bluuebunny/crossref_metadata_2025_split huggingface dataset:
Charge‐controlled nuclear polarization of a single InAs/GaAs quantum dot under optical pumping
Authors: Eble Benoît , Krebs Olivier , Lemaître Aristide , Kowalik Katarzyna , Kudelski Arkadiusz , Urbaszek Bernhard , Amand Thierry , Marie Xavier , Voisin Paul 
Published: November 2006

AbstractWe report on electron spin physics in a single charge‐tunable self‐assembled InAs/GaAs quantum dot. The hyperfine interaction between the optically oriented electron and nuclear spins leads to the polarization of the quantum dot nuclei. The sign of the resulting Overhauser‐shift depends on the trion state X + or X –, and remarkably its amplitude does not vanish in zero magnetic field. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimization of InAs/(Ga,In)As quantum dots in view of efficient emission at 1.5 µm
Authors: Hugues M. , Richter M. , Damilano B. , Chauveau J.‐M. , Duboz J.‐Y. , Massies J. , Wieck A. D. 
Published: November 2006

AbstractInAs self‐organized quantum dots covered by low temperature (Ga,In)As layer with different thicknesses and indium contents have been grown on GaAs substrates by molecular beam epitaxy. The most efficient emission is obtained for islands covered by 5 nm thick Ga0.85In0.15As cap layer. A strong room temperature emission at 1.33 µm with a linewidth as narrow as 21 meV is observed. Moreover, the analysis of temperature dependent photoluminescence intensity indicates that the main quenching mechanism comes from carrier escape from the dots to the confined level of the quantum well formed by the cap layer and the wetting layer. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transitions between electron‐molecule states in electrostatic quantum dots
Authors: Maksym P. A. , Aoki H. 
Published: November 2006

AbstractIntermediate spin states that occur in electrostatic dots in the magnetic field regime just beyond the maximum density droplet are investigated. The 5‐electron system is studied with exact diagonalization and group theory. The results indicate that the intermediate spin states are mixed symmetry states with a superposition of 5‐ and 4‐fold electron‐molecule configurations. A superposition of 5‐ and 4‐fold correlation functions is found to reproduce the exact mixed symmetry pair correlation function to around 2%. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Relative incorporation of linoleic and arachidonic acid in phospholipids and triglycerides of different rat tissues
Authors: Catala Angel , Brenner Rodolfo R. 
Published: November 2006

AbstractFat‐deficient rats were fed different amounts of methyl linoleate for increasing periods of time. The fatty acid composition of triglycerides and phospholipids of epididymal fat pad, epirenal fat depot, intestinal fat depot, liver, and the pool of heart, kidney, lungs and pancreas was determined. The distribution of the total amount of linoleic and arachidonic acid incorporated into phospholipids and triglycerides per rat was calculated. Phospholipids and triglycerides of depot tissues presented different fatty acid compositions.Although the phospholipids of liver and the pool of heart, kidney, lung and pancreas specifically incorporated linoleic acid at the beginning they very rapidly attained a rather steady composition, whereas triglycerides went on incorporating the acid. The amount of linoleic acid incorporated into the phospholipids of depot tissues was rather small. The triglycerides undoubtedly contributed in the highest proportion to the total pool of linoleic acid. However, the highest proportion of arachidonic acid was found in the total pool of phospholipids.The total amount of linoleic acid incorporated into the phospholipids was an approximately lineal function of the amount of phospholipids independent of period of administration and doses of methyl linoleate. Besides presenting two lineal functions of the amount of phospholipids, arachidonic acid showed a vertical increase coincident with a vertical decrease of the amount of eicosa‐5,8,11‐trienoic acid. At this period no change in the amount of the phospholipid was shown. This phenomenon is explaioned as a possible direct replacement of eicosatrienoic acid by arachidonic acid.
Fatty acid composition of milk phospholipids. II. Sheep, Indian buffalo and human milks
Authors: Morrison W. R. , Smith L. M. 
Published: November 2006

AbstractPhospholipids were isolated from sheep, Indian buffalo, and human milks, and their fatty acid compositions determined by gas chromatography. The specific distributions of fatty acids in phosphatidyl cholines (PC) and phosphatidyl ethanolamines (PE) were determined after phospholipase A hydrolysis.Fatty acid compositions and specific distributions were similar in sheep and buffalo milk phospholipids, and compared closely with those of bovine milk. Human milk phospholipids, particularly PE, contained much larger amounts of polyunsaturated acids, but negligible amounts of branchedchain acids. Palmitic and oleic acids were evenly distributed in human milk PC and PE, whereas they were preferentially located in the α′ position in PC and PE of ruminant milks.The results are discussed in the context of current theories of lipid biosynthesis.
Circum‐annual changes in triglyceride fatty acids of bat brown adipose tissue
Authors: Paulsrud John R. , Dryer R. L. 
Published: November 2006

AbstractA circum‐annual study of the fatty acids of brown adipose tissue triglycerides ofEptesicus fuscus has demonstrated a rhythmic pattern of change. This is seen as a reciprocal shift of the levels of oleic and linoleic acids. Oleic acid levels are lower during the summer months and higher in the winter months. Levels of palmitic and linoleic acids reach maximal values in midsummer and fall significantly during the winter.Homogenates of brown adipose tissue produce more14CO2 from 1‐14C‐palmitic acid than from 1‐14C‐oleic acid when incubated at temperatures below 20C. The formation of14CO2 from either substrate was maximal in the neighborhood of 30C, and the temperature effect was enhanced by stimulation with DL‐carnitine.It is proposed that the rhythmic change in brown adipose tissue triglyceride composition is a reflection of the different rates of fatty acid oxidation and the absence of normal food intake for extended periods of time.
The effect of a fat free diet on esterified monoenoic fatty acid isomers in rat tissues
Authors: Spence M. W. 
Published: November 2006

AbstractRats were maintained 120–140 days on a normal diet (group 1) or one deficient in fatty acids (group 2). Isomer composition was determined of monoenoic fatty acids (16∶1, 18∶1) isolated from total lipids of heart, kidney, lung, brain and lumbar fat, and from separated neutral lipids and phospholipids of heart and kidney. Group 1: The number of major isomers of C16∶1 and C18∶1 was similar in all tissues but their proportions varied in different tissues and types of lipid. Group 2: The proportions of 16∶1(n−7) increased and of other 16∶1 isomers decreased in all tissues; 18∶1(n−9) was increased at the expense of (n−7) in heart, to a lesser extent in kidney, and was little changed in lung, lumbar fat, or brain. The decrease in proportion of 18∶1(n−7) was greatest in heart‐muscle phospholipids. C20∶3 comprised 95% (n−9) and 5% (n−7) in heart and kidney lipids. The changes in group 2 probably represent the body's attempts to maintain lipids with the physical and chemical properties necessary to normal biological function.
The biosynthesis of cyclopropane and cyclopropene fatty acids in higher plants (Malvaceae)
Authors: Yano I. , Morris L. J. , Nichols B. W. , Jams A. T. 
Published: November 2006

AbstractThe biosynthesis of cyclopropane and cyclopropene fatty acids has been investigated in immature seeds, leaves and callus tissue cultures of several species of Malvaceae. Chemical characterization of labeled cyclopropane and cyclopropene fatty acids obtained from incubations withl‐[14CH3] methionine confirmed that the ring methylene group was derived from the methyl group of methionine. The variation with time in the distribution of radioactivity in the products of incubations with [14CH3] methionine and [2‐14C] acetate suggested that the pathway involved initial formation of dihydrosterculic acid from oleic acid with subsequent desaturation to sterculic acid and α‐oxidation to malvalic and dihydromalvalic acids. Direct evidence in favor of this pathway was provided by the conversion of [1‐14C] oleic acid to dihydrosterculic and sterculic acids and by the desaturation of [1‐14C] dihydrosterculic acid to sterculic acid, the first time that these processes have been demonstrated in higher plants. No conversion of [1‐14C] stearolic acid to sterculic acid could be obtained under the same conditions. The presence of an active fatty acid α‐oxidation system was demonstrated in the callus cultures.
Metabolism of odd‐numbered fatty acids inOchromonas danica
Authors: Gellerman J. L. , Schlenk H. 
Published: November 2006

AbstractThe lipids of the protozoon,Ochromonas danica, contain very small amounts of odd‐numbered fatty acids. Nevertheless the organism incorporates into its lipids odd‐ as well as evenumbered acids from the media. Unsaturated odd acids such as 9–17∶1 or 6,9,12–17∶3 were efficient substrates for elongation and desaturation in the proximal and the former acid also in the distal part of the chain. In contrast none of these conversions was observed with 7–17∶1, 10–17∶1 and 10,13–19∶2 acids, although these substrates were taken up by the organism. Elongation and desaturation of the proximal part of already unsaturated fatty acid chains appear to be subject to the same structural requirements inO. danica as in the rat, and the same effects apply to desaturation in the distal part of the chain.
The phospholipid and fatty acid composition of platelets in patients with primary defects of platelet function
Authors: Safrit Henry F. , Weiss Harvey J. , Phillips Gerald B. 
Published: November 2006

AbstractPlatelet phospholipid and fatty acid composition was determined in nine normal subjects and in 11 patients with primary defects in platelet function. Two of the patients had thrombasthenia (Glanzmann) and nine had various types of abnormalities in platelet aggregation and platelet factor 3 availability attributed to impairment of the platelet release reaction. The values observed for platelet lipids in the normal subjects were similar to those reported by others. Four of the patients with a disturbance in the platelet release reaction were in the same family and showed the same abnormal pattern of platelet lipid composition. Phospholipid analysis showed a decrease in the relative amount of phosphatidyl ethanolamine (PE) and an increase in lecithin. Abnormalities in fatty acids consisted of an increase in the relative amounts of 18∶1ω9, 20∶0 and 20∶1ω9 and a decrease in the 22∶4ω6+24∶1 fraction. Similar changes in PE and 18∶1ω9 were also observed in another patient with a similar defect in platelet function. In this patient the relative amount of platelet sphingomyelin was also increased. The platelet lipid composition in the other six patients and in one normal subject given aspirin was essentially normal.
2‐Alkylcyclobutanones from the radiolysis of triglycerides
Authors: Letellier P. R. , Nawar W. W. 
Published: November 2006

AbstractA cyclic compound was isolated from the radiolytic products of each of the simple triglycerides containing C6, C8, C10, C12, C14, C16 and C18 fatty acids. In each case the compound was identified as the 2‐alkylcyclobutanone of the same carbon number as the precursor fatty acid. A mechanism is proposed for the production of these compounds which involves the formation of a six‐membered ring intermediate, cyclization and cleavage at the acyl‐oxy bond.
Oxidation of fatty acids by heat treated hemoproteins
Authors: Eriksson Caj E. , Olsson Pär A. , Svensson Svante G. 
Published: November 2006

AbstractThe hemoproteins catalase and peroxidase, after heat treatment which decreased their enzyme activities, became more efficient as heme catalysts of linoleic acid oxidation. These effects might be of importance for preservation and storage of food.
The metabolism of 1‐14C‐palmitic acid in the testis of the rat
Authors: Coniglio J. G. , Bridges R. B. , Aguilar H. , Zseltvay R. R. 
Published: November 2006

AbstractThe metabolism of 1‐14C‐palmitic acid was studied in rat testis at various intervals after intratesticular injection and after a 2 hr incubation period. Significant catabolism occurred as evidenced by production of14CO2 in both in vivo and in vitro experiments. Of the14C activity retained in the injected testis, less than 15% remained as free fatty acid after 2 hr and less than 5% by the end of 2 weeks. Activity of14C appeared in phosphatides faster than in the triglyceride fraction, and with time (1–2 weeks) the activity in phosphatides decreased relative to that in triglycerides. In phosphatides of these experiments ca. 80% of the14C was in the palmitic acid fraction and the balance predominantly (98%) in palmitate with the balance in stearate and oleate. By the first and second weeks almost half of the14C‐palmitate present in the testes had been newly synthesized from14C‐acetyl CoA resulting from oxidation of the administered 1‐14C‐palmitate. In the incubated samples the only fatty acid with14C activity in any lipid fraction was palmitate. In these experiments ca 90% of the14C was in the free fatty acid fraction, 7% in the phosphatides and 2% in the triglycerides.
Biosynthesis of protein relative to the accumulation of fat in the liver of EFA deficient rats
Authors: Fukazawa Toshio , Privett O. S. 
Published: November 2006

AbstractEffect of an essential fatty acid (EFA) deficiency in the rat on the incorporation of leucine‐14C and glucosamine‐14C into serum and liver protein are reported. Weanling male rats of the Sprague‐Dawley strain were raised on a fat‐free diet for 10–12 weeks and then switched to diets supplemented with 10% corn oil or 10% hydrogenated coconut oil. Leucine‐14C or glucosamine‐14C was injected into the tail veins of the animals of each group. At selected intervals up to 120 min after the injections, the animals were sacrificed and the radioactivity of the liver and serum proteins was measured. The levels of triglyceride (TG) in the serum and the liver were also determined. Less radio‐activity was incorporated into the serum β‐lipoprotein (β‐LP) fraction of the hydrogenated coconut oil than the corn oil fed animals injected with leucine‐14C, but no differences were observed in the incorporation of radioactivity into the liver protein and both albumin and globulin fractions of the serum of these groups of animals. In the similar experiments with glucosamine‐14C less radioactivity was incorporated into the β‐LP fraction of the serum and into the smooth endoplasmic reticulum of the liver in the hydrogenated coconut oil (EFA deficient) than the corn oil fed animals. Time course studies also indicated that less radioactivity was incorporated into the β‐LP fraction than into the albumin and globulin fractions of the serum of the hydrogenated coconut oil group. These findings suggest that an EFA deficiency results in an impairment of the synthesis or release of lipoprotein.
Comparison of dialysis, thin layer and silicic acid column chromatography for prostaglandin isolation from biological material
Authors: Clausen J. , Srivastava K. C. 
Published: November 2006

AbstractChemical and biochemical methods assaying the total content of neutral lipids during some conventional procedures for purification and isolation of prostaglandins from biological fluids revealed all fractions to be contaminated with fatty acids, cholesterol, cholesterol esters, tri‐, di‐ and/or mono‐glycerides. It was demonstrated that it was not possible to make pure prostaglandin fractions by simple dialysis. On the basis of these findings a new preparative schedule involving either dialysis or column chromatography on silicic acid, combined with preparative thin layer chromatography, made it possible to isolate substantially pure PGE2 from a synthetic biological system involving arachidonic acid as a precursor and the microsomal synthesizing system from sheep vesicular glands.Sheep vesicular glands have been used for biosynthesis of prostaglandins (PG) (1). For the study of the metabolism of various prostaglandins, labeled PGE1 has been prepared from 8, 11, 14‐eicosatrienoic acid labeled at various positions (2). Recently a method employing arachidonic acid and sheep vesicular glands for the formation of PGE2 has been patented. The method claims a high purity (98%) with quick recovery of PGE2 from the incubation mixture. The essential feature of the method is the use of a dialysis step which is said to be superior to the time‐consuming chromatographic procedures (3). In our recent studies on the metabolism of essential fatty acids, we have found it impossible to prepare chemically pure prostaglandins by the above mentioned methods, since cholesterol, cholesterol esters, fatty acids and glycerides were found to contaminate the final products. The present paper therefore gives some data on these contaminants, and on this basis a new approach to the isolation of chemically pure prostaglandin (PGE2) has been developed.
The stereochemistry of enzymic hydration and of chemical cleavage of D‐(+)‐cis‐12,13‐epoxyoleic acid (Vernolic acid)
Authors: Morris L. J. , Crouchman M. L. 
Published: November 2006

AbstractThe absolute optical configurations of (+)‐threo‐12,13‐dihydroxyoleic acid, derived by enzymic hydration of endogenous vernolic acid in crushedVernonia anthelmintica seed, and of (−)‐threo‐12,13‐dihydroxyoleic acid, derived by acetolysis‐hydrolysis of vernolic acid, have been determined. The absolute configuration of the (+)‐enantiomer is L‐12,D‐13‐dihydroxyoleic acid and, as the parent vernolic acid is known to be D‐12,D‐13‐epoxyoleic acid, the stereochemistry of the enzymic hydration is thus shown to involve attack by hydroxyl at the 12 position with inversion at that position. Chemical cleavage of vernolic acid, on the other hand, involves preferential nucleophilic attack, with inversion, at the 13 position.
Labeling of liver and plasma lecithins after injection of 1–2‐14C‐2‐dimethylaminoethanol and14C‐L‐methionine‐methyl to choline deficient rats
Authors: Lombardi B. , Pani P. , Schlunk F. F. , Shi‐hua Chen 
Published: November 2006

AbstractGroups of rats were fed a choline‐deficient (CD) or a choline‐supplemented (CS) diet for 15 hr. Labeling of liver and plasma cephalins and lecithins was followed with time after injection of14C‐L‐methionine‐methyl or 1–2‐14C‐2‐dimethylaminoethanol, either alone or together with3H‐S‐adenosyl‐L‐methionine‐methyl. A reduced concentration of liver and plasma lecithins was found in CD rats. In the same animals, labeling of the phospholipid fractions was considerably greater and faster than in CS rats. Administration of choline to rats previously fed the CD diet resulted in both an increased concentration of liver and plasma lecithins and a reduction in the labeling of liver and plasma lecithins to levels seen in control rats. These results suggest that in CD rats, while the overall synthesis of lecithins may be reduced due to insufficient availability of choline, the synthesis of lecithins via stepwise methylation of cephalins may be increased.
Activation of long chain fatty acids by subcellular fractions of rat liver: I. Activation oftrans‐unsaturated acids
Authors: Lippel Kenneth 
Published: November 2006

AbstractThe optimal fatty acid to protein ratio for maximum rat liver microsomal or mitochondrial activation of thetrans‐monounsaturated acids elaidate ortrans‐vaccenate is similar to the ratio for maximum palmitate activation but approximately double the optimal ratio for maximum activation of thecis‐unsaturated fatty acids, oleate,cis‐vaccenate, or of thetrans‐diunsaturated linelaidic acid. However, when the substrate is a fatty acid‐albumin complex rather than free fatty acids, optimal fatty acid activation appears to be independent of geometrical configuration or degree of unsaturation. All‐trans retinoate, d‐α‐tocopheryl acid succinate, and dihomogeranoate are not activated themselves, but at low concentrations extensively inhibit activation ofcis‐acids (oleate,cis‐vaccenate, petroselenate, linoleate, linolenate, arachidonate) and thetrans‐diunsaturated linelaidate but do not affect activation of palmitate ortrans‐monounsaturated acids elaidate andtrans‐vaccenate. Anionic, cationic or nonionic detergents in a pH 7.4 buffered incubation medium were shown to inhibit, have no effect on, or apparently activate oleate activation, respectively, while not affecting or inhibiting palmitate and elaidate activation. The effect observed was dependent on the fatty acid to protein ratio, the fatty acid configuration and the detergent concentration.
Molecular species of wax esters in jaw fat of atlantic bottlenose dolphin,Tursiops truncatus
Authors: Ackman R. G. , Sipos J. C. , Eaton C. A. , Hilaman B. L. , Litchfield Carter 
Published: November 2006

AbstractThe jaw fat of the Atlantic bottlenose dolphin (Tursiops truncatus) contains unusual wax esters which can be separated into short chain (<C24) and long chain (>C24) fractions by thin layer chromatography. The short chain wax esters (28 wt. %) have been characterized as a 72∶24∶4 mixture of isovaleroyl, isobutoryl, and 2‐methylbutyrol, esters of C14–C18 n‐ and iso‐alcohols. The intact <C24 esters have been resolved into individual molecular species by gas liquid chromatography on open‐tubular polyester columns. The long chain wax esters (12 wt. %) contain C10–C22 n‐ and iso‐acids esterified to the same C14–C18 n‐ and iso‐alcohols. Gas liquid chromatography of the intact, hydrogenated >C24 esters on a short JXR column has characterized them according to carbon number and the number of methyl branches they contain.
Incorporation of acetate into fatty acids and complex lipids of soybean cotyledon slices under aerobic and anaerobic conditions
Authors: Stearns E. M. , Morton W. T. 
Published: November 2006

AbstractSoybean slices incubated with [1‐14C] acetate in the presence of air synthesized fatty acids to a greater extent than did slices in the absence of air. The proportion of radioactive fatty acids incorporated into the neutral lipid was ca. 35% in the presence or absence of air. However, both the proportion and the absolute amount of radioactive fatty acids in phospholipids were greater in the presence of air. This difference was particularly great in phosphatidic acid and in a minor uncharacterized phospholipid component. Significant incorporation of acetate into monoenoic acids was observed in these two lipids and in phosphatidyl choline. The latter also showed an accumulation of newly synthesized polyenoic acids when air was present. Stearic acid synthesis was greater under aerobic than under anaerobic conditions. The present results support the concept that a relationship exists between the synthesis of unsaturated fatty acids and their incorporation into phospholipids in plants.