bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrolysis of edible oils by lipases immobilized on hydrophobic supports: Effects of internal support structure
Authors: Al‐Duri B. , Robinson E. , McNerlan S. , Bailie P.
Published: January 2007

The hydrolysis of edible oil by immobilized lipases on novel support materials was investigated. Six hydrophobic polymers were studied with the following techniques: (i) determination of the surface area of each support by BET (Brunauer‐Emmett‐Teller) analysis of nitrogen adsorption isotherms; (ii) electron photomicrography; and (iii) measuring lipase activity by hydrolysis of olive oil with lipase fromCandida cylindracea immobilized on each support. A detailed structural analysis on one support also was carried out by mercury porosimetry. The composition and porosity of a support are more important than the surface area in determining activity for immobilized lipases. Furthermore, having selected the “most efficient” support, five lipases fromC. cylindracea, Rhizomucor miehei, andPseudomonas cepacia, were immobilized, and their hydrolytic activities were determined at several temperatures and pH values with olive oil and beef tallow as substrates in solvent‐free systems. For each parameter, twelve successive 2.5‐h hydrolysis reactions were conducted on a laboratory‐scale under batch conditions. Lipase AY fromC. cylindracea had the highest hydrolytic activity, in the range of 30–50°C at pH 5.5 with olive oil as the substrate. For beef tallow, lipase PS, fromP. cepacia, displayed the highest activity at 50°C and pH 7.
Lipase‐catalyzed reactions involving thia fatty acids and ester derivatives
Authors: Lie Ken Jie Marcel S. F. , Syed Rahmatullah M. S. K.
Published: January 2007

Enzymatic hydrolysis of synthetic methyl 5‐, 9‐, and 12‐thiastearates in aqueous media withCandida cyclindracea or porcine pancreatic lipases gave the corresponding fatty acids in 70–100% yield. Hydrolysis of the 3‐ and 4‐positional isomers gave only 15–25% of the free thia fatty acids, suggesting discrimination against these isomers by lipases. No lipolysis was achieved with methyl 2‐thialaurate under a range of reaction conditions. Esterification of the 3‐, 4‐, 5‐, 9‐, and 12‐thiastearic acids withn‐butanol inn‐hexane using Lipozyme (immobilizedRhizomucor miehei) as the biocatalyst gave the corresponding butyl esters in 80–95% yield. Interesterification (acyl exchange) of triolein with methyl 9‐thiastearate in the presence of Lipozyme showed the incorporation of 9‐thiastearoyl chain at only one of the α‐positions of triolein. In the case of methyl 2‐thialaurate, no lipase‐catalyzed acyl exchange reaction was possible. This study showed that the position of the sulfur atom in thia fatty esters affects the lipase‐catalyzed hydrolysis and interesterification reactions.
Kinetics of melt crystallization and transformation of tripalmitin polymorphs
Authors: Sato Kiyotaka , Kuroda Tatsuhiko
Published: January 2007

The rates of melt crystallization and phase transformation of three polymorphs of tripalmitin were examined by optical microscopy, X‐ray diffractometry and DSC with and without surfactant additives (sorbitan mono‐ and tristearates). The following results were obtained: (a) Crystallization rate increased in order ofα, β′ andβ; (b) transformation rate was slower than crystallization rate for each polymorph at the same temperature examined; (c) when the most stableβ form was recrystallized from the melt just after the melting ofα, its recrystallization rate was much higher than that by simple melt‐cooling; (d) surfactant additives retarded both the crystallization and transformation of all the polymorphs, yetβ′ was influenced the most. A mechanistic interpretation based on the molecular structures both of the melt and of each polymorph is presented.
Deacidification of high FFA rice bran oil by reesterification and alkali neutralization
Authors: Bhattacharyya A. C. , Bhattacharyya D. K.
Published: January 2007

Rice bran oils of 15 to 30% free fatty acid can be deacidified to low levels by reesterification with glycerol after degumming and dewaxing. The reesterification can by combined with conventional alkali neutralization and bleaching to produce light color edible oil.
Cotton dust standards for the raw cotton industries
Authors: Wakelyn P. J.
Published: January 2007

In June 1978, OSHA promulgated 2 new, far more severe, standards for occupational exposure to cotton dust. The Supreme Court recently upheld the cotton dust standard for general industry. However, other court or administrative actions have invalidated the standard, or otherwise delayed its enforcement, for all sectors except textile mills and some downstream manufacturing operations. OSHA is undertaking a review of the standard. How this review affects the various segments of the cotton industry is discussed.
Status of efforts by oil mill machinery manufacturers to control fugitive dust emissions
Authors: Sanders R. B.
Published: January 2007

Machinery manufacturers who serve the cottonseed crushing industry are fully aware of the existing fugitive dust problems. The main problem lies in the unique characteristic of cottonseed as being a non‐free‐flowing material until after lint removal. This characteristic is compounded by varying degrees of moisture. Therefore, a totally enclosed cottonseed cleaner in a dust‐tight shroud is not practical due to periodic choke‐ups, tail‐over from the top trays and the frequent necessity to manually clean the screens. Delintering equipment has been successfully equipped with canvas drapes connecting the feeder to the top of the roll box front as well as hinged doors that connect the black seed chutes to the bottom of the roll box. Dust and noise levels have been reduced, but not eliminated. Rock and shale traps between the white seed tank and cleaning rooms, as well as within the lint rooms and separating rooms, help reduce free‐fly lint within the processing streams. Rock and shale traps that operate under positive pressure can be another potential dust source which can be eliminated by a dual fan arrangement. After delintering, cottonseed becomes more predictable with regard to flowing ability and more conventional methods of dust control can be applied. Separators can be enclosed as long as maintenance accessibility and operator control visibility are not hindered. The operating air requirements for the machine can be used to maintain an air flow into the enclosure, thus greatly reducing dusty emissions.
Effects of adsorption on detergency phenomena: I
Authors: Schwuger M. J.
Published: January 2007

Knowledge of the adsorption of surface‐active substances onto different interfaces is of basic importance for its technical application in washing and cleaning processes. Important parameters are adsorption kinetics and adsorption equilibria. The criteria of adsorption kinetics and adsorption equilibrium change in opposite directions with increasing length of the hydrophobic group. Equilibrium adsorption increases exponentially, whereas the diffusion coefficient decreases linearly with increasing number of CH2 groups in then‐alkyl part of nonbranched surfactants. Branching of the hydrophobic group has the same effect as shortening the chain length. The wetting effect changes in the same direction as the diffusion coefficient, whereas the washing effect changes similarly to equilibrium adsorption. The generally positive temperature effect on soil removal may be reversed in the opposite direction for nonionic surfactants at temperatures above the cloud point. Separation of phases brings about a decrease of adsorption and washing performance.
Triglyceride analysis by combined argentation/nonaqueous reversed phase high performance liquid chromatography
Authors: Takano Satoshi , Kondoh Yukihiro
Published: January 2007

Full analysis of triglycerides of natural fats and oils has been investigated by the combination of argentation high performance liquid chromatography (HPLC) with nonaqueous reversed phase (NARP) HPLC. An infrared detector was used in argentation HPLC, because it indicated molar responsibility to all triglycerides. After peak trapping with argentation HPLC, each triglyceride fraction was analyzed with NARP chromatography using the glyceride‐selective post‐column reactor detector. The results of the analyses of triglycerides of palm oil and cocoa butter by the proposed method agreed well with those reported earlier.
Nature of palm oil in centrifuge sludge waste water
Authors: Chow M. C. , Ho C. C. , Sutanto J. , Ong S. H.
Published: January 2007

In attempting to improve oil recovery, palm oil retained in the centrifuge sludge waste has been categorized and quantified. It is composed of (i) 30% free oil droplets; (ii) 56% oil released after cellulase treatment followed by detergent washing, and (iii) 14% residual oil which remains diffused and bound to the cell debris. The fatty acid composition indicates that all three oils are palm oil. The separated oil is highly contaminated.
Cyclic fatty acid monomer formation in frying fats. I. Determination and structural study
Authors: Rojo José A. , Perkins Edward G.
Published: January 2007

The formation of monomeric cyclic fatty acids was studied in a model system in which partially hydrogenated soybean oil (PHSO) was heated intermittently for 80 hr of simulated deep fat frying. Oil samples (fresh and heated) and their methyl esters were fractionated according to their molecular size using gel permeation chromatography (GPC). Oils and GPC fractions were analyzed for cyclic monomers by the following steps: (i) preparation of fatty acid methyl esters (FAME); (ii) microhydrogenation of FAME; (iii) urea fractionation of hydrogenated FAME; (iv) analysis by capillary gas liquid chromatography (GLC), and (v) structural characterization of cyclic monomer peaks by mass spectrometry (GC‐MS). Under simulated frying conditions the concentration of cyclic monomers increased from 736 ppm (0.07%) in fresh oil to 1803 ppm (0.18%) in heated oil. GC‐MS with capillary columns allowed the identification of several C18α‐disubstituted cyclohexane and cyclopentane isomers as hydrogenated methyl esters. Other noncyclic and contaminant compounds eluting within the expected GLC retention range of cyclic monomers also were identified in all the samples and GPC fractions.
Two‐phase mixed indicator method for the determination of zwitterionic surfactants
Authors: Rosen Milton J. , Zhao Fulin , Murphy Dennis S.
Published: January 2007

The two‐phase, mixed indicator method for anionic surfactants has been modified and applied to zwitterionic surfactants. The modifications entail: (i) lowering the pH; (ii) adding 95% ethanol, and (iii) increasing the concentration of mixed indicator solution and adjusting the ratio of the indicators. By adjusting one parameter (the amount of 95% ethanol added), the method is applicable to different types of zwitterionic surfactants. Six different surfactants were examined; three were pure materials synthesized and purified in our laboratory, and the remaining three were commercial materials.
USING LAY COUNSELLORS TO PROMOTE COMMUNITY-BASED VOLUNTARY COUNSELLING AND HIV TESTING IN RURAL NORTHERN GHANA: A BASELINE SURVEY ON COMMUNITY ACCEPTANCE AND STIGMA
Authors: BAIDEN F. , AKANLU G. , HODGSON A. , AKWEONGO P. , DEBPUUR C. , BINKA F.
Published: January 2007

Access to voluntary counselling and HIV testing (VCT) remains limited in most parts of Ghana with rural populations being the least served. Services remain facility-based and employ the use of an ever-dwindling number of health workers as counsellors. This study assessed approval for the use of lay counsellors to promote community-based voluntary counselling and testing for HIV and the extent of HIV/AIDS-related stigma in the Kassena-Nankana district of rural northern Ghana. A cross-sectional questionnaire survey was conducted. Logistic regression was used to identify predictors of the tendency to stigmatize people living with HIV/AIDS (PLWHAs). Focus group discussions were held and analytical coding of the data performed. The majority (91·1%) of the 403 respondents indicated a desire to know their HIV status. Most (88·1%) respondents considered locations outside of the health facility as preferred places for VCT. The majority (98·7%) of respondents approved the use of lay counsellors. About a quarter (24%) of respondents believed that it was possible to acquire HIV through sharing a drinking cup with a PLWHA. About half (52·1%) of the respondents considered that a teacher with HIV/AIDS should not be allowed to teach, while 77·2% would not buy vegetables from a PLWHA. Respondents who believed that sharing a drinking cup with a PLWHA could transmit HIV infection (OR 2·50, 95%CI 1·52–4·11) and respondents without formal education (OR 2·94, 95%CI 1·38–6·27) were more likely to stigmatize PLWHAs. In contrast, respondents with knowledge of the availability of antiretroviral (ARV) drugs were less likely to do so (OR 0·40, 95%CI 0·22–0·73). Findings from the thirteen focus group discussions reinforced approval for community-based VCT and lay counsellors but revealed concerns about stigma and confidentiality. In conclusion, community-based VCT and the use of lay counsellors may be acceptable options for promoting access. Interventional studies are required to assess feasibility and cost-effectiveness.
Words across Space and Time: An Analysis of Lexical Items in Khmer Inscriptions, Sixth–Fourteenth Centuries CE
Authors: Lustig Eileen , Evans Damian , Richards Ngaire
Published: January 2007

The study presents a relational database of words referring to material items and institutional processes in over 700 Pre-Angkorian and Angkorian inscriptions, from the sixth to the fourteenth centuries CE. The lexical items within the database have been spatially and temporally referenced, and a geographic information system (GIS) is used to show trends and anomalies over time and space in the distributions of temple sites; key items and materials; and the roles of the rulers, the founders, the donors and temple workers. The current study identifies changes in the socio-economic institutions and relationships within Khmer society through the Pre-Angkorian and into the Angkorian period in Cambodia.
On the road to extinction? The status of elephant Loxodonta africana in Guinea Bissau and western Guinea, West Africa
Authors: Brugière David , Badjinca Iacouba , Silva Cristina , Serra Abubacar , Barry Mamadou
Published: January 2007

We carried out a nationwide survey of elephant Loxodonta africana in Guinea Bissau, a small West African country for which records of elephant are limited. We also investigated parts of western Guinea along the border with Guinea Bissau likely to harbour a transboundary elephant population. Standardized interviews with hunters were held in 110 villages in Guinea Bissau and 60 villages in Guinea, and field surveys were carried out to validate interviewee responses. Results suggest that elephants are mainly restricted to an area between the Corubal River (Guinea Bissau) and the Kogon River (Guinea) and that elephants occur only seasonally in Guinea. Based on the number, geographical localization and interpretation of observed tracks, our estimate of the minimum number of elephants in Guinea Bissau is 4–10 animals. We did not observe any signs of young elephants. The most immediate threat to elephants is a road scheme between Guinea Bissau and Guinea that cuts through elephant range. The future of elephants in this region depends on the capacity of the two countries to manage their common elephant population jointly. In particular, the creation of a transboundary park is urgently needed.
A census of the commercial bushmeat market in Yaoundé, Cameroon
Authors: Edderai David , Dame Mireille
Published: January 2007

Bushmeat is a major food and economic resource in sub-Saharan Africa, and with increasing urbanization bushmeat consumption has spread from villages to cities. To facilitate long-term monitoring of the bushmeat market in Yaoundé, Cameroon, we carried out a baseline survey of the transportation routes of bushmeat into the city and of urban bushmeat sales. We inventoried all bushmeat sales points, and located 15 markets and 145 restaurants and cafeterias selling an estimated total of 1,052 bushmeat dishes per day. This trade provides an occupation for 249 people, of whom 84.3% are women. Trains from Ngaoundere in the north and minibuses from the east supply more than 70% of the sales points in the Elig-Edzoa market, located next to the railway, and the Nkoldongo bus station. From these two places bushmeat is redistributed to other commercial sites within the city. The routes into Yaoundé transport bushmeat from a vast area of the country and in particular from the savannah and central provinces, which are rich in wildlife and contain National Parks and safari hunting areas. However, overall, bushmeat consumption at commercial outlets in the city is low relative to the number of inhabitants.
Ecological niche modelling and prioritizing areas for species reintroductions
Authors: Martínez-Meyer Enrique , Peterson A. Townsend , Servín Jorge I. , Kiff Lloyd F.
Published: January 2007

Species reintroduction programmes, in prioritizing areas for reintroductions, have traditionally used tools that include measures of habitat suitability and evaluations of area requirements for viable populations. Here we add two tools to this approach: evaluation of ecological requirements of species and evaluation of future suitability for species facing changing climates. We demonstrate this approach with two species for which reintroduction programmes are in the planning stages in Mexico: California condor Gymnogyps californianus and Mexican wolf Canis lupus baileyi. For the condor, we identify three areas clustered in the Sierra San Pedro Mártir, Baja California; for the wolf, we identify a string of suitable sites along the Sierra Madre Occidental of western Mexico. We discuss the limitations of this approach, identifying ways in which the models illustrated could be made more realistic and directly useful to reintroduction programmes.
TES and THEMIS study of proposed paleolake basins within the Aeolis quadrangle of Mars
Authors: Stockstill Karen R. , Moersch Jeffrey E. , McSween Harry Y. , Piatek Jennifer , Christensen Philip R.
Published: January 2007

Several studies have described photogeologic evidence for paleolacustrine basins on Mars, mostly within impact craters. If these basins contained persistent standing water subsequently lost through evaporation, they may have contained deposits of evaporite minerals. If still present and sufficiently exposed, these evaporites would be detectable in orbital thermal infrared spectra. Using data from Mars Orbiter–Thermal Emission Imaging System (MO‐THEMIS) and Mars Global Surveyor–Thermal Emission Spectrometer (MGS‐TES), we examined proposed paleolake basins within Aeolis quadrangle, including Gusev and Gale craters. Gusev Crater is dominated by units with a spectrally intermediate to thick layer of dust mantling the surface. TES linear deconvolutions of the low‐albedo deposits, which have a thinner dust mantling, include Surface Type 1 (basalt) materials when sulfates are included in the end‐member library. Otherwise, the linear deconvolution uses Surface Type 2 (andesite or weathered basalt). THEMIS surface emissivity spectra for the low‐albedo deposits do not display sufficient contrast to distinguish between Surface Types. Gale Crater is relatively dust‐free, except for the mound variably covered in a spectrally intermediate to thick layer of dust. TES linear deconvolutions of crater floor and less dusty portion of the mound are consistent with a mixture of Surface Types 1 and 2. THEMIS surface emissivity spectra are consistent with Surface Type 1 or a mixture of Surface Types 1 and 2 for the crater floor and surface dust for the mound. These results do not discriminate between several previously suggested origins (fluvial‐lacustrine, aeolian, or volcanic deposition) for the mound layers. We find no spectral evidence for evaporite deposits that might substantiate paleolakes existed in these craters.
Survey of TES high albedo events in Mars' northern polar craters
Authors: Armstrong J. C. , Nielson S. K. , Titus T. N.
Published: January 2007

Following the work exploring Korolev Crater (Armstrong et al., 2005) for evidence of crater interior ice deposits, we have conducted a survey of Thermal Emission Spectroscopy (TES) temperature and albedo measurements for Mars' northern polar craters larger than 10 km. Specifically, we identify a class of craters that exhibits brightening in their interiors during a solar longitude, Ls, of 60 to 120 degrees, roughly depending on latitude. These craters vary in size, latitude, and morphology, but appear to have a specific regional association on the surface that correlates with the distribution of subsurface hydrogen (interpreted as water ice) previously observed on Mars. We suggest that these craters, like Korolev, exhibit seasonal high albedo frost events that indicate subsurface water ice within the craters. A detailed study of these craters may provide insight in the geographical distribution of the ice and context for future polar missions.
Formation of hot flow anomalies and solitary shocks
Authors: Omidi N. , Sibeck D. G.
Published: January 2007

Interaction of a tangential discontinuity (TD) with the bow shock is investigated by using electromagnetic, global hybrid simulations in which ions are treated kinetically via particle‐in‐cell methods and electrons form a massless fluid. On the basis of previous studies, it was expected that the interaction would result in the formation of a hot flow anomaly (HFA) propagating along the curved bow shock surface. The results are unexpected in two major ways. First, the hot flow anomaly is only formed during the interaction of the TD with the quasi‐parallel side of the bow shock. The lack of a HFA on the perpendicular side is due to the inability of a large fraction of ions to escape into the solar wind, as is required for an HFA to form. Second, the interaction of the TD with the quasi‐perpendicular portion of the bow shock results in a previously unknown, shock structure which we name the “solitary shock.” The solitary shock consists of a finite width (a few ion inertial length), fast magnetosonic shock‐like structure followed by a relatively less compressed, more turbulent plasma with complex and spatially varying properties in the downstream region. We have determined that the formation of the solitary shock after the passage of the TD is due to the new direction of the interplanetary magnetic field. Further, this is not a transitory phenomena and when the interplanetary magnetic field cone angle is large (∼>50°) a significant portion of the bow shock surface is affected. Solitary shocks form in the regions where the motional electric field in the magnetosheath points away from the shock. We demonstrate that solitary shocks differ from regular quasi‐perpendicular shocks due to differences in ion dissipation processes. We also present the results of a detailed survey of the effects of simulation parameters such as cell size, resistivity, system size, and 2.5‐dimensional versus three‐dimensional domains on the solitary shock solutions.
Modeled variations of the reconnection electric field at the dayside magnetopause during continued flux transfer event activity
Authors: Penz T. , Farrugia C. J. , Ivanova V. V. , Semenov V. S. , Ivanov I. B. , Cowley S. W. H. , Biernat H. K. , Torbert R. B.
Published: January 2007

Three periods of repeated flux transfer event (FTE) observations made by the Cluster satellites are investigated by a novel method for extracting from the observations the reconnection electric field Erec. On 21 January 2001, a series of FTEs is observed at the poleward edge of the cusp around 15 magnetic local time (MLT). Another series of FTEs is observed on 14 February 2001, at somewhat earlier MLTs at the high‐latitude magnetopause at the equatorward edge of the cusp. In both cases, ground‐based radar observations confirm that Cluster observations refer to transient reconnection. Additionally, we consider an event of several magnetosheath FTEs on 26 January 2001, during very steady interplanetary conditions. Here we apply a model based on time‐dependent Petschek‐type magnetic reconnection to the in situ magnetic field data to obtain the temporal variations of the reconnection electric field responsible for each FTE of the three series. On 14 February 2001 we find peak average values of Erec = 2.1 ± 0.4 mV/m for the magnetospheric FTEs and peak average values Erec = 0.9 ± 0.5 mV/m for the magnetosheath FTEs. The corresponding result for the four FTEs on 21 January 2001 is 3.7 ± 0.8 mV/m. Finally, the four FTEs observed on 26 January 2001 give a reconnection rate of 2.85 ± 1.68 mV/m. These results are discussed in the context of estimates of the reconnection electric field at the magnetopause obtained from diverse techniques.
Mammalian SGO2 appears at the inner centromere domain and redistributes depending on tension across centromeres during meiosis II and mitosis
Authors: Gómez Rocío , Valdeolmillos Ana , Parra María Teresa , Viera Alberto , Carreiro Candelas , Roncal Fernando , Rufas Julio S , Barbero José L , Suja José A
Published: January 2007

Shugoshin (SGO) is a family of proteins that protect centromeric cohesin complexes from release during mitotic prophase and from degradation during meiosis I. Two mammalian SGO paralogues—SGO1 and SGO2—have been identified, but their distribution and function during mammalian meiosis have not been reported. Here, we analysed the expression of SGO2 during male mouse meiosis and mitosis. During meiosis I, SGO2 accumulates at centromeres during diplotene, and colocalizes differentially with the cohesin subunits RAD21 and REC8 at metaphase I centromeres. However, SGO2 and RAD21 change their relative distributions during telophase I when sister‐kinetochore association is lost. During meiosis II, SGO2 shows a striking tension‐dependent redistribution within centromeres throughout chromosome congression during prometaphase II, as it does during mitosis. We propose a model by which the redistribution of SGO2 would unmask cohesive centromere proteins, which would be then released or cleaved by separase, to trigger chromatid segregation to opposite poles.
Interpretation of the roughness for a competitive columnar growth
Authors: Rodríguez-Cañas E. , Vasco E. , Sacedón J. L. , Aznárez J. A.
Published: January 2007

The decomposition of the surface morphology of films into well-defined elements, which are spatially distributed, allows us to obtain a versatile set of parameters to describe the element shape. The roughness is explicitly expressed in terms of such shape parameters. Based on that, the thickness dependence of the resulting roughness for a competitive columnar growth of evaporated Au[111] thin films was predicted, exhibiting a good agreement with experimental data. The roughness expression is subsequently generalized to a wider set of functional systems with attractive morphologies. The decomposition method proposed here is thus revealed as a promising surface-analysis tool.
Alpha particle mitigation strategies to reduce chip soft error upsets
Authors: Cabral C. , Rodbell K. P. , Gordon M. S.
Published: January 2007

The continued scaling of complementary metal oxide semiconductor device technologies has lead to continued device shrinkage and decreases in the Vdd, the operating voltage of the device transistors. Scaling has meant denser circuitry overall, thinner silicon (e.g., silicon on insulator) in logic applications, and less charge on capacitors for volatile memory. These trends have resulted in devices being more sensitive to soft errors since now low energy alpha particles can flip a memory bit or alter timing in a logic circuit. The alpha particle source is, in many cases, self-inflicted, because alpha particles are commonly generated in materials adjacent to the chip, solders, and in the packaging. In this paper we discuss several schemes by which these alpha particles can be blocked, such that all of their energy is absorbed before reaching the sensitive silicon circuitry at the transistor level. These alpha blocking layers are shown to be effective both through the use of modeling and through experimental measurements.
Model colloidal fluid with competing interactions: Bulk and interfacial properties
Authors: Archer A. J. , Pini D. , Evans R. , Reatto L.
Published: January 2007

Using a simple mean field density functional theory (DFT), the authors investigate the structure and phase behavior of a model colloidal fluid composed of particles interacting via a pair potential which has a hard core of diameter σ, is attractive Yukawa at intermediate separations, and is repulsive Yukawa at large separations. The authors analyze the form of the asymptotic decay of the bulk fluid correlation functions, comparing results from DFT with those from the self-consistent Ornstein-Zernike approximation (SCOZA). In both theories the authors find rich crossover behavior, whereby the ultimate decay of correlation functions changes from monotonic to long wavelength damped oscillatory decay on crossing certain lines in the phase diagram or sometimes from oscillatory to oscillatory with a longer wavelength. For some choices of potential parameters the authors find, within the DFT, a λ line at which the fluid becomes unstable with respect to periodic density fluctuations. SCOZA fails to yield solutions for state points near such a λ line. The propensity towards clustering of particles, which is reflected by the presence of a long wavelength (⪢σ) slowly decaying oscillatory pair correlation function, and a structure factor that exhibits a very sharp maximum at small but nonzero wave numbers, is enhanced in states near the λ line. The authors present density profiles for the planar liquid-gas interface and for fluids adsorbed at a planar hard wall. The presence of a nearby λ transition gives rise to pronounced long wavelength oscillations in the one-body density profiles at both types of interface.
Highly spin-polarized tunneling in fully epitaxial Co2Cr0.6Fe0.4Al∕MgO∕Co50Fe50 magnetic tunnel junctions with exchange biasing
Authors: Marukame Takao , Ishikawa Takayuki , Hakamata Shinya , Matsuda Ken-ichi , Uemura Tetsuya , Yamamoto Masafumi
Published: January 2007

Fully epitaxial magnetic tunnel junctions (MTJs) with exchange biasing were fabricated with a full-Heusler alloy Co2Cr0.6Fe0.4Al (CCFA) thin film and a MgO tunnel barrier, where a Co50Fe50 upper electrode was used in a synthetic ferrimagnetic Co50Fe50∕Ru∕Co90Fe10 trilayer exchange-biased with an IrMn layer through the Co90Fe10∕IrMn interface. The fabricated MTJs exhibited clear exchange-biased tunnel magnetoresistance (TMR) characteristics with high TMR ratios of 109% at room temperature and 317% at 4.2K. A high tunneling spin polarization of 0.88 at 4.2K was estimated for epitaxial CCFA films with the B2 structure.
Electrically tunable negative permeability metamaterials based on nematic liquid crystals
Authors: Zhao Qian , Kang Lei , Du Bo , Li Bo , Zhou Ji , Tang Hong , Liang Xiao , Zhang Baizhe
Published: January 2007

An electrically tunable negative permeability metamaterial consisting of a periodic array of split ring resonators infiltrated with nematic liquid crystals is demonstrated. It shows that the transmitted resonance dip of the metamaterial can be continuously and reversibly adjusted by an applied electric field, and the maximum shift is about 210MHz with respect to the resonance frequency around 11.08GHz. Numerical simulation shows that the permeability is negative near the resonance frequency, and the frequency range with negative permeability can be dynamically adjusted and widened by about 200MHz by the electric field. It provides a convenient means to design adaptive metamaterials.
Motifs for molecular recognition exploiting hydrophobic enclosure in protein–ligand binding
Authors: Young Tom , Abel Robert , Kim Byungchan , Berne Bruce J. , Friesner Richard A.
Published: January 2007

The thermodynamic properties and phase behavior of water in confined regions can vary significantly from that observed in the bulk. This is particularly true for systems in which the confinement is on the molecular-length scale. In this study, we use molecular dynamics simulations and a powerful solvent analysis technique based on inhomogenous solvation theory to investigate the properties of water molecules that solvate the confined regions of protein active sites. Our simulations and analysis indicate that the solvation of protein active sites that are characterized by hydrophobic enclosure and correlated hydrogen bonds induce atypical entropic and enthalpic penalties of hydration. These penalties apparently stabilize the protein–ligand complex with respect to the independently solvated ligand and protein, which leads to enhanced binding affinities. Our analysis elucidates several challenging cases, including the super affinity of the streptavidin–biotin system.
In search of the small ones: improved prediction of short exons in vertebrates, plants, fungi and protists
Authors: Saeys Yvan , Rouzé Pierre , Van de Peer Yves
Published: January 2007

Motivation: Prediction of the coding potential for stretches of DNA is crucial in gene calling and genome annotation, where it is used to identify potential exons and to position their boundaries in conjunction with functional sites, such as splice sites and translation initiation sites. The ability to discriminate between coding and non-coding sequences relates to the structure of coding sequences, which are organized in codons, and by their biased usage. For statistical reasons, the longer the sequences, the easier it is to detect this codon bias. However, in many eukaryotic genomes, where genes harbour many introns, both introns and exons might be small and hard to distinguish based on coding potential.

Results: Here, we present novel approaches that specifically aim at a better detection of coding potential in short sequences. The methods use complementary sequence features, combined with identification of which features are relevant in discriminating between coding and non-coding sequences. These newly developed methods are evaluated on different species, representative of four major eukaryotic kingdoms, and extensively compared to state-of-the-art Markov models, which are often used for predicting coding potential. The main conclusions drawn from our analyses are that (1) combining complementary sequence features clearly outperforms current Markov models for coding potential prediction in short sequence fragments, (2) coding potential prediction benefits from length-specific models, and these models are not necessarily the same for different sequence lengths and (3) comparing the results across several species indicates that, although our combined method consistently performs extremely well, there are important differences across genomes.

Supplementary data:  

Contact:  yvan.saeys@psb.ugent.be
THE ELECTROSTATIC FIELD OF TWO EQUAL CIRCULAR CO-AXIAL CONDUCTING DISKS
Authors: LOVE E. R.
Published: January 2007

In the earliest discussion of this problem Nicholson (1) expressed the potential as a series of spheroidal harmonics with coefficients satisfying an infinite system of linear equations, and gave a formula for an explicit solution; but this formula appears to be meaningless and its derivation to contain serious errors.

In the present paper, starting tentatively from Nicholson's infinite system of linear equations, a much simpler, though still implicit, specification of the potential is developed; this involves a Fredholm integral equation the existence and uniqueness of whose solution are deducible from standard theory. The specification so obtained for the potential is shown rigorously to satisfy the differential equation and boundary conditions of the electrostatic problem.

The Neumann series of the integral equation is shown to converge to its solution, so that the potential, and other aspects of the field, can be explicitly formulated and thus computed.

The errors in Nicholson's process of solving his system of equations are exhibited in detail, and it is concluded that attempts to carry through that process without error cannot lead to an explicit solution.
Wittgenstein's aeronautical investigation
Authors: Lemco Ian
Published: January 2007

After a rigorous German education in the physical sciences, young Ludwig Wittgenstein entered Manchester University as an aeronautical engineering research student. There he devised and patented a novel aero-engine employing an airscrew propeller driven by blade tip-jets. Within the context of the growth of English aviation during the first half of the twentieth century (including the contributions of many Fellows of the Royal Society) and taking into account related aspects of his life, this paper examines an unfulfilled engineering aspiration. In enlarging upon what Wittgenstein might have accomplished during his stay at Manchester, it contrasts his invention with later comparable proven designs, albeit applied to hybrid rotorcraft. His engine employed centrifugal flow compression and arguably was a precursor of Sir Frank Whittle's gas turbine. In conclusion, reasons are given for Wittgenstein's departure from Manchester.
Theory of four-point alternating current potential drop measurements on conductive plates
Authors: Bowler John R , Bowler Nicola
Published: January 2007

Measurements of alternating current potential drop (ACPD) made at the surface of a conductive plate can be used to determine, non-destructively, the parameters of the plate such as its thickness, electrical conductivity and linear effective magnetic permeability. In order to invert the measured potential drop to yield values for these parameters, a theoretical model is needed. In this work, closed form analytical expressions are derived for the ACPD measured between the two voltage electrodes of a four-point probe. Alternating current is injected and extracted by two current electrodes. The problem is formulated in terms of a single, transverse magnetic, potential. The exact solution for the electromagnetic field is expressed in terms of a Green's function for a plate via the method of images. The ACPD is also expressed as a sum of contributions from multiple images. Two series representations are given: one converges more rapidly for plates which are somewhat thicker than the probe dimensions and the other for plates which are somewhat thinner. Theoretical expressions for the ACPD in special cases of thick (half space) and thin conductors are shown to agree with the results presented previously. In this paper, calculated ACPD values are compared with the experimental data taken on a titanium plate, in the regime in which the plate thickness is similar to the probe length and excellent agreement is obtained.
Hearing in eight species of northern Canadian freshwater fishes
Authors: Mann D. A. , Cott P. A. , Hanna B. W. , Popper A. N.
Published: January 2007

The hearing thresholds of eight fish species from northern Canada were measured using auditory evoked potential techniques. The species with the best hearing was the lake chub Couesius plumbeus, followed by the longnose sucker Catastomus catastomus, both which had relatively sensitive hearing over the frequency range tested from 100 to 1600 Hz. The remaining species (troutperch Percopsis omiscomaycus, nine‐spined stickleback Pungitius pungitius, pike Esox lucius, spoonhead sculpin Cottus ricei, burbot Lota lota and broad whitefish Coregonus nasus) all showed most sensitivity to low frequencies (<400 Hz) and had relatively insensitive high frequency hearing. The two species with the best hearing are otophysan fishes with connections between the swimbladder and inner ear. The spoonhead sculpin lacks a swimbladder, while the other non‐otophysan species have swimbladders, but no specialized connection to the inner ear. These results can be used to predict the potential impact of anthropogenic noise, such as seismic air gun blasts, on hearing in these species. The species with the most sensitive hearing (lake chub and longnose sucker) are most likely to be affected by activities such as seismic air gun surveys.
Sexual colouration and sperm traits in guppies
Authors: Pitcher T. E. , Rodd F. H. , Rowe L.
Published: January 2007

The relationships among the area, hue, saturation and brightness of orange colouration and sperm traits in the guppy Poecilia reticulata were investigated. Males with greater areas of orange colouration had significantly larger sperm loads, more motile sperm and longer sperm relative to males with relatively little orange colouration. Males with greater areas of orange colouration did not possess more viable sperm than males with relatively little orange colouration. There was no evidence that any of the sperm traits were related to the hue, saturation or brightness of the orange colouration. These results are discussed in the context of the roles that direct and indirect selection might play in maintaining female preference for male guppies with large areas of orange colouration.
Further analysis of gene‐for‐gene disease resistance specificity in flax
Authors: ELLIS JEFFREY G. , LAWRENCE GREGORY J. , DODDS PETER N.
Published: January 2007

The flax rust resistance gene L, a nucleotide binding site, leucine‐rich repeat (NBS‐LRR) class of plant resistance gene, has 12 characterized alleles with different gene‐for‐gene resistance specificities. Here the specificities of presumptive L1, L5, L8 and L11 genomic clones are confirmed by transgenic expression. L6 and L11 differ by 33 amino acids, 32 in the LRR region and one in the C‐terminal non‐LRR region, and recognize unrelated avirulence proteins, AvrL567 and AvrL11, respectively. To analyse the specificity differences, 13 L6L11 recombinant genes were constructed in vitro and tested in transgenic flax for resistance to F2 progeny of rust strain CH5, in which the unlinked avirulence genes AvrL567 and AvrL11 segregate. The data show that the single C‐terminal non‐LRR region polymorphism is not involved in L6–L11 specificity differences, that polymorphisms necessary for specificity are spread throughout the LRR region and that some polymorphisms essential for L11 are not essential for L6. Seven ‘null’ recombinants expressed no resistance when tested with CH5‐derived rusts. These were tested for new resistance specificities by inoculation with a strain of rust, Bs‐1, which is distantly related to CH5 and which potentially carries a different range of avirulence specificities. The ‘null’ recombinant L6L11RV, which differs from L6 and L11 by its susceptibility to CH5, was resistant to strain Bs‐1. The specificity difference is due to a reduction in the number of AvrL567 variants recognized by L6L11RV compared with L6 and not due to recognition of an unrelated Avr gene product in strain Bs‐1.
Negative bending in seismic reflection associated with time‐advanced and time‐retarded fields
Authors: Ikelle Luc T. , Gangi Anthony F.
Published: January 2007

We present an analysis of scattering diagrams (i.e., Feynman‐like diagrams for wave scattering) of the correlation‐type representation theorem for ordinary inhomogeneous media with both positive stiffnesses and positive Poisson's ratios. This analysis reveals scattering events whose scattering diagrams include “negative” bending (i.e., bending in the opposite direction of that of scattering diagrams in ordinary inhomogeneous media). Unlike common scattering events, these events are inconsistent with the current interpretation of some of the basic physical laws, such as Snell's law, just like the so‐called “negative refraction” in optics. Yet we find them very useful, for instance, in suppressing some undesired events from scattering data.
Paraxial ray methods for anisotropic inhomogeneous media
Authors: Jan Moser Tijmen , Červený Vlastislav
Published: January 2007

A new formalism of surface‐to‐surface paraxial matrices allows a very general and flexible formulation of the paraxial ray theory, equally valid in anisotropic and isotropic inhomogeneous layered media. The formalism is based on conventional dynamic ray tracing in Cartesian coordinates along a reference ray. At any user‐selected pair of points of the reference ray, a pair of surfaces may be defined. These surfaces may be arbitrarily curved and oriented, and may represent structural interfaces, data recording surfaces, or merely formal surfaces. A newly obtained factorization of the interface propagator matrix allows to transform the conventional 6 × 6 propagator matrix in Cartesian coordinates into a 6 × 6 surface‐to‐surface paraxial matrix. This matrix defines the transformation of paraxial ray quantities from one surface to another. The redundant non‐eikonal and ray‐tangent solutions of the dynamic ray‐tracing system in Cartesian coordinates can be easily eliminated from the 6 × 6 surface‐to‐surface paraxial matrix, and it can be reduced to 4 × 4 form. Both the 6 × 6 and 4 × 4 surface‐to‐surface paraxial matrices satisfy useful properties, particularly the symplecticity. In their 4 × 4 reduced form, they can be used to solve important boundary‐value problems of a four‐parametric system of paraxial rays, connecting the two surfaces, similarly as the well‐known surface‐to‐surface matrices in isotropic media in ray‐centred coordinates. Applications of such boundary‐value problems include the two‐point eikonal, relative geometrical spreading, Fresnel zones, the design of migration operators, and more.
Pharmacokinetics of a new long acting endectocide formulation containing 2.25% ivermectin and 1.25% abamectin in cattle
Authors: BORGES F. A. , CHO H. S. , SANTOS E. , OLIVEIRA G. P. , COSTA A. J.
Published: January 2007

The objective of this study was to determine the kinetic parameters of a new formulation that contained 2.25% ivermectin combined with 1.25% abamectin in bovine plasma. The results for 2.25% ivermectin: Cmax (37.11 ng/mL ± 7.42), Tmax (16 days ± 5.29), T1/2 (44.62 days ± 53.89), AUC (928.2 ng·day/mL ± 153.83) and MRT (36.73 days ± 33.64), and for 1.25% abamectin: Cmax (28.70 ng/mL ± 9.54), Tmax (14 days ± 4.04), T1/2 (15.40 days ± 11.43), AUC (618.05 ng·day/mL ± 80.27) and MRT (20.79 days ± 8.43) suggest that this combination of 2.25% ivermectin + 1.25% abamectin possesses properties that give this pharmaceutical formula a longer activity time than two of the commercial products tested (1% ivermectin and 1% abamectin), and showed similarity to 3.15% ivermectin.
Emotional Intelligence and Emotional Creativity
Authors: Ivcevic Zorana , Brackett Marc A. , Mayer John D.
Published: January 2007

ABSTRACT
Three studies examined the relationship between emotional intelligence (EI) and emotional creativity (EC) and whether each construct was predictive of creative behavior. It was hypothesized that the relationship between EI and EC corresponds to the relationship between cognitive intelligence and creative ability. Therefore, EI and EC were expected to be two distinct sets of abilities. Intercorrelations and confirmatory factor analyses supported the hypothesis. Furthermore, it was hypothesized that EC, but not EI, would correlate with behavioral creativity. Self‐report measures of EC significantly correlated with laboratory and self‐reported creativity measures in both studies, while ability measures of EC only correlated with self‐reported artistic activity. EI was uncorrelated with creative behavior.