bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of 13C nuclear magnetic resonance distortionless enhancement by polarization transfer pulse sequence and multivariate analysis to discriminate olive oil cultivars
Authors: Vlahov Giovanna , Shaw Adrian D. , Kell Douglas B.
Published: May 2007

Distortionless enhancement by polarization transfer (DEPT) pulse sequence was used to set up a quantitative high‐resolution 13C nuclear magnetic resonance (NMR) method to discriminate olive oils by cultivars and geographical origin. DEPT pulse sequence enhances the intensity of NMR signals from nuclei of low magnetogyric ratio. The nuclear spin polarization is transferred from spins with large Boltzmann population differences (usually protons) to nuclear species characterized by low Boltzmann factors, e.g., 13C. The signal enhancement of 13C spectra ensures the accuracy of resonance integration, which is a major task when the resonance intensities of different spectra must be compared. The resonances of triglyceride acyl chains Cn:0, C18:1, C18:2, and C18:3, were also assigned. Multivariate analysis was carried out on the 35 carbon signals obtained. By using variable reduction techniques, coupled with standard statistical methods—partial least squares and principal components analysis—it was largely possible to separate the samples according to their variety and region of origin. With one problem variety removed, 100% prediction of the three remaining varieties was achieved. Similarly, by using the three regions with greatest representation in the data, all but one of a test set of 34 samples were correctly predicted. Thus, the composition of olive oils from different cultivars and of different geographical origin were compared and successfully studied by multivariate analysis. These considerations in conjunction with the structural elucidations of triglyceride molecules demonstrated that 13C NMR is among the most powerful techniques yet described for analysis of olive oils.
Temperature and cultivar effects on soybean seed oil and protein concentrations
Authors: Piper Ernest L. , Boote Kenneth I.
Published: May 2007

The soybean [Glycine max (L.) Merr.] industry is interested in cultivar and climate effects on seed composition. These factors may underlie the known geographic variation in seed protein and oil concentrations. Regression analyses were used to test hypotheses of the effect of temperature and cultivar on oil and protein concentrations of soybean seed using a large data set from the U.S.A. Soybean Uniform Tests. The data set included 20 cultivars representing 10 maturity groups across 60 locations (latitude 29.4 to 47.5° N) for a total of 1863 cultivar by location by year observations. Temperature was determined for each observation as the average daily mean temperature from predicted first pod (first pod at least 5 mm long), using the SOYGRO phenology model, to observed maturity. The mean temperature ranged from 14.6 to 28.7°C among the observations. Linear, quadratic, and linear plateau regression models of oil and protein concentrations vs. temperature were evaluated. The quadratic model gave the best‐adjusted R2 values for oil and protein with temperature, of 0.239 and 0.003, respectively. The analyses showed that the oil concentration increased with increasing temperature and approached a maximum at a mean temperature of 28°C. Unaccounted variation in the protein concentration may be from other factors such as photoperiod, water stress, or high temperatures during seed fill. Protein plus oil had a linear relationship with temperature (adjusted partial R2=0.183). These data document the contribution of climate and cultivar to geographic variability of oil and protein concentrations in the United States.
Deacidification of high‐acid rice bran oil by reesterification with monoglyceride
Authors: De B. K. , Bhattacharyya D. K.
Published: May 2007

Autocatalytic esterification of free fatty acids (FFA) in rice bran oil (RBO) containing high FFA (9.5 to 35.0% w/w) was examined at a high temperature (210°C) and under low pressure (10 mm Hg). The study was conducted to determine the effectiveness of monoglyceride in esterifying the FFA of RBO. The study showed that monoglycerides can reduce the FFA level of degummed, dewaxed, and bleached RBO to an acceptable level (0.5±0.10 to 3.5±0.19% w/w) depending on the FFA content of the crude oil. This allows RBO to be alkali refined, bleached, and deodorized or simply deodorized after monoglyceride treatment to obtain a good quality oil. The color of the refined oil is dependent upon the color of the crude oil used.
Evaluation of surfactant‐aided degumming of vegetable oils by membrane technology
Authors: Subramanian R. , Nakajima M. , Yasui A. , Nabetani H. , Kimura T. , Maekawa T.
Published: May 2007

The first step in the process of vegetable oil refining is degumming, in which phospholipids and mucilaginous gums are removed that otherwise result in a low‐grade oil. A membrane process is remarkably simple yet potentially offers many advantages in degumming. Studies were conducted on surfactant‐aided membrane degumming with soybean and rapeseed oils in a magnetically stirred flat membrane batch cell with different types of microfiltration membranes. The reduction of phospholipids in soybean oil was in the range of 85.8–92.8% during the membrane process. The phosphorus content of membrane permeates of soybean oil was in the range of 20–58 mg/kg. Crude rapeseed oil contained higher amount of nonhydratable phospholipids and hence resulted in lower reduction in phospholipids, in the range of 66.4–83.2%. Addition of hydratable phospholipids could improve the efficiency of degumming in the membrane process without using any electrolyte, resulting in improvement of quality as well as quantity of the phospholipids.
Storage stability of potato chips fried in genetically modified canola oils
Authors: Petukhov I. , Malcolmson L. J. , Przybylski R. , Armstrong L.
Published: May 2007

The storage stability of potato chips fried in regular (RCO), hydrogenated (HYCO), low‐linolenic (LLCO), and high‐oleic (HOCO) canola oils was compared. Potato chips were fried in each oil over a 5‐d period for a total of 40 h of frying. Chips from frying day 1 and 5 were packaged and stored at 60°C for 0, 1, 2, 4, 8, and 16 d. Lipids were extracted from the stored chips and analyzed for peroxide values, free fatty acids (FFA), conjugated dienoic acids (CDA), and polar components. A trained sensory panel evaluated the stored chips for odors characteristic of oxidation. Chips were also analyzed for volatile components. Potato chips fried in RCO, LLCO and HOCO developed an intense painty odor, whereas chips fried in HYCO developed an intense stale/musty odor by the end of the 16 d of storage. Chips fried in RCO had greater rates of accumulation of peroxides, FFA, CDA, and polar components and developed higher levels of total volatiles over the 16 d of storage than chips fried in the other three oils. Chips fried in HYCO had lower rates of accumulation of peroxides and CDA than chips fried in LLCO and HOCO, and lower rates of FFA accumulation than chips fried in LLCO. Chips fried in HYCO and HOCO had the lowest amounts of total volatiles during storage. The effect of oil degradation products on potato chip storage stability was not shown in this study since only the chips fried in HYCO from frying day 5 exhibited a significantly greater rate of off‐odor development than chips from frying day 1, and only the chips fried in LLCO from frying day 5 had a greater rate of accumulation of volatiles than chips from frying day 1.
Kinetic model for autoxidation of β‐carotene in organic solutions
Authors: Takahashi Atsushi , Shibasaki‐Kitakawa Naomi , Yonemoto Toshikuni
Published: May 2007

Autoxidation of β‐carotene was studied experimentally using n‐decane as a solvent under various reaction conditions of temperature and dissolved oxygen concentration A novel kinetic model was proposed on the basis of an autocatalytic free‐radical chain reaction mechanism. A secondary initiation reaction by decomposition of hydroperoxide and reactions concerned with a β‐carotene‐derived C‐centered radical in propagation and termination processes were taken into consideration in the model. There were four unknown kinetic constants, and the constants were estimated by fitting the model with the experimental data. The fitted results are in good agreement with the experimental data in all stages of the kinetics of autoxidation and over a wide range of oxygen concentrations. The model described not only the appearance of the induction stage but also the effect of the oxygen concentration on the autoxidation rate. In addition, the model predicted the behavior of autoxidation in another solvent at low temperature that had been reported by other researchers.
Antioxidant synergy of α‐tocopherol and phospholipids
Authors: Bandarra Narcisa M. , Campos Regina M. , Batista Irineu , Nunes M. Leonor , Empis José M.
Published: May 2007

The prevention of oxidation of a refined sardine oil by α‐tocopherol at 0.04%, by several phospholipids [phosphatidylcholine (PC), phosphatidylethanolamine (PE), and cardiolipin (CL)] at 0.5%, as well as by combinations of α‐tocopherol with each phospholipid, was investigated. The evolution of the oxidation process during 1 mon at 40±2°C was followed by a series of methods, measuring peroxide value (PV), diene, triene, and polyene index, and absorbance at 430 nm, while α‐tocopherol and phospholipid content were being monitoried. Among these indices, PV was found to be the most adequate to follow the process. PC was the most effective individual antioxidant as shown by the PV values obtained at the end of the storage period, which were 54.0, 83.4, 87.9, and 97.7 meq O2/kg for PC, CL, PE, and α‐tocopherol, respectively. The highest synergistic effect was obtained with a mixture of α‐tocopherol and PE, and the second and third best by mixtures made with PC and CL, respectively. The corresponding PV values recorded at the end of the period were 27.0, 35.0, and 58.0 meq O2/kg. The high degree of synergy between PE and tocopherol is probably due to the occurrence of a simultaneous antioxidant mechanism involving Maillard compounds.
Tocopherol distribution and oxidative stability of oils prepared from the hypocotyl of soybeans roasted in a microwave oven
Authors: Yoshida Hiromi , Takagi Sachiko , Mitsuhashi Sayaka
Published: May 2007

Whole soybeans (Glycin max L.) were roasted by exposure to microwaves at a frequency of 2,450 MHz, and their hypocotyls were separated from other tissues (seed coat and cotyledons). The quality characteristics and composition in the hypocotyl oils were studied in relation to their tocopherol distributions and were evaluated as compared to an unroasted oil sample. Only minor increases (P<0.05) in chemical and physical changes of the oils, such as carbonyl value, anisidine value and color development, occurred with increased roasting time. Significant decreases (P<0.05) were observed in the amounts of phospholipids in the oils after microwave roasting. Nevertheless, compared to the original level, more than 80% tocopherols still remained after 20 min of roasting. These results suggest that the exposure of soybeans to microwaves for 6 to 8 min caused no significant loss or changes in the content of tocopherols and polyunsaturated fatty acids in the hypocotyls. Therefore, a domestic microwave oven would be useful as a simple and quick means for preparing hypocotyl oil of good quality.
Quenching mechanism and kinetics of ascorbyl palmitate for the reduction of the gamma irradiation‐induced oxidation of oils
Authors: Lee K. H. , Yook H. S. , Lee J. W. , Park W. J. , Kim K. S. , Byun M. W.
Published: May 2007

The effects of 0, 250, 500, and 1000 ppm (wt/vol) ascorbyl palmitate (AP) on the gamma irradiation‐induced oxidation of soybean oil, cottonseed oil, corn oil, tallow, lard, or linoleic acid either in a solvent mixture (benzene/methanol, 4:1 vol/vol) or in methanol, was studied immediately after gamma irradiation with a dose of 1–5 kGy. Steady‐state kinetic approximation was used to determine a quenching mechanism and quenching rate constant of AP on the gamma irradiation‐induced oxidation of purified soybean oil in a solvent mixture (benzene/methanol, 4:1 vol/vol). Irradiation greatly increased oxidation of all oils, as was expected. AP was extremely effective at minimizing oxidation in all oils, and its effectiveness was concentration dependent. AP showed significantly greater antioxidative activity than α‐tocopherol for the reduction of oxidation in all oils (P<0.05). The steady‐state kinetic studies indicated that AP quenched oxygen only to minimize the oxidation of oils. The calculated total quenching rate of AP was 7.51×107 M−1s−1. The present results clearly show the effective oxygen quenching ability of AP for the reduction of gamma irradiation‐induced oxidation of oils.
A rapid method for enzymatic synthesis and purification of the structured triacylglycerol, 1,3‐dilauroyl‐2‐oleoyl‐glycerol
Authors: Miura Susumu , Ogawa Asuka , Konishi Hiroaki
Published: May 2007

A rapid method for synthesis and purification of the structured triacylglycerol (TAG), 1,3‐dilauroyl‐2‐oleoylglycerol (LaOLa), has been developed. A fraction containing 70% LaOLa was obtained by enzymatic transesterification between triolein and lauric acid using Lipozyme IM, which has 1,3‐regioselectivity on the glycerol moiety of TAG. The fraction was passed through a Bond Elut SI Column to remove mono‐and diacylglycerols produced during the transesterification. The TAG fraction thus obtained was applied to a reversed‐phase column, eluted with acetonitrile/tetrahydrofuran (8:2, vol/vol) to separate different TAG species. The LaOLa fraction obtained by this method was of greater than 99% purity. The concentrations of total fatty acids and fatty acids bound to the sn‐2 position of this LaOLa fraction were determined by gas‐liquid chromatography after hydrolysis by pancreatic lipase, to confirm the purity of stereospecific isomers in this fraction. The final purity of LaOLa was found to be greater than 95%, which was in good agreement with the result obtained by high‐performance liquid chromatography using a Lichrosorb Si60 argentated column.
Determination of nonvolatile components of heated soybean oils separated with high‐efficiency mixed‐bed polystyrene/divinylbenzene columns
Authors: Abidi S. L. , Kim I. H. , Rennick K. A.
Published: May 2007

Whole heated soybean oils and their polar fractions were analyzed for nonvolatile components by high‐performance size‐exclusion chromatography (HPSEC) with evaporative light scattering detection (ELSD). High molecular‐weight (MW) polymer compounds with MW ≥ trimer were efficiently separated with new 3‐µm mixed‐bed styrene/divinylbenzene copolymer columns. Peaks of high MW polymer components in the new column system appeared to be sharper and more symmetrical than those obtained with other columns. In the model systems studied, continuous addition of water to partially simulate frying conditions resulted in a significant increase (up to 30%) in the polar lipid content of the heated oils evaluated. Due to relatively high concentrations of monomeric triglycerides (84.6–93.5%) present in the whole unfractionated oils, small but erratic variations in the compositional distribution of components were observed in oils containing different amounts of added water. On the other hand, HPSEC‐ELSD analyses of the polar fractions (monomeric triglycerides, 25.4–62.6%) showed significant changes in the content and composition of nonvolatile components with the amount of water added. In general, prolonged heating with increasing amounts of water accelerated hydrolysis and polymerization of heated soybean oils. Discrepancies in total polymerization of heated soybean oils. Discrepancies in total polymeric materials obtained from HPSEC composition data for whole oils and polar fractions are discussed in terms of nonuniformity in sample matrices, detection limitations for minor components, and a nonlinear ELSD response rationale.
The evaluation of frying oils with the p‐Anisidine value
Authors: Tompkins Carol , Perkins Edward G.
Published: May 2007

This study was conducted to examine the relationship of p‐anisidine value with headspace volatiles, sensory evaluation, and polymers. Partially hydrogenated soybean frying oil was used to fry shoestring potatoes. The oil was evaluated by p‐anisidine value, headspace volatile analysis, sensory evaluation, and polymer analysis. p‐Anisidine value was found to be correlated with hexanal (r=0.81), heptanal (r=0.66), t‐2‐hexenal (r=0.81), t‐2‐heptenal (r=0.71), t‐2‐octenal (r=0.92), and t,t‐2,4‐decadienal (r=0.86) contents. p‐Anisidine value was correlated with overall odor intensity (r=0.82) and correlated with fried food odor (r=0.53) and burnt odor (r=0.43). p‐Anisidine value and polymers were also correlated (r=0.84).
Polymorphic transformations in sn‐1, 3‐distearoyl‐2‐ricinoleyl‐glycerol
Authors: Boubekri Karima , Yano Junko , Ueno Satoru , Sato Kiyotaka
Published: May 2007

Polymorphic transformations of sn‐1,3‐distearoyl‐2‐ricinoleyl‐glycerol (SRS) have been studied with differential scanning calorimetry, X‐ray powder diffraction (XRD), synchrotron radiation X‐ray diffraction, and Fourier transform infrared spectroscopy (FTIR) techniques by using a 99.8% pure sample. Four polymorphs, α, γ, β′2, and β′1, were isolated. The thermal behavior of the four forms showed that the fusion of α at 25.8°C was followed by the crystallization of γ which melts at 40.6°C, and β′2 and β′1 revealed melting peaks at 44.3 and 48.0°C, respectively. No β form was observed, even when the two β′ forms were annealed around their melting points over one week. The XRD long spacing indicates that α packs into a double chain‐length structure; however, γ and the two β′ phases pack into a triple chain‐length structure. The polarized and nonpolarized FTIR spectra in methylene scissoring and methylene rocking regions indicated a parallel subcell packing in γ, and a mixture of orthorhombic perpendicular and parallel or hexagonal subcells in the β′2 and β′1 phases. Consequently, SRS exhibits quite a unique polymorphic behavior, compared to tristearoyl glycerol and sn‐1,3‐distearoyl‐2‐oleoyl‐glycerol.
Fatty acid composition and its relationship with physicochemical properties of pecan (Carya illinoensis) oil
Authors: Toro‐Vazquez J. F. , Charó‐Alonso M. A. , Pérez‐BriceɁo F.
Published: May 2007

The composition and physicochemical properties of pecan (Carya illinoensis) kernels and oils from different native trees of the central region of Mexico were investigated. The main compositional characteristic of the kernel was the high lipid content (70–79% w/w on dry basis) with elevated concentration of oleic acid (55–75% w/w). The results confirmed the relationship in the biosynthesis of linoleic and linolenic acids from oleic acid existing in oilseeds. Our results indicate that in pecans such relationship is a function of pecan tree age. The proportion of oleic, linoleic, and linolenic fatty acids determined the oxidative stability, viscosity, and melting/crystallization behavior of pecan oil. In general, these properties in pecan oils were similar or superior to extra‐virgin olive oil and unrefined sesame oil. Although all native pecan oils studied showed a significant concentration of oleic acid, a particular group of native Mexican pecan trees produces an oil with a fatty acid composition with the nutritional appeal that consumers demand nowadays (i.e., very high oleic acid, 60–75%), with excellent natural oxidative stability (i.e., induction time for oxidation between 8.5 and 10.8 h), and substantially higher concentrations of α‐, γ‐, and δ‐tocopherol than in pecan varieties previously reported in the literature.
Long‐term behavior of oil‐based varnishes and paints I. Spectroscopic analysis of curing drying oils
Authors: Mallégol Jacky , Gardette Jean‐Luc , Lemaire Jacques
Published: May 2007

The curing of drying oils at 60°C has been investigated by Fourier transform infrared spectroscopy and Fourier transform Raman analysis of linseed oil and poppyseed oil. In the first step, hydroperoxides are formed (broad vibration band centered around 3425 cm−1) with concomitant conjugation and cis‐trans isomerization of the double bonds (disappearance of cis bands at 3011 and 716 cm−1, appearance of trans conjugated and trans nonconjugated bands at 987 and 970 cm−1). The subsequent decomposition of hydroperoxides in the presence of oxygen leads to the formation of alcohols (nitrite band at 779 cm−1 after nitrogen monoxide treatment), aldehydes (bands at 2810 and 2717 cm−1 in gas phase), ketones (saturated and unsaturated at 1720 and 1698 cm−1, respectively), carboxylic acids (saturated and unsaturated acid fluorides identified at 1843 and 1810 cm−1 after SF4 treatment), and peresters or γ‐lactones (near 1770 cm−1). A rapid decrease in the double‐bond concentration is recorded when curing continues, and the formation of epoxides, characterized by a vibration band at 885 cm−1, is observed. Thermolysis experiments have suggested the proposal of a reaction of addition of peroxyl radicals on the conjugated double bonds as a probable mechanism. This mechanism explains both the rapid disappearance of conjugated double bonds and the formation of epoxides as intermediate products observed in the initial step of curing.
Effects of physical properties and operating parameters on soybean flaking
Authors: Singh P. P. , Maier D. E. , Okos M. R. , Cattanach E. , Trumble K. P.
Published: May 2007

The soybean crushing industry aims at attaining greater oil extraction by optimizing flake thickness. This involves modifying the physical and viscoelastic properties of cracked soybeans and adjusting operational settings of the flaking roll stands. Vibratory feeders distributed 20–32% fewer cracked soybeans at the roll ends and 12% fewer cracks at the center. This increased the variability in roll wear and flake thickness along the length of the rolls. The flow rate distribution produced by rotary feeders was more uniform. Vibratory feeders produced a uniform particle size distribution of cracks (diameter range 2.71–2.76 mm) along the length of the rolls. At constant roll pressure, the increased flow rate of cracks increased the flake thickness and power consumption. While roll stands were operating at their rated flow capacity, the desired flake thickness range (0.25–0.38 mm) could not be obtained by merely increasing the roll pressure, because it caused hot spots in the rolls. Modifications of the metallurgical properties of the rolls and the viscoelastic properties of the soybeans are possible means of reducing flake thickness. During six plant visits, 73.2% of the sampled flakes were thicker than the maximum desired value (0.38 mm). This may be costing the U.S. soybean milling industry an annual loss in oil revenues of S7–16 million.
Stripping medium requirement in continuous countercurrent deodorization
Authors: Dijkstra Albert J.
Published: May 2007

A mathematical formula was derived that allows the stripping steam requirement of the countercurrent deodorization process to be calculated as a function of system pressure, vapor pressure of the pure volatile compound, initial and final volatiles contents, and the number of transfer units (an equipment parameter) of the countercurrent deodorizer. Just as in batch or cross‐flow deodorization systems, the steam requirement in countercurrent systems is proportional to the system pressure and inversely proportional to the vapor pressure of the pure volatile compound. Increasing the number of transfer units (for instance, by increasing column height) to more than two makes the countercurrent system require less steam than cross‐flow systems with a vaporization efficiency of 0.6. In addition, the short residence time in a countercurrent deodorization column minimizes side reactions and allows the deodorization temperature to be raised without generating unwanted by‐products such as trans‐isomers and/or oligomers of unsaturated fatty acids. The increased deodorization temperature increases the vapor pressure of the pure volatiles and leads to further savings in stripping medium and motive steam. Countercurrent deodorization systems therefore require less energy than cross‐flow deodorization systems and/or produce oil with fewer unwanted by‐products.
Fatty methyl ester hydrogenation to fatty alcohol: Reaction inhibition by glycerine and monoglyceride
Authors: Thakur Deepak S. , Roberts Brian D. , White Geoffrey T. , Rieke Ross D.
Published: May 2007

The present work demonstrates the rate‐limiting effect of varying levels of both glycerine and monoglyceride through a series of batch hydrogenations of fatty dodecyl methyl ester, using copper chromite as the catalyst. Reactions were carried out at 3000 psig H2, 280°C with catalyst levels varying between 1.25 and 1.80%. With increasing contaminant levels of glycerine (0.0, 0.1, 0.5, 5 wt%), conversion of fatty methyl ester to alcohol is correspondingly reduced (95, 89, 80, 2 wt%). On a molar basis of contaminant, monoglyceride equally reduces the conversion of methyl ester to alcohol. In both cases the latent appearance of fatty‐fatty ester results from the slower hydrogenation rate. Chemistry is proposed outlining the thermal decomposition of glycerine or glyceride to intermediate components (acetol and acrolein), leading to the generation of propanediols. Experimental studies indicate that diols effectively deactivate the copper chromite catalyst, limiting the rate of fatty methyl ester hydrogenation. Catalyst deactivation is not permanent, suggesting catalyst site blockage by physical adsorption of the polyhydroxyl components. The complete understanding of this interaction holds promise for the development of glycerine/monoglyceride‐insensitive catalysts. In addition, a brief overview of methyl ester hydrogenation inhibition effects of some heteroelements, water, and soap is presented.
Expression and localization of CHODLΔE/CHODLfΔE, the soluble isoform of chondrolectin
Authors: Claessens An , Van de Vijver Koen , Van Bockstaele Dirk R. , Wauters Jan , Berneman Zwi N. , Van Marck Eric , Merregaert Joseph
Published: May 2007

The C‐type lectin family is a group of animal proteins which can be distinguished from other lectins by the presence of a Ca2+‐dependent carbohydrate recognition domain (CRD) in their protein sequence. They are classified into 17 groups according to their domain architecture and have a wide variety of functions. The human chondrolectin gene encodes transmembrane (CHODL, CHODLf) and soluble proteins (CHODLΔE, CHODLfΔE) belonging to the family of C‐type lectins because of the presence of one CRD domain in their N‐terminal region. The CHODL splice variants (CHODLf, CHODLΔE and CHODLfΔE) are differentially expressed in T lymphocytes. The transmembrane‐containing isoform CHODLf is localized in the ER—Golgi apparatus. CHODLΔE and CHODLfΔE are devoid of the transmembrane domain and terminate in QDEL, an ER retention signal. In this paper we have investigated the expression of the CHODLΔE/CHODLfΔE protein. This variant localizes in the late endoplasmic reticulum. We detected the protein in spleen and tonsils in a small population of lymphocytes. Moreover, the isoform seems to be differentially expressed in thymocytes and lymphocytes suggesting an important biological function during T cell development.
Dynamical Influences of the Last Magellanic Interaction on the Magellanic Clouds
Authors: Bekki Kenji , Chiba Masashi
Published: May 2007

We investigate the present distributions of gas and young stars in the Large and Small Magellanic Clouds (LMC and SMC) based on fully self-consistent numerical simulations of the Clouds for the last ∼0.8 Gyr. Our principal results, which can be tested against observations, are as follows. The last dynamical and hydrodynamical interaction between the Clouds about ∼0.2 Gyr ago can form the apparently off-center bar and peculiar Hı spirals of the LMC. The present spatial distributions of young stars with ages less than ∼20 Myr in the LMC can be significantly asymmetric and clumpy owing to the interaction. A small but non-negligible fraction of stellar and gaseous components can be transferred from the SMC into the LMC during the interaction to form diffuse halo components around the LMC. The burst of star formation in the SMC can be synchronized with that of the LMC about 0.2 Gyr ago in some models. New stars can form from gas in the SMC's tidal tails, one of which can be observed as the Magellanic Bridge (MB). The metallicity distribution function of new stars in the MB has a peak of [Fe/H] ∼ −0.8, which is significantly smaller than the stellar metallicity of the SMC. Based on these results, we discuss the origin of 30 Doradus, the southern molecular ridge of the LMC, the globular cluster ESO 121-SC03, metal-poor inter-Cloud stars within the MB, and giant Hı holes of the LMC.
Long-Term Changes in the Periods of SX Phe
Authors: Landes H. , Bambery K. R. , Coates D. W. , Thompson K.
Published: May 2007

We have used times of maximum light for SX Phe, obtained by ourselves and other workers over 55 years to study the behaviour of the fundamental and first overtone radial pulsation modes of the star. We find (1/P0)dP0/dt to be (+2.53 ± 0.05) × 10−8 yr−1 and (1/P1)dP1/dt to be (−1.60 ± 0.03) × 10−7 yr−1, which differ significantly from the value +1.9 × 10−9 yr−1 expected if the changes are due to standard evolution of the star. The residuals in O–C from a quadratic fit cannot be explained by a light–time effect in a binary. There is some evidence that the amplitudes of the two modes change slowly with time.
Resolving the Structure at the Heart of BAL Quasars Through Microlensing Induced Polarisation Variability
Authors: Hales Christopher A. , Lewis Geraint F.
Published: May 2007

While amongst the most luminous objects in the universe, many details regarding the inner structure of quasars remain unknown. One such area is the mechanism promoting increased polarisation in the broad absorption line troughs of certain quasars. This study shows how microlensing can be used to differentiate between two popular models that explain such polarisation through a realistic computational analysis. By examining a statistical ensemble of correlation data between two observables (namely image brightness and polarisation of the flux coming from the quasar), it was found that through spectropolarimetric monitoring it would be possible to discern between a model with an external scattering region and a model without one.
Synthesis of a Reversible Streptavidin Binder for Biomimetic Assemblies
Authors: Moore Nathan W. , Delacruz Anthony R. C. , Lancaster Katherine S. , Dieckmann Thorsten , Kuhl Tonya L.
Published: May 2007

The biotin/streptavidin ligand/receptor pair is used extensively in biotechnology. However, less is known about HABA (2-(4-hydroxyphenylazo)benzoic acid), which binds to streptavidin with a bond energy and dissociation constant that more closely mimics antibody/antigen interactions. In this work we demonstrate some of HABA’s useful properties that may make it a good substitute for biotin in a broad range of biochemical research. Specifically, we investigate its ease of conjugation to an anchoring pegylated lipid, characterization with MALDI, NMR, and visible-wavelength spectroscopies, and incorporation into lipid vesicles.
Molecular Engineering of G Protein-Coupled Receptors and G Proteins for Cell-Free Biosensing
Authors: Glatz Richard V. , Leifert Wayne R. , Cooper Tamara H. , Bailey Kelly , Barton Chris S. , Martin A. Scott , Aloia Amanda L. , Bucco Olgatina , Waniganayake Lakshmi , Wei Gang , Raguse Burkhard , Wieczorek Lech , McMurchie Edward J.
Published: May 2007

The ability to express and purify modified recombinant proteins, so they retain their biological function in a cell-free format, has provided a basis for development of molecular biosensors. Here we utilize recombinant G Protein-coupled receptors (GPCRs) and their G proteins for cell-free detection of various binding partners. Fusion peptides were used to improve surface-attachment and fluorescent-labelling capabilities. A novel homogeneous fluorescence resonance energy transfer (FRET)-based assay was developed to detect rearrangements in the G protein heterotrimer. By using this heterotrimeric ‘molecular switch’, we are developing a generic technology such that multiple GPCRs could be assayed for ligand-mediated activation while tethered to surfaces or in solution, with increased throughput compared to current assay platforms.
New Method for the Synthesis of a Mononucleating Cyclic Peptide Ligand, Crystal Structures of its Ni, Zn, Cu, and Co Complexes, and Their Inhibitory Bioactivity Against Urease
Authors: Cheng Kui , You Zhong-Lu , Zhu Hai-Liang
Published: May 2007

A novel cyclic peptide complex, NiL 1 (H2L = 12,24-dihydroxy-1,6-dioxo-2,5,14,17-tetraaza[6*6]metacyclophane-13,17-diene has been synthesized for the first time under solvothermal conditions through a one-pot synthetic procedure using nickel ion as the template reagent. It was found that other metal ions were not suitable for the direct template reagent in this reaction. The nickel ion was eliminated from the complex and the metal-free cyclic peptide ligand H2L was obtained through a series of reactions. Then, ZnII, CuII, and CoII were coordinated with H2L under the same solvothermal conditions to produce three isomorphous complexes ZnL 2, CuL 3, and CoL 4. Their inhibitory bioactivities against urease were then studied. The copper(ii) complex 3 was the strongest inhibitor against jack bean urease, while H2L, 2, and 4 showed weak or no inhibitory activity against this enzyme.
The Stereo Structures of Some Mycophenolic Acid Derivatives
Authors: Bernhardt Paul V. , Carman Raymond M. , Le Tri T.
Published: May 2007

X-Ray crystallography affords the stereochemistry of three iodo compounds derived from mycophenolic acid. These included the crystallographic structure of a tertiary iodide.
Optically Encoded Particles and Their Applications in Multiplexed Biomedical Assays
Authors: Battersby Bronwyn J. , Trau Matt
Published: May 2007

In the future, the rapid discovery of new cures, vaccines, and diagnostics for common diseases will depend on the ability of biomedical researchers to investigate complex mixtures of proteins or DNA. The need to measure the abundance of these entities, together with their level of interaction, has driven the development of new research tools that enable simultaneous analysis of multiple analytes (multiplexing). Optically encoded particles are emerging as the multiplexing tools of choice, especially for clinical research. In this Review, an overview of various new optical encoding methods will be presented, together with important biomedical applications in which particle-based assays are currently being used.
A learner support model based on peer tutor selection
Authors: Van Rosmalen P. , Sloep P. , Kester L. , Brouns F. , De Croock M. , Pannekeet K. , Koper R.
Published: May 2007

Abstract  The introduction of elearning often leads to an increase in the time staff spends on tutoring. To alleviate the workload of staff tutors, we developed a model for organizing and supporting learner‐related interactions in elearning systems. It makes use of the knowledge and experience of peers and builds on the assumption that (lifelong) learners, when instructed and assisted carefully, should be able to assist each other. The model operates at two levels. At level 1, prospective peer tutors are identified, based on a combination of workload and competency indicators. At level 2, the thus identified prospective peer tutors become the actual tutors; this is performed by empowering them with tools and guidelines for the task at hand. The article will situate the model in networks for lifelong learning. For one kind of interactions, answering content‐related questions, we will review a set of existing approaches and emerging technologies and describe our model. Finally, we will describe and discuss the results of a simulation of a prototype of the model and discuss to what extent it matches our requirements.
Localization of a novel autosomal recessive hypotrichosis locus (LAH3) to chromosome 13q14.11–q21.32
Authors: Wali A , Chishti MS , Ayub M , Yasinzai M , Kafaitullah  , Ali G , John P , Ahmad W
Published: May 2007

Autosomal recessive hypotrichosis is a rare form of alopecia characterized by sparse hair on scalp, sparse to absent eyebrows and eyelashes, and sparse auxiliary and body hair. Previously, for this form of hypotrichosis, two loci LAH (localized hereditary hypotrichosis) and AH (autosomal recessive hereditary hypotrichosis) have been mapped on chromosome 18q12.1 and 3q27.2, respectively. In the study presented here, we report the localization of a third locus for autosomal recessive form of hypotrichosis in two large Pakistani families. The patients in the two families exhibited typical features of the hereditary hypotrichosis. Genome scan using polymorphic microsatellite markers mapped the gene on chromosome 13q14.11–q21.32. A maximum combined two‐point logarithm of odds (LOD) score of 4.79 at θ= 0.0 was obtained for several markers. Multipoint linkage analysis resulted in a maximum LOD score of 5.9, which further supports the linkage. Haplotype analysis defined the linkage interval of 17.35 cM flanked by markers D13S325 and D13S1231 according to the Rutgers combined linkage‐physical map. This region contains 24.41 Mb according to the build 36 of the human genome sequence‐based physical map.
A benthic mucilage event in North‐Western Mediterranean Sea and its possible relationships with the summer 2003 European heatwave: short term effects on littoral rocky assemblages
Authors: Schiaparelli Stefano , Castellano Michela , Povero Paolo , Sartoni Gianfranco , Cattaneo‐Vietti Riccardo
Published: May 2007

In this contribution we document an anomalous mucilage growth which occurred in June 2003 along the rocky cliffs of the Portofino Promontory (Ligurian Sea, NW Mediterranean Sea), and we describe its dynamics and its negative effects on many benthic taxa. The zooxanthellate scleractinian Cladocora caespitosa underwent ‘bleaching’ and about 40% of biomass of the erect algae was detached by mucilage ‘lianas’ created and strengthened by bottom currents. The 2003 event differed from any other previously occurred in the northern Tyrrhenian Sea, in that the mucilage aggregates were formed by the free‐living form of the Phaeophyceae Acinetospora crinita (Harvey) Kornmann, a not usually dominant species in mucilage aggregates from the north Tyrrhenian Sea. The damage suffered by the benthic organisms living in this area was curtailed by a severe storm, occurred in July, which removed the mucilage to deeper depths, preventing irreversible damages. Only slow growing, perennant organisms, such as corallinales or scleractinians, were seriously affected, but a survey carried out 1 year later, in June 2004, allowed to appreciate a complete recovery of those organisms. This anomalous mucilage event occurred in coincidence of the 2003 European heatwave, and the anomalous temperature increase of seawater has to be regarded as the major contributing event that led to the mucilage outbreak.
Fluorescence in situ hybridization analysis of hindgut bacteria associated with the development of equine laminitis
Authors: Milinovich Gabriel J. , Trott Darren J. , Burrell Paul C. , Croser Emma L. , Al Jassim Rafat A. M. , Morton John M. , Van Eps Andrew W. , Pollitt Christopher C.
Published: May 2007

Carbohydrate‐induced laminitis in horses is characterized by marked changes in the composition of the hindgut microbiota, from a predominantly Gram‐negative population to one dominated by Gram‐positive bacteria. The objective of this study was to monitor changes in the relative abundance of selected hindgut bacteria that have previously been implicated in the pathophysiology of equine laminitis using fluorescence in situ hybridization (FISH). Caecal cannulae were surgically implanted in five Standardbred horses and laminitis induced by oral administration of a bolus dose of oligofructose. Caecal fluid and faecal specimens were collected over a 48 h period at 2 to 4 h intervals post‐oligofructose administration and subjected to FISH using probes specific for nine bacterial groups to determine changes in their relative abundance compared with total bacteria hybridizing to the generic EUBMIX probe. Additionally, hoof biopsies were taken over the course of the experiment at 6 h intervals and evaluated for histopathological changes consistent with laminitis, allowing changes in hindgut microbiota to be correlated with the onset of lesions in the foot. Of the microorganisms specifically targeted, streptococci of the Streptococcus bovis/equinus complex were the only bacteria that consistently proliferated in both caecal fluid and faeces immediately before the onset of histological signs of laminitis. Furthermore, lactobacilli, Enterobacteriaceae, Allisonella histaminiformans, enterococci, Bacteroides fragilis, Mitsuokella jalaludinii and Clostridium difficile did not establish significant populations in the hindgut before the onset of equine laminitis.
A robust identification and detection assay to discriminate the cucumber pathogens Fusarium oxysporum f. sp. cucumerinum and f. sp. radicis‐cucumerinum
Authors: Lievens Bart , Claes Loes , Vakalounakis Demetrios J. , Vanachter Alfons C. R. C. , Thomma Bart P. H. J.
Published: May 2007

The fungal species Fusarium oxysporum is a ubiquitous inhabitant of soils worldwide that includes pathogenic as well as non‐pathogenic or even beneficial strains. Pathogenic strains are characterized by a high degree of host specificity and strains that infect the same host range are organized in so‐called formae speciales. Strains for which no host plant has been identified are believed to be non‐pathogenic strains. Therefore, identification below the species level is highly desired. However, the genetic basis of host specificity and virulence in F. oxysporum is so far unknown. In this study, a robust random‐amplified polymorphic DNA (RAPD) marker‐based assay was developed to specifically detect and identify the economically important cucumber pathogens F. oxysporum f. sp. cucumerinum and F. oxysporum f. sp. radicis‐cucumerinum. While the F. oxysporum radicis‐cucumerinum strains were found to cluster in a separate clade based on elongation factor‐1α phylogeny, strains belonging to F. oxysporum f. sp. cucumerinum were found to be genetically more diverse. This is reflected in the observation that specificity testing of the identified markers using a broad collection of F. oxysporum strains with all known vegetative compatibility groups of the target formae speciales, as well as representative strains belonging to other formae speciales, resulted in two cross‐reactions for the F. oxysporum f. sp. cucumerimum marker. However, no cross‐reactions were observed for the F. oxysporum f. sp. radicis‐cucumerimum marker. This F. oxysporum f. sp. radicis‐cucumerimum marker shows homology to Folyt1, a transposable element identified in the tomato pathogen F. oxysporum f. sp. lycopersici and may possibly play a role in host‐range specificity in the target forma specialis. The markers were implemented in a DNA array that enabled parallel and sensitive detection and identification of the pathogens in complex samples from diverse origins.
Migration Rates and Genetic Structure of two Hungarian Ethnic Groups in Transylvania, Romania
Authors: Brandstätter A. , Egyed B. , Zimmermann B. , Duftner N. , Padar Z. , Parson W.
Published: May 2007

Transylvania's ethnic mosaic is composed of Romanians, German Saxons and Hungarians. The ethnic groups of the Hungarian minority that settled in Romania show differences in dialects, customs and religious affiliations. In this study entire mtDNA control region sequences from 360 individuals of Hungarian ethnicity from two populations (the Csángó and the Székely), settled in the historical region of Transylvania in Romania, were generated and analyzed following high quality sequencing standards. Phylogenetic analyses were used for haplogroup determination, quasi‐median network analyses were applied for the visualization of character conflicts, and median joining reconstructions were used for depicting haplotype structures. Affiliation of haplotypes to major west Eurasian haplogroups was confirmed using coding region SNPs. Gene flow between the two populations was low and biased towards a higher migration rate from the Csángó to the Székely than vice versa. Phylogeographic analyses revealed effects of genetic isolation within the Csángó population, which is, in its genetic structure, clearly different from the Székely population. The pronounced genetic divergence between the two populations is in sharp contrast to the expectation of high genetic similarity due to the close geographic proximity of their native homelands. The population data will be incorporated in the EMPOP database (http://www.empop.org).
An immunohistochemical study of the triangular fibrocartilage complex of the wrist: regional variations in cartilage phenotype
Authors: Milz S. , Sicking B. , Sprecher C. M. , Putz R. , Benjamin M.
Published: May 2007

The triangular fibrocartilage complex (TFCC) transmits load from the wrist to the ulna and stabilizes the distal radioulnar joint. Damage to it is a major cause of wrist pain. Although its basic structure is well established, little is known of its molecular composition. We have analysed the immunohistochemical labelling pattern of the extracellular matrix of the articular disc and the meniscal homologue of the TFCC in nine elderly individuals (age range 69–96 years), using a panel of monoclonal antibodies directed against collagens, glycosaminoglycans, proteoglycans and cartilage oligomeric matrix protein (COMP). Although many of the molecules (types I, III and VI collagen, chondroitin 4 sulphate, dermatan sulphate and keratan sulphate, the oversulphated epitope of chondroitin 6 sulphate, versican and COMP) were found in all parts of the TFCC, aggrecan, link protein and type II collagen were restricted to the articular disc and to entheses. They were thus not a feature of the meniscal homologue. The shift in tissue phenotype within the TFCC, from a fibrocartilaginous articular disc to a more fibrous meniscal homologue, correlates with biomechanical data suggesting that the radial region is stiff and subject to considerable stress concentration. The presence of aggrecan, link protein and type II collagen in the articular disc could explain why the TFCC is destroyed in rheumatoid arthritis, given that it has been suggested that autoimmunity to these antigens results in the destruction of articular cartilage. The differential distribution of aggrecan within the TFCC is likely to be reflected by regional differences in water content and mobility on the radial and ulnar side. This needs to be taken into account in the design of improved MRI protocols for visualizing this ulnocarpal complex of the wrist.