastatin (lova), an inhibitor of 3‐hydroxy‐3‐methylglutaryl‐CoA reductase. While this effect was attributed to a 30% fall in cholesterol (CH), possible effects of lova on the supply of prenyl group precursors could not be excluded. In the current study, strategies were devised to examine effects on TER of agents that simultaneously lower CH and increase the flux of intermediates through the CH biosynthetic pathway. Zaragozic acid, 20 μM, an inhibitor of squalene synthase known to increase the synthesis of isoprenoids and levels of prenylated proteins, lowered cell CH by 30% after 24 h, while accelerating development of TER in the same manner as lova. TER was also enhanced, despite a 23% increase in the rate of [3H]acetate incorporation into CH, when total CH was reduced by 45% during a 2‐h incubation with 2 mM methyl β‐cyclodextrin (MBCD), an agent that stimulates CH efflux from cells. The fact that the rate of TER development was diminished when cell CH content was elevated by incubation with a complex of CH and MBCD is further evidence that this sterol modulates development of the epithelial barrier. Cell associated CH derived from the complex was similar to endogenous CH with respect to its accessibility to cholesterol oxidase. Lova's effect on TER was diminished when 5 μg/mL of CH was added to the medium during the last 11 h of incubation with lova.
Fatty acid composition of late embryonic and early postnatal rat brain
Authors: Green Pnina , Yavin Ephraim
Published: November 2006

The fatty acid (FA) composition and distribution in a variety of phospholipids (PL) and neutral lipids (NL) at two discrete stages during the embryonic rat brain development were investigated. Over 96% of the FA were acylated into fetal brain PL at embryonic day 17 after the peak of neuronal proliferation and at embryonic day 20, one day prior to delivery. Phosphatidylcholine constituted approximately 60% of the total PL pool, phosphatidylethanolamine (PE) 30%, phosphatidylserine (PS) 6%, and phosphatidylinositol (PI) 4%. The diacylglycerols and triacylglycerols constituted 1–2% of the fetal brain lipids. α‐Linolenic acid (18∶3n−3) and linoleic acid (18∶2n−6) were found in very low amounts in all fetal brain PL and NL. The percentage of the n−6 polyunsaturated FA, consisting of arachidonic acid (AA), 22∶4n−6 and 22∶5n−6, remained unchanged in all the fractions, except in Pl, in which the proportion of AA increased. The concentration of docosahexaenoic acid (DHA) increased with age in all the fractions, with the bulk of accumulation accounted for by its increase in PE and, to a lesser extent, in PS. This finding suggests a “DHA accretion spurt” during the last three days of pregnancy.
Costs of egg caring in the skink, Mabuya longicaudata
Authors: Huang Wen‐San
Published: November 2006

Why do most animal species not provide parental care to their eggs or progeny? The “cost” hypothesis suggests that parental care can reduce food intake, probable survivorship, and/or subsequent fecundity of the reproductive female, and parental care is not adaptive unless it is balanced by considerable fitness trade‐offs. Therefore, parental care would be expected to evolve most often in species in which such costs are minor or insignificant. Although parental care has been reported in more than 140 species of reptiles, few records unambiguously demonstrate the cost of parental care. In the current study, I report the “costs” of maternal activities and survivorship, as well as egg attendance times, and within‐ and between‐seasonal body size variations, of females of Mabuya longicaudata after engaging in parental care. I used those data to test whether parental care necessarily entailed large costs to mother lizards. The proportion of nests guarded decreased with time after eggs were laid, with most females remaining at the nest for at least 1 week, but then some beginning to leave. The loss of mass by females over the first week of egg guarding was on average balanced by a gain in mass during subsequent foraging bouts. The snout–vent length (SVL), body mass (BM), recapture (survival) rates, fecundity, timing of a second clutch, and clutch frequencies of females that exhibited long‐term parental care (more than 28 days; mean, 31.6 ± 2.2 days) did not significantly differ from that of females that showed short‐term parental care (9∼16 days; mean, 12.5 ± 2.3 days). Thus, my data indicate that intense parental care over a long period does not necessarily entail major energy costs for the mother in terms of SVL, BM, recapture (survival) rates, or fecundity.
Lipase‐based quantitation of triacylglycerols in cellular lipid extracts: Requirement for presence of detergent and prior separation by thin‐layer chromatography
Authors: Van Veldhoven Paul P. , Swinnen Johannes V. , Esquenet Murielle , Verhoeven Guido
Published: November 2006

A protocol, based on the use of Pseudomonas lipase, is presented to measure quantitatively the amount of triacylglycerols in extracts from cultured cells or tissues. Since the lipase also acts on di‐ and monoacylglycerols, separation of the extracts by thin‐layer chromatography is recommended. In order to allow the lipase‐catalyzed hydrolysis to proceed efficiently, lipid extracts or eluates from silica scraping were mixed with the detergent Thesit [dodecylpoly(ethylene glycol ether)], prior to drying. After dissolution of the dried residues in water, the amount of triacylglycerols was quantified using Pseudomonas sp. lipase, glycerol kinase, glycerol‐phosphate oxidase, and peroxidase. The activity of the latter enzyme was followed either colorimetrically in the presence of 4‐aminoantipyrine and 2,4,6‐tribromo‐3‐hydroxybenzoic acid or fluorimetrically in the presence of homovanillic acid.
Ectopic Pregnancy
Authors: Kriebs Jan M. , Fahey Jenifer O.
Published: November 2006

The incidence of ectopic pregnancy in the United States has been reported to be as high as 20 per 1000 pregnancies, a more than 4‐fold increase over the last 20 years. Clinical presentation can range from subtle, nonspecific abdominal complaints to acute onset pain or hemorrhagic bleeding. This article reviews the associated risk factors, pathophysiology, diagnosis, and management of ectopic pregnancy. Clinicians must maintain a high index of suspicion whenever women who might be pregnant have abdominal complaints.
Vulvar Pain Syndromes: Vestibulodynia
Authors: Stone‐Godena Teri
Published: November 2006

Chronic pain anywhere on the body can be debilitating and demoralizing. When the pain is associated with sexuality, it can erode self‐esteem and diminish relationships. Vestibulodynia (pain in the vulvar vestibule) is poorly understood and presents a clinical challenge to the provider. Although the etiology of vestibulodynia is unclear, and randomized controlled trials of therapies are lacking, the knowledge of current theories and treatments will assist providers in caring for women with this enigmatic problem.
A rare case of nasal cysticercosis mimicking a nasal dermoid
Authors: Kuruvilla G , Job A , Thomas M
Published: November 2006

Cysticercosis, caused by infestation with the pork tapeworm Taenia solium, is known to commonly involve the brain, muscles and subcutaneous tissue. Diagnosing cysticercosis can be difficult as its clinical presentation is usually non-specific. When involving subcutaneous tissue, it can present as firm, non-tender, solitary or multiple nodules. We report a case of subcutaneous cysticercosis at the nasion mimicking a nasal dermoid.
Alternatives to anthelmintics for the control of nematodes in livestock
Authors: STEAR M. J. , DOLIGALSKA M. , DONSKOW-SCHMELTER K.
Published: November 2006

Efficient and welfare-friendly livestock production demands the control of nematode infection. Current control measures rely upon anthelmintic treatment but are threatened by the widespread evolution of drug-resistance in parasite populations. Several methods have been advocated to control nematodes without relying on effective anthelmintics. These include grazing management, biological control, nutritional supplementation, vaccination, and genetic approaches. Each method has its advantages and disadvantages. There are several grazing management schemes that can reduce the severity of infection but they are insufficient on their own to control infection. Biological control includes the use of predatory fungi to control nematode populations and the use of pasture species that can reduce the intensity of infection. Fungi can control nematodes but the current requirement for daily feeding means that this approach will be most useful for animals that are handled daily. Feeding supplementary protein can control nematode infection. The method is simple but can be expensive and may not be cost-effective for some marginal enterprises. Genetic approaches include the use of resistant breeds and selective breeding. Some breeds will thrive in conditions that kill animals from other breeds but substitution of resistant breeds is not always feasible. Selective breeding is effective and inexpensive but requires a high level of expertize. The most appropriate method or set of methods to minimize the adverse consequences of nematode infection may vary among farms.
Controls on methane concentration and stable isotope (δ2H‐CH4 and δ13C‐CH4) distributions in the water columns of the Black Sea and Cariaco Basin
Authors: Kessler J. D. , Reeburgh W. S. , Tyler S. C.
Published: November 2006

Methane (CH4) concentration and stable isotope (δ2H‐CH4 and δ13C‐CH4) depth distributions show large differences in the water columns of the Earth's largest CH4‐containing anoxic basins, the Black Sea and Cariaco Basin. In the deep basins, the between‐basin stable isotope differences are large, 83‰ for δ2H‐CH4 and 9‰ for δ13C‐CH4, and the distributions are mirror images of one another. The major sink in both basins, anaerobic oxidation of CH4, results in such extensive isotope fractionation that little direct information can be obtained regarding sources. Recent measurements of natural 14C‐CH4 show that the CH4 geochemistry in both basins is dominated (∼64 to 98%) by inputs of fossil (radiocarbon‐free) CH4 from seafloor seeps. We derive open‐system kinetic isotope effect equations and use a one‐dimensional (vertical) stable isotope box model that, along with isotope budgets developed using radiocarbon, permits a quantitative treatment of the stable isotope differences. We show that two main factors control the CH4 concentration and stable isotope differences: (1) the depth distributions of the input of CH4 from seafloor seeps and (2) anaerobic oxidation of CH4 under open‐system steady state conditions in the Black Sea and open‐system non‐steady‐state conditions in the Cariaco Basin.
Three‐dimensional attenuation (Qs) structure beneath the Kanto district, Japan, as inferred from strong motion records
Authors: Nakamura Ryoichi , Satake Kenji , Toda Shinji , Uetake Tomiichi , Kamiya Shin'ichiro
Published: November 2006

The three‐dimensional (3D) S‐wave attenuation (Qs) structure beneath the Kanto plain, where the Pacific and Philippine Sea plates subduct, was estimated using strong‐motion records of the K‐NET and KiK‐net. In addition to several low‐Qs zones corresponding to the volcanic front, a large NW–SE trending low‐Qs zone is estimated under the non‐volcanic Kanto area at depths of 20–60 km. This zone corresponds to a previously identified low‐velocity (both Vp and Vs) zone with a high Poisson's ratio at 40‐km depth; it further indicates a wedge immediately above the subducting Philippine Sea plate. Predicted seismic ground motions using the estimated 3D attenuation structure is very similar to the actually recorded by recent earthquake on July 2005 (M = 6).
The third-order optical nonlinearities of carbon nanotube modified conjugated polymer in the femtosecond and nanosecond regimes
Authors: Yi Wenhui , Feng Wei , Zhang Chunyu , Long Yingbing , Zhang Zhiguo , Li Baoming , Wu Hongcai
Published: November 2006

Multiwalled carbon nanotubes (MWCNTs) have been noncovalently modified with poly[2-methoxy 5-octyoxy]-p-phenylene vinylene (MO-PPV) to form a series of solution of MWCNTs and the conjugated polymers. The third-order nonlinearities of the solutions were investigated by the optical Kerr effect technique with femtosecond pulses, and degenerate four-wave mixing, open aperture, and closed aperture Z-scan techniques with nanosecond pulses. We attempted to quantify the contributions from various channels including the real and imaginary parts, the dynamic carriers, two-photon absorption, and thermal effect. The MO-PPV/MWCNTs composites showed much larger third-order nonlinearities than the pristine polymers. The enhanced optical nonlinearities were attributed to the strong interaction between the π-π electrons of MO-PPV and MWCNTs in their photoexcited state.
Temperature dependence of coherent A1g and Eg phonons of bismuth
Authors: Ishioka Kunie , Kitajima Masahiro , Misochko Oleg V.
Published: November 2006

Bismuth has been a model material in the study of femtosecond dynamics of coherent lattice oscillations. The generation mechanism was first proposed to be displacive for the symmetric A1g mode, which was the only mode observed as a coherent phonon. The absence of the other Raman active mode Eg has not been fully explained, but was phenomenologically attributed to the exclusive coupling of the hot electrons at k∼0 and high symmetry phonons. In the present study, we demonstrate that both A1g and Eg modes are excited as coherent phonons at low temperature and confirm that the coherent phonons are generated via a Raman process in bismuth. We found a puzzling π∕2 difference in the initial phases of the two coherent phonons, which suggests that the initial phase cannot be a clear-cut index for the generation mechanism in absorbing media.
Synthesis and analysis of Ag-doped ZnO
Authors: Ahn Byung Du , Kang Hong Seong , Kim Jong Hoon , Kim Gun Hee , Chang Hyun Woo , Lee Sang Yeol
Published: November 2006

The solid-solid interaction and thermal decomposition behavior of 2wt% Ag2O in ZnO powder have been investigated by using thermogravimetry analysis and differential thermal analysis. Ag2O, which remained stable in ZnO up to 200°C, was observed to be thermally decomposed to Ag+ ions in the temperature range of 200–250°C, suggesting that Ag+ ions were diffused into ZnO matrix. Based on thermal analysis, ZnO:Ag films have been fabricated on a (001) Al2O3 substrate using specifically synthesized Ag-doped ZnO target by pulsed laser deposition. The effect of (002) peak shift on the structural property of Ag-doped ZnO films has been systematically characterized to investigate the influence of the substitution of Ag+ for Zn+. Ag-doped p-type ZnO films have been successfully grown at a deposition temperature in the range of 200–250°C, which is in good agreement with thermally decomposed temperature for Ag2O to Ag+ in ZnO powder, with hole concentrations of 4.9×1016–6.0×1017cm−3, hole mobilities of 0.29–2.32cm2∕Vs, and resistivities of 34–54Ωcm. The effect of Ag doping in ZnO thin film has been systematically investigated and the p-type conduction mechanism has been proposed.
Electrical breakdown of short multiwalled carbon nanotubes
Authors: Tsutsui Makusu , Taninouchi Yu-ki , Kurokawa Shu , Sakai Akira
Published: November 2006

Electrical breakdown of short (∼50nm) multiwalled carbon nanotubes (MWNTs) is studied utilizing mechanically controllable break junction technique with gold electrodes. Measurements of the conductance-bias characteristics near the breakdown point revealed two different types of breakdown behavior for the short MWNTs. In one type designated as type I, the conductance increases nearly linearly with the bias and, over the breakdown point, decreases stepwise. On the other hand, in the type-II breakdown, the conductance shows a transient and irreversible increase right before the breakdown and subsequently jumps to zero. We consider that the type-II breakdown in vacuum is contact related, whereas the type-I breakdown occurs through the usual MWNT heating.
Catalytic mechanism of a Fe–Co bimetallic system for efficient growth of single-walled carbon nanotubes on Si∕SiO2 substrates
Authors: Murakami Toshiya , Mitikami Kazuya , Ishigaki Satoru , Matsumoto Kazuyo , Nishio Koji , Isshiki Toshiyuki , Harima Hiroshi , Kisoda Kenji
Published: November 2006

Single-walled carbon nanotubes (SWCNTs)were grown on Si∕SiO2 substrates by catalytic chemical vapor deposition using ethanol as a carbon source. We found that a bimetallic catalyst, Fe–Co, worked efficiently in growing SWCNTs in contrast to Fe or Co catalyst only. The underlying mechanism was carefully studied by observing the catalyst-substrate interactions by transmission electron microscopy. It is shown that preferential diffusion of Fe into a SiO2 layer occurs in the bimetallic case, which suppresses aggregation of nanometer- sized Co particles that play key roles in growing SWCNTs.
Improved performance of planar GaN-based p-i-n photodetectors with Mg-implanted isolation ring
Authors: Chen M. C. , Sheu J. K. , Lee M. L. , Tun C. J. , Chi G. C.
Published: November 2006

This study analyzes planar GaN p-i-n photodetectors (PDs) fabricated using Si implantation. The authors have used triple silicon implantation to form a selective n+ channel, acting like a contact wire to connect the underlying n layer and the n contact located on the surface, through a GaN-based p-i-n structure. In order to suppress the lateral current conduction from the n contact to p contact, an extra Mg-implanted isolation ring between the n+ channel and the active p-i-n layers was also performed to achieve improvement of device performance. Typical peak responsivity and cutoff wavelength of Si-implanted planar p-i-n PDs were around 0.11A∕W and 365nm, respectively.
Luminescent hydroxylapatite nanoparticles by surface functionalization
Authors: Wang Wei , Shi Donglu , Lian Jie , Guo Yan , Liu Guokui , Wang Lumin , Ewing Rodney C.
Published: November 2006

Hydroxylapatite (HA) nanoparticles were functionalized by depositing rare-earth-doped Y2O3 nanoparticles on the surface, and the structural evolutions of both HA and Y2O3 phases at different annealing temperatures were investigated by x-ray diffraction and transmission electron microscopy. Laser spectroscopy indicated that the surface functionalized HA nanoparticles exhibited strong visible emissions. No visible emissions were observed from rare-earth-doped Y2O3 without any substrate, suggesting a doping-induced environmental change of optically active rare-earth elements in the functionalized HA nanoparticles. The luminescent hydroxylapatite nanoparticles may find important applications as a biodegradable substrate for biomarking and drug delivery.
Encapsulation-free hybrid organic-inorganic light-emitting diodes
Authors: Morii Katsuyuki , Ishida Masaya , Takashima Takeshi , Shimoda Tatsuya , Wang Qing , Nazeeruddin Md. Khaja , Grätzel Michael
Published: November 2006

The authors have fabricated encapsulation-free hybrid organic inorganic light-emitting diodes (HOILEDs), with improved air stability performance by incorporating two different metal oxide layers. One metal oxide layer is a titanium dioxide layer that provides the electron-injection layer, and the other is a molybdenum oxide that injects holes. While our HOILED device exhibits a lower threshold voltage and a higher air stability than conventional devices using a Ca∕Al cathode, a similar luminance output was observed.
Vertical organic triodes with a high current gain operated in saturation region
Authors: Yang Chuan-Yi , Ou Tzu-Min , Cheng Shiau-Shin , Wu Meng-Chyi , Lin Shih-Yen , Chan I-Min , Chan Yi-Jen
Published: November 2006

The authors report the fabrication of vertical organic triodes operated in the pronounced saturation regions by using two back-to-back pentacene Schottky diodes. The device with an optimized 0.7nm LiF hole injection enhancement layer and a 70nm pentacene emitter can achieve an ultrahigh common-emitter current gain of 48 in the saturation region at a low applied voltage VCE of −4V and a base current density of 0.25mA∕cm2. In addition, the device exhibits a high output current density of 12.1mA∕cm2 and a high on/off current ratio of 103.
Density-cumulant functional theory
Authors: Kutzelnigg Werner
Published: November 2006

Starting point is the energy expectation value as a functional of the one-particle density matrix γ and the two-particle density cumulant λ2. We decompose γ into a best idempotent approximation κ and a correction τ, that is entirely expressible in terms of λ2. So we get the energy E as a functional of κ and λ2, which can be varied independently. Approximate n-representability conditions, derived by perturbation theory are imposed on the variation of λ2. A nonlinear system of equations satisfied by λ2 is derived, the linearized version of which turns out to be equivalent to the coupled electron-pair approximation, variant zero. The start for κ is Hartree-Fock, but κ is then updated to become the best idempotent approximation of γ. Relations to density matrix functional theory and Kohn-Sham type density functional theory are discussed.