bluuebunny/crossref_metadata_2025 huggingface dataset:
Discrimination of near‐native structures in protein–protein docking by testing the stability of local minima
Authors: Kozakov Dima , Schueler‐Furman Ora , Vajda Sandor
Published: February 2008

Fast Fourier transform (FFT) correlation methods of protein–protein docking, combined with the clustering of low energy conformations, can find a number of local minima on the energy surface. For most complexes, the locations of the near‐native structures can be constrained to the 30 largest clusters, each surrounding a local minimum. However, no reliable further discrimination can be obtained by energy measures because the differences in the energy levels between the minima are comparable with the errors in the energy evaluation. In fact, no current scoring function accounts for the entropic contributions that relate to the width rather than the depth of the minima. Since structures at narrow minima loose more entropy, some of the nonnative states can be detected by determining whether or not a local minimum is surrounded by a broad region of attraction on the energy surface. The analysis is based on starting Monte Carlo Minimization (MCM) runs from random points around each minimum, and observing whether a certain fraction of trajectories converge to a small region within the cluster. The cluster is considered stable if such a strong attractor exists, has at least 10 convergent trajectories, is relatively close to the original cluster center, and contains a low energy structure. We studied the stability of clusters for enzyme–inhibitor and antibody–antigen complexes in the Protein Docking Benchmark. The analysis yields three main results. First, all clusters that are close to the native structure are stable. Second, restricting considerations to stable clusters eliminates around half of the false positives, that is, solutions that are low in energy but far from the native structure of the complex. Third, dividing the conformational space into clusters and determining the stability of each cluster, the combined approach is less dependent on a priori information than exploring the potential conformational space by Monte Carlo minimizations. Proteins 2008. © 2008 Wiley‐Liss, Inc.
NMR structure and dynamics of human ephrin‐B2 ectodomain: The functionally critical C‐D and G‐H loops are highly dynamic in solution
Authors: Ran Xiaoyuan , Qin Haina , Liu Jingxian , Fan Jing‐Song , Shi Jiahai , Song Jianxing
Published: February 2008

Eph receptors and ephrins constitute the largest family of receptor tyrosine kinases with 15 individual receptors and nine ligands. Its ectodomains represent attractive targets not only for understanding fundamental mechanisms underlying axon guidance, cell migration, segmentation, tumorigenesis, and bone remodeling, but also for drug screening/design to treat cancers, bone diseases and viral infection. So far no NMR study on the ephrin ectodomains is available and as such their properties in solution still remain unknown. In this study, we presented the first NMR structure and dynamics of the human ephrin‐B2 ectodomain as well as its interaction with the receptor EphB2. Strikingly, the NMR study reveals a picture different from those previously obtained by X‐ray crystallography. Although in solution it still adopts the same Greek key fold, with the central β‐barrel (∼30% of the molecule) highly similar to that in crystal structures, the other regions are highly dynamic and accessible to the bulk solvent. In particular, the functionally critical C‐D and G‐H loops of the ephrin‐B2 ectodomain are highly flexible as reflected by several NMR probes including hydrogen exchange and 15N backbone relaxation data. Nevertheless, as revealed by ITC and NMR, the ephrin‐B2 ectodomain binds to EphB2 with a Kd of 22.3 nM to form a tight complex in which the tip of the C‐D loop and the C‐terminus still remain largely flexible. The present results may bear critical implications in understanding the molecular details as well as designing antagonists of therapeutic interest for Eph‐ephrin interactions. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Diurnal variation of walnut tree volatiles and electrophysiological responses in Cydia pomonella (Lepidoptera: Tortricidae)
Authors: Casado Daniel , Gemeno César , Avilla Jesús , Riba Magí
Published: February 2008

BACKGROUND: In recent years, many studies have been carried out on the behavioural and electrophysiological responses of Cydia pomonella (L.) to host volatile emissions, to find alternative attractants to the sex pheromone for pest monitoring. These studies have focused on apple and pear, and very little has been done on walnut. In the present work, the diurnal and seasonal variation in walnut volatile emissions and the electrophysiological response of C. pomonella have been studied.

RESULTS: Ninety compounds were detected in walnut emissions, mainly monoterpenes and sesquiterpenes. The most abundant compound was β‐pinene, which, together with (Z)‐3‐hexenyl acetate, (E)‐β‐ocimene, limonene, germacrene D, 1,8‐cineole, sabinene, (E)‐β‐farnesene, (E)‐β‐caryophyllene, β‐myrcene and β‐phellandrene, constituted between 81.9 and 90.5% of the total chromatographic area. Differences between seasonal periods were significant for 39 compounds, and between daytimes for 14 compounds. Discernible and consistent EAD responses were detected to 11 walnut‐origin compounds, and confirmed with synthetics to seven of them. Except for alloocimene, pinocarvone and caryophyllene oxide, all these compounds are also emitted by apple.

CONCLUSION: Walnut volatile emissions differ widely from apple ones, but both share many compounds that are EAD‐active in C. pomonella. However, among EAD‐active compounds there are three walnut‐specific ones, which should be further tested in behavioural assays. Copyright © 2008 Society of Chemical Industry
Effect of some biorational insecticides on Spodoptera eridania in organic cabbage
Authors: Michereff‐Filho Miguel , Torres Jorge B , Andrade Luzia NT , Nunes Maria Urbana C
Published: February 2008

BACKGROUND: To reduce pest attack, several biorational products are allowed for use on organic vegetables in Brazil. This study investigated eight biorational products applied singly or in combination against Spodoptera eridania Cramer in field plots of cabbage intercropped with coriander. The treatments were applied once a week over a 5 week period, beginning 34 days after transplanting. The evaluations consisted of counting the larvae of S. eridania on the day before and 7 and 21 days after spraying. The damage to leaves and cabbage head, the commercial weight of head and the percentage of head losses were evaluated.

RESULTS: Leaf injury in plots treated with Beauveria bassiana and neem oil (Dalneem®) yielded scores of 1.3 and 2.5 (scale ranging from 0 to 4) respectively, in comparison with a score of 3.6 from untreated plots. Head weight losses were 6.1, 5.3 and 4.9% with an aqueous extract of neem leaves, neem oil and B. bassiana respectively, compared with 24.6% lost from untreated plots.

CONCLUSION: Dalneem®, B. bassiana and the extract of neem leaves at 20% exhibited the best performance for control of S. eridania. Copyright © 2008 Society of Chemical Industry
Optically isotropic negative index of refraction metamaterial
Authors: Kussow Adil‐Gerai , Akyurtlu Alkim , Angkawisittpan Niwat
Published: February 2008

We report a metamaterial with optically isotropic negative refraction index, n, and small loss factor, k = |Im (n)/Re (n)| ≤ 0.4, that occurs near the visible/UV line. The metamaterial presented consists of two media. One medium (randomly distributed gold spherical nanoparticles with Drude‐like permittivity, in free space) ensures negative permittivity, and another medium (spherical SiC nanoparticles) ensures negative permeability via the Mie resonance within the same frequency range. We have found, self‐consistently, in the framework of both the effective medium approach and rigorous first‐principles based Finite Difference Time Domain (FDTD) simulations, that the metamaterial exhibits negative refraction index behavior. This result stands for both the random distribution of the SiC particles, and the regular simple‐cubic lattice of the same particles. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preface: phys. stat. sol. (c) 5/3
Authors: Baranovski Sergei
Published: February 2008

The following papers were presented at the 12th International Conference on Transport in Interacting and Disordered Systems (TIDS12) held 6–10 August 2007 in Marburg, Germany.

It followed previous meetings in Egmond aan Zee (2005), Trieste (2003), Shefayim (2001), Murcia (1999), Rackeve (1997), Jerusalem (1995), Glasgow (1993), Marburg (1991), Chapel Hill (1989), Bratislava (1987), and Trieste (1985). The conference was organized by the Faculty of Physics, Philipps‐University Marburg. It was co‐sponsored by the Deutsche Forschungsgemeinschaft, by the International Research Training Group “Electron–Electron Interactions in Solids” (Marburg/Budapest), by Isabellenhuette Heusler GmbH KG, Dillenburg, by Marburger Universitätsbund e.V., and by Ursula Kuhlmann‐Fond.

About 70 scientists from 17 countries attended the meeting. The program counted 12 invited talks, 30 oral and 30 poster contributions. They covered traditional topics for TIDS meetings. With respect to semiconductor inorganic materials, most emphasis was put on many‐particle interactions, electron glass, slow relaxations, metal–insulator transition, magnetoresistance, quantum Hall effect, and noise. In many talks transport processes in organic materials and polymers were considered, which has become a tradition for TIDS meetings. Also various aspects of transport in biological systems, such as membrane channels, DNA molecules, and bacteria were discussed in several talks.

Not every talk and poster given at the TIDS12 is present with a paper in these Proceedings. However, the reader should be able to come up with a general picture of the TIDS12. Furthermore, the proceedings illustrate that rather similar physical ideas are applicable to charge transport properties of chemically different materials. It is this generality of the fundamental transport mechanisms in disordered interacting systems that allows researchers from different fields to understand each other and to discuss at the TIDS meetings various aspects of transport processes in chemically very different materials: inorganic, organic and biological systems. Examples for the ideas invoked in the conference and related to these issues can be found among the papers of the proceedings.

The Guest Editor is highly indebted to Dr. Oleg Rubel and Dr. Kakhaber Jandieri, who contributed decisively to editing the TIDS12 Proceedings.

November 2007
Many electron theory of 1/f ‐noise in hopping conductivity
Authors: Burin Alexander L. , Shklovskii Boris I. , Kozub Veniamin I. , Galperin Yuri M. , Vinokur Valerii
Published: February 2008

The cover picture of this issue of physica status solidi (c) has been taken from the article [1]. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Extrusion of starch‐based loose‐fill packaging foams: effects of temperature, moisture and talc on physical properties
Authors: Pushpadass Heartwin Amaladhas , Babu Govindarajan Suresh , Weber Robert W. , Hanna Milford A.
Published: February 2008

Starch‐based loose‐fill packaging foams were made in a single‐screw laboratory‐scale extruder. Corn starch was blended with polystyrene in the ratio of 70  :  30 and extruded into foams using talc and polycarbonate as additives. Extrusions were carried out at moisture contents of 16, 18 and 20% (dry basis), and at barrel temperatures of 140 and 160°C. The influences of extrusion temperature, moisture content of starch, talc and polycarbonate on the radial expansion and other selected physical properties of starch foams were investigated. The effects of moisture and talc contents on the radial expansion of foams were found to be critical, while the role of temperature was close to significant. The expansion ratio increased when the moisture content was increased from 16 to 18%, and then decreased when moisture content was increased to 20%. In general, the expansion ratios of foams were higher at 160°C as compared to 140°C. Although polycarbonate mixed well with the starch–polystyrene melt, it was not effective as a structural and anti‐shrinking agent, and it did not contribute to the radial expansion. In general, the bulk densities and unit densities of the starch foams decreased as the moisture content and extrusion temperature increased. Scanning electron microscope images showed that the addition of talc yielded foams with smaller‐sized cells, with less expansion of the foam melt, and thus a higher density. X‐ray diffractograms revealed that the crystallinity of starch foams increased post‐extrusion, and there was adequate dispersion of the starch and polystyrene polymers to make the foam water‐resistant. Copyright © 2008 John Wiley & Sons, Ltd.
Micro‐ion beam analysis of physico‐chemical reactions at the interface between sol–gel derived glass particles in the SiO2CaO system and biological fluids
Authors: Lao J. , Nedelec J. M. , Moretto Ph. , Jallot E.
Published: February 2008

In this study, we benefited from the sensitivity of ion beam analysis methods to characterise in vitro the bioactive glass/biological fluids interface and to perform local measurements of elemental concentrations at the 10−6 g/g level. A glass in the SiO2CaO composition was elaborated by sol–gel processing. Samples of glass powders were soaked in biological fluids for periods up to 4 days. The surface changes were characterised using particle‐induced X‐ray emission (PIXE) associated to Rutherford backscattering spectroscopy (RBS), which are efficient methods for multi‐elemental analysis. In addition, these ion beam methods permit accurate trace elements quantification. Elemental maps of major and trace elements were obtained at a micrometer scale and revealed the bone‐bonding ability of the material. The formation of a calcium phosphate‐rich layer occurs after a few minutes of interaction and the glass particles are progressively coated with this thin film. Traces of magnesium are proved to be blended into the CaP layer. Kinetics of formation of the CaP layer shows the high reactivity of this material in contact with a biological medium. However the CaPMg layer is finally dissolved after a few days of interaction. The absence of P in the initial glass matrix may explain that SiO2CaO glass particles encounter great difficulties to achieve the transformation of their peripheral amorphous Ca‐P layer into a more stable bone‐like apatite phase. Copyright © 2008 John Wiley & Sons, Ltd.
Tribochemical reactions on polyimide sliding surfaces evaluated with Raman spectroscopy and atomic force microscopy
Authors: Samyn Pieter , Schoukens Gustaaf
Published: February 2008

The friction and wear properties of polyimide at high temperatures are influenced by important tribochemical reactions on the sliding surfaces. Hydrolysis at 100–140 °C causes high friction and low wear whereas imidisation at 180–260 °C causes low friction and high wear. Raman spectroscopy confirms that the imidised structure that forms during sliding is characterised by reorientation of the C‐N‐C imide bonds from transverse into axial conformation. Also, the CO and C‐O‐C groups become more flexible and reorient in the worn imide structure. Depending on the normal loads, reorientation is either concentrated on the CO side groups at low loads or on the C‐N‐C and C‐O‐C backbone structure at high loads. Black spots on the surface represent a degraded fraction of polyamic acid monomers. Different surface morphologies are observed from atomic force microscopy. Hydrolysed structures correspond to an irregular surface pattern with pits and are preferentially worn parallel to the sliding direction. The imidised surface is smoother due to high strength and has a structure oriented along the sliding direction. However, it is more brittle and hence craters are formed that are larger compared to those formed under low‐temperature sliding conditions. Depositions on the sliding surfaces at 220–260 °C represent interaction of debris particles on the polyimide surface. On the nanometer scale, a progressive orientation of polyimide clusters parallel to the sliding direction is detected. Copyright © 2008 John Wiley & Sons, Ltd.
Study of preferential sputtering and segregation effects on the surface composition of AlPdMn quasi‐crystals
Authors: Samavat Feridoun , Gladys Michael J. , Jenks Cynthia J. , Lograsso Thomas A. , King Bruce V. , O'Connor D. John
Published: February 2008

Using 2 keV He+ and Ne+ low‐energy ion scattering (LEIS), it was found that the Al/Pd concentration ratio at the surface of a nominally Al69.9Pd20.5Mn9.6 quasi‐crystal decreases to a steady‐state value under bombardment as a result of preferential sputtering. Sputtering of an annealed surface results in a significant increase in Mn concentration on the surface which remained at annealing temperatures below 575 K. Variations of the Mn/Pd and Al/Pd ratios have been measured by LEIS as a function of temperature in the range 295–975 K for clean‐annealed and sputtered surfaces. The results show that Al/Pd ratio does not significantly change from 295 to 575 K for both He+ and Ne+ but increases with sample temperatures up to 875 K. Copyright © 2008 John Wiley & Sons, Ltd.
Systems engineering metrics and applications in product development: A critical literature review and agenda for further research
Authors: Vanek Francis , Jackson Peter , Grzybowski Richard
Published: February 2008

The military/aerospace industries have several decades of experience in the application of systems engineering. In the world of complex systems developed under contract, systems engineering has a well‐articulated, generally accepted, client‐mandated methodology. This is not the case currently in most commercially oriented research and development organizations. Unlike the military/aerospace environment, it is not widely accepted that systems engineering can or will deliver value within commercial enterprises. This said, it is possible that a systems engineering‐like methodology may be routinely employed but not so stated, or is recognized under a different label. This seems likely since complex products continue to be successfully developed and commercialized via the use of methods that are closely related to systems engineering. The purpose of this paper is to establish the groundwork for measuring the effectiveness of the systems engineering methodology, and closely associated analogs, as part of the product development process in a commercial research and development organization. In this paper, we review the literature in systems engineering and related fields to identify measurement issues and methodologies, specific metrics proposed and in use, and case studies and best practices. We also identify gaps in the literature and propose the next steps in a research agenda. © 2008 Wiley Periodicals, Inc. Syst Eng
Green‐maize potential of hybrid and open‐pollinated cultivars at varying levels of applied nitrogen: relationship with grain yield
Authors: Kim SK , Adetimirin VO , Yoon ST , Adepoju MA , Gbadamosi BA
Published: February 2008

Two sets (white‐ and yellow‐kernelled) of six cultivars of field‐maize, each comprising three hybrids and three open‐pollinated (OP) varieties, were evaluated for green‐maize productivity under three levels of nitrogen fertilisation (0, 60 and 120  kg  ha−1) at two locations in southwestern Nigeria. The relationship between green‐maize and grain yield was also investigated. Numbers of marketable ears and marketable‐ear yield were significantly correlated. Green‐maize traits and grain yields showed different responses to increased nitrogen fertiliser application: grain yield was significantly greater at 120  kg  ha−1 than at 60  kg  ha−1 whereas marketable‐ear yield was not significantly changed by the higher rate. The hybrids showed higher green‐maize and grain yield responses than the OPs to fertiliser application. At 60  kg  ha−1 nitrogen application, marketable‐ear yield averaged 0.620  kg  m−2 and 0.567  kg  m−2 for white hybrids and OPs, respectively, and 0.576  kg  m−2 and 0.439  kg  m−2 for yellow hybrids and OPs. Marketable‐ear yield was significantly correlated with grain yield for both the white and yellow cultivars. Regressions of grain yield on marketable‐ear yield were significant and such regression equations can thus be used to estimate marketable‐ear yield potential from grain yield data. Copyright © 2008 John Wiley & Sons, Ltd
Nonlinear optimization for adaptive antenna array receivers with a small data‐record size
Authors: Xie Ning , Zhou Yuanping , Zhang Li , Qian Gongbin , Wang Hui , Li Xia
Published: February 2008

Design of a nonlinear adaptive antenna array receiver is a challenging task in wireless communications due to the limited number of antenna elements and the presence of correlated signals, which directly affect the performance of an antenna array. More importantly, a conventional nonlinear array receiver is often associated with a high computational complexity that undermines its applicability in practice. In this paper, we present a new approach to adaptive beamforming receiver that provides superior performance in antenna array overloading and in the presence of correlated signals with a low complexity. In particular, the proposed receiver requires a small data‐record size to estimate the beamformer weights, which is beneficial in applications with fast fading channels. Simulation examples illustrate the performance improvement of the proposed array receiver when it is compared to the conventional beamformers. Copyright © 2008 John Wiley & Sons, Ltd.
Trace metals in the seagrass Thalassia testudinum from the Mexican Caribbean coast
Authors: Solís C. , Isaac‐Olivé K. , Martínez A. , Lavoisier E. , Ruiz Z.
Published: February 2008

The impact of human activities on Mexican Caribbean zones is reflected in the partial or total destruction of these habitats and the increasing settlement of urban and tourist resorts. As a consequence, waste water discharged to sea increases the levels of chemical elements and foreign substances in the marine environment. In order to accomplish an adequate management and conservation of the coastal ecosystems, it is necessary to make an adequate diagnosis of the situation through factors that may monitor the vulnerability as well as the level of damage of the aquatic communities. In this work we present results on the use of seagrass Thalassia testudinum, as a potential bio‐indicator of metal pollution in Caribbean seawater. Seagrass was collected in Holbox and Puerto Morelos (considered as mildly influenced by human activities) in the State of Quintana Roo. Trace metals were determined by particle induced x‐ray emission (PIXE) and atomic absorption (AA). Results are reported for metals such as Fe, Mn, Cu, Zn, Pb, and Cd. The metal distribution on the different parts of the plant, the differences between two sites, and the effect of season are discussed. Copyright © 2008 John Wiley & Sons, Ltd.
Time and size resolved elemental component study of urban aerosol in Debrecen, Hungary
Authors: Kertész Zsófia , Dobos Erik , Fenyős Bernadett , Kéki Renáta , Borbély‐Kiss Ildikó
Published: February 2008

With the use of accelerator‐based PIXE (particle induced x‐ray emission) elemental analysis technique systematic investigation of aerosol samples have been performed in the Institute of Nuclear Research of the Hungarian Academy of Sciences for 15 years. In continuation of this research, we observe the short‐term time variation of the inorganic elemental components and the elemental mass size distributions in the spring of 2007, at the end of the heating season. Aerosol sampling campaigns were carried out with a PIXE International continuous streaker sampler (PM10) and a 9‐stage cascade impactor in a downtown site of Debrecen. Meteorological data were recorded simultaneously with aerosol sampling. Another campaign was carried out with 2‐stage nuclepore samplers (PM2.5 and PM2.5−10) in the same downtown and an outskirt site of the city.

The short‐time variation of urban aerosol combined with meteorological data and with mass size distribution serves as a basis to reach a better understanding of the aerosol sources and receptor areas, to select single episodes, to follow the evolution of aerosol, and to make a better estimate on the health impact. Copyright © 2008 John Wiley & Sons, Ltd.
Transport of Neolithic variscites demonstrated by PIXE analysis
Authors: Querré G. , Herbault F. , Calligaro Th.
Published: February 2008

The large grave mounds from the Carnac region in Brittany are among the most impressive funeral architecture of the Neolithic period in France. The exceptional quality of the adornments such as polished stones, axes and beads necklaces deposited in burial chambers, probably reflects the high status of the buried persons. Despite the importance of these artifacts, already pointed out by archaeologists during the early excavations of the 19th century, their origins have never been really established on the basis of objective criteria. This study is focused on the beads, green in majority, similar to turquoise colour. A combination of technotypological study and chemical analysis by external‐beam particle‐induced x‐ray emission (PIXE) has been performed on these archaeological artifacts. The composition in major elements gives the mineralogical nature of the material, which turns out to be variscite, a hydrated aluminum phosphate. By comparison with the composition of variscite reference samples from various geological sources of Western Europe, the concentrations in trace elements allowed us to establish that the beads originated from the Iberian Peninsula. The presence of these Iberian ornamental elements in archaeological sites in Western France thus reveals long‐distance relations between the Neolithic human groups during the fifth to second millennium BC. Copyright © 2008 John Wiley & Sons, Ltd.
Atomic bremsstrahlung of Al, Ag and Au targets bombarded with 1.5 MeV protons
Authors: Ishii K. , Matsuyama S. , Yamazaki H. , Kikuchi Y. , Momose G. , Satoh T.
Published: February 2008

Continuous x‐rays produced in light‐ion atom collisions have been experimentally and theoretically studied. The experimental results for aluminum target bombarded with ∼1.5 MeV protons can be mainly explained by atomic bremsstrahlung (AB) of K‐shell electrons. We measured the continuous x‐ray spectra from a silver target and gold target bombarded with 1.5 MeV protons at the detection angle of 90° with respect to the beam direction to investigate AB of L‐ and M‐shell electrons and found that the experimental production cross‐sections of continuous x‐rays are much smaller than the predictions based on the plane wave born approximation (PWBA) theory of AB. The discrepancy can be reduced by taking account of a screening effect previously introduced, but this does not resolve the problem completely. We applied the theory of AB based on the binary encounter approximation (BEA) and compared this with the experiment. It is shown by the BEA theory that, without consideration of the screening effect, the agreement between the theory and the experimental cross‐sections of the Al target, Ag target and Au target can be systematically explained by the AB of K‐, L‐ and M‐ electrons, respectively. Copyright © 2008 John Wiley & Sons, Ltd.
Developing a simple screening method for the identification of historic biocide residues on herbarium material in museum collections
Authors: Purewal V. , Colston B. , Röhrs S.
Published: February 2008

The National Museum of Wales (NMW), houses ca 250 000 higher plant specimens, with material dating back to the 17th century. Herbaria have been a major source of botanical research and reference for centuries and the collections have increased over time from donations and through collecting.

Owing to its organic content, botanical material is susceptible to insect and fungal attack. Even aged, dried material is a source of sugar and protein. Institutions and collectors have prevented such attacks through the application of pesticides. Treatments containing compounds of arsenic, lead and mercury were commonplace, and have remained stable over time. Consequently, present‐day handling of these collections presents a potential health risk to staff and visitors through inhalation and skin absorption, particularly since the quantity and nature of the pesticide applied is unknown. Occasionally the residues are visible, but research has shown that herbarium sheets, which appear untouched and have been previously treated, contain high concentrations of toxic metals.

The use of a UV hand‐held lamp has helped to identify sheets that have been treated, even though treatment is not visible to the naked eye. The UV causes areas to fluoresce on the herbarium mount sheet. These areas were analysed by particle induced x‐ray emission (PIXE), and have been found to correlate with pesticide applications containing mercury and arsenic.

This research has shown the feasibility of using a hand‐held UV lamp as a screening method for identifying contaminated samples within museum collections and provided a means to prioritise which collections require immediate re‐mounting. Copyright © 2008 John Wiley & Sons, Ltd.
Nuclear microprobe studies of grasshopper feeding on nickel hyperaccumulating plants
Authors: Augustyniak M. , Przybyłowicz W. , Mesjasz‐Przybyłowicz J. , Tarnawska M. , Migula P. , Głowacka E. , Babczyńska A.
Published: February 2008

Grasshopper Stenoscepa sp is an insect species feeding on the South‐African Ni‐hyperaccumulating plants. Large amounts of Ni ingested by them have no effect on their development. To explain their ability to survive in such extreme conditions, we investigated the distribution of elements in the insect body by means of a nuclear microprobe [micro‐particle induced x‐ray emission (PIXE) and backscattering (BS)]. GeoPIXE II software was used for quantitative elemental mapping complemented by evaluation of data extracted from arbitrarily selected micro‐areas. Micro‐PIXE analysis in Stenoscepa sp tissues showed the highest Ni level in the gut and Malpighian tubules. The activity of glutathione‐dependent enzymes and glutathione (GSH) content in the tissues of second‐stage larvae were measured. One of the ways to survive under chronic Ni exposure conditions is an intensified GSH synthesis. GSH concentration in tissues of the grasshoppers was very high, about six times higher than in larvae of other Acrididae species from areas contaminated with heavy metals in Europe. Catalase (CAT) activity was 5–10 times lower in comparison to other Orthoptera species. Glutathione reductase (GR) activity was unexpectedly low (at the detection limit level). Likely, the studied grasshoppers may use other metabolic pathways for regeneration of the reduced form of GSH, e.g. thioredoxine system. Copyright © 2008 John Wiley & Sons, Ltd.
The use of biomonitors and PIXE analysis in the study of air pollution in Mexico City
Authors: Cervantes L. , Ávila O. , Ruvalcaba J. L. , Miranda J. , Muñoz R.
Published: February 2008

An environmental study of air contamination in the Valley of Mexico is under investigation based on the use of two biomonitors: the epiphytic lichen Flavopunctelia flaventior (L.) Nyl, and bromeliaceae Thillandsia recurvata (Ruiz and Pav), which are rather sensitive to air pollution and have a great capability to absorb and accumulate airborne mineral elements, including heavy metals. The thalli of lichen samples were collected in a controlled area, La Marquesa National Park, while bromeliaceae were collected in San Juan Teacalco, Estado de México. Samples were subsequently transplanted to 13 sites corresponding to 12 stations of the automatic network of atmospheric monitoring in the metropolitan area of the Valley of Mexico and a control site. This region includes urban and industrial places and one rural station. The study area is located at an altitude of 2240 m, with about 20 million inhabitants; it includes 3.5 million vehicles and 35 000 industries as well. The samples of transplanted lichen and bromeliaceae were exposed during 6 months in different seasonal periods during the year from 2002 to 2003. Pellets were prepared from ashes of the exposed lichens and bromeliaceae. The contents of Cr, Cu, Fe, Ni, Mn, Pb, Zn, and other trace elements were determined by particle‐induced x‐ray emission (PIXE), using an external proton beam setup. Copyright © 2008 John Wiley & Sons, Ltd.
Fundamental study on an arsenic hyperaccumulator plant using submilli‐PIXE camera
Authors: Yamazaki H. , Ishii K. , Matsuyama S. , Kikuchi Y. , Takahashi Y. , Kawamura Y. , Watanabe R. , Tashiro K. , Inoue C.
Published: February 2008

We have developed an in‐air particle‐induced x‐ray emission(PIXE) analysis system that provides elemental distribution images in a region of 3 × 3 cm2 with a spatial resolution of ∼0.5 mm. We call this system an in‐air submilli‐PIXE camera. This system consists of a submilli‐beam line, beam scanners and a data acquisition system for elemental mapping. We applied the in‐air submilli‐PIXE camera to phytoremediation research. Phytoremediation is a technology for cleaning metal‐contaminated soils using plant physiology. Pteris vittata, which is known as a hyperaccumulator of arsenic, was analyzed by the PIXE camera. Elemental images of laminas were obtained in vivo without sample preparation. The elemental map of the laminas in several centimeters region showed that arsenic was accumulated in the edges of P. vittata fronds and redistributed in the laminas at different growth stages. The submilli‐PIXE camera is an effective tool for undertaking phytoremediation research. Copyright © 2008 John Wiley & Sons, Ltd.
PIXE in the study of archaeological and historical glass
Authors: Calligaro T.
Published: February 2008

The particle induced x‐ray emission (PIXE) method, especially when carried out with an external beam, is a remarkable tool for the scientific investigation of objects of cultural heritage. We present here two case studies addressing important issues of archaeological and historical glass: deformulation of ancient glass recipes, determination of provenance of raw materials and understanding the weathering processes endangering these precious artifacts. This contribution illustrates the place of the PIXE technique among other analytical methods based on radiations in the study of this specific material. In the first example, PIXE is used to determine the provenance of a natural glass, obsidian, which forms the support of two paintings of the Spanish master Murillo (17th century.) on display in the Louvre museum. The comparison of the chemical fingerprints obtained by PIXE with an obsidian composition database established by instrumental neutron activation (INAA) and XRF shows that the rectangular obsidian panels were imported from Mexico. These investigations also permit to highlight the complementarities of these analytical techniques. In the second example, PIXE is applied to a 12th‐century stained glass window from the Saint‐Denis basilica (Paris) to determine the various medieval glasses (soda and potash types) employed in this panel. In addition, by combining p‐PIXE with He‐PIXE, PIGE (proton‐induced gamma‐ray emission), p‐RBS (Rutherford Backscattering Spectrometry) and He‐RBS, alteration markers of the glass surface, useful in conservation science, are evidenced. Copyright © 2008 John Wiley & Sons, Ltd.
The Neglect of the Global Surgical Workforce: Experience and Evidence from Uganda
Authors: Ozgediz Doruk , Galukande Moses , Mabweijano Jacqueline , Kijjambu Stephen , Mijumbi Cephas , Dubowitz Gerald , Kaggwa Samuel , Luboga Samuel
Published: February 2008

Background

Africa’s health workforce crisis has recently been emphasized by major international organizations. As a part of this discussion, it has become apparent that the workforce required to deliver surgical services has been significantly neglected.

Methods

This paper reviews some of the reasons for this relative neglect and emphasizes its importance to health systems and public health. We report the first comprehensive analysis of the surgical workforce in Uganda, identify challenges to workforce development, and evaluate current programs addressing these challenges. This was performed through a literature review, analysis of existing policies to improve surgical access, and pilot retrospective studies of surgical output and workforce in nine rural hospitals.

Results

Uganda has a shortage of surgical personnel in comparison to higher income countries, but the precise gap is unknown. The most significant challenges to workforce development include recruitment, training, retention, and infrastructure for service delivery. Curricular innovations, international collaborations, and development of research capacity are some of the initiatives underway to overcome these challenges. Several programs and policies are addressing the maldistribution of the surgical workforce in urban areas. These programs include surgical camps, specialist outreach, and decentralization of surgical services. Each has the advantage of improving access to care, but sustainability has been an issue for all of these programs. Initial results from nine hospitals show that surgical output is similar to previous studies and lags far behind estimates in higher‐income countries. Task‐shifting to non‐physician surgical personnel is one possible future alternative.

Conclusions

The experience of Uganda is representative of other low‐income countries and may provide valuable lessons. Greater attention must be paid to this critical aspect of the global crisis in human resources for health.
The Diffusion of Youth‐Led Participatory Research in Urban Schools: The Role of the Prevention Support System in Implementation and Sustainability
Authors: Ozer Emily J. , Cantor Jeremy P. , Cruz Gary W. , Fox Brian , Hubbard Elizabeth , Moret Lauren
Published: February 2008

This article discusses the dissemination of a process of youth‐led participatory research in urban secondary schools within the Interactive Systems Framework for Dissemination and Implementation (ISF) developed in collaboration with the CDC and its university partners (Wandersman et al. American Journal of Community Psychology, 41(3–4) 2008). The focus here is on the development of the Prevention Support System with respect to general and innovation‐specific capacity building. The specific process under study involves youth‐led needs assessment and research to inform the planning of prevention programs and policies to address students' health and developmental needs. The article first briefly describes the youth‐led research process, its potential benefits, and a case example in two urban secondary schools. It then describes challenges and responses in providing support for the diffusion of this model in 6 secondary schools. The settings are urban public schools with a majority of students of color from diverse ethnic groups: Asian‐American, Latino, and African‐American. This project constitutes a collaborative partnership with a university school of public health and community‐based organizations (CBOs) to build capacity for long‐term, sustainable implementation of this innovative process within the local school system. The perspectives of the university‐based researcher and the CBO partners on the development and effectiveness of the Prevention Support System are presented.
Detritivory: stoichiometry of a neglected trophic level
Authors: Martinson Holly M. , Schneider Katie , Gilbert James , Hines Jessica E. , Hambäck Peter A. , Fagan William F.
Published: February 2008

Previous syntheses have identified the key roles that phylogeny, body size, and trophic level play in determining arthropod stoichiometry. To date, however, detritivores have been largely omitted from such syntheses, despite their importance in nutrient cycling, biodiversity, and food web interactions. Here, we report on a compiled database of the allometry and nutritional stoichiometry (N and P) of detritivorous arthropods. Overall, both N and P content for detritivores varied among major phylogenetic lineages. Detritivore N content was similar to the N content of herbivores, but below that of predators. By contrast, detritivore P content was independent of trophic level. Contrary to previous reports, neither nutrient varied with body size. This analysis places detritivores in the context of related herbivores and predators, and as such, sets the stage for future investigations into the causes and consequences of elemental (mis)matches between detritivores and their detrital resources.
Microemulsion Formation and Detergency with Oily Soil: IV. Effect of Rinse Cycle Design
Authors: Tanthakit Parichat , Chavadej Sumaeth , Scamehorn John F. , Sabatini David A. , Tongcumpou Chantra
Published: February 2008

The objective of this work was to apply a microemulsion‐based formulation for the removal of motor oil in laundry detergency at low salinity. To produce the desired phase behavior, three surfactants were used: alkyl diphenyl oxide disulfonate (ADPODS), sodium dioctyl sulfosuccinate (AOT) and sorbitan monooleate (Span 80). The mixed surfactant system of 1.5% ADPODS, 5% AOT and 5% Span 80 (13 parts ADPODS, 43.5 parts AOT, and 43.5 parts Span 80 of the total actives) was found to form a middle phase microemulsion (Type III) at a relatively low salinity of 2.83% NaCl. When this formulation was diluted, detergency performance increased with increasing total surfactant concentration and leveled off above about 0.1% total actives on the three types of fabrics studied (pure cotton, 65/35 polyester/cotton blend, and pure polyester). Detergency was found to improve with increasing hydrophilicity of the fabric with cotton being cleanest after washing and polyester the most difficult to clean. To achieve a specified oil removal, less rinse water can be used if a higher number of lower‐volume rinses are employed. An interesting characteristic of microemulsion‐based formulations is that a substantial fraction of oil removal occurs during the rinse cycle. In this work, this removal is shown to be due to the low oil/water interfacial tension during initial rinsing and is therefore strongly correlated to residual surfactant concentration in the rinse steps. As a result, the number of rinses and the volume of water per rinse can profoundly affect detergency in these systems.
The Effect of Natural and Synthetic Antioxidants on the Oxidative Stability of Biodiesel
Authors: Tang Haiying , Wang Anfeng , Salley Steven O. , Ng K. Y. Simon
Published: February 2008

A significant problem associated with the commercial acceptance of biodiesel is poor oxidative stability. This study investigates the effectiveness of various natural and synthetic antioxidants [α‐tocopherol (α‐T), butylated hydroxyanisole (BHA), butyl‐4‐methylphenol (BHT), tert‐butylhydroquinone (TBHQ), 2, 5‐di‐tert‐butyl‐hydroquinone (DTBHQ), ionol BF200 (IB), propylgallate (PG), and pyrogallol (PY)] to improve the oxidative stability of soybean oil (SBO‐), cottonseed oil (CSO‐), poultry fat (PF‐), and yellow grease (YG‐) based biodiesel at the varying concentrations between 250 and 1,000 ppm. Results indicate that different types of biodiesel have different natural levels of oxidative stability, indicating that natural antioxidants play a significant role in determining oxidative stability. Moreover, PG, PY, TBHQ, BHA, BHT, DTBHQ, and IB can enhance the oxidative stability for these different types of biodiesel. Antioxidant activity increased with increasing concentration. The induction period of SBO‐, CSO‐, YG‐, and distilled SBO‐based biodiesel could be improved significantly with PY, PG and TBHQ, while PY, BHA, and BHT show the best results for PF‐based biodiesel. This indicates that the effect of each antioxidant on biodiesel differs depending on different feedstock. Moreover, the effect of antioxidants on B20 and B100 was similar; suggesting that improving the oxidative stability of biodiesel can effectively increase that of biodiesel blends. The oxidative stability of untreated SBO‐based biodiesel decreased with the increasing indoor and outdoor storage time, while the induction period values with adding TBHQ to SBO‐based biodiesel remained constant for up to 9 months.
Muscle Lipids and Fatty Acid Profiles of the Sea Catfish (Arius madagascariensis) in Madagascar Inland Waters
Authors: Rasoarahona J. R. E. , Ramanoelina P. A. R. , Bianchini J.‐P. , Gaydou E. M.
Published: February 2008

Muscle lipids and fatty acids (FA) of catfish Arius madagascariensis were determined in catfish caught in the Betsiboka River, Madagascar, during a 5‐month sampling period. Total lipids from muscle were extracted and quantified. Fatty acids were identified by means of gas chromatography–mass spectrometry of FA methyl esters and FA pyrrolidides, leading to the identification of 42 FA. Lipid content was relatively high in our fish sample and ranged from 4.3 to 6.6% of wet muscle. Three FA dominated the FA composition: palmitic acid (C16:0, 22.9–32.6%), oleic acid (C18:1n‐9, 11.3–13.4%) and stearic acid (C18:0, 10.8–12.0%). A number of polyunsaturated FA (PUFA) were present in appreciable amounts, including arachidonic acid (C20:4n‐6, 4.7–7.6%), docosahexaenoic acid (C22:4n‐6, 3.0–8.1%), eicosapentaenoic acid (C20:5n‐3, 0.6–1.0%), n‐3 docosapentaenoic acid (C22:5n‐3, 1.1–1.6%), n‐6 docosatetraenoic acid (C22:4n‐6, 0.7–1.2%) and n‐6 docosapentaenoic acid (22:5n‐6, 0.9–1.8%). The sum of the n‐6 PUFA and n‐3 PUFA was 11.3–18.8 and 7.5–13.4%, respectively. These results indicate that A. madagascariensis, an abundant freshwater fish in Madagascar rivers, may be good source of dietary PUFA.
Attention deficit/hyperactivity disorder and video games: A comparative study of hyperactive and control children
Authors: Bioulac Stéphanie , Arfi Lisa , Bouvard Manuel P.
Published: February 2008

Introduction

This study describes and compares the behavior of hyperactive and control children playing video games.

Subjects and methods

The sample consisted of 29 ADHD children and 21 controls aged between 6 and 16 years playing video games. We used the Child Behavior Checklist and the Problem Videogame Playing scale (PVP scale). This instrument gives objective measures of problem use, which can be considered as an indication of addictive videogame playing. We designed a questionnaire for the parents, eliciting qualitative information about their child's videogame playing. There were no significant differences concerning frequency or duration of play between ADHD children and controls but differences were observed on the PVP scale. None of the controls scored above four whereas 10 hyperactive children answered affirmatively to five or more questions. These children presented a greater intensity of the disorder than the other ADHD children.

Conclusion

While no differences concerning video game use were found, ADHD children exhibited more problems associated with videogame playing. It seems that a subgroup of ADHD children could be vulnerable to developing dependence upon video games.
Retracted: Cardiac release of urocortin precedes the occurrence of irreversible myocardial damage in the rat heart exposed to ischemia/reperfusion injury
Authors: Knight Richard A. , Chen-Scarabelli Carol , Yuan Zhaokan , McCauley Roy B. , Di Rezze J. , Scarabelli Gabriele M. , Townsend Paul A. , Latchman David , Saravolatz Louis , Faggian Giuseppe , Mazzucco Alessandro , Chowdrey Hardial S. , Stephanou Anastasis , Scarabelli Tiziano M.
Published: February 2008

This study evaluates whether cardiac ischemia induces release of urocortin, before and independently from myocyte cell death. Urocortin levels rose after 5‐min ischemia and peaked after 10‐min ischemia, when cell death was not detected. However, myocyte apoptosis and/or necrosis occurred following 20‐ and 30‐min ischemia, which paralleled a fall in urocortin levels, suggesting that urocortin expression and release are mainly sustained by metabolically challenged, though still viable myocytes. Hence, since cardiac release of urocortin, unlike that of conventional biomarkers, occurs before and apart from cell death, urocortin levels may be clinically useful in the diagnosis of sublethal myocardial ischemia.