bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of sunflower lecithins on the stability of water‐in‐oil and oil‐in‐water emulsions
Authors: Pan L. G. , Tomás M. C. , Añón M. C.
Published: November 2006

Lecithins are frequently applied in the food industry as emulsifiers, viscosity regulators, and dispersing agents. The main aim of the present work was to study the emulsifying capability of diverse sunflower lecithins so as to evaluate the functionality of these by‐products, which are not extensively used at present. The experimental results obtained for water‐in‐oil (W/O) emulsions showe that dispersions containing levels of 0.1% lecithins were more stable against coalescence than a control system, whereas those with 1% emulsifying agent exhibited the opposite behavior. On the other hand, faster sedimentation kinetics were observed at a concentration of 0.1% than at 1%. Lecithins with high phospholipid content, especially phosphatidylethanolamine and phosphatidylinositol, were found to be the best emulsifying agents for W/O dispersions. In the case of oil‐in‐water emulsions, it was possible to observe two processes: creaming of emulsions with the addition of 1% of lecithins, and instant creaming followed by coalescence of the cream phase in those cases corresponding to 0.1% added lecithin.
Commercial synthesis of monoalkyl phosphates
Authors: Tracy David J. , Reierson Robert L.
Published: November 2006

Historically, phosphate esters have been prepared by the reaction of alcohols with phosphoric anhydride or polyphosphoric acid. Recently, hybrid reagents have been developed. A review of the commercial production of long‐chain monoalkyl phosphate esters is presented. The titled esters are the subject of increased interest, especially in low‐irritation surfactant formulations.
A study on the long‐term stability and removal of quats on treated fabric
Authors: Steiger Phil , Friedli Floyd E.
Published: November 2006

Static hydrolysis of triethanolamine‐based esterquats was studied in a system where the esterquat was deposited on fabric swatches and stored under ambient conditions in the laboratory for 3 mon. It was concluded that esterquat‐based fabric softeners do not appreciably hydrolyze on the fabrics under ambient conditions. Fabric softeners based on dihydrogenated tallow dimethyl ammonium quats were compared to triethanolamine‐based esterquats for removal from fabric during the next wash cycle. It was found that saturated quats did not totally wash off fabrics in cold water but remained mostly as the quat‐anionic complex. Esterquats washed off better than alkyl quats, thereby leaving less residue than alkyl quats.
Upgrading triethanolamine esterquat performance to new levels
Authors: Friedli F. E. , Koehle H. J. , Fender M. , Watts M. , Keys R. , Frank P. , Toney C. J. , Doerr M.
Published: November 2006

Triethanolamine (TEA)‐based esterquat has been the primary ingredient in European fabric softeners for several years and is becoming the global molecule of choice. Although it has an excellent environmental profile, TEA esterquat has been plagued by mediocre performance compared to historical molecules such as dihydrogenated tallow dimethyl ammonium chloride and ditallow imidazoline quat. In this study, the chain lengths, the level of unsaturation, and the source of the raw material (tallow or palm stearine) were varied to better understand their effect on softening and dispersion viscosity. Palm stearine derivatives generally soften as well as tallow derivatives despite the lower C18 content of palm. Various additives were examined to improve dispersibility and other properties such as dye transfer inhibition (DTI) and ease of ironing. DTI is normally accomplished in the wash cycle by additives to the laundry detergent such as polyvinylpyrrolidone. In this study, we found that fabric softener molecules themselves provide some color care, or DTI. Certain additives to fabric softeners, such as monoalkylquats, greatly enhance the color care of the fabric. DTI treatment in the rinse cycle of the washing sequence makes more sense scientifically and to the consumers, since fabric softeners are designed to coat the textile. Because no competing detergency operations are occurring during the rinse cycle, color care works well in the fabric softener cycle. Addition of organosilicones to fabric softeners reduces wrinkling of fabrics and makes them easier to iron. Softening increases slightly.
Microemulsion formation and detergency with oily soils: I. Phase behavior and interfacial tension
Authors: Tongcumpou C. , Acosta E. J. , Quencer L. B. , Joseph A. F. , Scamehorn J. F. , Sabatini D. A. , Chavadej S. , Yanumet N.
Published: November 2006

The ultimate objective of the project was to investigate the relationship between microemulsion phase behavior and detergency for oily soils. In this study, surfactant phase behavior was evaluated for hexadecane and motor oil as model oily soils. Producing microemulsions with these oils is particularly challenging because of their large hydrophobic character. To produce the desired phase behavior we included three surfactants with a wide range of hydrophilic/lipophilic character: alkyl diphenyl oxide disulfonate (highly hydrophilic), dioctyl sodium sulfosuccinate (intermediate character), and sorbitan monooleate (highly hydrophobic). This mixed surfactant was able to bridge the hydrophilic/lipophilic gap between the water and the oil phases, producing microemulsions with substantial solubilization and ultralow interfacial tension. The effects of surfactant composition, temperature, and salinity on system performance were investigated. The transition of microemulsion phases could be observed for both systems with hexadecane and motor oil. In addition, the use of surfactant mixtures containing both anionic and nonionic surfactants leads to systems that are robust with respect to temperature compared to single‐surfactant systems. Under conditions corresponding to “supersolubilization”, the solubilization parameters and oil/microemulsion interfacial tensions are not substantially worse than at optimal condition for a middle‐phase system, so a middle‐phase microemulsion is not necessary to attain quite low interfacial tensions. A potential drawback of the formulations developed here is the fairly high salinity (e.g., 5 wt% NaCl) needed to attain optimal middle‐phase systems. The correlation between interfacial tension and solubilization follows the trend predicted by the Chun‐Huh equation.
Formulating middle‐phase microemulsions using mixed anionic and cationic surfactant systems
Authors: Doan T. , Acosta E. , Scamehorn J. F. , Sabatini D. A.
Published: November 2006

Although mixtures of anionic and cationic surfactants can show great synergism, their potential to precipitate and form liquid crystals has limited their use. Previous studies have shown that alcohol addition can prevent liquid crystal formation, thereby allowing formation of middle‐phase microemulsions with mixed anionic‐cationic systems. This research investigates the role of surfactant selection in designing alcohol‐free anionic‐cationic microemulsions. Microemulsion phase behavior was studied for three anionic‐cationic surfactant systems and three oils of widely varying hydrophobicity [trichloroethylene (TCE), hexane, and n‐hexadecane]. Consistent with our hypothesis, using a branched surfactant and surfactants with varying tail length allowed us to form alcohol‐free middle‐phase microemulsion using mixed anionic‐cationic systems (i.e., liquid crystals did not form). The anionic to cationic molar ratio required to form middle‐phase microemulsions approached 1∶1 for univalent surfactants as oil hydrophobicity increased (i.e., TCE to hexane to n‐hexadecane); even for these equimolar systems, liquid crystal formation was avoided. To test the use of these anionic‐cationic surfactant mixtures in surfactant‐enhanced subsurface remediation, we performed soil column studies: Greater than 95% of the oil was extracted in 2.5 pore volumes using an anionic‐rich surfactant system. By contrast, cationic‐rich systems performed very poorly (<1% oil removal), reflecting significant losses of the cationic‐rich surfactant system in the porous media. The results thus suggest that, when properly designed, anionic‐rich mixtures of anionic and cationic surfactants can be efficient for environmental remediation. By corollary, other industrial applications and consumer products should also find these mixtures advantageous.
Synthesis and characterization of polyethoxylate surfactants derived from phenolic lipids
Authors: Tyman John H. P. , Bruce Ian E.
Published: November 2006

Polyethoxylates from cardanol and from cardol, the main component phenolic lipids in technical cashew nutshell liquid derived from the replenishable source Anacardium occidentale, were obtained by reaction with ethylene oxide under base‐catalyzed conditions. Oligomeric mixtures resulted. In the cardanol series, the first six members of the mixture were independently synthesized for characterization purposes by a variety of reactions. The members in the oligomeric mixture were separated by HPLC, and the composition was determined by 1H NMR spectroscopy and by chromatography. These studies were preparatory to surfactant and biodegradation studies involving comparison with commercially available polyethoxylates derived from petrochemical nonylphenol.
A new test for cleaning efficiency assessment of cleaners for hard surfaces
Authors: Chateau Marie‐Elise , Galet Laurence , Soudais Yannick , Fages Jacques
Published: November 2006

A new test was developed to assess the efficiency of no‐wiping hard‐surface cleaning. The test allows cleaner comparisons according to their ability to remove greasy soils. The chosen approach minimizes the mechanical forces applied while cleaning so that the interactions between a detergent solution and the soil to be removed can be characterized. For this, immersion cleaning was chosen, with coated stainless steel as substrate and pigmented oils as the model soil. Several parameters were studied in defined ranges using the Experimental Design method and systematic comparisons. The test shows high reliability on degreasing assessments and is there‐fore especially suited to optimization of nonionic surfactant mixes. The originality of the test lies in the possibility of keeping a visual trace of the cleaned substrate appearance by imprinting it on a piece of paper. The validation of the test leads to corroboration of several practical observations. Temperature and agitation play a major role in cleaning efficiency. Detergent solution concentration is a more relevant parameter than pH. Sodium carbonate is shown to have a higher buffering effect than pentahydrated sodium metasilicate. The test is easy to set up, highly sensitive, and can be adapted to solve the problems encountered by formulators of detergent cleaners, such as screening the best ethoxylated fatty alcohol mix for better degreasing properties.
Organization of amphiphiles VI. A comparative study of the orientation of polyoxyethylated alkyl phenols at the air‐water and the silica‐water interface
Authors: Misra Pramila K. , Somasundaran P.
Published: November 2006

The adsorption behavior on silica of a series of polyoxyethylated alkyl phenols of varying hydrophobicities and hydrophilicities was studied by determining the adsorption isotherm along with the zeta potential of silica. An increase in the concentration of each of the surfactants caused the zeta potential to become less negative and ultimately to reach a plateau; similarly, the adsorption isotherm also plateaued. These results were attributed to the flat orientation of the surfactants caused by hydrogen bonding of the oxygen atom of the oxyethylene group with the silanol group of the silica, which led to the formation of a thin oxyethylene layer at the silica‐water interface. This layer masked a constant fraction of the silica surface. A model for the orientation of the surfactants at the silica‐water interface was proposed, based on a “molecular parking area” (i.e., space occupied by the molecule during adsorption at the silica‐water interface) of the surfactants on the silica surface.
Alanine‐based surfactants: Synthesis and some surface properties
Authors: Mohamed A. S. , Mohamed M. Z. , Ismail D. A.
Published: November 2006

A homologous series of anionic surfactants, namely, sodium‐N‐(alkyloxycarbonyl) alanine (where alkyl=octyl‐, dodecyl‐, hexadecyl‐, and octadecyl‐) were synthesized having the formula: R‐OCO‐CH2NH‐CH2‐CH2‐COONa. Surface properties of their solutions, including surface tension, critical micelle concentration, effectiveness, maximum surface excess, and minimum surface area, were investigated for different concentrations at 25°C. The effects of these surfactants on the solubilization of a polar and a nonpolar solute were studied. Standard free energies of micellization and adsorption were calculated for the prepared surfactants in aqueous solution.
Mixtures of anionic and cationic surfactants with single and twin head groups: Solubilization and adsolubilization of styrene and ethylcyclohexane
Authors: Fuangswasdi A. , Charoensaeng A. , Sabatini D. A. , Scamehorn J. F. , Acosta E. J. , Osathaphan K. , Khaodhiar S.
Published: November 2006

Mixtures of anionic and cationic surfactants with single and twin head groups were used to solubilized styrene and ethylcyclohexane into mixed micelles and adsolubilize them into mixed admicelles on silica and alumina surfaces. Two combinations of anionic and cationic surfactants were studied: (i) a single‐head anionic surfactant, sodium dodecyl sulfate (SDS), with a twin‐head cationic surfactant, pentamethyl‐octadecyl‐1,3‐propane diammonium dichloride (PODD), and (ii) a twin‐head anionic surfactant, sodium hexadecyl‐diphenyloxide disulfonate (SHDPDS), with a single‐head cationic surfactant, dodecylpyridinium chloride (DPCl). Mixtures of SDS/PODD showed solubilization synergism (increased oil solubilization capacity) when mixed at a molar ratio of 1∶3; however, the SHD‐PDS/DPCl mixture at a ratio of 3∶1 did not show solubilization enhancement over SHDPDS alone. Adsolubilization studies of SDS/PODD (enriched in PODD) adsorbed on negatively charged silica and SHDPDS/DPCl adsorbed on positively charged alumina showed that while mixtures of anionic and cationic surfactants had little effect on the adsolubilization of styrene, the adsolubilization of ethylcyclohexane was greater in mixed SHPDS/DPCl systems than for SHDPDS alone. Finally, it was concluded that whereas mixing anionic and cationic surfactants with single and double head groups can improve the solubilization capacity of micelles or admicelles, the magnitude of the solubilization enhancement depends on the molecular structure of the surfactant and the ratio of anionic surfactant to cationic surfactant in the micelle or admicelle.
Small‐angle neutron scattering studies on sodium dodecylbenzenesulfonate‐tetra‐n‐butylammonium bromide systems
Authors: Kumar Sanjeev , Sharma Daksha , Sharma Deepti , Kabir‐ud‐Din
Published: November 2006

A phase study was completed on aqueous sodium dodecylbenzenesulfonate (SDBS) and tetra‐n‐butyl‐ammonium bromide (Bu4NBr) systems, and consolute boundaries were drawn through cloud points. Samples were selected from both miscibility regions [under the lower consolute boundary (LCB) and above the upper consolute boundary (UCB)] for small‐angle neutron scattering (SANS) studies. In the first set of experiments, the effect of varying Bu4NBr concentration on micellular parameters of 100 mM SDBS was studied at 30°C. The pure SDBS micelle has an aggregation number (ns) of 51, and the effective charge on the monomer (α) is 0.17. With the addition of Bu4NBr, the ns of SDBS micelles increases while α decreases. The system with [Bu4NBr]=39.5 mM (an above‐UCB sample) showed clouding near room temperature (≈29°C) and had a high ns value (300) and a low α (=0.09). The data indicated that the micelles lose ionic character in the presence of Bu4NBr. The temperature effect on this sample shows that α remains almost constant, while ns decreases on heating. A similar effect was observed with samples of lower Bu4NBr concentration (32 or 25 mM) in the presence of 100 mM SDBS. The same type of temperature effect was seen on a sample of under‐LCB region (50 mM SDBS+32 mM Bu4NBr); the ns values increased significantly as the LCB was approached. The overall SANS observations suggest that the micelles have low ionic character together with high ns values (a case of micellar growth) near LCB/UCB.
Conjugated linoleic acid supplementation in humans: Effects on body composition and energy expenditure
Authors: Zambell Kirsten L. , Keim Nancy L. , Van Loan Marta D. , Gale Barbara , Benito Paloma , Kelley Darshan S. , Nelson Gary J.
Published: November 2006

Recent animal studies have demonstrated that dietary conjugated linoleic acid (CLA) reduces body fat and that this decrease may be due to a change in energy expenditure. The present study examined the effect of CLA supplementation on body composition and energy expenditure in healthy, adult women. Seventeen women were fed either a CLA capsule (3 g/d) or a sunflower oil placebo for 64 d following a baseline period of 30 d. The subjects were confined to a metabolic suite for the entire 94 d study where diet and activity were controlled and held constant. Change in fat‐free mass, fat mass, and percentage body fat were unaffected by CLA supplementation (0.18±0.43 vs. 0.09±0.35 kg; 0.01±0.64 vs. −0.19±0.53 kg; 0.05±0.62 vs. −0.67±0.51%, placebo vs. CLA, respectively). Likewise, body weight was not significantly different in the placebo vs. the CLA group (0.48±0.55 vs. −0.24±0.46 kg change). Energy expenditure (kcal/min), fat oxidation, and respiratory exchange ratio were measured once during the baseline period and during weeks 4 and 8 of the intervention period. At all three times, measurements were taken while resting and walking. CLA had no significant effect on energy expenditure, fat oxidation, or respiratory exchange ratio at rest or during exercise. When dietary intake was controlled, 64 d of CLA supplementation at 3 g/d had no significant effect on body composition or energy expenditure in adult women, which contrasts with previous findings in animals.
High doses of atorvastatin and simvastatin induce key enzymes involved in VLDL production
Authors: Roglans Núria , Verd Joan C. , Peris Cristina , Alegret Marta , Vázquez Manuel , Adzet Tomás , Diaz Cristina , Hernández Gonzalo , Laguna Juan C. , Sánchez Rosa M.
Published: November 2006

Treatments with high doses of 3‐hydroxy‐3‐methylglutaryl‐coenzyme A (HMG‐CoA) reductase inhibitors may induce the expression of sterol regulatory element binding protein (SREBP)‐target genes, causing different effects from those attributed to the reduction of hepatic cholesterol content. The aim of this study was to investigate the effects of high doses of statins on the key enzymes involved in VLDL production in normolipidemic rats. To examine whether the effects caused by statin treatment are a consequence of HMG‐CoA reductase inhibition, we tested the effect of atorvastation on these enzymes in mevalonatefed rats. Atorvastatin and simvastatin enhanced not only HMG‐CoA reductase but also the expression of the SREBP‐2 gene itself. As a result of the overexpression of SREBP‐2 caused by the statin treatment, genes regulated basically by SREBP‐1, as FA synthase and acetyl‐coenzyme A carboxylase, were also induced and their mRNA levels increased. DAG acyltransferase and microsomal IG transfer protein mRNA levels as well as phosphatidate phosphohydrolase activity were increased by both statins. Simvastatin raised liver cholesterol content, ACAT mRNA levles, and CTP:phosphocholine cytidylyltransferase activity, whereas it reduced liver DAG and phospholipid content. Mevalonate feeding reversed all changes induced by the atorvastatin treatment. These results show that treatment with high doses of statins induces key enzymes controlling rat liver lipid synthesis and VLDL assembly, probably as a result of SREBP‐2 overexpression. Despite the induction of the key enzymes involved in VLDL production, both statins markedly reduced plasma TG levels, suggesting that different mechanisms may be involved in the hypotriglyceridemic effect of statins at high or low doses.
Effect of dietary cholesterol oxidation products on the plasma clearance of chylomicrons in the rat
Authors: Vine D. F. , Croft K. D. , Beilin L. J. , Mamo J. C. L.
Published: November 2006

Oxidized cholesterols in the diet have been shown to exacerbate arterial cholesterol deposition and the development of atherosclerosis in animal models. Dietary oxidized cholesterols are absorbed through the intestine and incorporated into lymph chylomicrons. The aim of this study was to investigate the effect of oxidized cholesterols on the metabolism of nascent chylomicrons in vivo. It was shown that oxidized cholesterols markedly delay the clearance of chylomicrons from plasma compared to rats given TG alone. However, there was no difference in the clearance of chylomicrons containing oxidized cholesterols vs. purified cholesterol, although the presence of oxysterols did appear to exacerbate the removal of these particles from circulation. The impaired clearance of chylomicrons containing oxidized cholesterols was not due to impaired lipolysis and slower conversion to the remnant form. Moreover, the incorporation of oxidized cholesterols did not alter the hepatic or splenic uptake of chylomicrons compared to chylomicrons isolated from rats given purified cholesterol or TG alone. Collectively, the results of this study suggest that the exacerbated delay in clearance of chylomicron remnants enriched with oxysterols may be due to impaired uptake by tissues other than the liver and spleen. Apolipoprotein (apo) analysis showed that oxysterol incorporation reduced the apoE content and altered the apoC phenotype of chylomicrons, which may have an impact on the removal of chylomicron remnants from plasma. In conclusion, dietary oxysterols appear to have the potential to adversely affect chylomicron metabolism. Therefore, further investigations in humans are required to determine whether dietary oxidized cholesterols found in cholesterol‐rich processed foods delay the clearance of postprandial remnants, which may contribute to and exacerbate the development of atherosclerosis.
Peroxisome proliferator‐activated receptor α,γ coagonist LY465608 inhibits macrophage activation and atherosclerosis in apolipoprotein E knockout mice
Authors: Zuckerman Steven H. , Kauffman Raymond F. , Evans Glenn F.
Published: November 2006

The apolipoprotein F (apoF) knockout mouse has provided an approach to the investigation of the effect of both cellular and humoral processes on atherosclerotic lesion progression. In the present study, pharmacologic modulation of both interferon gamma (IFNγ)‐inducible macrophage effector functions, and atherosclerotic lesions in the apoE knockout mouse were investigated using the peroxisome proliferator‐activated receptor (PPAR) α,γ coagonist LY465608. LY465608 inhibited, in a concentration‐dependent manner, IFNγ induction of both nitric oxide synthesis and the β2 integrin CD11a in elicited peritoneal macrophages from apoE knockout mice. Similar effects were observed ex vivo following 10 d of treating mice with 10 mg/kg of LY465608. Treatment of apoE knockout mice for 18 wk with LY465608 resulted in a statistically significant 2.5‐fold reduction in atherosclerotic lesion area in en face aorta preparations. These effects were apparent in the absence of any reduction in total serum cholesterol or in lipoprotein distribution. Finally, treatment of apoE knockout mice with established atherosclerotic disease resulted in a modest but not statistically significant decrease in aortic lesional surface area. These results demonstrate the utility of PPAR coagonists in reducing the progression of the atherosclerotic lesion.
Evidence of a tetradocosahexaenoic cardiolipin in some marine bivalves
Authors: Kraffe Edouard , Soudant Philippe , Marty Yanic , Kervarec Nelly , Jehan Philippe
Published: November 2006

Separation of phospholipid classes in lipid extracts from the scallop Pecten maximus, the Pacific oyster Crassostrea gigas, and the blue mussel Mytilus edulis was conducted using HPLC. An isolated polar lipid fraction was found to contain a very high level of DHA, up to 80 mol% of the total FA. MS with electrospray ionization in the positive‐ion mode, tandem MS (MS‐MS) and multidimensional NMR spectroscopy were used to analyze the detailed chemical structure of this polar lipid fraction. The isolated fraction contained exclusively cardiolipin (CL) molecules, predominantly in a form with four docosahexaenoyl chains (Do4CL). To the best of our knowledge, this is the first time that such a CL form has been analytically characterized and described in these three bivalve species. This tetradocosahexaenoic CL is presumed to reflect a specific adaptation in bivalves that enhances the structural and functional mechanisms of biomembranes in response to variations in environmental conditions (temperature, salinity, emersion).
Analysis of FA contents in individual lipid fractions from human placental tissue
Authors: Klingler M. , Demmelmair H. , Larque E. , Koletzko B.
Published: November 2006

Data on FA contents in the human placenta are limited. Different methods have been used for the FA analysis, and only percentage results have been presented. We developed and evaluated a method for the determination of FA concentrations in placental tissue. Lipids were extracted from placental tissue with a chloroform/methanol mixture; and phospholipids (PL), nonesterified FA (NEFA), TG, and cholesterol esters (CE) were isolated by TLC. Individual lipid fractions were derivatized with methanolic hydrochloric acid, and the FAME, were quantified by GC with FID. The CV of intra‐assay (n=8) of absolute concentrations were evaluated for FA showing a, tissue content >0.01 mg/g. CV ranges were 4.6–11.0% for PL, 6.4–9.3% for NEFA, 6.1–8.9% for TG, and 11.4–16.3% for CE. The relative FA composition across a term placenta indicated no differences between samples of central and peripheral locations of maternal and fetal site (CV 0.5–9.9%), whereas the absolute FA concentrations were only reproducible in the PL fraction (CV 7.0–12.8%). The method shows a reasonably high precision that is well suited for physiological and nutritional studies.
Astonishing diversity of natural surfactants: 4. Fatty acid amide glycosides, their analogs and derivatives
Authors: Dembitsky Valery M.
Published: November 2006

FA amide glycosides are of great interest, especially for the medicinal and pharmaceutical industries. These biologically active natural surfactants are good prospects for future chemical preparation of compounds useful as antibiotics, anticancer agents, or for industry. More than 200 unusual and interesting natural surfactants, including their chemical structures and biological activities, are described in this review article.
Expression of fatty acyl‐CoA binding proteins in colon cells: response to butyrate and transformation
Authors: Gossett Ruanna E. , Schroeder Friedhelm , Gunn J. Martyn , Kier Ann B.
Published: November 2006

Fatty acyl‐CoA affect many cellular functions as well as serving as cellular building blocks. Several families of cytosolic fatty acyl‐CoA binding proteins may modulate the activities of fatty acyl‐CoA. Intestinal enterocytes contain at least three unique families of cytosolic proteins that bind fatty acyl‐CoA: acyl‐CoA binding protein (ACBP), fatty acid binding proteins (including the liver, L‐FABP and intestinal, I‐FABP), and sterol carrier protein‐2 (SCP‐2). Immortalized rat colon epithelial cell lines expressed only ACBP and SCP‐2 at levels of 0.75±0.13 and 0.42±0.02 ng/μg protein. Ras and src transformation increased colon cell density and differentially altered ACBP and SCP‐2 expression without affecting I‐FABP or L‐FABP levels. ACBP levels were 1.8‐fold and 1.5‐fold increased in ras‐ and src‐transformed cells, respectively. In contrast, SCP‐2 expression was significantly decreased 55 and 67% in ras‐ and src‐transformed cells, respectively. Butyrate treatment of ras‐ and src‐transformed cells decreased cell proliferation up to 60–85% as compared to 25–30% in control cells. Butyrate treatment decreased ACBP expression in all cell lines but had no effect on the levels of SCP‐2, I‐FABP, or L‐FABP. These studies suggest that the differential expression of ACBP and SCP‐2 in rat colonic cell lines, as well as their modulation by butyrate, may be altered by cell transformation.
Stiefkind Anamnese
Authors: Cuculi  , Brink  , Gebbers
Published: November 2006

Eine 52-jährige Frau wurde zur Abklärung rechtsseitiger Oberbauchschmerzen zugewiesen. Drei Wochen zuvor war in Italien eine Dünndarmresektion wegen akuter ileo-ilealer Invagination bei Dünndarmtumor durchgeführt worden. Der Tumor wurde vom dortigen Pathologen als gastrointestinaler Stromatumor (GIST) und eine Lungenverschattung als bronchogene Zyste interpretiert – beides in Unkenntnis der persönlichen Anamnese. Wir fanden in der Vorgeschichte mehrere Rezidive eines vor fünf Jahren entfernten malignen Melanoms am rechten Unterlid. Aktuell war eine erneute Manifestation des Melanoms an dieser Stelle tastbar und Dünndarmtumor wie Lungenverschattung waren Metastasen.
Electrical and optical properties of silver core-lithium niobate shell nanostrucures within a glass medium
Authors: Ghosh B. , Chakravorty D. , Das G. C.
Published: November 2006

Silver nanoparticles of diameters in the range of 4.2–46nm have been used to grow nanoshells of lithium niobate with thicknesses in the range of 2.2–22nm in a silicate glass matrix. The lithium niobate shells form a percolative network and show electronic conduction. This has been explained as due to Mott’s variable range hopping conduction mechanism. The hopping is interparticle because the density of localized states is found to be in reasonable agreement with the density of nanoparticles with a core-shell structure. The ac conductivity is shown to be dependent on frequency with the exponent having a value around 0.5. This arises due to the charge motion’s being operative in a two-dimensional structure with one of these dimensions involved in such motion. Optical absorption of the core-shell structured nanoparticles exhibits two peaks—one around 350nm is ascribed to plasmon resonance of silver nanoparticles which are not covered by a niobate shell, and the other in the range of 550–650nm is caused by light scattering from the core-shell structure.
Charge driven, electrohydrodynamic patterning of thin films
Authors: Pease Leonard F. , Russel William B.
Published: November 2006

In electrohydrodynamic patterning, electrical forces and surface tension acting at the interface between two fluids sandwiched between silicon wafers compete to set the period of pillar arrays, gratings, and concentric rings. Shrinking the period to deep submicron lengths requires a precise understanding of the source of the electric field. Previous modeling efforts have assumed that applied voltages, contact potentials, and static charge drive the flow. Here we show the location of that charge and the tangential stress it engenders to impact profoundly how the period and growth rate depend on the dielectric contrast and the relative film thickness. The pillar-to-pillar spacing scales inversely proportional to the charge density, and densities of ∼1mC∕m2 (∼1charge∕100nm2) suffice to produce micron sized pillars.
Domain wall induced modes of high-frequency response in ferromagnetic elements
Authors: Queitsch Ute , McCord Jeffrey , Neudert Andreas , Schäfer Rudolf , Schultz Ludwig , Rott Karsten , Brückl Hubert
Published: November 2006

The influence of domain wall density on the magnetization dynamics of amorphous CoZrTa thin-film elements was investigated by a combination of microwave magnetometry and quasistatic plus time-resolved wide-field Kerr microscopy. In addition to domain wall motion, permeability rolloff at low frequencies occurs due to rotational processes. The dominating ferromagnetic resonance modes depend on the domain wall density due to the formation of a zone of magnetization curling at the domain walls, which results from a phase lag of domain and domain wall response. Both the amount of permeability reduction and the increase in precessional frequency, can be varied with magnetic history. All effects are avoided by lamination of the ferromagnetic films. The results demonstrate the importance of detailed domain control for the optimization of patterned films for high-frequency applications, beyond the elementary adjustment of material’s high-frequency properties.
Improved diffusion Monte Carlo propagators for bosonic systems using Itô calculus
Authors: Håkansson P. , Mella M. , Bressanini Dario , Morosi Gabriele , Patrone Marta
Published: November 2006

The construction of importance sampled diffusion Monte Carlo (DMC) schemes accurate to second order in the time step is discussed. A central aspect in obtaining efficient second order schemes is the numerical solution of the stochastic differential equation (SDE) associated with the Fokker-Plank equation responsible for the importance sampling procedure. In this work, stochastic predictor-corrector schemes solving the SDE and consistent with Itô calculus are used in DMC simulations of helium clusters. These schemes are numerically compared with alternative algorithms obtained by splitting the Fokker-Plank operator, an approach that we analyze using the analytical tools provided by Itô calculus. The numerical results show that predictor-corrector methods are indeed accurate to second order in the time step and that they present a smaller time step bias and a better efficiency than second order split-operator derived schemes when computing ensemble averages for bosonic systems. The possible extension of the predictor-corrector methods to higher orders is also discussed.
Ab initio potential energy surfaces, bound states, and electronic spectrum of the Ar–SH complex
Authors: Doyle Richard J. , Hirst David M. , Hutson Jeremy M.
Published: November 2006

New ab initio potential energy surfaces for the Π2 ground electronic state of the Ar–SH complex are presented, calculated at the RCCSD(T)/aug-cc-pV5Z level. Weakly bound rotation-vibration levels are calculated using coupled-channel methods that properly account for the coupling between the two electronic states. The resulting wave functions are analyzed and a new adiabatic approximation including spin-orbit coupling is proposed. The ground-state wave functions are combined with those obtained for the excited Σ+2 state [D. M. Hirst, R. J. Doyle, and S. R. Mackenzie, Phys. Chem. Chem. Phys. 6, 5463 (2004)] to produce transition dipole moments. Modeling the transition intensities as a combination of these dipole moments and calculated lifetime values [A. B. McCoy, J. Chem. Phys. 109, 170 (1998)] leads to a good representation of the experimental fluorescence excitation spectrum [M.-C. Yang, A. P. Salzberg, B.-C. Chang, C. C. Carter, and T. A. Miller, J. Chem. Phys. 98, 4301 (1993)].
Theoretical investigation of the stability of highly charged C60 molecules produced with intense near-infrared laser pulses
Authors: Sahnoun Riadh , Nakai Katsunori , Sato Yukio , Kono Hirohiko , Fujimura Yuichi , Tanaka Motohiko
Published: November 2006

We theoretically investigated the stability of highly charged C60z+ cations produced from C60 with an ultrashort intense laser pulse of λ∼1800nm. We first calculated the equilibrium structures and vibrational frequencies of C60z+ as well as C60. We then calculated key energies relevant to dissociation of C60z+, such as the excess vibrational energy acquired upon sudden tunnel ionization from C60. By comparing the magnitudes of the calculated energies, we found that C60z+ cations up to z∼12 can be produced as a stable or quasistable (microsecond-order lifetime) intact parent cation, in agreement with the recent experimental report by V. R. Bhardwaj et al. [Phys. Rev. Lett. 93, 043001 (2004)] that almost only intact parent C60z+ cations up to z=12 are detected by a mass spectrometer. The results of Rice-Ramsperger-Kassel-Marcus calculation suggest that the lifetime of C60z+ drastically decreases by ten orders of magnitude as z increases from z=11 to z=13. Using the time-dependent adiabatic state approach, we also investigated the vibrational excitation of C60 and C60z+ by an intense near-infrared pulse. The results indicate that large-amplitude vibration with energy of >10eV is induced in the delocalized hg(1)-like mode of C60z+.
IR plus vacuum ultraviolet spectroscopy of neutral and ionic organic acid molecules and clusters: Acetic acid
Authors: Hu Y. J. , Fu H. B. , Bernstein E. R.
Published: November 2006

Infrared (IR) vibrational spectroscopy of acetic acid (A) neutral and ionic monomers and clusters, employing vacuum ultraviolet (VUV), 10.5eV single photon ionization of supersonically expanded and cooled acetic acid samples, is presented and discussed. Molecular and cluster species are identified by time of flight mass spectroscopy: the major mass features observed are AnH+ (n=1–9), ACOOH+ (VUV ionization) without IR radiation present, and A+ with both IR and VUV radiation present. The intense feature ACOOH+ arises from the cleavage of (A)2 at the β-CC bond to generate ACOOH++CH3 following ionization. The vibrational spectrum of monomeric acetic acid (2500–7500cm−1) is measured by nonresonant ionization detected infrared (NRID-IR) spectroscopy. The fundamentals and overtones of the CH and OH stretches and some combination bands are identified in the spectrum. Mass selected IR spectra of neutral and cationic acetic acid clusters are measured in the 2500–3800cm−1 range employing nonresonant ionization dip-IR and IR photodissociation (IRPD) spectroscopies, respectively. Characteristic bands observed at approximately 2500–2900cm−1 for the cyclic ring dimer are identified and tentatively assigned. For large neutral acetic acid clusters An(n>2), spectra display only hydrogen bonded OH stretch features, while the CH modes (2500–2900cm−1) do not change with cluster size n. The IRPD spectra of protonated (cationic) acetic acid clusters AnH+ (n=1–7) exhibit a blueshift of the free OH stretch with increasing n. These bands finally disappear for n⩾6, and one broad and weak band due to hydrogen bonded OH stretch vibrations at approximately 3350cm−1 is detected. These results indicate that at least one OH group is not involved in the hydrogen bonding network for the smaller (n⩽5) AnH+ species. The disappearance of the free OH stretch feature at n⩾6 suggests that closed cyclic structures form for AnH+ for the larger clusters (n⩾6).
Trapping mechanism on oxygen-terminated diamond surfaces
Authors: Itoh Yutaka , Sumikawa Yu , Umezawa Hitoshi , Kawarada Hiroshi
Published: November 2006

Mechanisms of the hole trap and detrap on the oxygen-terminated diamond surfaces measured by diamond in-plane-gated field-effect transistors (FETs) have been investigated. Reproducible hysteresis characteristics are observed in the IDS-VGS characteristics of the diamond in-plane-gated FETs. They are caused by carrier trapping in the oxidized diamond surface and detrapping under a light irradiation, the wavelength of which affects the hysteresis width. Carriers are trapped by continuous surface states deeper than 2.0eV from the valence band maximum in the oxidized diamond surface, where the position of the highest occupied level (Fermi level) is located between 2.0 and 2.4eV.
p
-type semiconducting dendrimers bearing thiophenyl peripheral moieties for organic field effect transistors
Authors: Kim Kyung Hwan , Chi Zhenguo , Cho Min Ju , Choi Dong Hoon , Kang Han Saem , Cho Mi Yeon , Joo Jin-Soo
Published: November 2006

First generation thiophene-labeled conjugated dendrimers have been synthesized through the Heck coupling reaction between the 5-hexyl-5-propenyl thiophene derivative and 1, 2, 4, 5-tetrabromo-benzene as the core. They display a p-type semiconducting behavior and a considerably better solubility than the linear conjugated oligothiophene. Two crystalline dendrimers such as 4(HPBT)-benzene and 4(HPTT)-benzene showed carrier mobilities as high as 6.2×10−3 and 2.4×10−4cm2V−1s−1, respectively.
Depth-resolved optical studies of excitonic and phonon-assisted transitions in ZnO epilayers
Authors: Cho Yong-Hoon , Kim Ji-Young , Kwack Ho-Sang , Kwon Bong-Joon , Dang Le Si , Ko Hang-Ju , Yao Takafumi
Published: November 2006

The authors report depth-resolved optical properties of excitonic and phonon-assisted transitions in ZnO epilayers by photoluminescence (PL) and cathodoluminescence. A weaker free exciton (FX) emission than its first longitudinal optical phonon replica (FX-1LO) is observed at elevated temperatures (T>150K) for interior area, while a stronger FX than FX-1LO is seen at all temperatures for top surface area of the sample. The authors exclude out a possible self-absorption process by PL excited at back surface of the sample. Therefore, the authors conclude that the different intensity ratios of FX and FX-1LO depending on the sample depth are strongly associated with extrinsic features of ZnO.
Monte Carlo simulation of high power microwave window breakdown at atmospheric conditions
Authors: Krile John T. , Neuber Andreas A. , Krompholz Hermann G. , Gibson Thomas L.
Published: November 2006

A Monte Carlo-type electron motion simulation program was developed to calculate the increasing electron density for pulsed high power microwave window flashover in air and nitrogen at atmospheric pressures, i.e., >90torr. Through comparison of experimental and simulated results several processes such as flashover delay time’s strong dependence on pressure and the lack of significant surface charge buildup have been confirmed. The quantitative agreement of the code results with the experiment is a clear step towards predicting high power microwave flashover under a wide range of atmospheric conditions as well as for different gases and more complex window geometries.
Highly efficient top-emitting organic light-emitting diodes with self-assembed monolayer-modified Ag as anodes
Authors: Hung Ming-Chin , Wu Kun-Yang , Tao Yu-Tai , Huang Hung-Wei
Published: November 2006

A series of p-substituted benzylmercaptans was used to form self-assembled monolayers (SAMs) on silver surface to serve as the anode in the fabrication of top-emitting organic light-emitting diodes. SAMs with electron-withdrawing substituents such as cyano and trifluoromethyl groups led to enhanced hole injection and electroluminescent performance, whereas the opposite is true for electron-donating groups. Direct quantitative correlation between the molecular dipole moment/work function or work function/hole injection does not exist. A high current efficiency of ∼12cd∕A was obtained, which is two and half times that of the conventional bottom-emitting device of the same layer structure.
Resonance energy transfer from a fluorescent dye to a metal nanoparticle
Authors: Bhowmick Somnath , Saini Sangeeta , Shenoy Vijay B. , Bagchi Biman
Published: November 2006

A quantum mechanical theory of the rate of excitation energy transfer from a fluorescent dye molecule to the surface plasmonic modes of a spherical metal nanoparticle is presented. The theory predicts the distance dependence of the transfer rate to vary as 1∕dσ, with σ=3–4 at intermediate distances, in partial agreement with the recent experimental results. Förster’s 1∕d6 dependence is recovered at large separations. The predicted rate exhibits nontrivial nanoparticle size dependence, ultimately going over to an asymptotic, a3 size dependence. Unlike in conventional fluorescence resonance energy transfer, the orientational factor is found to vary between 1 and 4.
The Anomalous Reactions of Some Fluoronitrobenzenes With Some N,N-Dialkylamines
Authors: Gale DJ , Rosevear J , Wilshire JFK
Published: November 2006

The reactions of 1-fluoro-2,4- and -2,6-dinitrobenzene with certain N,N- dialkylamines in dimethyl sulfoxide solution in the presence of potassium carbonate give the corresponding dinitrophenyl N,N- dialkylcarbamates as well as the corresponding N,N- dialkyldinitroanilines. The extent of carbamate formation is governed by steric factors. The corresponding reactions of 1-fluoro-4-nitrobenzene with diisopropylamine and di-s-butylamine give poor yields of the corresponding 4-nitrophenyl N,N- dialkylcarbamates but none of the corresponding N,N-dialkyl-4-nitroanilines; in these reactions, the major product is 4,4'-dinitrodiphenyl ether. The 1H and 13C n.m.r. spectra of the 2,4- and 2,6-dinitrophenyl N,N- dialkylcarbamates reveal that their aliphatic protons and carbon atoms are magnetically non-equivalent.
Studies in the Cycloproparene Series: Electron Transfer Induced Dimerizations of Cyclopropa[b]naphthalene
Authors: Cooney MJ , Halton B , Baumgarten M , Gherghel L
Published: November 2006

Attempts to characterize the radical anion from 1H-cyclopropa[b]naphthalene (1) by conventional electron transfer techniques has led instead to detection of the pentacene radical anion (10)•- and the pentaphene analogue (11)•- by ENDOR spectroscopy. Reactions of (1) with potassium in tetrahydrofuran on a preparative scale depend upon the surface, and 6,13-dihydropentacene (8), 6,7-dihydropentaphene (9), pentacene (10), 2-methylnaphthalene (12) and 1,2-di(2′-naphthyl)ethane (13) are formed.
Does resource availability govern vertical stratification of small mammals in an Australian lowland tropical rainforest?
Authors: Rader R. , Krockenberger A.
Published: November 2006

Mammal assemblages of rainforest communities are commonly vertically stratified. This can be associated with competition for, or access to, resources in the upper canopy layers of the forest. This study investigated the extent of vertical stratification in a small mammal community of a tropical rainforest and whether any structure was related to resource abundance. The mammal community was vertically stratified, with Pogonomys mollipilosus and Cercartetus caudatus found only in the upper canopy layers and Rattus sp., Isoodon macrourus and Antechinus flavipes rubeculus on the ground and in the understorey layer. Melomys cervinipes and Uromys caudimaculatus were found at all four height layers. Total rodent captures were not significantly correlated with the abundance of fruit and flower resources, but arboreal captures of M. cervinipes and P. mollipilosus were correlated with the number of individual canopy trees of four prominent flower- and fruit-yielding species: Syzigium sayeri, Acmena graveolens, Argyrodendron perelatum and Castanospermum australe. We suggest that arboreal behaviour in these rodents serves to provide the advantages of first access to food resources, the availability of abundant resources in the canopy, and, ultimately, reduced competition in the upper strata.
Should the 40-year-old practice of releasing virulent myxoma virus to control rabbits (Oryctolagus cuniculus) be continued?
Authors: Berman D. , Kerr P. J. , Stagg R. , van Leeuwen B. H. , Gonzalez T.
Published: November 2006

Release of virulent myxoma virus has been a key component of rabbit-control operations in Queensland, Australia, since the 1960s but its use rests on anecdotal reports. During a routine operation to release virulent myxoma virus we found no evidence to support the continued regular use of the technique in south-west Queensland. Radio-tagged rabbits inoculated with virulent myxoma virus contracted the disease but failed to pass enough virus to other rabbits to spread the disease. Rabbits with clinical signs of myxomatosis that were shot were infected with field strain derived from the original laboratory strain released in 1950 rather than the virulent strain that has been released annually. There was no change in rabbit survival or abundance caused by the release. Nevertheless, the release of virulent virus may be useful against isolated pockets of rabbits mainly because field strains are less likely to be present. Such pockets are more common now that rabbit haemorrhagic disease virus is established in Queensland.