bluuebunny/crossref_metadata_2025 huggingface dataset:
Cultivar identification inBrassica napus L. by reversed‐phase high‐performance liquid chromatography of ethanol extracts
Authors: Mailer R. J. , Daun J. , Scarth R.
Published: January 2007

A method has been developed to identify cultivars of oilseed rape (Brassica napus L.), an outcrossing species, by reversed‐phase high‐performance liquid chromatography (HPLC) based on the separation of ethanol‐extractable seed components. Defatted flour was extracted into 70% ethanol in water, and chromatography was carried out in a reversed‐phase C18 column. Optimum results were achieved with water solvent and a gradient to 50% acetonitrile, and peak detection at 210 nm and 240 nm. Trifluoroacetic acid (0.1%) was added to dissociate proteins. Extraction and chromatographic conditions were reproducible, and significant differences were found in the chromatograms of the 29 cultivars studied. The chromatographic differences between these cultivars were stable over a range of growing environments. It was possible to allocate unknown cultivars to their correct classes with the HPLC method together with discriminate analysis. This test has potential as a method of characterization for cultivar registration.
The mixed surfactant system of linear alkylbenzene sulfonate and alpha olefin sulfonate
Authors: Suri Sushil K. , Thakur Manmohan S. , Bhardwaj Satish
Published: January 2007

Physicochemical and detergency studies on the mixed surfactant system of linear alkylbenzene sulfonate‐sodium salt (LABS) and alpha olefin sulfonate‐sodium salt (AOS) have been carried out. The binary surfactant system exhibits minima in the surface tension and in the critical micelle concentration when the two surfactants are present in the ratio 80:20, indicating synergism in the mixed monolayer and in mixed micelles at this proportion of the two surfactants. The mixed micelles improve hard‐water tolerance of LABS and reduce the loss of LABSvia Ca(LABS)2 precipitation. Addition of AOS to LABS improves its lime soap dispersion properties. The effect is highly significant when AOS is present at the 20% level in the mixed surfactant system. A synergistic mixture of the two surfactants, when used in phosphate‐free, carbonate‐built detergent product formulation, exhibits superior detergency, low ash deposit and better stainremoving ability when compared to products containing LABS as the sole active surfactant.
Determination of betaine and free amine in alkyldimethyl betaine by potentiometric titrations
Authors: Plantinga J. M. , Donkerbroek J. J. , Mulder R. J.
Published: January 2007

Two selective analytical methods are presented for the determination of betaine and free amine contents, respectively, in commercial alkyl dimethyl betaines. Both methods are based on titrations with potentiometric end point detection. The accuracy and precision are discussed.
Vitamin E in foods: Determination of tocols and tocotrienols
Authors: Slover Hal T. , Lehmann Joanna , Valis Robert J.
Published: January 2007

A method is described for the analysis of foods for the forms of vitamin E. Detailed procedures are given for extraction, saponification and partial purification by thin layer chromatography. The individual tocopherols (both tocols and tocotrienols) are identified and estimated as their trimethylsilyl ethers by gas liquid chromatography on SE‐30 or Apiezon L at 235 C. Retention ratios are also given for separations on OV‐17. Response factors relative to didecyl pimelate as an internal standard and overall recoveries were determined for α‐tocopherol, β‐tocopherol, γ‐tocopherol, δ‐tocopherol, β‐tocotrienol and α‐tocotrienol. Sample sizes depended on tocopherol content and were usually chosen to contain 3–50 µg of the individual tocopherols. Data for a number of seeds and oils are given. The greatest variety of forms was found in barley, which contains all the forms listed above, plus γ‐tocotrienol.
Phospholipid concentration in cocoa butter and its relationship to viscosity in dark chocolate
Authors: Parsons J. G. , Keeney P. G.
Published: January 2007

Fats extracted from chocolate liquor with a polar solvent, chloroform‐methanol, was found to be 0.65% phospholipid. The evidence indicates that the phospholipids are associated primarily with the nonfat solids since concentrations were much lower in fat recovered with nonpolar solvents, hydraulic pressing and centrifugation. Seven of the 11 commercial cocoa butters analyzed had phospholipid concentrations between 0.05% and 0.13%. The highest concentration found was 0.57%. The reduction in viscosity caused by the addition of these butters, 14% by weight, to chocolate was related to the phospholipid concentration in cocoa butter. The higher the phospholipid level, the greater was the viscosity‐reducing effect of the cocoa butter.
Distillation and solvent recovery for soybean and other oilseeds plants
Authors: Becker Kenneth W.
Published: January 2007

Features which a modern, well designed distillation and solvent recovery system should contain in order to permit safe and profitable operation will be discussed. The technology has advanced rapidly during the past 10 years in the development of more efficient and profitable distillation and solvent recovery systems. These systems operate with less down‐time and far more efficiency than they did 20 years ago. The application of good chemical engineering practice, together with a long background of plant operations, will permit continued improvements of these systems in the future. To permit continuous development in this area it is essential that design and operating companies have a two‐way interchange of information.
Polymorphic behavior of erucic acid
Authors: Suzuki M. , Sato K. , Yoshimoto N. , Tanaka S. , Kobayashi M.
Published: January 2007

Polymorphic behavior of erucic acid was examined by differential scanning calorimetry (DSC), X‐ray diffractometry (XRD) and optical microscopy. Four individual polymorphs were observed, α1, γ1, α and γ. The single crystals of α and α1 were obtained from acetonitrile solutions. DSC and XRD studies exhibited reversible transformations between α and γ, and between α1 and γ1. The two transformations were characterized by an order (γ and γ1)‐disorder (α and α1) transformation due to melting of the aliphatic chain between acis double bond and a methyl end group, as revealed in α and γ of oleic acid. The thermodynamic stability among the four polymorphs was determined based on the transformation features and the solubility data. α1 is most stable above 25.9 C, melting at 34.0 C, α is most stable in a range of temperature between −1.0 and 25.9 C, transforming in a crystalline state to α1 at 31.2 C on heating. γ is most stable below −1.0 C. It can be concluded that the polymorphism of erucic acid is different from that of oleic acid with respect to the thermal and structural behaviors, although some similarities are revealed.
Liquid fuels fromMesua ferrea L. seed oil
Authors: Konwer Dolon , Taylor Scott E. , Gordon B. E. , Otvos John W. , Calvin Melvin
Published: January 2007

Mesua ferrea L. seed oil consists of triglycerides of linoleic, oleic, palmitic and stearic acids. These acids were pyrolyzed separately in the presence of different amounts of solid sodium carbonate. Pyrolysis experiments revealed that linoleic and oleic acids can be converted to hydrocarbons of a wide range of molecular weights by pyrolyzing them with even 1% by wt of sodium carbonate up to a temperature of 500°C, whereas palmitic and stearic acids can be converted to hydrocarbons only by pyrolyzing them with equivalent amounts or more of sodium carbonate up to a temperature of about 650°C.

The fractions of boiling range 60–320°C of all of the pyrolytic oils were analyzed for their hydrocarbon types by the method of fluorescent indicator adsorption (FIA). The aromatic contents of the pyrolytic oils of linoleic and oleic acids were found to be much higher than those of palmitic and stearic acids. GS and GC‐MS analyses of all the saturate fractions indicated mainly normal alkanes with a carbon number range of 6 to 17.
The structures of cyclopentenyl fatty acids in the seed oils of flacourtiaceae species by GC‐MS of their 4,4‐dimethyloxazoline derivatives
Authors: Zhang J. Y. , Wang H. Y. , Yu Q. T. , Yu X. J. , Liu B. N. , Huang Z. H.
Published: January 2007

The structures of cyclopentenyl fatty acids in the seed oils ofHydnocarpus anthelmintica Pierre et Laness.,H. alphina Wight,H. hainanensis (Merr.) andTaraktogenos merrilliana C.Y. Wu, all belonging to the family Flacourtiaceae, have been identified by GC‐MS of the mixed 2‐substituted 4,4‐dimethyloxazoline (DMOX) derivatives. These variations are characterized by the presence of key fragments at (M‐43), (M‐55) and (M‐67), while the location of a double bond in the chain is indicated by a 12‐mass interval between the highest peaks of two adjacent homologous ion clusters. The unique fragmentation pattern coupled with the good gas chromatographic qualities of these derivatives enable convenient structure determination of cyclopentenyl fatty acids in complex mixtures.
Synthesis of four chiral pharmaceutical intermediates by biocatalysis
Authors: Patel Ramesh N. , Banerjee Amit , Szarka Laszlo J.
Published: January 2007

Chiral intermediates were prepared by biocatalytic processes for the chemical synthesis of four pharmaceutical drug candidates. These include: (i) the microbial reduction of 3,5‐dioxo‐6‐(benzyloxy) hexanoic ethyl ester to (3S,5R)‐dihydroxy‐6‐(benzyloxy) hexanoic acid ethyl ester, an intermediate for a new anticholesterol drug; (ii) synthesis of (2R,3S)‐(‐)‐N‐benzoyl‐3‐phenyl isoserine ethyl ester, a taxol side‐chain synthon; (iii) the microbial oxygenation of 2,2‐dimethyl‐2H‐1‐benzopyran‐6‐carbonitrile to the corresponding (3S,4S) epoxide and (3S,4R)‐trans diol, intermediates for synthesis of potassium channel opener; (iv) the biotransformation of (exo,exo)‐7‐oxabicyclo [2.2.1] heptane‐2,3‐dimethanol to the corresponding chiral lactol and lactone, intermediates for thromboxane A2 antagonist.
Large‐scale immobilization of lipase fromPseudomonas fluorescens biotype I and an application for sardine oil hydrolysis
Authors: Kosugi Yoshitsugu , Takahashi Katsuo , Lopez Claudia
Published: January 2007

Large‐scale production of thermostable lipase fromPseudomonas fluorescens biotype I was carried out in a fermenter with an antifoaming agent and physical deforming treatments. After cultivation, heat treatment was applied to kill the bacteria and to inactivate other enzmes. Large‐scale immobilization of the lipase to a macroporous weak‐anion exchange resin was performed with a lipase solution that had an ionic strength of less than 0.1 and an ethanol concentration of 50%. Almost all eicosapentaenoic acid and docosahexaenoic acid were liberated continuously from sardine oil by the immobilized lipase in a countercurrent fluidized‐bed reactor. The cost of enzyme used in the reactor has been compared with a process in which soluble lipase fromCandida rugosa was used.
Preparation of therapeutic phospholipids through porcine pancreatic phospholipase A2‐mediated esterification and lipozyme‐mediated acidolysis
Authors: Hosokawa Masashi , Takahashi Koretaro , Kikuchi Yuji , Hatano Mutsuo
Published: January 2007

Highly unsaturated fatty acid‐containing phospholipids (HUFA‐PL), which serve to increase the deformability of human red blood cells, were prepared through porcine phospholipase A2‐mediated esterification of the lysophosphatidylcholine, which was derived from soy phosphatidylcholine (PC), and by Lipozyme‐mediated acidolysis. Through these processes, phospholipase A2, with formamide as a water mimic, enhanced the incorporation of HUFA into positionsn‐2 of PC and suppressed hydrolysis of the synthesized PL. On the other hand, Lipozyme‐mediated acidolysis between positionsn‐1 of soy PC and HUFA was enhanced by a combination of water and propylene glycol. Simultaneously, the recovered PL products showed decreased hydrolysis of newly synthesized health‐beneficial HUFA‐PL.
Lipase‐catalyzed synthesis and properties of estolides and their esters
Authors: Hayes Douglas G. , Kleiman Robert
Published: January 2007

Eight lipases were screened for their ability to synthesize estolides from a mixture that contained lesquerolic (14‐hydroxy‐11‐eicosenoic) acid and octadecenoic acid. With the exception ofAspergillus niger lipase, all 1,3‐specific enzymes (fromRhizopus arrhizus andRhizomucor miehei lipases) were unable to synthesize estolides.Candida rugosa andGeotrichum lipases catalyzed estolide formation at >40% yield, with >80% of the estolide formed being monoestolide from one lesquerolic and one octadecenoic acyl group:Pseudomonas sp. lipase synthesized estolides at 62% yield, but the product mixture contained significant amounts of monoestolide with two lesquerolic acyl groups as well as diestolide. ImmobilizedR. miehei lipase was chosen to catalyze the esterification of mono‐and polyestolide, derived synthetically from oleic acid, with fatty alcohols or α,ω‐diols. Yields were >95% for fatty alcohol reactions and >60% for diol reactions. In addition, the estolide linkage remained intact through the course of the esterification process. Esterification of estolides improved the estolide’s properties—for example, lower viscosity and higher viscosity index—but slightly raised the melting point. Estolides and, particularly, estolide esters may be suitable as lubricants or lubricant additives.
Enzymatic modification of trilinolein: Incorporation of n‐3 polyunsaturated fatty acids
Authors: Akoh Casimir C. , Jennings Brenda H. , Lillard Dorris A.
Published: January 2007

Two immobilized lipases, IM60 fromMucor miehei and SP435 fromCandida antarctica, were used as biocatalysts for the modification of trilinolein with n‐3 polyunsaturated fatty acids (PUFA), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), by using their ethyl esters as acyl donors (EEPA and EDHA, respectively). Transesterification (ester‐ester interchange) reactions were carried out in organic solvent. The products were analyzed according to their equivalent carbon number and polarity by reverse‐phase high‐performance liquid chromatography, and the fatty acid profiles were determined by gas‐liquid chromatography. Modified triacylglycerol products contained 1 or 2 molecules of n‐3 PUFA. With EEPA as the acyl donor, the total EPA product yields with IM60 and SP435 as biocatalysts were 79.6 and 81.4%, respectively. However, with EDHA as the acyl donor and IM60 and SP435 as biocatalysts, the total DHA product yields were 70.5 and 79.7%, respectively. Effects of reaction parameters, such as type of solvent, enzyme load, time course, and molar ratio of substrates on the n‐3 PUFA incorporation, were followed with SP435 as the biocatalyst. High yields were obtained, even in the absence of organic solvent. These lipids do hold promise for specialty nutrition and other therapeutic uses.
Continuous lipolysis reactor with a loop connecting an immobilized lipase column and an oil‐water separator
Authors: Kosugi Yoshitsugu , Tomizuka Noboru
Published: January 2007

A continuous lipolysis system is described that consists of a loop connecting a fixed‐bed reactor with the immobilized lipase fromPseudomonas fluorescens biotype I and an oil‐water separator. In addition to continuous lipolysis, good continuous separation of oil product and water‐soluble product and continuous concentration of glycerol can be integrated in this simple reactor.
Kinetics of organic solvent‐soluble and native lipase
Authors: Tsuzuki Wakako , Akasaka Kazuaki , Kobayashi Shoichi , Suzuki Tateo
Published: January 2007

Organic solvent‐soluble lipase was prepared with a synthetic detergent. The solvent‐soluble lipase was presumed to be a complex of the enzyme and the detergent. To investigate the effect of the detergent attachment to the enzyme on the reaction properties, the kinetics of the solvent‐soluble lipase and of the native lipase were estimated by using glycerides in a homogeneous solution of buffer and tetrahydrofuran. Analysis of the direct interaction between the enzyme and the substrate could serve to characterize the steric structure around the active site of the lipase. The Km values also differentiated the solvent‐soluble lipase from the native lipase. These findings show for the first time that the detergent surrounding the enzyme molecule may affect not only the solubility of the enzyme, but its kinetics as well.
Solvent‐free enzymatic glycerolysis of marine oils
Authors: Myrnes Bjørnar , Barstad Harald , Olsen Ragnar L. , Elvevoll Edel O.
Published: January 2007

Marine triglyceride oils (cod liver oil and oils from blubber of harp seal and minke whale) were reacted with glycerol using lipase as a catalyst at low temperature. A solvent‐free batch system with magnetic stirring was used. Solidification of the reaction mixture occurred, and a mixture of mono‐, di‐, and triglycerides was obtained in all cases. The recovered glyceride mixtures were solid at room temperature. The yield of monoglyceride (MG) and the fatty acid profile of the MG fractions were dependent on oil and the type of lipase used as a catalyst. Of the commercially‐available lipases investigated, lipase AK fromPseudomonas sp. synthesized the highest yield of MG (42–53%) at 5°C. These MG fractions were low in saturated fatty acids (4–11%) and high in long‐chain monounsaturated fatty acids (52–69%). The concentration of n‐3 polyunsaturated fatty acids was 12–20%.
Pseudomonas sp. lipase‐catalyzed synthesis of geranyl esters by transesterification
Authors: Yee Lisa N. , Akoh Casimir C. , Phillips Robert S.
Published: January 2007

Pseudomonas sp. lipase was immobilized by adsorption onto five supports and tested for its ability to synthesize geranyl esters by transesterification using short‐chain triacylglycerols as acyl donors. Reaction mixtures were prepared in 2 mL ofn‐hexane, 0.1 M geraniol, 0.03M triacylglycerol, and 200 units of lipase, and incubated at 30°C and 200 rpm for 24 h. Overall, glass beads were the best support. Geranyl acetate and caproate performed best with Duolite (77.5 and 95.3%, respectively). Geranyl butyrate and caprylate performed best with polyvinylpyrrolidone, (80.2 and 95.5%, respectively). Values for nonimmobilized enzyme also were obtained. Immobilization improved yields, with geranyl caproate exhibiting best results.
Retro‐aldol degradations of unsaturated aldehydes: Role in the formation ofc4‐heptenal fromt2,c6‐nonadienal in fish, oyster and other flavors
Authors: Josephson David B. , Lindsay Robert C.
Published: January 2007

Alterations of cucumber‐, melon‐like notes in aromas and flavors caused by retro‐aldol degradations oft2,c6‐nonadienal were confirmed using gas chromatographic measurements of volatile compounds in model systems. The data indicated that 3‐hydroxy‐c6‐nonenal was formed first by the addition of water to the alpha/beta double bond oft2,c6‐nonadienal, and this was followed by a retro‐aldol condensation of 3‐hydroxy‐c6‐nonenal to yieldc4‐heptenal and ethanal. Compared to the reaction rate in aqueous systems at neutral pH, formation ofc4‐heptenal was enhanced substantially at alkaline pH, but was greatly diminished at acidic pH values. Heating (to 90 C) of aqueous model systems oft2,c6‐nonadienal held at neutral pH also enhanced the rate of formation ofc4‐heptenal substantially compared to that at ambient temperature (21 C). Rates of formation ofc4‐heptenal in aqueous model systems held under air or nitrogen atmospheres were similar.c4‐Heptenal was not formed whent2,c6‐nonadienal was held at 21 C for 96 hr under air or nitrogen in nonaqueous commercial corn oil.
Prince Phetsarath (1890–1959): Nationalism and Royalty in the Making of Modern Laos
Authors: Ivarsson Søren , Goscha Christopher E.
Published: January 2007

A biography of Prince Phetsarath highlights how a specific idea about Laos and its culture was formed under French colonial rule and nurtured under the Japanese occupation and its aftermath. During these periods, Phetsarath's understanding of Lao cultural nationalism was transformed into a political and anticolonial nationalism. While ultimately a study of failure, Phetsarath's activities show that anticolonial nationalism did not always have to be linked to Communist movements to be ‘revolutionary’, and suggests the importance of taking into account non-revolutionary and non-Communist actors – even members of royal blood – in order to better understand the complexity that went into the making of modern postcolonial states.
Solubility of KF and NaCl in water by molecular simulation
Authors: Sanz E. , Vega C.
Published: January 2007

The solubility of two ionic salts, namely, KF and NaCl, in water has been calculated by Monte Carlo molecular simulation. Water has been modeled with the extended simple point charge model (SPC/E), ions with the Tosi-Fumi model and the interaction between water and ions with the Smith-Dang model. The chemical potential of the solute in the solution has been computed as the derivative of the total free energy with respect to the number of solute particles. The chemical potential of the solute in the solid phase has been calculated by thermodynamic integration to an Einstein crystal. The solubility of the salt has been calculated as the concentration at which the chemical potential of the salt in the solution becomes identical to that of the pure solid. The methodology used in this work has been tested by reproducing the results for the solubility of KF determined previously by Ferrario et al. [J. Chem. Phys. 117, 4947 (2002)]. For KF, it was found that the solubility of the model is only in qualitative agreement with experiment. The variation of the solubility with temperature for KF has also been studied. For NaCl, the potential model used predicts a solubility in good agreement with the experimental value. The same is true for the hydration chemical potential at infinite dilution. Given the practical importance of solutions of NaCl in water the model used in this work, whereas simple, can be of interest for future studies.
Effect of metal electrodes on rubrene single-crystal transistors
Authors: Takenobu Taishi , Takahashi Tetsuo , Takeya Jun , Iwasa Yoshihiro
Published: January 2007

The authors herein have investigated the effect of the metal work function on the performance of rubrene single-crystal transistors using gold and calcium metal electrodes. The current-voltage characteristic is controlled by the metal work function, which offers the possibility of controlling the Schottky barrier height by the choice of the metal. In the process of the study of metal-rubrene contacts, the authors have realized an ambipolar transistor and a Schottky diode in an identical single-crystal device with asymmetric electrodes. These data provide direct evidence of the weak Fermi level pinning and formation of depletion layer on metal-rubrene contacts.
Depolarization effects in (112¯2)-oriented InGaN∕GaN quantum well structures
Authors: Park Seoung-Hwan , Ahn Doyeol
Published: January 2007

Depolarization effects on electrical and optical properties of (112¯2)-oriented wurtzite (WU) InGaN∕GaN quantum well (QW) were investigated using the multiband effective-mass theory. These results are compared with those of (0001)- and (101¯0)-oriented WU InGaN∕GaN QW structures. The internal field is shown to become zero for (112¯2) crystal orientation near the crystal angle of 56°, irrespective of the In composition in the well. This is because the sum of the piezoelectric and spontaneous polarizations in the barrier is equal to that in the well. The optical gain of the (112¯2)-oriented QW is significantly larger than that of the (0001)-oriented QW. This is caused mainly by the increase of the optical matrix element due to the disappearance of the internal field. Also, the (112¯2)-oriented QW is found to have the optical gain comparable to that of the (101¯0)-oriented QW.
High capacitance density metal-insulator-metal structure based on Al2O3–HfTiO nanolaminate stacks
Authors: Mikhelashvili V. , Eisenstein G. , Lahav A.
Published: January 2007

The authors describe metal-insulator-metal (MIM) capacitors comprising a five layer Al2O3–HfTiO nanolaminate stack with a total thickness of ∼29nm. At room temperature they demonstrate a capacitance density of ∼14fF∕μm2, a leakage current density of ∼1×10−6A∕cm2 at 1V, a temperature capacitance coefficient of 380ppm∕°C as well as corresponding linear and quadratic voltage coefficients of 350ppm∕V and 570ppm∕V2, respectively. They compare the structure to a MIM capacitor having a uniform HfTiO insulator film. That device exhibits a larger capacitance density (∼28fF∕μm2) but its electrical properties are found to be poorer than those of the structures utilizing the nanolaminate stack.
Increase in midwave infrared light emitting diode light output due to substrate thinning and texturing
Authors: Das N. C.
Published: January 2007

Midwave infrared (MWIR) light sources with high optical power are required for many applications. The authors report here the MWIR (3.8μm peak) light emission from an interband cascade light emitting diode (LED) structure with 18 cascaded active/injection regions grown on GaSb substrate. The light emission is observed from the substrate side of the device. An increase of six times of light output power is observed due to substrate thinning and another 50% increase is observed due to texturing the emission surface. The authors observed 400μW emission power for room temperature operation with 15mA LED injection current. Experiments were carried out with different grating patterns and etch depths. The device with a 2μm square grating and a 1μm etch depth has the highest optical emission power.
Spontaneous emission control of colloidal nanocrystals using nanoimprinted photonic crystals
Authors: Reboud V. , Kehagias N. , Sotomayor Torres C. M. , Zelsmann M. , Striccoli M. , Curri M. L. , Agostiano A. , Tamborra M. , Fink M. , Reuther F. , Gruetzner G.
Published: January 2007

The authors report on the fabrication and optical characterizations of two-dimensional photonic crystals fabricated by nanoimprint lithography in a nanocomposite polymer incorporating highly luminescent and red emitting (CdSe)ZnS core-shell colloidal nanocrystals. Photonic crystal structures enhance the light emitted from the quantum sized nanoparticles in the composite layer by slowing the propagation speed of the photons, thus increasing the coupling to the out-of-plane radiative modes. A 200% enhancement of the light collection is achieved compared to an unpatterned sample.
Stabilization of linear carbon structures in a solid Ag nanoparticle assembly
Authors: Casari C. S. , Russo V. , Li Bassi A. , Bottani C. E. , Cataldo F. , Lucotti A. , Tommasini M. , Del Zoppo M. , Castiglioni C. , Zerbi G.
Published: January 2007

Linear sp carbon nanostructures are gathering interest for the physical properties of one-dimensional systems. At present, the main obstacle to the synthesis and study of these systems is their instability. Here the authors present a simple method to obtain a solid system where linear sp chains (i.e., polyynes) in a silver nanoparticle assembly display a long term stability at ambient conditions. The presence and the behavior of linear carbon are investigated by surface enhanced Raman scattering exploiting the plasmon resonance of the silver nanoparticle assembly. This model system opens the possibility to investigate an intriguing form of carbon nanostructures.
In vivo analysis of Pim-1 deficiency
Authors: Laird Peter W. , Van der Lugt Nathalie M.T. , Clarke Alan , Domen Jos , Linders Koert , McWhir James , Berns Anton , Hooper Martin
Published: January 2007

The Pim-1 proto-oncogene encodes a highly conserved serine/threonine phosphokinase (1–5) which is predominantly expressed in hematopoietic organs and gonads in mammals (6-9). Overexpression of Pim-1 predisposes to lymphomagenesis in mice (8, 10, 11). To develop a further understanding of Pim-1 in molecular terms, as well as in terms of its potential role in hematopoietic development, we have generated mice deficient in Pim-1 function. P/m-7-deficient mice are ostensibly normal, healthy and fertile. Detailed comparative analyses of the hematopoietic systems of the mutant mice and their wild-type littermates showed that they are indistinguishable for most of the parameters studied. Our analyses revealed one unexpected phenotype that correlated with the level of Pim-1 expression: Pim-1 deficiency correlated with a erythrocyte microcytosis, whereas overexpression of Pim-1 in E/i-P/7n-7-transgenic mice resulted in erythrocyte macrocytosis. In order to confirm that the observed decrease in erythrocyte Mean Cell Volume (MCV) was attributable to the Pim-1 deficiency, we developed mice transgenic for a Pim-1 gene construct with its own promoter and showed that this transgene could restore the low erythrocyte Mean Cell Volume observed in the Pirn-/-deficient mice to near wild-type levels. These results might be relevant to the observed involvement of the Pim-1 gene in mouse erythroleukemogenesis (12). The surprising lack of a readily observed phenotype in the lymphoid compartment of the P/m-7-deficient mice, suggests a heretofore unrecognized degree of in vivo functional redundancy of this highly conserved proto-oncogene.
Adenoidectomy for Middle Ear Effusion: A Study of 50,000 Children Over 24 Years
Authors: Kadhim Abdul Latif , Spilsbury Katrina , Semmens James B. , Coates Harvey L. , Lannigan Francis J.
Published: January 2007

Objective: To compare the incidence and outcomes of myringotomy plus ventilation tube insertion (MVTI) alone and that concurrent with pharyngeal surgery (adenoidectomy, adenotonsillectomy, or tonsillectomy) at a population level.

Study Design: Observational, retrospective, population‐based study using hospital administrative data.

Methods: All hospital morbidity information was obtained for children who underwent a first MVTI procedure while less than 10 years of age in any Western Australian hospital from 1981 to 2004. Further MVTI procedures and additional pharyngeal surgery were subsequently identified for each child.

Results: There were 51,373 children less than 10 years of age who underwent at least one MVTI procedure from 1981 to 2004. Twenty‐nine percent underwent pharyngeal surgery at the time of first MVTI procedure, and of these, 7.4% (1,096) had pharyngeal surgery in the absence of adenoid or tonsil disease. Adenoid surgery at time of MVTI was associated with reduced odds of subsequent MVTI procedures in children with or without adenoid/tonsil disease. In more recent calendar periods, no differences in the length of hospital stay between MVTI alone and with adenoidectomy was observed, whereas procedures involving tonsils required an additional bed day per procedure and were associated with more episodes of operative and postoperative hemorrhage.

Conclusion: Having adenoidectomy or adenotonsillectomy surgery at time of first or subsequent MVTI was associated with reduced risk of further MVTI surgery. The low complication rates for adenoidectomy and short hospital stays make adjunctive adenoidectomy a potentially cost‐effective first line management option for otitis media with effusion.
Communication using eye roll reflective signalling
Authors: Novales Flamarique I , Mueller G.A , Cheng C.L , Figiel C.R
Published: January 2007

Body reflections in the ultraviolet (UV) are a common occurrence in nature. Despite the abundance of such signals and the presence of UV cones in the retinas of many vertebrates, the function of UV cones in the majority of taxa remains unclear. Here, we report on an unusual communication system in the razorback sucker,Xyrauchen texanus, that involves flash signals produced by quick eye rolls. Behavioural experiments and field observations indicate that this form of communication is used to signal territorial presence between males. The flash signal shows highest contrast in the UV region of the visual spectrum (λmax∼380 nm), corresponding to the maximum wavelength of absorption of the UV cone mechanism in suckers. Furthermore, these cones are restricted to the dorsal retina of the animal and the upwelling light background is such that their relative sensitivity would be enhanced by chromatic adaptation of the other cone mechanisms. Thus, the UV cones in the sucker have optimal characteristics (both in terms of absorbance and retinal topography) to constitute the main detectors of the flash signal. Our findings provide the first ecological evidence for restricted distribution of UV cones in the retina of a vertebrate.
A two‐second delay confers first‐male fertilization precedence within in vitro sperm competition experiments in Atlantic salmon
Authors: Yeates S. , Searle J. , Ward R. G. , Gage M. J. G.
Published: January 2007

In vitro paired‐male sperm competition experiments in Atlantic salmon Salmo salar for a single female’s eggs revealed that 2 s delays in sperm release caused significant reductions in paternity, with second males achieving only 30% fertilization success (against an expected 50%). This first‐male fertilization precedence supports previous work suggesting that sperm competition follows the principles of a race in Atlantic salmon, and suggests that any timing asymmetry in sperm release within natural competitive spawnings could have significant consequences for male fertilization success.
Reproductive sensitivity to elevated water temperatures in female Atlantic salmon is heightened at certain stages of vitellogenesis
Authors: King H. R. , Pankhurst N. W. , Watts M.
Published: January 2007

In order to compare the effects on reproductive performance of short‐term or prolonged exposure to elevated temperatures during vitellogenesis, female Atlantic salmon Salmo salar were held at a water temperature of 22° C for periods of 4 or 6 weeks during the austral summer and autumn. Plasma levels of 17β‐oestradiol (E2), testosterone (T) and vitellogenin (Vtg) were monitored and reproductive success was compared to that in groups of fish maintained at 14 or 22° C for 12 weeks from mid‐January. Significant endocrine effects were observed within as few as 3 days of the commencement of exposure to 22° C, when plasma levels of E2 (c. 0·5 ng ml−1) and Vtg (c. 1·4 mg ml−1) were approximately half those observed in fish maintained at 14° C (c. 1·0 ng ml−1 and 2·7 mg ml−1 respectively). The fertility and survival to the eyed stage of ova from fish held at 14° C exceeded 85 and 70% respectively, whereas ova from fish held at 22° C for 6 or 12 weeks exhibited significantly reduced fertility (<70 and <45% respectively) and survival (c. 40 and 13% respectively). In spite of significant endocrine effects at all stages, a 4 week exposure to 22° C only generated significant reductions in egg fertility (<65%) and survival (c. 30%) when it occurred between mid‐February and mid‐March. Together, these data confirm that high temperature spikes can affect reproductive success as strongly as more prolonged exposures, and indicate that there is a critical period of reproductive sensitivity to elevated temperature in late February and early March in this stock of Atlantic salmon.
Streptococcus oligofermentans inhibits Streptococcus mutans through conversion of lactic acid into inhibitory H2O2: a possible counteroffensive strategy for interspecies competition
Authors: Tong Huichun , Chen Wei , Merritt Justin , Qi Fengxia , Shi Wenyuan , Dong Xiuzhu
Published: January 2007

The oral microbial flora contains over 500 different microbial species that often interact as a means to compete for limited space and nutritional resources. Streptococcus mutans, a major caries‐causing pathogen, is a species which tends to interact competitively with other species in the oral cavity, largely due to its ability to generate copious quantities of the toxic metabolite, lactic acid. However, during a recent clinical study, we discovered a novel oral streptococcal species, Streptococcus oligofermentans, whose abundance appeared to be inversely correlated with that of S. mutans within dental plaque samples and thus suggested a possible antagonistic relationship with S. mutans. In this study, we used a defined in vitro interspecies interaction assay to confirm that S. oligofermentans was indeed able to inhibit the growth of S. mutans. Interestingly, this inhibitory effect was relatively specific to S. mutans and was actually enhanced by the presence of lactic acid. Biochemical analyses revealed that S. oligofermentans inhibited the growth of S. mutans via the production of hydrogen peroxide with lactic acid as the substrate. Further genetic and molecular analysis led to the discovery of the lactate oxidase (lox) gene of S. oligofermentans as responsible for this biological activity. Consequently, the lox mutant of S. oligofermentans also showed dramatically reduced inhibitory effects against S. mutans and also exhibited greatly impaired growth in the presence of the lactate produced by S. mutans. These data indicate that S. oligofermentans possesses the capacity to convert its competitor's main ‘weapon’ (lactic acid) into an inhibitory chemical (H2O2) in order to gain a competitive growth advantage. This fascinating ability may be an example of a counteroffensive strategy used during chemical warfare within the oral microbial community.
GABA excitation in mouse hilar neuropeptide Y neurons
Authors: Fu Li‐Ying , Van Den Pol Anthony N.
Published: January 2007

Neuropeptide Y‐containing interneurons in the dentate hilar area play an important role in inhibiting the activity of hippocampal circuitry. Hilar cells are often among the first lost in hippocampal epilepsy. As many types of neurons are found in the hilus, we used a new transgenic mouse expressing green fluorescent protein (GFP) in a subset of neurons that colocalized neuropeptide Y (NPY), somatostatin (SST), and GABA for whole‐cell, perforated, and cell‐attached recording in 240 neurons. As these neurons have not previously been identifiable in live slices, they have not been the focus of physiological analysis. Hilar NPY neurons showed modest spike frequency adaptation, a large 15.6 ± 1.0 mV afterhyperpolarization, a mean input resistance of 335 ± 26 mΩ, and were capable of fast‐firing. Muscimol‐mediated excitatory actions were found in a nominally Ca2+‐free/high‐Mg2+ bath solution using cell‐attached recording. GABAA receptor antagonists inhibited half the recorded neurons and blocked burst firing. Gramicidin perforated‐patch recording revealed a GABA reversal potential positive to both the resting membrane potential and spike threshold. Together, these data suggest GABA is excitatory to many NPY cells. NPY and SST consistently hyperpolarized and reduced spike frequency in these neurons. No hyperpolarization of NPY on membrane potential was detected in the presence of tetrodotoxin, AP5, CNQX and bicuculline, supporting an indirect effect. Under similar conditions, SST hyperpolarized the cells, suggesting a direct postsynaptic action. Depolarizing actions of GABA and GABA‐dependent burst‐firing may synchronize a rapid release of GABA, NPY, and SST, leading to pre‐ and postsynaptic inhibition of excitatory hippocampal circuits.
Morphological and physiological evidence for interstitial cell of Cajal‐like cells in the guinea pig gallbladder
Authors: Lavoie Brigitte , Balemba Onesmo B. , Nelson Mark T. , Ward Sean M. , Mawe Gary M.
Published: January 2007

Gallbladder smooth muscle (GBSM) exhibits spontaneous rhythmic electrical activity, but the origin and propagation of this activity are not understood. We used morphological and physiological approaches to determine whether interstitial cells of Cajal (ICC) are present in the guinea pig extrahepatic biliary tree. Light microscopic studies involving Kit tyrosine kinase immunohistochemistry and laser confocal imaging of Ca2+ transients revealed ICC‐like cells in the gallbladder. One type of ICC‐like cell had elongated cell bodies with one or two primary processes and was observed mainly along GBSM bundles and nerve fibres. The other type comprised multipolar cells that were located at the origin and intersection of muscle bundles. Electron microscopy revealed ICC‐like cells that were rich in mitochondria, caveolae and smooth endoplasmic reticulum and formed close appositions between themselves and with GBSM cells. Rhythmic Ca2+ flashes, which represent Ca2+ influx during action potentials, were synchronized in any given GBSM bundle and associated ICC‐like cells. Gap junction uncouplers (1‐octanol, carbenoxolone, 18β‐glycyrrhetinic acid and connexin mimetic peptide) eliminated or greatly reduced Ca2+ flashes in GBSM, but they persisted in ICC‐like cells, whereas the Kit tyrosine kinase inhibitor, imanitib mesylate, eliminated or reduced action potentials and Ca2+ flashes in both cell types, as well as associated tissue contractions. This study provides morphological and physiological evidence for the existence of ICC‐like cells in the gallbladder and presents data supporting electrical coupling between ICC‐like and GBSM cells. The results support a role for ICC‐like cells in the generation and propagation of spontaneous rhythmicity, and hence, the excitability of gallbladder.
Polycystin‐2 cation channel function in the human syncytiotrophoblast is regulated by microtubular structures
Authors: Montalbetti Nicolás , Li Qiang , Wu Yuliang , Chen Xing‐Zhen , Cantiello Horacio F.
Published: January 2007

Polycystin‐2 (PC2), encoded by PKD2, which is one of the genes whose mutations cause polycystic kidney disease, is abundantly produced in the apical domain of the syncytiotrophoblast (hST) of term human placenta. PC2, a TRP‐type (TRPP2) non‐selective cation channel, is present in primary cilia of renal epithelial cells, a microtubule‐based ancillary structure with sensory function. The hST has abundant cytoskeletal structures, and actin filament dynamics regulate PC2 channel function in this epithelium. However, it is expected that the apical hST excludes microtubular structures. Here, we demonstrated by Western blot and immunocytochemical analyses that hST apical vesicles indeed contain microtubule structural components, including tubulin isoforms, acetylated α‐tubulin, and the kinesin motor proteins KIF3A and KIF3B. PC2 and tubulin were substantially colocalized in hST vesicles. Treatment of hST vesicles with either the microtubular disrupter colchicine (15 μm) or the microtubular stabilizer paclitaxel (taxol, 15 μm) resulted in distinct patterns of microtubular re‐organization and PC2 redistribution. We also observed that changes in microtubular dynamics regulate PC2 channel function. Addition of colchicine rapidly inhibited PC2 channel activity in lipid‐bilayer reconstituted hST membranes. Addition of either tubulin and GTP, or taxol, however, stimulated PC2 channel activity in control hST membranes. Interestingly, we found that the kinesin motor protein KIF3A was capable of increasing PC2 channel activity in hST. We believe that the data are the first to provide a direct demonstration of a microtubular interaction with PC2 in the hST. This interaction thus plays an important regulatory role in the control of ion transport in the human placenta.
Framing, truth telling and the problem with non-directive counselling
Authors: Kirklin D
Published: January 2007

In this paper several reasons as to why framing issues should be of greater interest to both medical ethicists and healthcare professionals are suggested: firstly, framing can help in explaining health behaviours that can, from the medical perspective, appear perverse; secondly, framing provides a way of describing the internal structure of ethical arguments; and thirdly, an understanding of framing issues can help in identifying clinical practices, such as non-directive counselling, which may, inadvertently, be failing to meet their own stated ethical aims. The effect of framing on how individuals interpret information and how healthcare choices are influenced by framing are described. Next, the role of framing in ethical discourse is discussed with specific reference to Judith Jarvis Thomson’s philosophical mind experiment about abortion and the violinist. Finally, the implications of this analysis are examined for the practice of non-directive counselling, which aims at communicating information in a neutral, value-free way and thereby protecting patient autonomy.
Vagal modulation of intestinal afferent sensitivity to systemic LPS in the rat
Authors: Liu C. Y. , Mueller M. H. , Grundy D. , Kreis M. E.
Published: January 2007

The central nervous system modulates inflammation in the gastrointestinal tract via efferent vagal pathways. We hypothesized that these vagal efferents receive synaptic input from vagal afferents, representing an autonomic feedback mechanism. The consequence of this vagovagal reflex for afferent signal generation in response to LPS was examined in the present study. Different modifications of the vagal innervation or sham procedures were performed in anesthetized rats. Extracellular mesenteric afferent nerve discharge and systemic blood pressure were recorded in vivo before and after systemic administration of LPS (6 mg/kg iv). Mesenteric afferent nerve discharge increased dramatically following LPS, which was unchanged when vagal efferent traffic was eliminated by acute vagotomy. In chronically vagotomized animals, to eliminate both vagal afferent and efferent traffic, the increase in afferent firing 3.5 min after LPS was reduced to 3.2 ± 2.5 impulses/s above baseline compared with 42.2 ± 2.0 impulses/s in controls ( P < 0.001). A similar effect was observed following perivagal capsaicin, which was used to eliminate vagal afferent traffic only. LPS also caused a transient hypotension (<10 min), a partial recovery, and then persistent hypertension that was exacerbated by all three procedures. Mechanosensitivity was increased 15 min following LPS but had recovered at 30 min in all subgroups except for the chronic vagotomy group. In conclusion, discharge in capsaicin-sensitive mesenteric vagal afferents is augmented following systemic LPS. This activity, through a vagovagal pathway, helps to attenuate the effects of septic shock. The persistent hypersensitivity to mechanical stimulation after chronic vagal denervation suggests that the vagus exerts a regulatory influence on spinal afferent sensitization following LPS.
Iron chelation acutely stimulates fetal human intestinal cell production of IL-6 and VEGF while decreasing HGF: the roles of p38, ERK, and JNK MAPK signaling
Authors: Markel Troy A. , Crisostomo Paul R. , Wang Meijing , Herring Christine M. , Lahm Tim , Meldrum Kirstan K. , Lillemoe Keith D. , Rescorla Frederick J. , Meldrum Daniel R.
Published: January 2007

Bacteria have developed mechanisms to sequester host iron via chelators such as deferoxamine (DFO). Interestingly, DFO has been shown to stimulate acute intestinal epithelial cell inflammatory cytokine production in the absence of bacteria; however, this mechanism has not been elucidated. Intestinal epithelial cell production of IL-6 and TNF-α is elevated in various gastrointestinal pathologies, including acute intestinal ischemia. Similarly, VEGF and HGF are essential to intestinal epithelial cell integrity. Therapeutic strategies that decrease IL-6 and TNF-α while increasing VEGF and HGF therefore have theoretical appeal. We hypothesized that 1) fetal human intestinal epithelial cells acutely produce increased IL-6, TNF-α, VEGF, and HGF during iron chelation and 2) the MAPK pathway mediates these effects. Fetal human intestinal epithelial cells were stimulated by iron chelation (1 mM DFO) with and without p38 MAPK, ERK, or JNK inhibition. Supernatants were harvested after 24 h of incubation, and IL-6, TNF-α, VEGF, and HGF levels were quantified by ELISA. Activation of MAPK pathways was confirmed by Western blot analysis. DFO stimulation resulted in a significant increase in epithelial cell IL-6 and VEGF production while yielding a decrease in HGF production ( P < 0.05). Unexpectedly, TNF-α was not detectable. p38 MAPK, ERK, and JNK inhibition significantly decreased IL-6, VEGF, and HGF production ( P < 0.05). In conclusion, DFO acutely increases fetal human intestinal epithelial cell IL-6 and VEGF expression while causing an unexpected decrease in HGF expression and no detectable TNF-α production. Furthermore, chelator-induced intestinal epithelial cell cytokine expression depends on p38, ERK, and JNK MAPK pathways.