bluuebunny/crossref_metadata_2025 huggingface dataset:
Antioxidant activity of some plant extracts of the family labiatae
Authors: Economou K. D. , Oreopoulou V. , Thomopoulos C. D.
Published: July 2007

The antioxidant activities of methanol extracts of oregano, dittany, thyme, marjoram, spearmint, lavender and basil were tested in lard stored at 75°C. The concentration of extracts in lard varied from 0.01 to 0.20%. Oregano extract was found to be the most effective in stabilizing lard, followed by thyme, dittany, marjoram and lavender extracts, in a decreasing order. The induction period of lard increased with antioxidant concentration. After the induction period, peroxide formation proceeded rapidly, following pseudo‐zero order reaction kinetics. The rate of the reaction decreased slightly with increasing plant extract concentration. Combined addition of plant extracts in lard showed a low synergistic action between thyme extract and spearmint extract.
A comparative study of analytical methods for evaluation of soybean oil quality
Authors: Chu Yan‐ Hwa
Published: July 2007

This study is focused on the improvement of soybean oil stability by addition of additives and blending with more stable oils. The methods for evaluation of oil deterioration include changes in dielectric constant (DC), total polar (TP) compounds, refractive index (RF), fritest (FT), acid value (AV), iodine value (IV), anisidine value (AnV), carbonyl value (COV), viscosity and color. Statistically significant correlations were obtained between changes in DC and increase in the TP compounds, RF, FT, AV, AnV, COV and the decrease in the IV, respectively. Food oil sensor reading of 4 as a measure of changes in DC of oil has been suggested as the criterion of low oil quality. Consequently, the cut‐off level for straight and blended soybean oils were thereby identified by using the above parameters.
Supercritical carbon dioxide extraction of evening primrose oil
Authors: Favati Fabio , King Jerry W. , Mazzanti Monica
Published: July 2007

The oil extracted from the seeds ofOenothera biennis L. (evening primrose) is a major commercial source of gamma‐linolenic acid, a fatty acid having potential therapeutic value in the treatment of several diseases. This fatty acid is prone to oxidation and thermal rearrangement; therefore, the conventional recovery of the oil via mechanical expression and hexane extraction must be carried out under very mild and controlled conditions. In this study, supercritical fluid extraction with carbon dioxide has been employed as an alternative method to recover evening primrose oil (EPO). Extractions were performed over the pressure range of 20–70 MPa and at temperatures from 40 to 60°C, with a CO2 mass flow rate of 18 g/min. The experimental data permitted the determination of EPO solubility in supercritical CO2 at the tested extraction conditions. Supercritical fluid Chromatographic analysis of fractions collected during the extraction showed a subtle shift in the triglyceride composition. Fatty acid methyl ester analysis on similar fractions indicated that the fatty acid content was invariant with respect to extraction time.
Effects of various tocopherol‐containing diets on tocopherol secretion into bile
Authors: Yamashita Kanae , Takeda Noriko , Ikeda Saiko
Published: July 2007

γ‐Tocopherol is abundant in common vegetable oil, but its concentration in plasma and liver is much lower than that of α‐tocopherol. Discrimination between different forms of tocopherol is thought to take placevia the hepatic α‐tocopherol transfer protein (α‐TTP). γ‐Tocopherol, with a low binding capacity to α‐TTP, is thought to be excretedvia the bile. Our previous studies showed that γ‐tocopherol administered with sesame seed exhibits significantly higher concentrations in the plasma and liver of rats than γ‐tocopherol alone. Thus, we attempted to confirm whether a much higher amount of γ‐tocopherol rather than γ‐tocopherol would be secreted in the bile, and whether sesame seed would suppress the secretion of γ‐tocopherol. In one experiment, we examined the concentrations of α‐or γ‐tocopherol in the plasma, liver, and bile of rats fed diets containing 300 mg/kg of α‐tocopherol, 300 mg/kg of γ‐tocopherol, or 300 mg/kg each of α‐tocopherol+γ‐tocopherol, and in the other experiment, we compared the γ‐tocopherol concentrations of rats fed a diet of γ‐tocopherol alone to those of rats fed a γ‐tocopherol+sesame seed diet (each diet contained 300 mg/kg γ‐tocopherol). The bile collection was done over 6 h. The γ‐tocopherol concentration in the bile was markedly lower than that of α‐tocopherol, paralleling the concentrations in the plasma and liver. Intake of α‐tocopherol and γ‐tocopherol together further lowered the concentration of γ‐tocopherol in the bile as well as in the plasma and liver, compared to the intake of γ‐tocopherol alone. The γ‐tocopherol concentration in the bile, as well as in the plasma and liver, was markedly higher in the sesame seed‐fed group than in the γ‐tocopherol alone group. We found that the concentrations of α‐ or γ‐tocopherol in the bile showed a good correlation with the concentrations of α‐ or γ‐tocopherol in the liver, though the concentrations in the bile were substantially lower than those in the liver. These findings suggest that secretion into the bile is not a major metabolic route of α‐ or γ‐tocopherol.
A convenient laboratory method for preparingtrans, trans‐9, 11‐octadecadienoic acid
Authors: Schneider Wilma J. , Gast L. E. , Teeter H. M.
Published: July 2007

A convenient laboratory method to preparetrans,trans‐ 9,11‐octadecadienoic acid (TTA) via a polyester intermediate is described. Ricinelaidic acid was heated at 235C under vacuum for 3–4 hr to form a polyester having a mol wt of 1,500–1,600. Pyrolysis of this polyester and simultane‐ous distillation of the products gave crude dehy‐drated acids. TTA was crystallized from a 95% ethanol solution of these acids, in a yield of 35%. Of the variables affecting pyrolysis, the mol wt of polyester had the greatest effect on yield of TTA.
Reaction of methyl alpha‐eleostearate with mercuric acetate
Authors: Planck Ralph W. , O'Connor Robert T. , Goldblatt Leo A.
Published: July 2007

Methyl alpha‐eleostearate has been reacted with mercuric acetate in acetic acid solution. Carrying out the reaction below room temperature gave products having the highest mercury content. Even these products were relatively unstable, gradually decomposing to produce mercury or mercurous acetate or both at room temperature. A typical product obtained at 10°C. is a viscous, pale yellow oil, insoluble in petroleum ether but soluble in alcohol, ether, and chloroform. Each C18 chain contained, on the average, 1.4 acetoxymercuri‐groups (CH3COOHg−), 1.5 acetoxyl groups attached directly to the carbon chain and 0.4 double bonds. For each mole of mercuric acetate added to the methyl eleostearate approximately one mole of mercuric acetate was reduced to mercurous acetate and a double bond in the ester chain was oxidized to an oxygen‐containing group of undetermined structure. Treatment of the acetoxymercuri‐, acetoxy‐ester with aqueous chlorides or bases yielded the corresponding chloromercuri‐ or hydroxymercuri‐derivative. Refluxing the acetoxymercuri‐, acetoxy‐ester in alcoholic potassium hydroxide saponified all the ester linkages and removed the acetoxymercuri‐groups with the formation of an equal number of double bonds, most of which are present in conjugatedtrans‐trans systems. The Marvel‐Rands chromatographic procedure was modified to permit determination of total acetoxyl groups and of acetoxyl groups attached to mercury atoms. Acetoxyl groups of the latter kind can also be determined by direct titration with standard base.
Reliability of fatty acid values purporting to represent composition of oil from different species of fish
Authors: Stansby M. E.
Published: July 2007

Data reveal a very large variation in fatty acid pattern of oil from the same species of fish even when each batch of oil represents many thousands of individual fish. The necessity for using samples involving a much larger number of fish for studies to determine fatty acid patterns for a given species is emphasized. Other sources of error are considered briefly.
Potentiometric titration of cyclopropene esters
Authors: Zeringue H. J. , Feuge R. O.
Published: July 2007

The quantitative determination of cyclopropene acids occurring as esters in seed oils can be made by a direct titration with hydrogen bromide in toluene, but the color indicator used heretofore to determine the end point presented problems. A potentiometric titration that avoids these problems was devised. A silver‐silver chloride indicator electrode and a calomel reference electrode connected to the titration cell by a salt bridge were employed. The precision of the cyclopropene analysis of purified samples seems to depend primarily on the accuracy to which the amount of titrant can be determined. At the 1% level, reproductible values to about ±0.01% are obtained.
Rapid analysis of ionic and nonionic surfactant homologs by high performance liquid chromatography
Authors: Nakamura K. , Morikawa Y. , Matsumoto I.
Published: July 2007

Several ionic and nonionic surfactants were separated into their homologs and their homologous distributions were determined by high performance liquid chromatography on an octadecyl‐silica (TSK Gel LS‐410) column with a water‐methanol‐sodium chloride mixture as a mobile phase. The recommended condition for the separation was as follows: column size, 4 mm id x 250 mm; mobile phase, water/methanol (15/85, v/v) containing 0.4 M/L sodium chloride; column temp., 50 C. Under this condition, three nonionic, four anionic and one cationic surfactants were efficiently separated into their respective homologs. The addition of sodium chloride affected particularly the separation of strongly ionogenic surfactants such as sodium alkylsulfates and alkylbenzyldimethylammonium chlorides. Analytical results of homologous distributions of several commercial surfactants were in good accordance with those obtained by the conventional gas chromatography (GC) method.
Surfactant raw material outlook for the eighties
Authors: Bindo J. S. , Smith G. D.
Published: July 2007

Over the next decade, the surfactant industry should be able to secure an adequate supply of the raw materials necessary to provide its need for surfactant intermediates. Since the U.S. will continue to rely on foreign imports for marginal crude supplies, periodic disruptions in raw material supply are likely to occur. World crude prices are expected to rise more rapidly than the general U.S. inflation rate and surfactant feedstocks are expected to track world crude prices as a whole. Over the next few years, ethylene prices should increase faster than other surfactant feedstocks. This should occur as a result of natural gas price decontrol and improved ethylene profit margins. Otherwise, in the long term, the major driving force for all three synthetic feedstocks should be the price of world crude. Of course, short term perturbations, e.g., plant shutdowns and over‐supply situations, may cause one feedstock or the other to increase at somewhat higher or somewhat lower rates for short periods of time. Natural oils may represent an interesting alternative to crude‐oil‐based alcohols. Longer term, average prices for natural oils should increase at lower rates than world crude oil. However, natural oil prices have historically been much more cyclic than crude prices and “natural” alcohol producers run the risk of being noncompetitive during tight supply/demand periods.
Chromatographic analysis of polyglycerols and their fatty acid esters
Authors: Sahasrabudhe M. R.
Published: July 2007

Polyglycerols and their fatty acid esters have been analyzed by gas‐liquid chromatography (GLC) as trimethylsilyl ether derivatives. Linear diglycerols and triglycerols were isolated from commercial polyglycerols by vacuum distillation. Mono‐ and di‐fatty acid esters were synthesized in the laboratory. Two isomers of diglycerol have been separated and identified. GLC analysis was carried out on columns packed with 3% JXR on Gas Chrom Q. Response factors for diglycerol and triglycerol relative to glycerol have been established. Commercial polyglycerol esters are shown to be mixtures of glycerol, free fatty acids, mono‐ and diglycerides, and mono‐ fatty acid esters of diglycerol and triglycerol. Separation of free polyglycerols and their esters is also demonstrated by thin‐layer chromatography on Silica Gel‐G containing 4.0% boric acid.
The alpha‐sulfonation of alkyl palmitates and stearates
Authors: Smith F. D. , Stirton A. J.
Published: July 2007

Methyl, ethyl, and isopropyl esters of palmitic or stearic acid werea‐sulfonated directly by the dropwise addition of a 2.4 molar ratio of liquid sulfur trioxide to the ester, with or without solvent, at 0C. Scission of the ester apparently takes place during sulfonation. Yield of the ester RCH‐(SO3Na)CO2R was increased, and yield of by‐product disodium salt was decreased by reesterification with methyl, ethyl, or isopropyl alcohol prior to neutralization. Direct sulfonation of the ester by sulfur trioxide, without solvent, gave 70–80% yields, increased 10% by the presence of a small amount of CCl4 as the solvent (1 ml/g of ester). Mixtures of thea‐sulfo ester and the disodium salt can be analyzed by infrared spectra.
The isolation and partial characterization of gangliosides and ceramide polyhexosides from the lens of the human eye
Authors: Feldman Gerald L. , Feldman Lutrell S. , Rouser George
Published: July 2007

The first isolation of glycolipids from the lens of the human eye is described. Neutral (ceramide polyhexosides) and acidic (gangliosides) glycolipids were separated by column chromatography and further resolved by thin‐layer chromatography. The components were methanolyzed, converted to trimethyl silyl ethers and the ratios of the components determined. Two types of monosialogangliosides were found. The most abundant ganglioside contained long chain base/fatty acid/glucose/galactose/neuraminic acid in the ratio 1/1/1/2/1. The ratio of components of the minor ganglioside fraction was 1/1/1/1/1. Dihydrosphingosine was the major base and the major fatty acids were palmitate and nervonate. The ceramide polyhexosides all had a glucose/galactose molor ratio of 1/1 and the mixture of ceramide polyhexosides had a dihydrosphingosine/sphingosine molar ratio of 7.85. The fatty acids ranged from C10 to C25 with both odd and even carbon chains and were saturated or monounsaturated with palmitate, oleate, and nervonate predominating.
Polymorphism of palm oil and palm oil products
Authors: Yap Peck Hong , de Man J. M. , de Man L.
Published: July 2007

Palm oil, palm stearin, hydrogenated palm oil (IV 27.5) and hydrogenated palm olein (IV 28) were crystallized at 5°C, temperature cycled between 5 and 20°C, and kept isothermally at 5°C for 36 days. The polymorphic state of the fats was monitored by X‐ray diffraction analysis. Soft laser scanning of X‐ray films was used to establish the increase inβ crystal content. Palm stearin was least stable in theβ′ form, followed by palm oil. The hydrogenated oils were very stable in theβ′ form. Differential scanning calorimeter (DSC) analysis was used to complement the X‐ray data.
Triglyceride specific heat determined by differential scanning calorimetry
Authors: Hampson J. W. , Rothbart H. L.
Published: July 2007

The specific heats of the three polymorphic forms of trilaurin, trimyristin, tripalmitin and tristearin have been determined by differential scanning calorimetry (DSC). Results from ‐90 to +100 C for the triglycerides were obtained and compared with the literature values determined by classical methods. Agricultural Research Service, US Department of Agriculture.
Jojoba. I. establishment of commercial plantations
Authors: Yermanos D. M.
Published: July 2007

Although jojoba withstands a wide spectrum of environmental stresses, plantations should be established at first in areas where environmental factors offer a maximum likelihood of success for this crop. The two major limiting factors that will determine location of plantations appear to be temperature and soil type: flower damage occurs at temperatures lower than 22 F (‐5 C), and poor growth results on heavy soils with poor water penetration. Optimum planting plan appears to consist of continuous hedge type rows spaced 15 ft (5 m) apart with plants 3 ft (90 cm) apart on the row.
Correlations for trans‐isomer formation during partial hydrogenation of oils and fats
Authors: Puri P. S.
Published: July 2007

Two empirical models are proposed to correlate the amount of trans‐isomers formed during the partial hydrogenation of oils and fats as a function of the degree of hydrogenation and process variables. From minimal experimental data, constants for these models can be obtained and used to interpolate or extrapolate the trans‐isomer data to predict the amount of trans‐isomers formed during a partial hydrogenation or to select processing conditions for a desired amount of trans‐unsaturation. The application of these models has been demonstrated using hydro‐genation data for soybean and rapeseed oils.
Periodate‐permanganate oxidations for determining location and amount of unsaturation in monounsaturated fatty acids
Authors: Jones E. P. , Stolp J. A.
Published: July 2007

Conclusions

Periodate‐permanganate oxidation of three samples of oleic acid considered to be of high purity has given reproducible but less than theoretical amounts of total dibasic acids. Recovery approximated 92% with about 90.3% of the expected azelaic acid. Recovery of other dibasic acids indicated that about 1.5% of the total unsaturation of these samples of oleic acid was present in positions 8 or 10 in the fatty acid molecule.

Oxidation of elaidic acid produced from one of the oleic acids has given total dibasic acid yield of about 96%, with a smaller amount of its total unsaturation in the same position as in the parent oleic acid.

Oxidation of high purity 9,10‐dihydroxystearic acid has given essentially quantitative yield of total dibasic acids. The method described should be useful in determining the composition of similar unsaturated positional isomers.

Controls showing the effect of the method on azelaic acid and on a mixture of azelaic acid with pelargonic have shown essentially quantitative recovery of azelaic acid. Failure to establish quantitative recovery on oxidation of oleic acid must be caused by some unknown factor during oxidationper se. The experimental technique described was satisfactory for quantitative studies of the type undertaken.

Oxidation of moderate‐purity, mono‐unsaturated fatty acids, such as erucic, 10‐undecenoic, and vaccenic acid, has given mixed dibasic acids corresponding to the respective positions of unsaturation.

The data indicate that the method described shows the position of minor unsaturation within about 1%.
Further studies on the isomerization of polyunsaturated fatty acids by potassium tertiary butoxide
Authors: Sreenivasan B. S. , Brown J. B.
Published: July 2007

A temperature and time study revealed that the best conditions for the isomerization and estimation of polyunsaturated acids are heating in a sealed tube for 2 hrs. at 140° with potassium‐t‐butoxide in t‐butanol. Under these conditions conjugation of linolenic and arachidonic acids appears to have attained completion. With linoliec acid a higher degree of conjugation than by other methods and a shift of peak to lower wavelength (231–232 mμ) are observed. Extinction coefficients obtained by this method for isomerized pure linoleic (k232, 98.0) and linolenic (k268, 138.4) acids are the highest so far reported. Ultraviolet and infrared examination of the conjugated trienes isolated from isomerized linolenic acid concentrate showed that, under these conditions, trienes similar to both alpha‐ and beta‐eleostearic acids are produced. Analyses of samples of oils for component polyunsaturated acids, by this method, compare well with those by other methods. The presence of small amounts of a tetraenoic acid in linseed oil is noted.
An international training and support programme for the establishment of neonatal screening in developing countries
Authors: Fukushi M.
Published: July 2007

We report our experience in developing and implementing a training programme aimed at introducing neonatal screening to health care professionals in developing countries. It was originally envisioned as a 10‐year programme but was later extended to 15. Our institute initially began offering the training course in neonatal screening on an annual basis in 1990, under the auspices of the Japan International Cooperation Agency (JICA). The aims of the programme were to enhance the participants’ technical knowledge and skills, as well as deepen their understanding of the principles involved in neonatal screening. Over the 15 years that the programme ran, up to March 2005, a total of 130 participants originating from 36 countries completed the course, the participants comprising some 85 paediatricians, 4 obstetricians, 34 biochemists and 7 administrative officers or public health specialists, a number of whom have subsequently implemented neonatal screening programmes in their respective institutes, regions or countries. Having thus completed the initial 15‐year phase of the training course, after a thorough evaluation we initiated the second phase of our international training and support programme for neonatal screening in 2006. With the objective of supporting the establishment of a neonatal screening system for congenital hypothyroidism, the new programme consists of not only specialist training in Japan but also financial and technical assistance for helping to establish neonatal screening in the participants’ respective countries.
Doubly Robust-Type Estimation for Covariate Adjustment in Latent Variable Modeling
Authors: Hoshino Takahiro
Published: July 2007

Due to the difficulty in achieving a random assignment, a quasi-experimental or observational study design is frequently used in the behavioral and social sciences. If a nonrandom assignment depends on the covariates, multiple group structural equation modeling, that includes the regression function of the dependent variables on the covariates that determine the assignment, can provide reasonable estimates under the condition of correct specification of the regression function. However, it is usually difficult to specify the correct regression function because the dimensions of the dependent variables and covariates are typically large. Therefore, the propensity score adjustment methods have been proposed, since they do not require the specification of the regression function and have been applied to several applied studies. However, these methods produce biased estimates if the assignment mechanism is incorrectly specified. In order to make a more robust inference, it would be more useful to develop an estimation method that integrates the regression approach with the propensity score methodology. In this study we propose a doubly robust-type estimation method for marginal multiple group structural equation modeling. This method provides a consistent estimator if either the regression function or the assignment mechanism is correctly specified. A simulation study indicates that the proposed estimation method is more robust than the existing methods.
Highly Efficient Enzymatic Synthesis of 2‐Monoacylglycerides and Structured Lipids and their Production on a Technical Scale
Authors: Pfeffer Jan , Freund Andreas , Bel‐Rhlid Rachid , Hansen Carl‐Erik , Reuss Matthias , Schmid Rolf D. , Maurer Steffen C.
Published: July 2007

We report here a two‐step process for the high‐yield enzymatic synthesis of 2‐monoacylglycerides (2‐MAG) of saturated as well as unsaturated fatty acids with different chain lengths. The process consists of two steps: first the unselective esterification of fatty acids and glycerol leading to a triacylglyceride followed by an sn1,3‐selective alcoholysis reaction yielding 2‐monoacylglycerides. Remarkably, both steps can be catalyzed by lipase B from Candida antarctica (CalB). The whole process including esterification and alcoholysis was scaled up in a miniplant to a total volume of 10 l. With this volume, a two‐step process catalyzed by CalB for the synthesis of 1,3‐oleoyl‐2‐palmitoylglycerol (OPO) using tripalmitate as starting material was established. On a laboratory scale, we obtained gram quantities of the synthesized 2‐monoacylglycerides of polyunsaturated fatty acids such as arachidonic‐, docosahexaenoic‐ and eicosapentaenoic acids and up to 96.4% of the theoretically possible yield with 95% purity. On a technical scale (>100 g of product, >5 l of reaction volume), 97% yield was reached in the esterification and 73% in the alcoholysis and a new promising process for the enzymatic synthesis of OPO was established.
Double emulsions of water‐in‐oil‐in‐water stabilized by α‐form fat microcrystals. Part 1: Selection of emulsifiers and fat microcrystalline particles
Authors: Garti N. , Aserin A. , Tiunova I. , Binyamin H.
Published: July 2007

Double emulsions are commonly stabilized by monomeric and/or polymeric emulsifiers. Pickering stabilization by solid particles such as colloidal microcrystalline cellulose has been mentioned only once as a possible technique to stabilize the external interface of the water‐in‐oil‐in‐water emulsion. No further work was carried out exploring this option. The present study shows that solid microcrystalline fat particles of α‐form are capable of adsorbing at the water‐oil interface and, together with other hydrophobic emulsifiers, can stabilize water‐in‐oil (W/O) emulsions. The crystals must be submicron in size in order to effectively adsorb and arrange at the interface. Large crystals do not fit and were found to flocculate as free crystals in the continuous oil phase. The α‐form crystals can be obtained by flash‐cooling saturated triglycerides in vegetable oils in the presence of emulsifiers, such as polyglycerol polyricinoleate (PGPR), that stabilize the dispersion and serve as α‐tending crystal structure modifiers. It was assumed that PGPR also serves as a cross‐linker or bridge between the crystalline fat particles and the water, and facilitates the anchoring of the fat particles in the oil phase in one direction while dangling itself in the water phase. The double emulsion droplets prepared with these W/O emulsions are relatively large in size (6–18 µm), but stable to coalescence. The marker (NaCl) does not seem to release with time, suggesting that the fat particles form microcapsules on the water interface, totally sealing the water from releasing its addenda. The systems seem to have a significant potential for food emulsions.
Chief Lamidi Adedibu and patronage politics in Nigeria
Authors: Omobowale Ayokunle Olumuyiwa , Olutayo Akinpelu Olanrewaju
Published: July 2007

Since the acceptance of multi-party democracy as the most viable alternative to autocracy and military rule in Africa, democratic rule has become the vogue. Nigeria's attempt at democracy was (and is) accompanied by patronage politics, whereby certain personalities exact great influence on the political process. This study spotlights Chief Lamidi Adedibu and his patronage style in Nigerian politics, and shows that Adedibu gained political ‘patronic’ prominence during Nigeria's Third Republic in the 1990s, through the provision of the survival needs of the poor majority who are, mostly, used as thugs for protection against challenges from opponents and for political leverage. Since then, he has remained a ‘valuable tool’ of ‘any government in power’ and politicians ready to provide the necessary goods for onward transmission to clients.
Evidence for the use of probiotics and prebiotics in inflammatory bowel disease: a review of clinical trials
Authors: Hedin Charlotte , Whelan Kevin , Lindsay James O.
Published: July 2007

Human subjects and their enteric microbiota have evolved together to reach a state of mutual tolerance. Mounting evidence from both animal models and human studies suggests that inflammatory bowel disease (IBD) represents a malfunction of this relationship. The enteric microecology therefore represents an attractive therapeutic target with few side effects. Probiotics and prebiotics have been investigated in clinical trials as treatments for IBD, with conflicting results. The evidence for the use of probiotics in the management of pouchitis is persuasive and several studies indicate their effectiveness in ulcerative colitis. Trials of probiotics and prebiotics in Crohn's disease are less convincing. However, methodologies vary widely and a range of probiotic, prebiotic and combination (synbiotic) treatments have been tested in a variety of patient groups with an assortment of end points. Conclusions about any one treatment in a specific patient group can therefore only be drawn on evidence from relatively small numbers of patients. The present article reviews the role of the intestinal microbiota in the pathogenesis of IBD and addresses the clinical evidence for the therapeutic manipulation of bowel microbiota using probiotics, prebiotics and synbiotics in IBD.
Integration of physiological and molecular mechanisms of the developmental origins of adult disease: new concepts and insights
Authors: Symonds Michael E.
Published: July 2007

It is now well established that an imbalance or reduction in the maternal diet either through pregnancy and lactation or at defined time points therein can have long-term effects on cardiovascular and metabolic health in the resulting offspring; the exact outcome varying greatly with the period of development or growth targeted. The EARly Nutrition programming – long-term follow up of Efficacy and Safety Trials and integrated epidemiological, genetic, animal, consumer and economic research (EARNEST), or metabolic programming, project aims to determine the primary physiological and molecular mechanisms that cause long-term changes in both cardiovascular function and metabolic homeostasis. Thereafter, it also aims to examine nutritional interventions that could be adopted in order to overcome such complications. The present review summarises some of the more recent findings from a range of nutritional interventions in both small and large animals that are beginning to uncover novel pathways by which long-term health can be determined. These interventions include nutritional manipulations that can increase or decrease blood pressure in the resulting offspring as well as indicating their dissociation from adaptations in the kidney. Particular emphasis will be placed on growth during lactation in conjunction with the extent to which central and peripheral tissue adaptations can act to amplify, or protect, the offspring from later disease when born to nutritionally-manipulated mothers.
Heat asymptotics with spectral boundary conditions. II
Authors: Gilkey Peter , Kirsten Klaus
Published: July 2007

Let P be an operator of Dirac type on a compact Riemannian manifold with smooth boundary. We impose spectral boundary conditions and study the asymptotics of the heat trace of the associated operator of Laplace type.
Hypersurfaces of extremal slope
Authors: Rieger J. H.
Published: July 2007

The hypersurface of extremal slope consists of extrema of the gradient magnitude along integral curves of the gradient vector field of a smooth function. We study the singularities, and other geometric features, of hypersurfaces of extremal slope associated with generic functions and with one-parameter families of functions representing generic solutions to the heat equation.
Existence of renormalized solutions of degenerate elliptic-parabolic problems
Authors: Ammar Kaouther , Wittbold Petra
Published: July 2007

We consider a general class of degenerate elliptic-parabolic problems associated with the equation b(υ)t = div a(υ, Dυ) + f. Existence of renormalized solutions is established for general L1 data. Uniqueness of renormalized solutions has already been shown in a previous work.
Relaxation in an L∞-optimization problem
Authors: Ishii Hitoshi , Loreti Paola
Published: July 2007

Let Ω be an open bounded subset of Rn and f a continuous function on Ω̄ satisfying f(x) > 0 for all x ∈ Ω̄. We consider the maximization problem for the integral ∫Ωf(x)u(x)dx over all Lipschitz continuous functions u subject to the Dirichlet boundary condition u = 0 on ∂Ω and to the gradient constraint of the form H(Du(x)) ≤ 1, and prove that the supremum is ‘achieved’ by the viscosity solution of Ĥ(Du(x)) = 1 in Ω and u = 0 on ∂Ω, where Ĥ denotes the convex envelope of H. This result is applied to an asymptotic problem, as p → ∞, for quasi-minimizers of the integral

An asymptotic problem as k → ∞ for inf

is also considered, where the infimum is taken all over and the set K is given by {ξ | H(ξ) ≤ 1}.
Weak solutions for equations defined by accretive operators. I
Authors: Portilheiro Manuel
Published: July 2007

We propose a notion of weak solution for certain nonlinear contractive equations: ‘dissipative solution’. We show that this notion coincides with the viscosity solutions for Hamilton–Jacobi equations, as introduced by Crandall and Lions, and with the entropy solutions for conservation laws introduced by Kružkov. The proposed notion is based on the properties of accretive operators.
Homogenization of Dirichlet parabolic systems with variable monotone operators in general perforated domains
Authors: Calvo-Jurado Carmen , Casado-Díaz Juan
Published: July 2007

We consider the homogenization of parabolic systems with Dirichlet boundary conditions when the operators and the domains in which the problems are posed vary simultaneously. We assume the operators do not depend on t. Then we show that the corrector obtained in a previous paper for the elliptic problem still gives a corrector for the parabolic one. From this result, we easily obtain the limit problem in the parabolic case.
Partial regularity of local minimizers of quasiconvex integrals with sub-quadratic growth
Authors: Carozza Menita , di Napoli Antonia Passarelli
Published: July 2007

We prove partial regularity for local minimizers of quasiconvex integrals of the form I(v) = ∫ΩF(Dv(x))dx, where the integrand f(ξ) has sub-quadratic growth, i.e. |F(ξ)| ≤ L(1 + |ξ|p), with 1 < p < 2. A function u ∈ W1,p(Ω;RN) is a W1,q(Ω;RN) local minimizer of I(v) if there exists a δ > 0 such that I(u) ≤ I(v) whenever v and ‖Dv − Du‖q ≤ δ.
On skew-symmetric maps on Lie algebras
Authors: Chebotar Mikhail A. , Ke Wen-Fong
Published: July 2007

For certain Lie subalgebras L of associative algebras Q, we characterize the multi-additive skew-symmetric maps f : Ln → Q, which are covariant under the action of L.
Very singular solutions to a nonlinear parabolic equation with absorption II. Uniqueness
Authors: Benachour Saïd , Koch Herbert , Laurençot Philippe
Published: July 2007

We prove the uniqueness of the very singular solution to

when 1 < p < (N + 2)/(N + 1), thus completing the previous result by Qi and Wang, restricted to self-similar solutions.
Curvatures of complete hypersurfaces in space forms
Authors: Cheng Qing-Ming
Published: July 2007

In this paper we investigate three-dimensional complete minimal hypersurfaces with constant Gauss-Kronecker curvature in a space form M4(c) (c ≤ 0). We prove that if the scalar curvature of a such hypersurface is bounded from below, then its Gauss-Kronecker curvature vanishes identically. Examples of complete minimal hypersurfaces which are not totally geodesic in the Euclidean space E4 and the hyperbolic space H4(c) with vanishing Gauss-Kronecker curvature are also presented. It is also proved that totally umbilical hypersurfaces are the only complete hypersurfaces with non-zero constant mean curvature and with zero quasi-Gauss-Kronecker curvature in a space form M4(c) (c ≤ 0) if the scalar curvature is bounded from below. In particular, we classify complete hypersurfaces with constant mean curvature and with constant quasi-Gauss-Kronecker curvature in a space form M4(c) (c ≤ 0) if the scalar curvature r satisfies r≥ ⅔c.
Non-classical global solutions for a class of scalar conservation laws
Authors: Baiti Paolo
Published: July 2007

We consider the Cauchy problem for a class of scalar conservation laws with flux having a single inflection point. We prove existence of global weak solutions satisfying a single entropy inequality together with a kinetic relation, in a class of bounded variation functions. The kinetic relation is obtained by the travelling-wave criterion for a regularization consisting of balanced diffusive and dispersive terms. The result is applied to the one-dimensional Buckley-Leverett equation.
Umbilicity of space-like submanifolds of Minkowski space
Authors: Izumiya Shyuichi , Pei Donghe , del Carmen Romero Fuster María
Published: July 2007

We study some properties of space-like submanifolds in Minkowski n-space, whose points are all umbilic with respect to some normal field. As a consequence of these and some results contained in a paper by Asperti and Dajczer, we obtain that being ν-umbilic with respect to a parallel light-like normal field implies conformal flatness for submanifolds of dimension n − 2 ≥ 3. In the case of surfaces, we relate the umbilicity condition to that of total semi-umbilicity (degeneracy of the curvature ellipse at every point). Moreover, if the considered normal field is parallel, we show that it is everywhere time-like, space-like or light-like if and only if the surface is included in a hyperbolic 3-space, a de Sitter 3-space or a three-dimensional light cone, respectively. We also give characterizations of total semi-umbilicity for surfaces contained in hyperbolic 4-space, de Sitter 4-space and four-dimensional light cone.
Existence and isoperimetric characterization of steady spherical vortex rings in a uniform flow in RN
Authors: Burton Geoffrey R. , Preciso Luca
Published: July 2007

We study a boundary-value problem for a particular semilinear elliptic equation on Rn (n ≥ 2), whose solutions represent generalized stream functions for steady axisymmetric ideal fluid flows. Solutions are shown to exist that generalize those already known in dimensions 2 and 3. An isoperimetric characterization is given for our solutions, which represent generalized spherical vortex-rings. As a corollary, a sharp Sobolev-type inequality is obtained.
Lp and endpoint estimates for multi-linear singular integral operators
Authors: Hu Guoen
Published: July 2007

The relationship of the Lp (Rn) estimate and two endpoint estimates for the multi-linear singular integral operators is considered. Some conditions are given under which one of these estimates implies the others.
Solutions with boundary layer and positive peak for an elliptic Dirichlet problem
Authors: Li Gongbao , Yang Jianfu , Yan Shusen
Published: July 2007

In this paper, we study existence of solutions with boundary layer and peaks for an elliptic problem. We prove that the problem has a mountain-pass-type solution, which has a boundary layer and a single peak near the boundary. Moreover, we also study the existence of solutions with interior peak.
Convergent asymptotic expansions of Charlier, Laguerre and Jacobi polynomials
Authors: López José L. , Temme Nico M.
Published: July 2007

Convergent expansions are derived for three types of orthogonal polynomials: Charlier, Laguerre and Jacobi. The expansions have asymptotic properties for large values of the degree. The expansions are given in terms of functions that are special cases of the given polynomials. The method is based on expanding integrals in one or two points of the complex plane, these points being saddle points of the phase functions of the integrands.
On a variational characterization of the Fučík spectrum of the Laplacian and a superlinear Sturm–Liouville equation
Authors: Massa Eugenio
Published: July 2007

In the first part of this paper, a variational characterization of parts of the Fučík spectrum for the Laplacian in a bounded domain Ω is given. The proof uses a linking theorem on sets obtained through a suitable deformation of subspaces of H1 (Ω). In the second part, a nonlinear Sturm–Liouville equation with Neumann boundary conditions on an interval is considered, where the nonlinearity intersects all but a finite number of eigenvalues. It is proved that, under certain conditions, this equation is solvable for arbitrary forcing terms. The proof uses a comparison of the minimax levels of the functional associated to this equation with suitable values related to the Fucík spectrum.
The sectional category of a map
Authors: Arkowitz M. , Strom J.
Published: July 2007

We study a generalization of the Svarc genus of a fibre map. For an arbitrary collection ɛ of spaces and a map f : X → Y, we define a numerical invariant, the ɛ-sectional category of f, in terms of open covers of Y. We obtain several basic properties of ɛ-sectional category, including those dealing with homotopy domination and homotopy pushouts. We then give three simple axioms which characterize the ɛ-sectional category. In the final section, we obtain inequalities for the ɛ-sectional category of a composition and inequalities relating the ɛ-sectional category to the Fadell–Husseini category of a map and the Clapp–Puppe category of a map.
Local regularity theorems for the stationary thermistor problem
Authors: Xu Xiangsheng
Published: July 2007

In this paper we present a simpler proof of a result of Lewis concerning the continuity of weak solutions to the two-dimensional thermistor problem in the case where the temperature can blow up in a region with non-empty interior. Some other regularity properties are also discussed.
Quasi-convex functions on subspaces and boundaries of quasi-convex sets
Authors: Zhang Kewei
Published: July 2007

We embed truncations of the epi-graph of quasi-convex functions defined on linear subspaces E ⊂ MN × n of real matrices into MN × n to bound quasi-convex sets by the graph of the functions. We also characterize subspaces E on which all quasi-convex functions are convex and show, by using the Tarski–Seidenberg theorem in real algebraic geometry, that if dim (E) > N + n − 1, then there exist non-trivial quasi-convex functions on E.
On surjective linear maps preserving commutativity
Authors: Beidar K. I. , Lin Ying-Fen
Published: July 2007

We describe surjective linear maps preserving commutativity from (symmetric elements of) any algebra (with involution) onto (symmetric elements of) a prime algebra (with involution) not satisfying polynomial identities of low degree. Bijective commutativity preservers on skew elements of centrally closed prime algebras with involution of the first kind are also investigated.
Homogenization of the anisotropic heterogeneous linearized elasticity system in thin reticulated structures
Authors: Casado-Díaz J. , Luna-Laynez M.
Published: July 2007

The aim of this paper is to study the asymptotic behaviour of the solutions of the linearized elasticity system, posed on thin reticulated structures involving several small parameters. We show that this behaviour depends on the relative size of the parameters. In each case, we obtain a limit system where the microstructure and macrostructure appear simultaneously. From it, we get a suitable approximation in L2 of the displacements and the linearized strain tensor.
Optimality of embeddings of Bessel-potential-type spaces into Lorentz–Karamata spaces
Authors: Gogatishvili Amiran , Opic Bohumír , Neves Júlio S.
Published: July 2007

We establish sharpness of embedding theorems for Bessel-potential spaces modelled upon Lorentz–Karamata (LK) spaces and we prove the non-compactness of such embeddings. Target spaces in our embeddings are LK spaces. As a consequence of our results, we get growth envelopes of Bessel-potential spaces modelled upon LK spaces.
Asymptotic stability of heteroclinic cycles in systems with symmetry. II
Authors: Krupa Martin , Melbourne Ian
Published: July 2007

Systems possessing symmetries often admit robust heteroclinic cycles that persist under perturbations that respect the symmetry. In previous work, we began a systematic investigation into the asymptotic stability of such cycles. In particular, we found a sufficient condition for asymptotic stability, and we gave algebraic criteria for deciding when this condition is also necessary. These criteria are satisfied for cycles in R3.

Field and Swift, and Hofbauer, considered examples in R4 for which our sufficient condition for stability is not optimal. They obtained necessary and sufficient conditions for asymptotic stability using a transition-matrix technique.

In this paper, we combine our previous methods with the transition-matrix technique and obtain necessary and sufficient conditions for asymptotic stability for a larger class of heteroclinic cycles. In particular, we obtain a complete theory for ‘simple’ heteroclinic cycles in R4 (thereby proving and extending results for homoclinic cycles that were stated without proof by Chossat, Krupa, Melbourne and Scheel). A partial classification of simple heteroclinic cycles in R4 is also given. Finally, our stability results generalize naturally to higher dimensions and many of the higher-dimensional examples in the literature are covered by this theory.
Geometric two-scale convergence on forms and its applications to Maxwell's equations
Authors: Pak Hee Chul
Published: July 2007

We develop the geometric two-scale convergence on forms in order to describe the homogenization of partial differential equations with random variables on non-flat domain. We prove the compactness theorem and some two-scale behaviours for differential forms. For its applications, we investigate the limiting equations of the n-dimensional Maxwell equations with random coefficients,

with given initial and boundary conditions, where are symmetric positive-definite matrices for x ∈ M, and M is an n-dimensional compact oriented Riemannian manifold with smooth boundary. The limiting system of n-dimensional Maxwell equations turns out to be degenerate and it is proven to be well-posed. The homogenized coefficients affected by the geometry of the domain are presented, and compared with the homogenized coefficient of the second order elliptic equation. We present the convergence theorem in order to explain the convergence of the solutions of Maxwell system as a parabolic partial differential equation.
A sharp Hölder estimate for elliptic equations in two variables
Authors: Ricciardi Tonia
Published: July 2007

We prove a sharp Hölder estimate for solutions of linear, two-dimensional, divergence-form, elliptic equations with measurable coefficients, such that the matrix of the coefficients is symmetric and has unit determinant. Our result extends some previous work by Piccinini and Spagnolo. The proof relies on a sharp Wirtinger type inequality.
Global existence for the heat equation with nonlinear dynamical boundary conditions
Authors: Vitillaro Enzo
Published: July 2007

This paper deals with local and global existence for the solutions of the heat equation in bounded domains with nonlinear boundary damping and source terms. The typical problem studied is

where Ω ⊂ Rn (n ≥ 1) is a regular and bounded domain, ∂Ω = Γ0 ∪ Γ1, m > 1, 2 ≤ p < r, where r = 2(n − 1)/(n − 2) when n ≥ 3, r = ∞ when n = 1, 2 and u0 ∈ H1(Ω), u0 = 0 on Γ0. We prove local existence of the solutions in H1(Ω) when m > r/(r + 1−p) or n = 1, 2 and global existence when p ≤ m or the initial datum is inside the potential well associated to the stationary problem.
On the contracted l1-algebra of a 0-bisimple inverse semigroup
Authors: Crabb M. J. , Munn W. D.
Published: July 2007

Let S be a 0-bisimple inverse semigroup and let denote the contracted l1-algebra of S; that is, the Banach algebra l1 (S)/Z, where Z is the ideal spanned by the zero of S. It is shown that, if l1 (G) is primitive for some non-zero maximal subgroup G of S, then is primitive. The same result also holds with primitivity replaced by a stronger condition, here called *-primitivity