bluuebunny/crossref_metadata_2025 huggingface dataset:
12th International Conference on High Pressure Semiconductor Physics (HPSP‐12): Concluding remarks
Authors: Cardona M.
Published: December 2006

These concluding remarks discuss the attractiveness of Barcelona as a venue for conferences like the HPSP and the highlights of the work presented at the HPSP‐12. The discussion is complemented by information concerning the previous eleven HPSP and a historical review of the field. These concluding remarks end with a few bibliometric data which include the development of the field in Spain, and in particular in Barcelona, since 1975. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High pressure studies of mid‐infrared type‐II “W” diode lasers at cryogenic temperatures
Authors: O'Brien K. , Adams A. R. , Sweeney S. J. , Jin S. R. , Ahmad C. N. , Murdin B. N. , Canedy C. L. , Vurgaftman I. , Meyer J. R.
Published: December 2006

Using high hydrostatic pressure and spontaneous emission characterisation techniques we have investigated the important loss processes in type‐II “W” diode lasers, which emit at 3.24 μm at 78 K. Our studies indicate that Auger recombination involving the excitation of holes in the valence band and/or inter‐valence‐band absorption may contribute to the temperature sensitivity of these devices, even at cryogenic temperatures. Defect/impurity related recombination, which was of concern in these structures does not appear to make a significant contribution to the threshold current over the temperature and pressure ranges investigated. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Multiple linear regression with some correlated errors: Classical and robust methods
Authors: Pires Ana M. , Rodrigues Isabel M.
Published: December 2006

In this paper we consider classical and robust methods of estimation and diagnostics for the multiple linear regression model when some of the errors are correlated. This work was motivated by the analysis of a medical data set, from an observational study aimed at identifying factors affecting the outcome of a surgical method for the correction of scoliosis (abnormal lateral spinal curvature). There are 392 observations but some of them are on the same patient (double curves). It seems adequate to consider a multiple linear regression model but, since it is not desirable to discard the double curves, the assumption of non‐correlated errors is clearly violated, and this is indeed confirmed by related diagnostics on the residuals (Durbin–Watson test). A more appropriate model retains the linear structure but allows for non‐null correlation between the errors on the same patient. We propose two different procedures for the estimation of the parameters of the linear model and the correlation parameters: maximum likelihood assuming normal errors and a robustified version obtained by plugging‐in results from robust linear regression. The latter procedure is designed to be resistant to outlying observations or error distributions with heavy tails and has produced the most satisfactory results for the analysed data set. Copyright © 2006 John Wiley & Sons, Ltd.
The catalytic activity of lipases toward hydroxy fatty acids—A review
Authors: Hayes Douglas G.
Published: December 2006

Hydroxy fatty acids, derived from several natural and synthetic sources, have many applications. Lipases have been employed to catalyze reactions involving hydroxy acids to narrowly shape the product distribution via their regio‐ and stereoselectivities. This manuscript reviews the action of lipase on hydroxy acids and their derivatives. The formation of estolides or lactones by lipase‐catalyzed reactions depends strongly on the position of the hydroxyl moiety on the hydroxy acyl group and slightly on the hydroxy acid chainlength and concentration.Pseudomonas sp. and porcine pancreatic lipases are the most useful for catalyzing formation of optically pure lactones, while lipases lacking positional selectivity catalyzed estolide formation best. The product distribution of lipase‐catalyzed esterification between hydroxy‐ and nonhydroxy‐acyl groups is strongly dependent on the lipase type. Lipase‐catalyzed reactions between hydroxy acids and alcohols yield hydroxy esters, not estolides, as the major product.
Structure determination of long‐chain polyunsaturated triacylgyycerols by high‐resolution13C nuclear magnetic resonance
Authors: Bergana Marti M. , Lee Theresa W.
Published: December 2006

The application of13C nuclear magnetic resonance to determine the positional distribution of fatty acids on the glycerol backbone has been investigated. A systematic approach and synthetic triacylglycerols were used to measure the effect on the carbonyl chemical shifts of triacylglycerols by the positional distribution on the glycerol backbone and the number and position of the double bonds within the fatty acids. The correlation of13C carbonyl chemical shift to the molecular structure of triacylglycerol was delineated. The assignments for the chemical shifts of the carbonyl nuclei of monoacyltriacylglycerol standards were compiled. The resonance from the carbonyl carbons at the 1,3 positions is resolved from that at the 2 position. The13C carbonyl chemical shift was more dependent on the position of the double bonds than the degree of unsaturation of the fatty acids. In particular, little effect was observed in the chemical shifts for fatty acids containing more than two double bonds. However, the chemical shifts were influenced significantly by the position of the first double bond. The difference in the chemical shift of the unsaturated species from that of the saturated species was plotted against the position of the first double bond. A natural logarithmic relationship was found between carbon numbers 5 and 11. Inflection points were found outside of this region at carbon numbers 4 and 13. In addition, the resonances from the saturated species, independent of their chainlength, were degenerate in oil systems, even though small differences were observed in the standards. The applicability of this method was demonstrated in the determination of the composition and positional distribution of the fatty acids in borage and evening primrose oils.
Identification of α‐parinaric acid in the seed oil ofSebastiana brasiliensis sprengel (Euphorbiaceae)
Authors: Spitzer Volker , Tomberg Werner , Zucolotto Mônica
Published: December 2006

Besides some usual fatty acids, the seed oil ofSabastiana brasiliensis (Euphorbiaceae) contains up to 39% (estimated by ultraviolet spectroscopy) of α‐parinaric acid (cis, trans, trans, cis‐9, 11, 13, 15‐octadecatetraenoic acid). The fatty acids were analyzed by gas chromatography and gas chromatography/mass spectrometry as their methyl esters. The structure of α‐parinaric acid was proven by a combination of chemical and spectroscopic methods, conducted with the crude oil, the methyl ester mixture, and the isolated fatty acid methyl ester. Complete assignment of the1H and13C nuclear magnetic resonance (NMR) shifts of α‐parinaric acid was carried out by two‐dimensional NMR experiments
Effect of genetic modification on the content and composition of bioactive constituents in soybean oil
Authors: Mounts T. L. , Abidi S. L. , Rennick K. A.
Published: December 2006

The content and composition of tocopherols, sterols, and phospholipids in soybean oils derived from genetically‐modified soybeans were determined by normal and reverse‐phase high‐performance liquid chromatography and gas‐liquid chromatography. Tocopherol content was lowered in oils from soybeans selected to yield high palmitate and stearate contents. However, β‐tocopherol, which amounts to less than 1 ppm in control oils, was increased to 25–53 ppm in these oils. Sterol content was higher in one reduced‐linolenate oil, which also had the highest oleate content. The greatest variability was observed in the content of β‐sitosterol, which ranged from 46.9–151.6 mg/100/g in the modified oils. Although, in general, there was little impact on the phospholipids, the content of phosphatidic acid was elevated in crude oils from three of the lines. Increases in phosphatidic acid are generally associated with storage deterioration of soybeans. Individual major classes of phospholipid were isolated, and the molecular species composition of each was determined. Compositional variations in molecular species indicated that there was an impact of the genetic modification of soybeans at the molecular level of the phospholipids that are primary plant cell components.
Immobilized lipase‐catalyzed production of structured lipids with eicosapentaenoic acid at specific positions
Authors: Lee Ki‐Teak , Akoh Casimir C.
Published: December 2006

Structured lipids (SL) were synthesized by the interesterification reaction between medium‐chain triacylglycerols and eicosapentaenoic acid (EPA) ethyl ester. The products were partially purified, and the fatty acid at thesn‐2 position was determined after pancreatic lipase‐catalyzed hydrolysis. The effect of additives (water and glycerol) on the rate of reaction was also investigated. Mol% EPA incorporated into the triacylglycerols was increased by adding water when trilaurin and tricaprylin were the substrates and IM 60 was the biocatalyst. With SP 435, EPA incorporation was always less with additional water than without water. The addition of glycerol (0.005 g or 0.01 g) improved interesterification catalyzed by IM 60 to some degree, but an excess amount (0.02 g) inhibited the reaction. The reaction with glycerol showed no significant difference with SP 435. After scale‐up and fractionation by column chromatography, we could recover approximately 0.3–0.4 g of product/g of reaction products. After hydrolysis by pancreatic lipase, we can conclude that IM 60 has a high specificity forsn‐1,3 positions. With SP 435 lipase, 34.8–39.3 mol% of EPA was found at thesn‐2 position of the recovered SL.
Kinetic evaluation of 3β‐hydroxycholest‐5‐en‐7‐one (7‐ketocholesterol) stability during saponification
Authors: Park Peter W. , Guardiola Francesc , Park Susan H. , Addis Paul B.
Published: December 2006

To clarify conflicting information regarding 7‐ketocholesterol (7‐KC) recovery from saponification, we evaluated the stability of 7‐KC in methanolic alkaline medium. We added 1 N alcoholic KOH to 7‐KC or lard spiked with 7‐KC and held the mixtures at 45, 55, 65, and 75°C for different times to simulate various saponification conditions. Gas‐chromatographic determination of residual 7‐KC with 5α‐cholestane as the internal standard (IS) showed that the higher the saponification temperature, the greater the 7‐KC degradation. Hot saponification at 75°C for 30 min caused extensive destruction and left only 31% 7‐KC. 7‐KC loss during saponification could be described by pseudo first‐order kinetics, and the dependence of degradation rate on temperature (T, K) byk (h−1)=(2.6×1017) exp (−1.36×104/T). As predicted by the kinetic equation, 7‐KC loss during room‐temperature saponification (21°C) was practically negligible; following the exposure of 7‐KC or lard spiked with 7‐KC to 1 N alcoholic KOH for 18 h, about 97% 7‐KC was recovered. 6‐Ketocholestanol, when used as an IS, should be looked at carefully because of potential tautomerization, leading to the formation of two enol isomers when in extended contact with trimethylsilyl derivatization reagents.
Reducing the crystallization temperature of biodiesel by winterizing methyl soyate
Authors: Lee Inmok , Johnson Lawrence A. , Hammond Earl G.
Published: December 2006

Methyl soyate, made from typical soybean varieties, has a crystallization onset temperature (Tco) of 3.7°C and, as a biodiesel fuel, is prone to crystallization of its high‐melting saturated methyl esters at cold operating temperatures. Removal of saturated esters by winterization was assessed as a means of reducing theTco of methyl soyate. Winterizing neat methyl esters of typical soybean oil produced aTco of −7.1°C, but this was not an efficient way of removing saturated methyl esters because of the low yield (26%) of the separated liquid fraction. However, aTco of −6.5°C with 86% yield was obtained by winterizing the neat methyl esters of a low‐palmitate soybean oil; aTco of −5.8°C with 77% yield was obtained by winterizing methyl esters of normal soybean oil diluted with hexane.
Preparation of sorbitol fatty acid polyesters, potential fat substitutes: Optimization of reaction conditions by response surface methodology
Authors: Chung Ha‐Yull , Park Jiyong , Kim Jung‐Han , Kong Un‐Yong
Published: December 2006

Effects of the reaction temperature, reaction time, mole ratio of fatty acid methyl esters (FAME) to sorbitol, and mole ratio of fatty acid sodium soaps (FASS) to sorbitol on yields of sorbitol fatty acid polyester (SFPE) were examined with a response surface methodology. The optimum reaction conditions selected with response surface analysis were as follows: reaction temperature, 144°C; reaction time, 6.65 h; mole ratio of FAME to sorbitol, 10.7∶1; and mole ratio of FASS to sorbitol, 0.77∶1. Under these reaction conditions, the experimental yield of sorbitol fatty acid polyester (mean value: 92% range: 89–94%) obtained from seven replications was close to the predicted value (94%) calculated from the polynomial response surface model equation. The response surface methodology approach used in this study was able to predict the reaction conditions necessary for a high yield of sorbitol fatty acid polyester.
Antioxidative activity and phenolic composition of pilot‐plant and commercial extracts of sage and rosemary
Authors: Cuvelier Marie‐Elisabeth , Richard Hubert , Berset Claudette
Published: December 2006

Eight sage (Salvia officinalis) and twenty‐four rosemary (Rosmarinus officinalis) extracts, originating from pilot‐plant or commercial sources, had different antioxidative activities as measured by accelerated autoxidation of methyl linoleate. Twenty‐seven compounds were characterized in the Labiatae family extracts by high‐performance liquid chromatography (HPLC) coupled with mass spectrometry, equipped with an atmospheric pressure chemical ionization interface, and by HPLC coupled with a photodiode array spectrophotometer. Twenty‐two compounds were identified, including phenolic acids, carnosol derivatives, and flavonoids. The extracts showed great variation in their HPLC profiles, and no correlation was apparent between their antioxidative efficiency and their composition, in twenty specific phenols. Data indicated that the most effective compounds were carnosol, rosmarinic acid, and carnosic acid, followed by caffeic acid, rosmanol, rosmadial, genkwanin, and cirsimaritin.
Assignment of13C nuclear magnetic resonance signals in fatty compounds with allylic hydroxy groups
Authors: Knothe G. , Bagby M. O.
Published: December 2006

13C Nuclear magnetic resonance (NMR) signals in several fatty compounds with allylic mono‐ and dihydroxy groups were assigned by comparing compounds with and without other functional groups (allylic hydroxy, carboxylic acid, respectively, methyl ester at C1). The simple13C NMR spectra of hydroxylated compounds derived from symmetrical alkenes are particularly useful in making assignments. The compounds whose signals were partially assigned are 8‐hydroxy‐9(E)‐octadecenoic acid, 11‐hydroxy‐9(E)‐octadecenoic acid, 8, 11‐dihydroxy‐9(E)‐octadecenoic acid, 9(E)‐octadecen‐8‐ol, and 9(E)‐octadecene‐8, 11‐diol. The present evaluation can be used for assigning signals in other fatty compounds.
A simple and sensitive method for detecting avocado seed oil in various avocado oils
Authors: Werman M. J. , Mokady S. , Neeman I.
Published: December 2006

The presence of avocado seed oil in various avocado oils was detected by thin‐layer chromatography (TLC). An unsaponifiable compound, called Component‐C, was identified in the avocado seed oil. This compound is unique to avocado seed and has a blue color when developed on the TLC plate. At least 9.2 μg of avocado seed unsaponifiables were needed at a single TLC spot to detect the unique blue color definitely. Admixtures of as little as 0.16% avocado seed oil in various avocado oils can be detected by the proposed procedure.
Evaluation of the diffusion coefficient of rapeseed oil during solvent extraction with hexane
Authors: Şaşmaz Dursun Ali
Published: December 2006

The diffusion coefficient of rapeseed oil was determined from data obtained during time‐varied solvent extraction experiments. The experiments were carried out in a Gülbaran extractor‐diffuser with hexane as the solvent. A relationship was found between the slope of the diffusion line and the shape and size of the rapeseed particles. This relation can be used to calculate the diffusion coefficient. A diffusion coefficient of 3.4×10−8 cm2/s was determined from the experimental data.
Effects of arbuscular mycorrhizal infection on the growth and reproduction of the annual legumeKummerowia striatagrowing in a nutrient‐poor alluvial soil
Authors: Nakatsubo Takayuki
Published: December 2006

A culture experiment was conducted to examine the effects of arbuscular mycorrhizal (AM) fungi on the growth and reproduction ofKummerowia striata, a common annual legume of river floodplains of Japan. The plants were grown from seeds in pots with nutrient‐poor sandy soil collected from a fluvial bar. Arbuscular mycorrhizal infection increased the aboveground biomass, nodule weight, leaf nitrogen concentration and seed production. However, flowering occurred earlier in plants without AM fungi. These effects of AM fungi were insignificant in plants supplied with phosphate. These results suggest that AM fungi may influence the establishment ofK. striatain nutrient‐poor, disturbed habitats.
Food utilization of aphidophagous hoverfly larvae (Diptera: Syrphidae, Chamaemyiidae) on herbaceous plants in an urban habitat
Authors: Mizuno Masayuki , Itioka Takao , Tatematsu Yoshihiro , Itô Yosiaki
Published: December 2006

We examined food utilization in a community of aphidophagous hoverfly larvae (Diptera: Syrphidae and Chamaemyiidae) in open lands in an urban habitat in central Japan for 3 years. The community consisted of 17 hoverfly species feeding on 20 aphid species occurring on 14 species of dominant herbaceous plants. In terms of larval prey preference, the dominant eight species of hoverfly were categorized into three groups: a polyphagous ‘generalist’ group consisting of four species, Episyrphus balteatus, Betasyrphus serarius, Syrphus vitripennis and Sphaerophoria sp.; an oligophagous ‘specialist’ group consisting of three species, Metasyrphus hakiensis, Dideoides latus and Paragus hemorrhous; and Leucopis puncticornis, which showed a preference for two aphid species on the plant Torilis scabra. The prey aphids of the second group have behavioral or morphological defense mechanisms that are effective for preventing attacks by generalist hoverflies; two prey aphids are aggressive toward generalist predators and the others are protected by ant‐attendance. The specialist hoverflies seem to be adapted to overcome these defense mechanisms. The prey ranges overlapped little between the generalist and the specialist groups, while those within the generalist group overlapped greatly.
Seed germination and seedling survival in a colony of the common cormorant, Phalacrocorax carbo
Authors: Ishida Akira
Published: December 2006

Germination and seedling survival of some woody plants were examined in a colony of the common cormorant at Unoyama, central Japan. The germination of Quercus serrata and Pinus densiflora was less successful in the colony than outside the colony. The percentage of germination success was negatively correlated with the amount of cormorant faeces scattered on the ground and also with the soil water conent. Most of the germinated seedlings inside of the colony died with symptoms such as necrosis spreading from the edge of leaves. Saplings of Q. serrata also tended to die more in the colony than outside the colony. The survival rate of Quercus glauca seedlings with scattered faeces on their leaves and/or on the the surrounding soil was significantly lower than the rate of those free of faeces. These results suggest that in the cormorant colony, germination of seeds and seedling survival are greatly inhibited due to both the direct and indirect effects of cormorant faeces.
Application of a rapid thin section method for observations on decomposing litter in mor humus form in a subalpine coniferous forest
Authors: Tian Xing‐jun , Takeda Hiroshi , Ando Tatsuo
Published: December 2006

Morphological changes in the decomposing litter ofAbiesspp. andBetulaspp. in a mor humus form were studied by a rapid thin section method. According to the morphological characteristics, the epidermis, mesophyll and vascular bundleof Abiesneedle litter were classified into four types: (i) newly fallen; (ii) slightly decomposed; (iii) moderately decomposed; and (iv) greatly decomposed. The distribution of these tissue types along the profile of the forest floor was then investigated. The morphological changes in other litter types, such as branches, scales andBetulaleaves during decomposition were observed directly with microscope and electron microscope. Five vertical thin sections and 80 horizontal thin sections were used for these observations and investigations. the decomposition ofAbieslitter was slower than that ofBetulalitter. The relative decomposition rate of the tissues was in the order of: mesophyll>vascular bundle >epidermis inAbiesneedles; mesophyll≥epidermis>vascular bundles inBetulaleaves; and inner bark >xylem>outer bark in bothAbiesandBetulabranches. The last remains of the litter were usually stomata, segments of seminiferous scale and outer bark ofAbies. The decomposition of plant litter occurred mainly within the L and F layers of the soil (0–5 cm in depth).Abiesneedles andBetulaleaves completely disappeared at depths of 0–6 cm and 0–4 cm, respectively. Branches disappeared within the top of 5 cm and 6–8 cm forBetulaand forAbies, respectively. The scales ofAbieswere most slowly decomposed in the soil layers.
Mortality can produce predictable dynamics in chaotic populations
Authors: Gonzalez‐Andujar J. L. , Perry J. N.
Published: December 2006

Recent theoretical studies have pointed out that a relatively small degree of dispersion between chaotic subpopulations produces predictable, simple dynamics and severely reduces the frequency of the occurrene of chaos. In this paper, we show that the introduction of mortality to models which are initially chaotic, alone or combined with dispersal, can produce similar effects.
Carbon input from plant to soil through root exudation in Digitaria adscendens and Ambrosia artemisiifolia
Authors: Bekku Yukiko , Kimura Makoto , Ikeda Hiroaki , Koizumi Hiroshi
Published: December 2006

The amount of carbon released into soil through root exudation by Digitaria adscendens Herrm. and Ambrosia artemisiifolia L. var. elatior Desc., which often predominate at the early stages of secondary succession, was evaluated in a laboratory experiment conducted over a 60‐day period. Differences in the amount of exuded carbon between these species and between the developmental stages were examined. The amount of carbon exuded increased with growth in both species. The percentage of exuded carbon to photosynthetically net fixed carbon, which was higher at younger stages (13%) in D. adscendens, decreased to 3.1% with time. On the other hand, no reduction in the amount of carbon exuded was observed in A. artemisiifolia (4.7–8.1% range). The total amount of carbon released through root exudation in D. adscendens and A. artemisiifolia was estimated at 3.1% and 6.9% of photosynthetically net fixed carbon, respectively. These results suggest the possibility that wild plants exude a considerable amount of carbon from their roots to the soil, and emphasizes the necessity for considering root exudation in the carbon cycle.
Comparative ecophysiology of Chrysanthemum pacificum Nakai and solidago altissima L. 1. why S. altissima cannot be established on the seashore
Authors: Yura Hiroshi
Published: December 2006

A field survey was made to elucidate whether salt spray is a major factor in preventing a common inland weed, Solidago altissima, from being established on the seashore of Boso Peninsula. Seasonal changes in the intensity of salt spray, sodium content in the soil water and soil water contents were measured at the seashore and inland. Seeds of S. altissima were sown at both sites with those of a common maritime species, Chrysanthemum pacificum. The number of surviving shoots of the seedlings were periodically counted for 1 year. The intensity of the salt spray, sodium content and water contents of the soil on the seashore fluctuated seasonally. There were some periods when the intensity of salt spray was comparable to that of the inland site. Most of the S. altissima seedlings survived at the inland site. All S. altissima seedlings germinated at the seashore were completely eliminated. The death rate of S altissima seedlings at the seashore was not constant. Ninety‐five percent of the S. altissima seedling in total died out during the four periods of intensive salt spray. The death rate of C. pacificum seedlings on the seashore was not especially high during those periods. Correlation between seasonal changes in the death rate of S. altissima seedlings and the sodium content or water content of the soil was low. These results indicate that intensive salt spray, intermittently blown in from the sea, is one of the most critical environmental factors that eliminates S. altissima from the seashore.
Is tuna critically endangered? Extinction risk of a large and overexploited population
Authors: Matsuda Hiroyuki , Yahara Tetsukazu , Uozumi Yuji
Published: December 2006

In 1994, (the World Conservation Union (IUCN) made new quantitative criteria for Red List Categories. Among these, criterion A is based on the reduction rate of population size and is not linked to absolute population size. This is because for most unexploited threatened species absolute population size is completely uncertain. Criterion E is directly concerned with the extinction probability within a specified period. Criterion A is applied to marine fish species, including tuna, which are exploited by commercial fishing. However, for many fish that are commercially exploited, the absolute number of mature individuals and the variance in its yearly reduction rate are often known. In addition, extinction probability depends on absolute population size. There is an inconsistency between criterion A and E when population size is large enough. This is the case for tuna. In this paper, we propose a new criterion for threatened species based on the average reduction rate and the current population size. Criterion A is consistent with criterion E as long as the population size is very small. We also propose a method for estimating the extinction risk of tuna based on the variance of the reduction rate. We investigated the sensitivity in the uncertain parameters involved in the models and concluded that tuna is unlikely to be listed as critically endangered but that southern bluefin tuna may be listed as vulnerable.
Temperature effect on maintenance and growth respiration coefficients of young, field‐grown hinoki cypress (Chamaecyparis obtusa)
Authors: Adu‐Bredu Stephen , Yokota Taketo , Hagihara Akio
Published: December 2006

Respiration measurements were made on the entire aboveground parts of young, field‐grown hinoki cypress (Chamaecyparis obtusa) trees at monthly intervals over a 5‐year period, to examine the effect of temperature on maintenance and growth respiration coefficients. The respiration rate of the trees was grouped on a monthly basis and then partitioned into maintenance and growth components. The maintenance respiration coefficient increased exponentially with air temperature. The maintenance respiration coefficient at a temperature of 0°C and its Q10 value were 0.205 mmol CO2 g−1 d.w. month−1 and 1.81, respectively. The growth respiration coefficient, which was virtually independent of temperature, had a mean value of 38.06±1.95 (SE) mmol CO2g−1 d.w. The growth rate increased exponentially with increasing temperature up to a peak at around 18°C, and thereafter declined, thereby resulting in the growth respiration rate being increasingly less sensitive to increasing air temperature. The reported decreases in the Q10 value of total respiration with increasing air temperature is due to the way in which the growth component of respiration responds to temperature.
Synthesis of Ethoxylated Alkyl Sulfosuccinate Surfactants and the Investigation of Mixed Solutions
Authors: Al‐Sabagh A. M. , Azzam E. M. S. , Mahmoud S. A. , Saleh N. E. A.
Published: December 2006

A series of ethoxylated sodium monoalkyl sulfosuccinate (ESMASS) ester surfactants were prepared by reacting polyethylene glycol (molecular weight 600) with sodium monoalkyl sulfosuccinate (SMASS). The esters were prepared by reacting octyl, lauryl, or cetyl alcohol with sodium sulfosuccinate (SSS) to prepare E(14)SMOSS, E(14)SMLSS, and E(14)SMCSS. The chemical structures of the prepared surfactants were confirmed by Fourier transform infrared (FTIR) and1H‐NMR spectroscopy. The surface tension of the synthesized surfactants was measured at 25 °C individually or mixing at different molar fractions with sodium dioctyl sulfosuccinate. The surface active properties were calculated and the micellization process of the mixture was investigated. The molar ratio of anionic (SDOSS) and anionic–nonionic surfactant moieties [E(14)SMOSS, E(14)SMLSS, and E(14)SMCSS] in the mixed aggregates were deduced using the regular solution approximation equations. Depending on the critical micelle concentration values measured for each surfactant individually, and as well as the mixed systems, the minimum surface tension was exhibited at a ratio of 0.6 SDOSS:0.4 E(14)SMCSS. The micellar composition of the mixed aggregates were explained and discussed based on the effect of their chemical structures. The activity coefficient (f1,f2), interaction parameter (β), and ideality of anionic–nonionic mixed aggregates were evaluated.
Hearing threshold assessment post grommet insertion. Is it reliable?
Authors: Griffiths H , James D , Davis R , Hartland S , Molony N
Published: December 2006

We aimed to investigate whether auditory brainstem response (ABR), assessed immediately after grommet insertion, was an accurate measure of hearing threshold.

Ten children were recruited (20 ears). Patients underwent transient evoked otoacoustic emission (TEOAE) and ABR tests before and after grommet insertion under general anaesthetic. A third assessment was conducted at a six-week review, without anaesthetic or sedation. The hearing threshold in dB and the presence of TEOAE were recorded by senior audiologists. The results of each investigation were compared. At review, only 15 ABR and 17 TEOAE tests, of a possible 20, were recorded.

Transient evoked otoacoustic emissions were recorded in 30 per cent of ears pre-operatively, 20 per cent of ears post-operatively and 82 per cent of ears at six-week review. The average ABR thresholds were 23.75 dB (range 10–45 dB) pre-operatively, 27.25 (range 15–40 dB) post-operatively and 15 dB (range 5–25 dB) at six-week review. Comparing pre- and post-operative assessment, decreased thresholds were seen in six ears and elevated thresholds in 11. Comparing the six-week review ABR with the post-operative ABR, 13 ears had decreased thresholds, by as much as 20 dB. Thresholds of 35 dB or greater were measured in six ears immediately after grommet insertion (maximum 40 dB). Threshold shifts of 15 dB or greater was observed in seven ears. The intra-subject variation was shown to be significant (p<0.001) when repeated measures analysis of variance was applied.

We conclude that there is evidence that ABR can be inaccurate after grommet insertion, overestimating hearing thresholds. We believe that the mechanism by which the error is realised is temporary threshold shift.
Bioplastique™ injection laryngoplasty: voice performance outcome
Authors: Hamilton D W , Sachidananda R , Carding P N , Wilson J A
Published: December 2006

Aim: To compare voice performance following Bioplastique™ injection with that following Isshiki thyroplasty.

Measures: A 12 item, self-reported voice performance questionnaire was completed and observer-rated perceptual voice analysis scores were also measured, before and after Bioplastique injection, for 14 patients. Results were compared with our previously reported outcomes for 28 thyroplasty patients.

Results: Only 14 of 30 patients had complete datasets. For these patients, the mean pre-operative voice performance questionnaire score improved significantly, from 40.3 to 18.9 (p=0.002, Wilcoxon test). All perceptual analysis parameters showed significant improvement. These results compare favourably with the thyroplasty cohort (mean voice performance questionnaire score: pre-operative 35; post-operative 18; p<0.001). One Bioplastique patient developed contralateral paresis, requiring partial removal of the material 18 months later. Two thyroplasty patients experienced complications and three required revision.

Conclusions: Both Bioplastique injection and Isshiki thyroplasty resulted in a significant improvement in both subjective and perceptual voice performance. Our data suggest that the effect size of the two interventions is approximately similar (in nonrandomised cohorts of surviving patients). As in many similar studies, the incomplete follow-up data reflect severe comorbidity. Bioplastique injection is a quicker procedure associated with fewer complications, and thus appears superior to framework surgery in patients with limited life expectancy.
High‐Level Production of a Monoclonal Antibody in Murine Myeloma Cells by Perfusion Culture Using a Gravity Settler
Authors: Choo Chiou‐Yu , Tian Yuan , Kim Wan‐Seop , Blatter Erich , Conary Jon , Brady Ciaran P.
Published: December 2006

A perfusion system is described for the production of a human monoclonal antibody in non‐secreting murine myeloma (NS0) cells that was previously shown to be difficult to produce at high levels using fed‐batch culture. The perfusion system was based on the use of a commercially available cell settler as the separation device to separate the cells from the culture. Separation efficiency of the cell settler was above 98%. Based on the growth and glucose consumption rates, fresh media was added to the culture and the turnover rate for the bioreactor was set at a maximum of 1.5 times the bioreactor volume per day. The perfusion process resulted in twice the maximum viable cell densities and up to three times the total protein production in a 53‐day run period when compared to the fed‐batch process. In addition, charge heterogeneity of the antibody as measured by ion exchange chromatography was lower for material purified from the perfusion runs compared to fed‐batch. Perfusion mode of culture using a commercially available gravity settler is therefore a viable alternative to fed‐batch mode for high‐level production of this monoclonal antibody in NS0 cells.
Wavelength dependence of electro-optic effect in tetragonal lead magnesium niobate lead titanate single crystals
Authors: He Chongjun , Ge Wenwei , Zhao Xiangyong , Xu Haiqing , Luo Haosu , Zhou Zhongxiang
Published: December 2006

The refractive indices, birefringence, and linear electro-optic (EO) effect of 0.62Pb(Mg1∕3Nb2∕3)O3–0.38PbTiO3 single crystals have been characterized as a function of wavelength. The dispersions of refractive indices for both ordinary and extraordinary rays were accurately described by a two-term Sellmeier dispersion equation, in which the parameters connected to the energy band structure were determined. A strong dispersion was found for birefringence and EO coefficient γc=γ33−(no∕ne)3γ13. With the increasing wavelengths, both of them decrease fast. The two-term Sellmeier dispersion model, in which one oscillator frequency is polarization dependent, was shown to represent closely all the results. The polarization potential, which specifies the magnitude of the oscillator frequency shift, was 0.40eVm4C−2.
Controlling electric field and electron density in a double-gated GaAs/AlGaAs quantum well
Authors: Yamaguchi M. , Nomura S. , Miyakoshi K. , Tamura H. , Akazaki T. , Takayanagi H.
Published: December 2006

We demonstrate that the vertical electric field and the electron density of a two-dimensional electron system (2DES) can be controlled in a double-gated GaAs/AlGaAs quantum well (QW). Photoluminescence (PL) spectra from the recombination of an electron with a hole bound to a beryllium acceptor atom are measured as functions of gate biases applied to front and back gates. By comparing the measured spectra with theoretical models, we analyze the effect of the potential gradient in the QW on the PL energy for different electron filling. While a photoexcited electron recombines with a bound hole in an empty QW, a layer of 2DES is induced when the conduction band bottom of the QW lowers below the Fermi energy by the back-gate bias. In this case, a simple capacitor model gives a good estimation of the electron density. When we increase the front-gate bias, another electron layer is formed on the other side of the QW. These two electron layers screen the electric field inside the QW where the PL energy is insensitive to the gate bias.
A polycrystal model for the anisotropic behavior of a fully poled ferroelectric ceramic
Authors: Su Y. , Weng G. J.
Published: December 2006

When an initially isotropic ferroelectric ceramic is fully poled with application of an axial electric field, it turns into a transversely isotropic one. The nonlinear response of such a material is then orientation dependent. Such an anisotropic behavior is studied by a self-consistent polycrystal model in this article. The model makes use of two separate levels of micromechanical analysis: the first one involves domain switch inside the constituent grains and the second one involves the transition from the grains to the polycrystal level. Domain switch inside the grains is taken to be a thermodynamic-driving process, and the self-consistent transition from the grain to the polycrystal is accomplished through a secant-modulus approach. This polycrystal model is applied to calculate the nonlinear electric displacement versus electric field relations (D vs E) of a PZT-5H along several loading directions from the original poling axis. This calculation takes into account the intercrystalline heterogeneity, and the results indicate that, as the loading direction changes from 0° to 45°, 90°, 135°, and finally to 180°, the magnitude of the electric displacement and the change in remnant polarization of the polycrystal all increase. These theoretical results are found to be consistent with the test data. In order to reveal the heterogeneity of the switching process among the constituent grains, the evolution of new domain concentration c1 in some selected grains is also illustrated.
Defect generation of anatase nanocondensates via coalescence and transformation from dense fluorite-type TiO2
Authors: Tsai Meng-Hsiu , Shen Pouyan , Chen Shuei-Yuan
Published: December 2006

The anatase nanocondensates produced by energetic pulse laser ablation on Ti target under oxygen background gas have been observed by transmission electron microscopy. They were found to coalesce in approximately parallel orientation on the (001) plane to form dislocations and in twin orientation on the (112) plane to form faulty and twinned crystals. The anatase phase (denoted as a) was also derived from the dense fluorite-type (denoted as f) condensates by a martensitic-type transformation to form twin variants following the crystallographic relationship ⟨001⟩f‖[100]a with a habit plane close to {100}f‖(001)a for a beneficial lower interfacial strain energy. The f-a transformation route of TiO2 can be rationalized by a metastable phase change in terms of the intersection of the internal energy versus cell volume curves of the polymorphs.
Plasma generation using high-power millimeter-wave beam and its application for thrust generation
Authors: Oda Yasuhisa , Komurasaki Kimiya , Takahashi Koji , Kasugai Atsushi , Sakamoto Keishi
Published: December 2006

Propagation of an ionization front in the beam channel was observed after plasma was generated using a 170GHz millimeter-wave beam in the atmosphere. The propagation velocity of the ionization front was found to be supersonic when the millimeter-wave power density was greater than 75kWcm−2. The momentum coupling coefficient Cm, a ratio of the propulsive impulse to the input energy, was measured using conical and cylindrical thruster models. A Cm value greater than 350NMW−1 was recorded when the ionization front propagated with supersonic velocity.
A cancer-associated PCNA expressed in breast cancer has implications as a potential biomarker
Authors: Malkas Linda H. , Herbert Brittney Shea , Abdel-Aziz Waleed , Dobrolecki Lacey E. , Liu Yang , Agarwal Beamon , Hoelz Derek , Badve Sunil , Schnaper Lauren , Arnold Randy J. , Mechref Yehia , Novotny Milos V. , Loehrer Patrick , Goulet Robert J. , Hickey Robert J.
Published: December 2006

Two isoforms of proliferating cell nuclear antigen (PCNA) have been observed in breast cancer cells. Commercially available antibodies to PCNA recognize both isoforms and, therefore, cannot differentiate between the PCNA isoforms in malignant and nonmalignant breast epithelial cells and tissues. We have developed a unique antibody that specifically detects a PCNA isoform (caPCNA) associated with breast cancer epithelial cells grown in culture and breast-tumor tissues. Immunostaining studies using this antibody suggest that the caPCNA isoform may be useful as a marker of breast cancer and that the caPCNA-specific antibody could potentially serve as a highly effective detector of malignancy. We also report here that the caPCNA isoform functions in breast cancer-cell DNA replication and interacts with DNA polymerase δ. Our studies indicate that the caPCNA isoform may be a previously uncharacterized detector of breast cancer.
Evolutionary constraint on
Otx2
neuroectoderm enhancers-deep conservation from skate to mouse and unique divergence in teleost
Authors: Kurokawa Daisuke , Sakurai Yusuke , Inoue Ai , Nakayama Rika , Takasaki Nobuyoshi , Suda Yoko , Miyake Tsutomu , Amemiya Chris T. , Aizawa Shinichi
Published: December 2006

Otx2
is a paired type homeobox gene that plays essential roles in each step and site of head development in vertebrates. In the mouse,
Otx2
expression in the anterior neuroectoderm is regulated primarily by two distinct enhancers: anterior neuroectoderm (AN) and forebrain/midbrain (FM) enhancers at 92 kb and 75 kb 5′of the
Otx2
locus, respectively. The AN enhancer has activity in the entire anterior neuroectoderm at headfold and early somite stages, whereas the FM enhancer is subsequently active in the future caudal forebrain and midbrain ectoderm. In tetrapods, both AN and FM enhancers are conserved, whereas the AN region is missing in teleosts, despite overt
Otx2
expression in the anterior neuroectoderm. Here, we show that zebrafish and fugu FM regions drive expression not only in the forebrain and midbrain but also in the anterior neuroectoderm at headfold stage. The analysis of coelacanth and skate genomic
Otx2
orthologues suggests that the utilization of the two enhancers, AN and FM, is an ancestral condition. In contrast, the AN enhancer has been specifically lost in the teleost lineage with a compensatory establishment of AN activity within the FM enhancer. Furthermore, the AN activity in the fish FM enhancer was established by recruiting upstream factors different from those that direct the tetrapod AN enhancer, yet zebrafish FM enhancer is active in both mouse and zebrafish anterior neuroectoderm at the headfold stage.
Structure of a bacterial pyridoxal 5′-phosphate synthase complex
Authors: Strohmeier Marco , Raschle Thomas , Mazurkiewicz Jacek , Rippe Karsten , Sinning Irmgard , Fitzpatrick Teresa B. , Tews Ivo
Published: December 2006

Vitamin B
6
is an essential metabolic cofactor that has more functions in humans than any other single nutrient. Its
de novo
biosynthesis occurs through two mutually exclusive pathways that are absent in animals. The predominant pathway found in most prokaryotes, fungi, and plants has only recently been discovered. It is distinguished by a glutamine amidotransferase, which is remarkable in that it alone can synthesize the cofactor form, pyridoxal 5′-phosphate (PLP), directly from a triose and a pentose saccharide and glutamine. Here we report the 3D structure of the PLP synthase complex with substrate glutamine bound as well as those of the individual synthase and glutaminase subunits Pdx1 and Pdx2, respectively. The complex is made up of 24 protein units assembled like a cogwheel, a dodecameric Pdx1 to which 12 Pdx2 subunits attach. In contrast to the architecture of previously determined glutamine amidotransferases, macromolecular assembly is directed by an N-terminal α-helix on the synthase. Interaction with the synthase subunit leads to glutaminase activation, resulting in formation of an oxyanion hole, a prerequisite for catalysis. Mutagenesis permitted identification of the remote glutaminase and synthase catalytic centers and led us to propose a mechanism whereby ammonia shuttles between these active sites through a methionine-rich hydrophobic tunnel.
Selectivity for the configural cues that identify the gender, ethnicity, and identity of faces in human cortex
Authors: Ng Minna , Ciaramitaro Vivian M. , Anstis Stuart , Boynton Geoffrey M. , Fine Ione
Published: December 2006

We used psychophysical and functional MRI (fMRI) adaptation to examine how and where the visual configural cues underlying identification of facial ethnicity, gender, and identity are processed. We found that the cortical regions showing selectivity to these cues are distributed widely across the inferior occipital cortex, fusiform areas, and the cingulate gyrus. These regions were not colocalized with areas activated by traditional face area localizer scans. Traditional face area localizer scans isolate regions defined by stronger fMRI responses to a random series of face images than to a series of non-face images. Because these scans present a random assortment of face images, they presumably produce the strongest responses within regions containing neurons that are face-sensitive but not highly tuned for face type. These areas might be expected to show only weak selective adaptation effects. In contrast, the largest responses to our selective adaptation paradigm would be expected within areas containing more selectively tuned neurons that might be expected to show only a sparse collective response to a series of random faces. Many aspects of face processing (e.g., prosopagnosia, recognition, and configural vs. featural processing) are likely to rely heavily on regions containing high proportions of neurons that show selective tuning for faces.