bluuebunny/crossref_metadata_2025 huggingface dataset:
A comparison of Arctic Ocean sea ice concentration among the coordinated AOMIP model experiments
Authors: Johnson Mark , Gaffigan Steve , Hunke Elizabeth , Gerdes Ruediger
Published: March 2007

Sea ice concentration is a fundamental property of the Arctic ice‐ocean‐atmosphere system reflecting both dynamics and thermodynamics. Concentration integrates across space and time and is useful for characterizing both observed and numerically simulated systems. Concentration is reasonably well measured by remote sensing, and several high‐quality sea ice concentration data sets exist beginning with the satellite era. In this paper we examine the simulated sea ice concentration from nine ice‐ocean numerical models that are part of the coordinated experiments of the Arctic Ocean Model Intercomparison Project (AOMIP). Spatial patterns of means and differences between models and observations, and among models, are compared for a multiyear record and for the September sea ice minimum. Interannual variations are assessed on data with monthly climatology removed. As a proxy for the annual cycle of open water for each model, the total areas with concentration less than 10% are compared among models. Mean ice statistics are computed for grid points with greater than 1% and greater than 10% concentrations. The results show that the models have similar characteristics for the winter months when 100% cover is produced, and most models reproduce an observed minimum in sea ice concentration for 1990. The compared observational data sets use the NASA Team algorithm (Goddard Space Flight Center data, the adjusted or Walsh data, and the Hadley Centre data) and the Bootstrap algorithm. Variability in sea ice concentration is less among the four observational records than among models.
Miscible displacement fronts of shear thinning fluids inside rough fractures
Authors: Boschan A. , Auradou H. , Ippolito I. , Chertcoff R. , Hulin J. P.
Published: March 2007

The miscible displacement of a shear‐thinning fluid by another fluid with the same rheological properties is studied experimentally in a transparent fracture by an optical technique that images relative concentration distributions. The fracture walls have complementary self‐affine geometries and are shifted laterally in the direction perpendicular to the mean flow velocity U: The flow field is strongly channelized and macrodispersion controls the front structure for Péclet numbers above a few units. The global front width increases therefore linearly with time and reflects the velocity distribution between the different channels. In contrast, at the local scale, front spreading is similar to Taylor dispersion between plane‐parallel surfaces. Both dispersion mechanisms depend strongly on the fluid rheology, which shifts from Newtonian to shear thinning when the flow rate increases. In the latter domain, increasing the concentration enhances the global front width but reduces both Taylor dispersion (due to the flattening of the velocity profile in the gap of the fracture) and the size of medium scale front structures.
A Fragrant Introduction to Terpenoid Chemistry
Authors: Sell Charles S
Published: March 2007

Terpenoids play an important part in all our lives, from Vitamin A and hormones to perfumes and pharmaceuticals. This book provides an introduction to terpenoid chemistry, concentrating on the lower terpenoids, but the basic principles taught are also the foundation for the chemistry of the higher terpenoids. Coverage includes: the biogenesis of terpenoids; some of the history of the field; the principles of structural determination; and the importance of stereochemistry and stereoselective synthesis. Carbocation chemistry is introduced, as are the principles of total and partial synthesis. Finally, industrial chemistry (both discovery chemistry and chemical process development) is discussed, using the volatile terpenoids of perfumery to illustrate basic concepts. Ideal as both an introduction to terpenoid chemistry and as a refresher course, A Fragrant Introduction to Terpenoid Chemistry, with its real-life problems and appreciation of the relevance of chemistry to everyday life, will prove invaluable to students, lecturers and industrialists alike.
Chromatographic Integration Methods
Authors: Dyson Norman
Published: March 2007

The second edition of the popular Chromatographic Integration Methods has been completely revised and updated. Written by an expert with many years' experience with two of the world's largest manufacturers of computing integrators, it has been expanded to include a new section on validation of integrators in response to regulatory requirements for quality and validation. A new literature survey, additional diagrams and Author Index have also been added. Well illustrated and easily read, this is an excellent source book for those who wish to increase their understanding of integrators. Chromatographic Integration Methods describes and discusses both manual and electronic techniques used, with the aim of aiding analysts to obtain more data from their chromatograms, and assist them with understanding how integrators work so that results are never accepted unquestioningly. As with the first edition, this book will be welcomed by all those in the chromatography field, particularly those at the bench.
Colour Chemistry
Authors: Christie Robert
Published: March 2007

This book provides an up-to-date insight into the chemistry behind the colour of the dyes and pigments that make our world so colourful. The impressive breadth of coverage starts with a dip into the history of colour science. Colour Chemistry then goes on to look at the structure and synthesis of the various dyes and pigments, along with their applications in the traditional areas of textiles, coatings and plastics, and also the ever-expanding range of "high-tech" applications. Also discussed are some of the environmental issues associated with the manufacture and use of colour. The broad and balanced coverage presented in this book makes it ideal for students and graduates. In addition, many specialists in industry or academia will also benefit from the overview of the subject that is provided.
Free Energy Relationships in Organic and Bio-organic Chemistry
Authors: Williams Andrew , Williams Judith
Published: March 2007

Introducing the application of free energy correlations to elucidating the mechanisms of organic and bio-organic reactions, this book provides a new and illuminating way of approaching a potentially complex topic. The idea of how free energy correlations derive from polar substituent change is introduced, and common pitfalls encountered in the application of free energy relationships are described, along with the use of these anomalies in mechanistic studies. The concept of effective charge is described in detail, with examples of its application. Throughout, worked answers are provided for the problems posed. Databases of parameters, an extensive bibliography and comprehensive lists of further reading are also included. The text provides an invaluable source of information to senior undergraduates, postgraduates and to industrial researchers with an interest in mechanistic studies. It is the first such book in more than thirty years.
Mechanisms in Organic Reactions
Authors: Jackson Richard A
Published: March 2007

An increasing knowledge and understanding of organic reaction mechanisms has been a major factor in the rapid advance of organic chemistry, biochemistry and pharmacology in the last century. It therefore forms a vital part of today's chemistry courses. Mechanisms in Organic Reactions helps students to make sensible proposals for the mechanisms of particular organic reactions, and then how to distinguish between different possible mechanisms. Techniques for this include product studies, kinetics, and the identification of intermediates. Three chapters on intermediates discuss likely points of attack on molecules by anions, radicals and cations, and the important role of acid- and base-catalysed reactions and radical chain reactions. The prediction of reaction rates and the effects of structural changes on reaction rate are also covered. It concludes with a discussion of molecular reactions, both thermal and photochemical - reactions which provide deep and beautiful insights into the reasons why some reactions go and others do not, and why the majority of real-life reactions involve multi-step processes. The book provides both illuminating insights into fundamental chemistry, and also practical value for students who will go on to teach, research, or be involved in other scientific roles (administration, policy making or journalism). Ideal for the needs of undergraduate chemistry students, Tutorial Chemistry Texts is a major series consisting of short, single topic or modular texts concentrating on the fundamental areas of chemistry taught in undergraduate science courses. Each book provides a concise account of the basic principles underlying a given subject, embodying an independent-learning philosophy and including worked examples.
Polymers and the Environment
Authors: Scott G
Published: March 2007

As environmental performance becomes increasingly important, the development of man-made polymers and their associated benefits has been overshadowed by problems relating to their ultimate disposal. In the light of wider acceptance of polymers for use in high technology applications, Polymers and the Environment aims to redress the balance. The book reviews the properties and industrial applications of polymers and discusses their environmental benefits compared with traditional materials. It also addresses the issues of polymer durability, recycling processes to aid waste minimization and biodegradable polymers. This text is intended to introduce the non-specialist reader to the benefits and limitations of polymeric materials from an environmental viewpoint, and will prove a useful book for both students and professionals.
Statistical Analysis Methods for Chemists
Authors: Gardiner William P
Published: March 2007

Many forms of chemical experimentation generate data needing analysis and interpretation in respect of the goals of the experiment and also the chemical factors which may influence the outcome. Statistical data analysis techniques provide the tools which enable a chemist to assess the information obtained from experiments. Statistical Analysis Methods for Chemists: A Software-based Approach aims to give a broad introduction to practical data analysis, and provides comprehensive coverage of basic statistical principles and reasoning. With practical examples, and integration of software output as the basis of data analysis, this useful book gives unique coverage of the statistical skills and techniques required in modern chemical experimentation. It will prove invaluable to students and researchers alike. Software update information is available from W Gardiner at w.gardiner@gcal.ac.uk or fax +44 (0)141 331 3608. Please accompany requests for information with details of the software version to be used.
Trace Element Analysis of Food and Diet
Authors: Aras Namik K , Ataman O Yavuz
Published: March 2007

Trace element analysis has a key role to play in quality control of food and diet. This timely book introduces the subject in a practical way - from sampling and the techniques available for trace analysis, to procedures for specific elements and data analysis. Beginning with a brief introduction and discussion of statistical evaluation of data, the subsequent chapter looks at trace analysis in general, with its essentials and terminology. Another section introduces sampling and preparation of foodstuffs such as wheat, potato, vegetables and milk. This is followed by descriptions of the various spectrometric techniques (atomic absorption, atomic emission, atomic fluorescence) that are available. Plasma techniques for both optical emission and mass spectrometry are presented, as are nuclear activation analysis and X-ray methods. A comparison of the various analytical techniques is provided, and a separate chapter handles speciation analysis. Finally, procedures for determining essential and toxic elements such as arsenic, iron, selenium and zinc are suggested, using several recent references. Detailed explanations and a simple format will appeal to laboratory technicians and graduate students, as well as more experienced researchers. Comprehensive coverage, coupled with illustrations and a guide to relevant literature and manufacturers, will make Trace Element Analysis of Food and Diet a valuable source of information for anyone working on analysis of trace elements in food, diet or other biological or environmental samples - particularly food engineers, agricultural scientists and government testing agency employees.
Catalysis
Authors: Kung Harold H , Masel Richard I , Niemantsverdriet J W , Schwarz James A , Haller Gary L , Guczi Laszlo , Iglesia Enrique , Moro-Oka Yoshihiko , Trifiro Ferruccio , Anderson Paul J , Borg Herman J , Bartholomew Calvin H , Cavani Fabrizio , Sarkany Antal , Ueda Wataru , Resasco Daniel E , Reyes Sebastian C , Yagasaki Eriko , Foulds Gary A , Lapszewicz Jack A , Contescu Cristian , Jagiello Jacek
Published: March 2007

There is an increasing challenge for chemical industry and research institutions to find cost-efficient and environmentally sound methods of converting natural resources into fuels chemicals and energy. Catalysts are essential to these processes and the Catalysis Specialist Periodical Report series serves to highlight major developments in this area. This series provides systematic and detailed reviews of topics of interest to scientists and engineers in the catalysis field. The coverage includes all major areas of heterogeneous and homogeneous catalysis and also specific applications of catalysis such as NOx control kinetics and experimental techniques such as microcalorimetry. Each chapter is compiled by recognised experts within their specialist fields and provides a summary of the current literature. This series will be of interest to all those in academia and industry who need an up-to-date critical analysis and summary of catalysis research and applications. Catalysis will be of interest to anyone working in academia and industry that needs an up-to-date critical analysis and summary of catalysis research and applications. Specialist Periodical Reports provide systematic and detailed review coverage in major areas of chemical research. Compiled by teams of leading experts in their specialist fields, this series is designed to help the chemistry community keep current with the latest developments in their field. Each volume in the series is published either annually or biennially and is a superb reference point for researchers. www.rsc.org/spr
Catalysis
Authors: Resasco Daniel E , Dixon Anthony G , Boudart Michel , Broadbelt Linda J , Hoelderich Wolfgang F , Johansson E Magnus , Sanati Mehri , Jaras Sven G , Chin Ya-Huei , Heinz D , Papadias Dennis , Thevenin Philippe O , Ersson Anders G , Gabrielsson Rolf , Menon P Govind , Bjornbom Pehr H , Jaras Sven G , Hornell Christina
Published: March 2007

There is an increasing challenge for chemical industry and research institutions to find cost-efficient and environmentally sound methods of converting natural resources into fuels chemicals and energy. Catalysts are essential to these processes and the Catalysis Specialist Periodical Report series serves to highlight major developments in this area. This series provides systematic and detailed reviews of topics of interest to scientists and engineers in the catalysis field. The coverage includes all major areas of heterogeneous and homogeneous catalysis and also specific applications of catalysis such as NOx control kinetics and experimental techniques such as microcalorimetry. Each chapter is compiled by recognised experts within their specialist fields and provides a summary of the current literature. This series will be of interest to all those in academia and industry who need an up-to-date critical analysis and summary of catalysis research and applications. Catalysis will be of interest to anyone working in academia and industry that needs an up-to-date critical analysis and summary of catalysis research and applications. Specialist Periodical Reports provide systematic and detailed review coverage in major areas of chemical research. Compiled by teams of leading experts in their specialist fields, this series is designed to help the chemistry community keep current with the latest developments in their field. Each volume in the series is published either annually or biennially and is a superb reference point for researchers.
Electron Paramagnetic Resonance
Authors: Beckert Dieter , Burkitt Mark , Canters Gerard , Groenen Edgar , Collison David , McInnes Eric , Eaton Gareth R , Eaton Sandra S , Giamello Elio , Huttermann Juergen , Kappl Reinhard , Kay Chris , Weber Stefan , Lurie David , Smirnov Alex , Smith Graham , Riedi Peter
Published: March 2007

Electron Paramagnetic Resonance (EPR) Volume 18 highlights major developments in this area reported in 2001 and 2002, with results being set into the context of earlier work and presented as a set of critical yet coherent overviews. The topics covered describe contrasting types of application ranging from biological areas such as EPR studies of free-radical reactions in biology and medically-related systems to experimental developments and applications involving EPR imaging the use of very high fields and time-resolved methods. Critical and up-to-the-minute reviews of advances involving the design of spin-traps advances in spin-labelling paramagnetic centres on solid surfaces exchange-coupled oligomers metalloproteins and radicals in flavoenzymes are also included. As EPR continues to find new applications in virtually all areas of modern science including physics chemistry biology and materials science this series caters not only for experts in the field but also those wishing to gain a general overview of EPR applications in a given area.
General and Synthetic Methods
Authors: Cousins R P C , Richardson Stuart K , Harrison Tim , Sweeney Jo B , Robertson G M , Thomas Susan E , Wills M , Kilburn Jeremy D , Street S D A , Steele J , Crawford L P , Kiefel Milton J , Harrowven Dave C , Perrio Stephanie , Riant Olivier , Marcos Carlos F
Published: March 2007

Specialist Periodical Reports provide systematic and detailed review coverage of progress in the major areas of chemical research. Written by experts in their specialist fields the series creates a unique service for the active research chemist, supplying regular critical in-depth accounts of progress in particular areas of chemistry. For over 80 years the Royal Society of Chemistry and its predecessor, the Chemical Society, have been publishing reports charting developments in chemistry, which originally took the form of Annual Reports. However, by 1967 the whole spectrum of chemistry could no longer be contained within one volume and the series Specialist Periodical Reports was born. The Annual Reports themselves still existed but were divided into two, and subsequently three, volumes covering Inorganic, Organic and Physical Chemistry. For more general coverage of the highlights in chemistry they remain a 'must'. Since that time the SPR series has altered according to the fluctuating degree of activity in various fields of chemistry. Some titles have remained unchanged, while others have altered their emphasis along with their titles; some have been combined under a new name whereas others have had to be discontinued. The current list of Specialist Periodical Reports can be seen on the inside flap of this volume.
Conservation Science
Authors: Barker B Des , Wyeth Paul , Rule Margaret , Koestler Robert J , Garside Paul , Thomson Roy , Eaton Rod , Daniels Vincent , Inkpen Rob , Roemich Hannelore , Petersen Karin , Gregory David J , Shashoua Yvonne R , Matthiesen Henning , Charola A Elena
Published: March 2007

Conservation of artefacts and heritage materials is an increasingly popular and fascinating area, spanning both historical and scientific disciplines. Materials come in many forms ranging from sunken ships to tapestries, from buildings to books. With this wide range of matrices and materials to analyse and preserve, an interdisciplinary approach is needed drawing upon skills from many areas of knowledge. Conservation Science: Heritage Materials links these fields of research together forming a comprehensive text book that discusses analytical aspects, wall paintings, organic and inorganic materials. It provides up to date information on subjects including research on decay and degradation and an understanding of the deterioration mechanisms of historic and artistic works. Also included are a number of case studies of particularly important finds including the upkeep of the Mary Rose and the preservation of the sail on Nelsons ship HMS Victory. This book provides an essential guide and reference source for those working in all areas of heritage conservation.
Nanoscopic Materials
Authors: Roduner Emil
Published: March 2007

Nanotechnology has been hailed as a key technology of the 21st century. The scope of this field is huge and could have a wide influence on many aspects of life. Nanoscience; the manipulation of matter at the atomic and molecular level, and nanomaterials; materials so small that their behaviour and characteristics deviate from those of macroscopic specimens and may be predicted by scaling laws or by quantum confinement effects, are discussed in Nanoscopic Materials: Size - Dependent Phenomena.

The book focuses on a qualitative and quantitative approach discussing all areas of nanotechnology with particular emphasis on the underlying physico-chemical and physical principles of nanoscience. Topics include electronic structure, magnetic properties, thermodynamics of size dependence and catalysis. There is also a section discussing the future potential of the field and the ethical implications of nanotechnology.

The book is ideal for graduate students of chemistry and materials science and researchers new to the field of nanoscience and nanotechnology.
Temperature-, concentration- and cholesterol-dependent translocation of L- and D-octa-arginine across the plasma and nuclear membrane of CD34+ leukaemia cells
Authors: Fretz Marjan M. , Penning Neal A. , Al-Taei Saly , Futaki Shiroh , Takeuchi Toshihide , Nakase Ikuhiko , Storm Gert , Jones Arwyn T.
Published: March 2007

Delineating the mechanisms by which cell-penetrating peptides, such as HIV-Tat peptide, oligoarginines and penetratin, gain access to cells has recently received intense scrutiny. Heightened interest in these entities stems from their ability to enhance cellular delivery of associated macromolecules, such as genes and proteins, suggesting that they may have widespread applications as drug-delivery vectors. Proposed uptake mechanisms include energy-independent plasma membrane translocation and energy-dependent vesicular uptake and internalization through endocytic pathways. In the present study, we investigated the effects of temperature, peptide concentration and plasma membrane cholesterol levels on the uptake of a model cell-penetrating peptide, L-octa-arginine (L-R8) and its D-enantiomer (D-R8) in CD34+ leukaemia cells. We found that, at 4–12 °C, L-R8 uniformly labels the cytoplasm and nucleus, but in cells incubated with D-R8 there is additional labelling of the nucleolus which is still prominent at 30 °C incubations. At temperatures between 12 and 30 °C, the peptides are also localized to endocytic vesicles which consequently appear as the only labelled structures in cells incubated at 37 °C. Small increases in the extracellular peptide concentration in 37 °C incubations result in a dramatic increase in the fraction of the peptide that is localized to the cytosol and promoted the binding of D-R8 to the nucleolus. Enhanced labelling of the cytosol, nucleus and nucleolus was also achieved by extraction of plasma membrane cholesterol with methyl-β-cyclodextrin. The data argue for two, temperature-dependent, uptake mechanism for these peptides and for the existence of a threshold concentration for endocytic uptake that when exceeded promotes direct translocation across the plasma membrane.
Electrical conductivity of cluster-assembled carbon/titania nanocomposite films irradiated by highly focused vacuum ultraviolet photon beams
Authors: Amati M. , Lenardi C. , Agostino R. G. , Caruso T. , Ducati C. , La Rosa S. , Bongiorno G. , Cassina V. , Podestà P. , Ravagnan L. , Piseri P. , Milani P.
Published: March 2007

We investigated the electrical transport properties of nanostructured carbon and carbon/titanium oxide nanocomposite films produced by supersonic cluster beam deposition and irradiated by highly focused vacuum UV photon beam. We have observed a relevant increase of the density of states at Fermi level, suggesting that the films acquire a “metallic” character. This is confirmed by the increment of the conductivity of four orders of magnitude for pure nanostructured carbon films and at least eight orders of magnitude for films containing 9at.% of titanium. A partial reversibility of the process is observed by exposing the modified films to molecular oxygen or directly to air. We demonstrate the capability of writing micrometric conductive strips (2–3μm width and 60μm length) and controlling the variation of the conductivity as a function of the titanium concentration.
A comparison between detailed and configuration-averaged collisional-radiative codes applied to nonlocal thermal equilibrium plasmas
Authors: Poirier M. , de Gaufridy de Dortan F.
Published: March 2007

A collisional-radiative model describing nonlocal-thermodynamic-equilibrium plasmas is developed. It is based on the HULLAC (Hebrew University Lawrence Livermore Atomic Code) suite for the transitions rates, in the zero-temperature radiation field hypothesis. Two variants of the model are presented: the first one is configuration averaged, while the second one is a detailed level version. Comparisons are made between them in the case of a carbon plasma; they show that the configuration-averaged code gives correct results for an electronic temperature Te=10 eV (or higher) but fails at lower temperatures such as Te=1 eV. The validity of the configuration-averaged approximation is discussed: the intuitive criterion requiring that the average configuration-energy dispersion must be less than the electron thermal energy turns out to be a necessary but far from sufficient condition. Another condition based on the resolution of a modified rate-equation system is proposed. Its efficiency is emphasized in the case of low-temperature plasmas. Finally, it is shown that near-threshold autoionization cascade processes may induce a severe failure of the configuration-average formalism.
Characterization and modeling of InGaAs/InAsP thermophotovoltaic converters under high illumination intensities
Authors: Su Ning , Fay Patrick , Sinharoy Samar , Forbes David , Scheiman David
Published: March 2007

Thermophotovoltaic converters based on In0.69Ga0.31As/InAs0.34P0.66 have been fabricated, characterized experimentally, and modeled. Good device performance has been achieved with an open-circuit voltage of 1.46 V, short-circuit current density of 1.06 A/cm2, and a fill factor of 71.3% for a four-junction cell under an optical power density of 3.4 W/cm2. Key material parameters have been extracted from measured device characteristics, providing a detailed quantitative understanding of the dependence of device performance on the electro-optical properties of the InGaAs/InAsP material system. Extracted minority carrier lifetimes of 106 ns in the p-type base and 0.3 ns in the n-type emitter regions were obtained, limited by radiative and Auger recombination, respectively. The recombination velocity for the InGaAs/InAsP interface is found to be below 2000 cm/s. The parameter analysis provides guidance for the design of a high-efficiency monolithically integrated module for use under high illumination intensities.
Erasing diffraction orders: Opal versus Langmuir-Blodgett colloidal crystals
Authors: Romanov S. G. , Bardosova M. , Whitehead D. E. , Povey I. M. , Pemble M. , Sotomayor Torres C. M.
Published: March 2007

The optical transmission of photonic crystals self-assembled from colloidal nanospheres in opals and assembled from two-dimensional colloidal crystals in a periodic stack by the Langmuir-Blodgett technique has been compared. Elimination of all related zero order diffraction resonances other than that from growth planes and broadening and deepening of the remaining one-dimensional diffraction resonance have been observed for samples prepared by the Langmuir-Blodgett approach, which are explained in terms of the partial disorder of a crystal lattice.
Capturing and depositing one nanoobject at a time: Single particle dip-pen nanolithography
Authors: Wang Ying , Zhang Yi , Li Bin , Lü Junhong , Hu Jun
Published: March 2007

A convenient technique for transferring nanoparticles in a one-particle-at-a-time fashion is presented. This technique, termed as single particle dip-pen nanolithography, employs an atomic force microscope (AFM) tip to “grab” individual gold nanoparticles on surfaces. The nanoparticles attached to the AFM tips can be then controllably released and redeposited site specifically on surfaces. Patterns composed of single gold particles have been fabricated.
Qualification of a fluorescence spectrometer for measuring true fluorescence spectra
Authors: DeRose Paul C. , Early Edward A. , Kramer Gary W.
Published: March 2007

New analytical methods using fluorescence detection are becoming increasingly quantitative and require easy-to-use material standards for fluorometer qualification and method validation. NIST is responding to this need by developing and producing such standards. Reported here is the first step in this process, which is to qualify a research-grade fluorescence spectrometer for measuring true fluorescence spectra of reference material candidates. “True” spectra are defined here as those with fluorescence intensity, either relative or absolute as required, and wavelength both being reported with high accuracy and known precision, after wavelength has been calibrated and corrections for excitation intensity and detection system response have been applied. The uncertainties determined in relative and absolute intensity-corrected fluorescence spectra using both calibrated source (CS)- and calibrated detector (CD)-based methods were compared. The CS-based method gave uncertainties, typically about ±5% for relative spectral correction, that were about half that of the CD-based method for determining both relative and absolute spectral correction factors. Absolute spectral correction factors can be determined using either method without knowing the optical geometry of the instrument. The absolute spectral correction factors were found to have much larger uncertainties than the corresponding relative correction factors with uncertainties for the CS-based method of ±10% to ±15% being typical and ±20% or more not being uncommon, particularly for excitation and emission wavelengths below 400nm. Uncertainties arising from detection system nonlinearity and instrument polarization ratios were also explored.
Three-dimensional nanoscale subsurface optical imaging of silicon circuits
Authors: Ramsay E. , Serrels K. A. , Thomson M. J. , Waddie A. J. , Taghizadeh M. R. , Warburton R. J. , Reid D. T.
Published: March 2007

Three-dimensional subsurface imaging through the back side of a silicon flip chip is reported with a diffraction-limited lateral resolution of 166nm and an axial performance capable of resolving features only 100nm deep. This performance was achieved by implementing sample-scanned two-photon optical beam induced current microscopy using a silicon solid immersion lens and a peak detection algorithm. The excitation source was a 1530nm erbium:fiber laser, and the lateral optical resolution obtained corresponds to 11% of the free-space wavelength.
Mass-controlled capillary viscometer for a Newtonian liquid: Viscosity of water at different temperatures
Authors: Digilov Rafael M. , Reiner M.
Published: March 2007

The operation principle of the mass-controlled capillary viscometer is presented for a Newtonian liquid. The derived equation for the temporal changes of the mass in a liquid column draining under gravity through a discharge capillary tube accounts self-consistently for the inertial convective term associated with the acceleration effect. The viscosity of water measured at different temperatures using the new approach is in good agreement with literature data.
District Variations in Road Curvature in England and Wales and their Association with Road-Traffic Crashes
Authors: Haynes Robin , Jones Andrew , Kennedy Victoria , Harvey Ian , Jewell Tony
Published: March 2007

Bends in roads are known to cause road-traffic crashes, but do areas with many road bends have more collisions than areas with straighter roads? A geographical information system was used to generate indicators of average road curvature from a road-network dataset of England and Wales at the local-authority district level. The indicators were the number of bends per kilometre, the ratio of road distance to straight distance, the proportion of road lengths that were straight, the cumulative angle turned per kilometre and the mean angle of each bend. Generally the five measures were associated. Road curvature was highest on minor roads and least on major roads, and metropolitan districts had straighter road networks than nonmetropolitan districts. Counts of the number of road-traffic crashes resulting in fatalities, serious injuries, and slight injuries in each district were obtained from police ‘Stats 19’ records. The association between each of the curvature measures and the number of fatal, serious, and slight collisions in each district was determined by negative binomial regression analysis. Collision numbers were negatively related to road curvature after adjusting for other risk factors, so districts with straighter roads had more crashes. The cumulative angle was the curvature measure most strongly related to fatal road crashes. An increase of 1° per km was associated with approximately a 0.5% reduction in crashes, enough to explain more than a two fold difference in collision rates over the range of the data. Separate analysis of crashes on major roads, ‘B’ class roads, and minor roads confirmed the conclusion. Although individual road bends may be hazardous, these results suggest that road curvature at the district scale is protective.
Investigating the Potential Effects of Small Cell Adjustment on Interaction Data from the 2001 Census
Authors: Duke-Williams Oliver , Stillwell John
Published: March 2007

Although the population census is the most important source of information about people in small areas, the government is required by law to prevent the disclosure of information about identifiable individuals or households. In this paper we use data from the 1991 Census to simulate the effects of the disclosure method proposed for use in adjusting the 2001 Census interaction datasets. The results suggest differing impacts on the frequencies of certain counts as data at the level of adjustment are aggregated, with varying implications for the analytical measures of migration used in comparative research.
Essential role of protein kinase C ζ in transducing a motility signal induced by superoxide and a chemotactic peptide, fMLP
Authors: Kuribayashi Kageaki , Nakamura Kiminori , Tanaka Maki , Sato Tsutomu , Kato Junji , Sasaki Katsunori , Takimoto Rishu , Kogawa Katsuhisa , Terui Takeshi , Takayama Tetsuji , Onuma Takayuki , Matsunaga Takuya , Niitsu Yoshiro
Published: March 2007

Under various pathological conditions, including infection, malignancy, and autoimmune diseases, tissues are incessantly exposed to reactive oxygen species produced by infiltrating inflammatory cells. We show augmentation of motility associated with morphological changes of human squamous carcinoma SASH1 cells, human peripheral monocytes (hPMs), and murine macrophage-like cell line J774.1 by superoxide stimulation. We also disclose that motility of hPMs and J774.1 induced by a chemotactic peptide (N-formyl-methionyl-leucyl-phenylalanine [fMLP]) was inhibited by superoxide dismutase or N-acetylcystein, indicating stimulation of motility by superoxide generated by fMLP stimulation. In these cells, protein kinase C (PKC) ζ was activated to phosphorylate RhoGDI-1, which liberated RhoGTPases, leading to their activation. These events were inhibited by dominant-negative PKCζ in SASH1 cells, myristoylated PKCζ peptides in hPMs and J774.1, or a specific inhibitor of RhoGTPase in SASH1, hPMs, and J774.1. These results suggest a new approach for manipulation of inflammation as well as tumor cell invasion by targeting this novel signaling pathway.
The actin-based motor protein myosin II regulates MHC class II trafficking and BCR-driven antigen presentation
Authors: Vascotto Fulvia , Lankar Danielle , Faure-André Gabrielle , Vargas Pablo , Diaz Jheimmy , Le Roux Delphine , Yuseff Maria-Isabel , Sibarita Jean-Baptiste , Boes Marianne , Raposo Graça , Mougneau Evelyne , Glaichenhaus Nicolas , Bonnerot Christian , Manoury Bénédicte , Lennon-Duménil Ana-Maria
Published: March 2007

Antigen (Ag) capture and presentation onto major histocompatibility complex (MHC) class II molecules by B lymphocytes is mediated by their surface Ag receptor (B cell receptor [BCR]). Therefore, the transport of vesicles that carry MHC class II and BCR–Ag complexes must be coordinated for them to converge for processing. In this study, we identify the actin-associated motor protein myosin II as being essential for this process. Myosin II is activated upon BCR engagement and associates with MHC class II–invariant chain complexes. Myosin II inhibition or depletion compromises the convergence and concentration of MHC class II and BCR–Ag complexes into lysosomes devoted to Ag processing. Accordingly, the formation of MHC class II–peptides and subsequent CD4 T cell activation are impaired in cells lacking myosin II activity. Therefore, myosin II emerges as a key motor protein in BCR-driven Ag processing and presentation.
Jagunal is required for reorganizing the endoplasmic reticulum during Drosophila oogenesis
Authors: Lee Sangil , Cooley Lynn
Published: March 2007

Vesicular traffic in the Drosophila melanogaster oocyte occurs actively during vitellogenesis. Although endocytosis in the oocyte has been well characterized, exocytic vesicular traffic is less well understood. We show that the oocyte endoplasmic reticulum (ER) becomes concentrated into subcortical clusters during vitellogenesis. This ER reorganization requires Jagunal, which is an evolutionarily conserved ER membrane protein. Loss of Jagunal reduces vesicular traffic to the oocyte lateral membrane, but does not affect posterior polarized vesicular traffic, suggesting a role for Jagunal in facilitating vesicular traffic in the subcortex. Reduced membrane traffic caused by loss of Jagunal affects oocyte and bristle growth. We propose that ER reorganization is an important mechanism used by cells to prepare for an increased demand for membrane traffic, and Jagunal facilitates this process through ER clustering.
A Conformation Change in the Extracellular Domain that Accompanies Desensitization of Acid-sensing Ion Channel (ASIC) 3
Authors: Cushman Kenneth A. , Marsh-Haffner Josephine , Adelman John P. , McCleskey Edwin W.
Published: March 2007

Acid-sensing ion channels (ASICs) are thought to trigger some forms of acid-induced pain and taste, and to contribute to stroke-induced neural damage. After activation by low extracellular pH, different ASICs undergo desensitization on time scales from 0.1 to 10 s. Consistent with a substantial conformation change, desensitization slows dramatically when temperature drops (Askwith, C.C., C.J. Benson, M.J. Welsh, and P.M. Snyder. 2001. PNAS. 98:6459–6463). The nature of this conformation change is unknown, but two studies showed that desensitization rate is altered by mutations on or near the first transmembrane domain (TM1) (Coric, T., P. Zhang, N. Todorovic, and C.M. Canessa. 2003. J. Biol. Chem. 278:45240–45247; Pfister, Y., I. Gautschi, A.-N. Takeda, M. van Bemmelen, S. Kellenberger, and L. Schild. 2006. J. Biol. Chem. 281:11787–11791). Here we show evidence of a specific conformation change associated with desensitization. When mutated from glutamate to cysteine, residue 79, which is some 20 amino acids extracellular to TM1, can be altered by cysteine-modifying reagents when the channel is closed, but not when it is desensitized; thus, desensitization appears to conceal the residue from the extracellular medium. D78 and E79 are a pair of adjacent acidic amino acids that are highly conserved in ASICs yet absent from epithelial Na+ channels, their acid-insensitive relatives. Despite large effects on desensitization by mutations at positions 78 and 79—including a shift to 10-fold lower proton concentration with the E79A mutant—there are not significant effects on activation.
Ancestrally high elastic modulus of gecko setal β-keratin
Authors: Peattie Anne M , Majidi Carmel , Corder Andrew , Full Robert J
Published: March 2007

Typical bulk adhesives are characterized by soft, tacky materials with elastic moduli well below 1 MPa. Geckos possess subdigital adhesives composed mostly of β-keratin, a relatively stiff material. Biological adhesives like those of geckos have inspired empirical and modelling research which predicts that even stiff materials can be effective adhesives if they take on a fibrillar form. The molecular structure of β-keratin is highly conserved across birds and reptiles, suggesting that material properties of gecko setae should be similar to that of β-keratin previously measured in birds, but this has yet to be established. We used a resonance technique to measure elastic bending modulus in two species of gecko from disparate habitats. We found no significant difference in elastic modulus betweenGekko gecko(1.6 GPa±0.15 s.e.;n=24 setae) andPtyodactylus hasselquistii(1.4 GPa±0.15 s.e.;n=24 setae). If the elastic modulus of setal keratin is conserved across species, it would suggest a design constraint that must be compensated for structurally, and possibly explain the remarkable variation in gecko adhesive morphology.
Facial ontogeny in Neanderthals and modern humans
Authors: Bastir Markus , O'Higgins Paul , Rosas Antonio
Published: March 2007

One hundred and fifty years after the discovery of Neanderthals, it is held that this morphologically and genetically distinct human species does not differ from modern
Homo sapiens
in its craniofacial ontogenetic trajectory after the early post-natal period. This is striking given the evident morphological differences between these species, since it implies that all of the major differences are established by the early post-natal period and carried into adulthood through identical trajectories, despite the extent to which mechanical and spatial factors are thought to influence craniofacial ontogeny. Here, we present statistical and morphological analyses demonstrating that the spatio-temporal processes responsible for craniofacial ontogenetic transformations differ. The findings emphasize that pre-natal as well as post-natal ontogeny are both important in establishing the cranial morphological differences between adult Neanderthals and modern humans.
Life history and the evolution of family living in birds
Authors: Covas Rita , Griesser Michael
Published: March 2007

The reason why some bird species live in family groups is an important question of evolutionary biology that remains unanswered. Families arise when young delay the onset of independent reproduction and remain with their parents beyond independence. Explanations for why individuals forgo independent reproduction have hitherto focused on dispersal constraints, such as the absence of high-quality breeding openings. However, while constraints successfully explain within-population dispersal decisions, they fail as an ultimate explanation for variation in family formation across species. Most family-living species are long-lived and recent life-history studies demonstrated that a delayed onset of reproduction can be adaptive in long-lived species. Hence, delayed dispersal and reproduction might be an adaptive life-history decision rather than ‘the best of a bad job’. Here, we attempt to provide a predictive framework for the evolution of families by integrating life-history theory into family formation theory. We suggest that longevity favours a delayed onset of reproduction and gives parents the opportunity of a prolonged investment in offspring, an option which is not available for short-lived species. Yet, parents should only prolong their investment in offspring if this increases offspring survival and outweighs the fitness cost that parents incur, which is only possible under ecological conditions, such as a predictable access to resources. We therefore propose that both life-history and ecological factors play a role in determining the evolution of family living across species, yet we suggest different mechanisms than those proposed by previous models.
Erythropoietin/erythropoietin‐receptor system is involved in angiogenesis in human hepatocellular carcinoma
Authors: Ribatti D , Marzullo A , Gentile A , Longo V , Nico B , Vacca A , Dammacco F
Published: March 2007

Aims:  To correlate microvascular density and erythropoietin (Epo)/Epo‐receptor (EpoR) expression in endothelial and tumour cells with histopathological type in hepatocellular carcinoma (HCC).

Methods and results:  Specimens of primary HCC obtained from 50 patients who had undergone curative hepatectomy were investigated immunohistochemically by using anti‐CD31, anti‐Epo and anti‐EpoR antibodies. Poorly differentiated HCC had a higher degree of vascularization than other stages and Epo/EpoR expression in both tumour and endothelial cells increased in parallel with grade of malignancy and was highly correlated with the extent of angiogenesis.

Conclusions:  Epo/EpoR levels correlate with angiogenesis and progression of patients with HCC and these findings suggest the presence of a loop in the Epo/EpoR system, i.e. Epo is secreted by hepatic tumour cells and it affects vascular endothelial cells via its receptors and promotes angiogenesis in a paracrine manner. It is thus suggested that Epo is an important factor in hepatic tumour angiogenesis. Understanding the mechanisms of HCC angiogenesis provides a basis for a rational approach to the development of antiangiogenic therapy in patients with hepatic cancer.
Multinucleated stromal giant cells in colonic lamina propria
Authors: Wu M L , Zhao X
Published: March 2007

Aims:  Multinucleated stromal giant cells occur in the anus, genitals and many other organs. They resemble myofibroblasts, react to local injury and are found incidentally or in association with various lesions. They have only rarely been reported to occur in the colon. The aim was to firmly establish their existence in colorectal lamina propria.

Methods and results:  Specimens from one hundred biopsies taken from throughout the colon (70%) and rectum (30%) were retrospectively reviewed. Multinucleated stromal giant cells occurred in 23 specimens (23%), were pancolonic but surprisingly spared rectal mucosa (0%). Multinucleated stromal giant cells occurred in both normal mucosa and abnormal mucosa and appeared to be larger and more numerous in abnormal mucosa than in normal mucosa. Specimens with tubular adenomas appeared to have strikingly abundant multinucleated stromal giant cells with large numbers of nuclei. Immunohistochemistry and ultrastructural examination showed features consistent with myofibroblastic differentiation.

Conclusions:  We have firmly established the existence of multinucleated stromal giant cells in colonic lamina propria and confirm their myofibroblastic differentiation. They may be more common in abnormal mucosa and particularly prominent in the setting of tubular adenoma. Absence of rectal multinucleated stromal giant cells may represent a microanatomical difference between the colon and rectum.