bluuebunny/crossref_metadata_2025_split huggingface dataset:
A method for site‐specific labeling of multiple protein thiols
Authors: Kuiper Johanna M. , Pluta Radek , Huibers Wim H. C. , Fusetti Fabrizia , Geertsma Eric R. , Poolman Bert 
Published: March 2009

AbstractWe present a generic method for the site‐specific and differential labeling of multiple cysteine residues in one protein. Phenyl arsenic oxide has been employed as a protecting group of two closely spaced thiols, allowing first labeling of a single thiol. Subsequently, the protecting group is removed, making available a reactive dithiol site for labeling with a second probe. For proof‐of‐principle, single and triple Cys mutants of the sulphate binding protein of an ABC transporter were constructed. The closely spaced thiols were engineered on the basis of the crystal structure of the protein and placed in different types of secondary structure elements and at different spacing. We show that phenyl arsenic oxide is a good protecting group for thiols spaced 6.3–7.3 Å. Proteins were labeled with two different fluorescent labels and the labeling ratios were determined with UV‐Vis spectroscopy and MALDI‐Tof mass spectrometry. The average labeling efficiency was ∼80% for the single thiol and 65–90% for the dithiol site.
Key role of the N‐terminus of chicken annexin A5 in vesicle aggregation
Authors: Turnay Javier , Guzmán‐Aránguez Ana , Lecona Emilio , Barrasa Juan I. , Olmo Nieves , Lizarbe Ma Antonia 
Published: March 2009

AbstractAnnexins are calcium‐dependent phospholipid‐binding proteins involved in calcium signaling and intracellular membrane trafficking among other functions. Vesicle aggregation is a crucial event to make possible the membrane remodeling but this process is energetically unfavorable, and phospholipid membranes do not aggregate and fuse spontaneously. This issue can be circumvented by the presence of different agents such as divalent cations and/or proteins, among them some annexins. Although human annexin A5 lacks the ability to aggregate vesicles, here we demonstrate that its highly similar chicken ortholog induces aggregation of vesicles containing acidic phospholipids even at low protein and/or calcium concentration by establishment of protein dimers. Our experiments show that the ability to aggregate vesicles mainly resides in the N‐terminus as truncation of the N‐terminus of chicken annexin A5 significantly decreases this process and replacement of the N‐terminus of human annexin A5 by that of chicken switches on aggregation; in both cases, there are no changes in the overall protein structure and only minor changes in phospholipid binding. Electrostatic repulsions between negatively charged residues in the concave face of the molecule, mainly in the N‐terminus, seem to be responsible for the impairment of dimer formation in human annexin A5. Taking into account that chicken annexin A5 presents a high sequence and structural similarity with mammalian annexins absent in birds, as annexins A3 and A4, some of the physiological functions exerted by these proteins may be carried out by chicken annexin A5, even those that could require calcium‐dependent membrane aggregation.
Field experiments to assess approaches for spray drift incident investigation
Authors: Rimmer Duncan A , Johnson Paul D , Kelsey Adrian , Warren Nicholas D 
Published: March 2009

AbstractBACKGROUND: Spray trials were conducted to determine the variation in primary spray drift deposition between trials under very similar conditions, in order to assess the feasibility of developing a computational tool to aid post‐event investigations of pesticide spray incidents. Pesticide deposition was examined by analysis of filter paper and vegetation samples.RESULTS: Considerable variation in the drift profile was found. The overall estimate of the spray drift decay term was −1.13 (95% confidence interval −1.02 to −1.24), with statistically significant differences between plots. Variation in the drift profile between neighbouring essentially identical plots indicates the variation in deposition that might be expected over small distances. Vegetation samples were found to have considerably lower capture efficiency than filter papers. Importantly, degradation of pesticides was found to have little effect on the pesticide drift profile over a 14 day period.CONCLUSIONS: The levels of spatial variation in spray drift deposits between runs and plots observed in this study suggest serious limitations to the inferences that may be drawn from limited numbers of post‐incident samples. In particular, they would limit inferences about the spray conditions that could be drawn from an estimate of the drift profile derived from limited post‐incident samples. © Crown copyright 2009. Reproduced with permission of Her Majesty's Stationery Office. Published by John W iley & Sons, Ltd.
Shape of indium nitride quantum dots and nanostructures grown by metal organic vapour phase epitaxy
Authors: Ploch Simon , Meissner Christian , Pristovsek Markus , Kneissl Michael 
Published: March 2009

AbstractWe report on the shape of indium nitride quantum dots (QDs) grown on 2 μm thick c‐plane (0001) GaN on sapphire in a horizontal MOVPE (Metal Organic Vapour Phase Epitaxy) reactor at temperatures between 550 °C and 590 °C. Ex situ X‐ray deflection (XRD) suggested pure relaxed InN. Atomic Force Microscopy (AFM) investigations show two different types of QDs, mesa shaped and cone like structures. The density of the mesa increases with decreasing temperature while the density of the cones remains constant at 2 × 108/cm2. The mean height varies between 15 nm and 40 nm for mesa and 70 nm for conic structures.The mean diameter increases with increasing temperature from 70 nm at 550 °C to 230 nm at 590 °C for both structure types. The mesa type structures exhibit a hexagonal footprint the cone type structures often deviate slightly from this. With increasing growth temperatures the ratio of cone to mesa type structures increases. For both structures {1$ \bar 1 $02} and {$ \bar 1 $102} side facets, which seem to be the most temperature stable ones dominate. The origin for the two different structure types will be discussed. Possible causes are two different growth polarities of the InN QDs, but also nucleation on different types of defects (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of GaN nanorods grown catalyst‐free on r‐plane sapphire
Authors: Sebald K. , Kalden J. , Voss T. , Gutowski J. , Aschenbrenner T. , Kunert G. , Kruse C. , Figge S. , Hommel D. 
Published: March 2009

AbstractEnsembles and single GaN nanorods grown by catalyst‐ and mask‐free molecular beam epitaxy on r‐plane sapphire are characterized by photoluminescence spectroscopy. The nanorods are well aligned and symmetrically tilted in two directions with an angle of 62° to the substrate surface. They possess an average length of 2 μm with an aspect ratio of about 1:10. The emission peaks of free and bound excitons can be identified and their temperature dependence is analysed. The high crystalline quality is indicated by the spectral width of the dominant emission peaks being comparable for the ensemble and single nanorods as well as by the absence of the stacking‐fault‐related yellow photoluminescence. The comparison of the photoluminescence spectra for an ensemble of nanorods and a single one gives insight into the heating of the nanorod under illumination when it is detached from the sample substrate (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermally induced acoustic waves in porous silicon
Authors: Gavrilchenko Iryna V. , Benilov Arthur I. , Shulimov Yuriy G. , Skryshevsky Valeriy A. 
Published: March 2009

AbstractThermally induced acoustic waves in structures with porous silicon have been studied. Two different schemas of acoustic phenomena recording are compared: in the first one a signal from microphone was measured as function of output frequency, in second one the resistance of porous silicon was measured using Wheatstone bridge. For both methods, the resonance peak is situated in same frequencies depending on difference in thermal properties between porous silicon and c‐Si as well as geometry of studied structures. 1.0 kHz shifting of resonance peak in saturated alcohol vapors comparing to ambient air is observed. It can be applied as new transducer for chemical sensors based on porous silicon. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Conformal P‐N junctions in macroporous silicon for photovoltaic energy conversion
Authors: Clarkson Jeffrey P. , See Gloria G. , Veeramachaneni Bharat , Gadeken Larry L. , Hirschman Karl D. , Fauchet Philippe M. 
Published: March 2009

AbstractWe report on the fabrication of a macroporous silicon diode that successfully operates in a photovoltaic mode of energy conversion. Typical device structures are fabricated on 4″, Cz grown, <100>, p‐type, 5 – 30 Ω‐cm, Si substrates and make use of random or pre‐patterned macroporous silicon films up to 100 μm thick with pores ∼1 μm in diameter and a center‐to‐center pore spacing of 2.5 μm. Phosphorous dopants are introduced throughout the porous silicon region with a newly adapted technique based on proximity rapid thermal diffusion. This development effort has enhanced the uniformity of dopant diffusion into the pores and subsequently improved device performance. The resulting p‐n diode within the porous silicon is of a three‐dimensional nature and exhibits an extremely high internal surface area up to ∼6690 cm2/cm3. To our knowledge, this is the first use of such a technique to fabricate conformal, three‐dimensional p‐n junctions for photovoltaic applications. The large internal surface area of this diode makes it applicable to next generation photovoltaics. Moreover, the porous silicon within this device is not simply an antireflection coating; rather it is a light trapping medium that has the ability to become a large surface area diode and can serve as a host matrix for photoactive compounds. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Skin peptides from anurans of theLitoria rubellaGroup: sequence determination using electrospray mass spectrometry. Opioid activity of two major peptides
Authors: Jackway Rebecca J. , Maselli Vita M. , Musgrave Ian F. , Maclean Micheal J. , Tyler Michael J. , Bowie John H. 
Published: March 2009

AbstractMany species of frogs of the genusLitoriasecrete bioactive peptides from their skin glands. These peptides are normally host‐defence compounds and may have one, or more of the following activities; smooth muscle contraction, analgesic, antimicrobial, antiviral, lymphocyte proliferator (immunomodulator) and neuronal nitric oxide synthase (nNOS) inactivation. Two frog species of theLitoria rubellaGroup that have been studied before, namely,Litoria electricaandLitoria rubella, are different from other species of the genusLitoriain that they produce small peptides that show neither membrane, lymphocyte nor nNOS activity. In this study we have used electrospray mass spectrometry together with Edman sequencing to identify eight skin peptides of the third member of this Group,Litoria dentata: surprisingly, none of these peptides show activity in our biological screening program. However, two major peptides (FPWL‐NH2and FPWP‐NH2) fromL. electricaandL. rubellaare opioids at the micromolar concentration. Copyright © 2009 John Wiley & Sons, Ltd.
Computer‐assisted therapy in orbital and mid‐facial reconstructions
Authors: Schramm A. , Suarez‐Cunqueiro M. M. , Rücker M. , Kokemueller H. , Bormann K.‐H. , Metzger M. C. , Gellrich N.‐C. 
Published: March 2009

AbstractBackgroundManagement of orbital and mid‐facial fractures requires a thorough ophthalmic evaluation and precise imaging. A principle goal of therapy is to anatomically reduce fracture segments and to restore a normal orbital volume as soon as possible. Diagnostic advances such as new surgical and imaging techniques have dramatically improved both the functional and aesthetic outcome of reconstructions.MethodsOrbital reconstruction is performed using computer‐assisted navigation. This technique makes preoperative simulation by mirroring the unaffected side onto the affected side.ResultsResults from computer‐assisted navigation application to both primary and secondary orbital and mid‐facial reconstruction are shown.ConclusionNavigation technique it offers significant advantages in both primary and secondary reconstructions. Navigation facilitates reconstruction in unilateral defects through mirroring techniques, and in bilateral defects by importing virtual models from standard CT datasets improving the software tool to fulfil the need for maxillofacial surgery reconstruction. Copyright © 2009 John Wiley & Sons, Ltd.
Surface analysis of nitride layers formed on Fe‐based alloys through plasma nitride process
Authors: Sato Shigeo , Omori Koji , Araki Sawa , Takahashi Yohei , Wagatsuma Kazuaki 
Published: March 2009

AbstractNitriding phenomena that occur on the surfaces of pure Fe and FeCr alloy (16 wt% Cr) samples were investigated. An Ar + N2 mixture‐gas glow‐discharge plasma was used so that surface nitriding could occur on a clean surface etched by Ar+ ion sputtering. In addition, the metal substrates were kept at a low temperature to suppress the diffusion of nitrogen. These plasma‐nitriding conditions enabled us to characterize the surface reaction between nitrogen radicals and the metal substrates. The emission characteristics of the band heads of the nitrogen molecule ion (N2+) and nitrogen molecule from the glow‐discharge plasma suggest that the active nitrogen molecule is probably the major nitriding reactant. AES and angle‐resolved XPS were used to characterize the thickness of the nitride layer and the concentration of elements and chemical species in the nitride layer. The thickness of the nitride layer did not depend on the metal substrate type. An oxide layer with a thickness of a few nanometers was formed on the top of the nitride layer during the nitriding process. The oxide layer consisted of several species of Nx‐Fey‐O, NO+, and NO2−. In the FeCr alloy sample, these oxide species could be reduced because chromium is preferentially nitrided. Copyright © 2009 John Wiley & Sons, Ltd.
Development of a low‐energy x‐ray fluorescence system with sub‐micrometer spatial resolution
Authors: Alberti R. , Klatka T. , Longoni A. , Bacescu D. , Marcello A. , De Marco A. , Gianoncelli A. , Kaulich B. 
Published: March 2009

AbstractWe report on a low‐energy x‐ray fluorescence (LEXRF) spectrometer system implemented in the European TwinMic x‐ray spectromicroscope,1which is operated in the 280–2200 eV energy range and allows sub‐100 nm optical resolution by means of focusing with diffractive optics. The LEXRF setup is a modular system based on the use of multiple windowless large‐area silicon drift detectors (SDD). The detectors are read out by a custom pulsed reset preamplifier system optimized for SDDs and specially designed and adapted to geometrical requirements for microscopies at synchrotron facilities. Moreover, a customized fast multi‐channel acquisition system developed for elemental mapping applications has been adapted to the microscope requirements. Acquisition of elemental composition by LEXRF maps is accomplished by simultaneous acquisition of absorption and phase contrast images to correlate the morphological structure. The instrumental setup is described and its potential illustrated by recently performed pilot experiments. Copyright © 2009 John Wiley & Sons, Ltd.
The necessity of maximum information utilization in x‐ray analysis
Authors: Papp T. , Maxwell J. A. , Papp A. T. 
Published: March 2009

AbstractThere are significant discrepancies in the experimental data needed in the analysis of x‐ray spectra. Examination of the data in detail shows that they often contradict simple logic, elemental arithmetic, even parity and angular momentum conservation laws. We have identified that the main source of the problems, other than the human factor, is rooted in the signal processing electronics. We have developed a line of fully digital signal processors that not only have excellent resolution and line shape but also allow proper accounting. We achieve this by processing all events and separating them into two or more spectra where the first spectrum is the accepted or good spectrum and the second spectrum is the rejected spectrum. It is not enough to know that an event was rejected, and increment the input counter—it is necessary to know what happened and why, whether it was pure noise, a noisy or disturbed event, a true event, or any pile up combination of the above in order to account properly for true event input rate and processor dead time. The data processing methodology cannot be reliably established on the partial and fractional information offered by other approaches. The availability of all the events allows one to see the other part of the spectrum. To our surprise the total information explains many of the shortcomings and contradictions of the x‐ray database. We call this a maximum information utilization approach in signal processing. Also a fundamental parameter x‐ray fluorescence analysis program (CSX‐XRF) has been developed to utilize all the information offered by the signal processor. The fundamental parameter method is only as good as the database it uses and the description of the x‐ray fluorescence analysis system. This latter poses significant difficulties, and to ease the demand we have developed an inverse fundamental parameter program package for x‐ray tube based equipment characterization. Copyright © 2009 John Wiley & Sons, Ltd.
Algebra and logic for access control
Authors: Collinson Matthew , Pym David 
Published: March 2009

AbstractThe access control problem in computer security is fundamentally concerned with the ability of system entities to see, make use of, or alter various system resources. We provide a mathematical framework for modelling and reasoning about (distributed) systems with access control. This is based on a calculus of resources and processes together with a Hennessy–Milner-style modal logic, based on the connectives of bunched logic, for which an appropriate correspondence theorem obtains. As a consequence we get a consistent account of both operational behaviour and logical reasoning for systems with access control features. In particular, we are able to introduce a process combinator that describes, as a form of concurrent composition, the action of one agent in the role of another, and provide a logical characterization of this operator via a modality ‘says’. We give a range of examples, including analyses of co-signing, roles, and chains of trust, which illustrates the utility of our mathematical framework.
Burden of Surgical Disease: Does the Literature Reflect the Scope of the International Crisis?
Authors: Taira Breena R. , Kelly McQueen K. A. , Burkle Frederick M. 
Published: March 2009

AbstractBackgroundLittle is factually known about the burden of surgical disease and less is known about global surgical provision of care for diseases that may be treated, cured, or palliated by a surgical intervention. Despite the lack of information, surgical interventions are provided by a variety of agencies every day in the developing world. This literature review represents the first published comprehensive review of the global surgical literature. The primary goal was to collect and summarize what has been published on the current global burden of surgical disease and thereby encourage and promote the allocation of further research and resources.MethodsA systematic review of English language publications on Pubmed or Medline was performed.Results and conclusionsThis report summarizes what little is known in terms of numeric estimates for the global burden of surgical disease. Globally, access and availability of surgical care in developing countries remains scarce, but the problem is receiving more attention for the first time in surgical circles. Much work remains in the effort to obtain reliable estimates of the global burden of surgical disease.
The use of melodic formulas in responsories: constancy and variability in the manuscript tradition
Authors: Helsen Kate 
Published: March 2009

ABSTRACTThe basis of this study comes from the great responsory repertory in the twelfth-century French monastic manuscript, Paris 12044 from Saint-Maur-des-Fossés. A computerised database containing each component phrase was used to create a more accurate melodic taxonomy of responsories than has hitherto been available. Building on the research of W.H. Frere, H-J. Holman, and others, it is possible to obtain clearer insight into formulaic composition in an oral culture. This is achieved by comparing the use of recurrent, or ‘standard’, musical material in Paris 12044 to that found in several other manuscripts. The presence of standard material in a respond melody is found to be linked to the consistency of form and tonal structure.
Detector Solid Angle Formulas for Use in X-Ray Energy Dispersive Spectrometry
Authors: Zaluzec Nestor J. 
Published: March 2009

AbstractWith the advent of silicon drift X-ray detectors, a range of new geometries has become possible in electron optical columns. Because of their compact size, these detectors can potentially achieve high geometrical collection efficiencies; however, using traditional approximations detector solid angle calculations rapidly break down and at times can yield nonphysical values. In this article we present generalized formulas that can be used to calculate the variation in detection solid angle for contemporary Si(Li) as well as new silicon drift configurations.
Ultrastructure of the Epithelial Cells Associated with Tooth Biomineralization in the ChitonAcanthopleura hirtosa
Authors: Shaw Jeremy A. , Macey David J. , Brooker Lesley R. , Stockdale Edward J. , Saunders Martin , Clode Peta L. 
Published: March 2009

AbstractThe cusp epithelium is a specialized branch of the superior epithelium that surrounds the developing teeth of chitons and is responsible for delivering the elements required for the formation of biominerals within the major lateral teeth. These biominerals are deposited within specific regions of the tooth in sequence, making it possible to conduct a row by row examination of cell development in the cusp epithelium as the teeth progress from the unmineralized to the mineralized state. Cusp epithelium from the chitonAcanthopleura hirtosawas prepared using conventional chemical and microwave assisted tissue processing, for observation by light microscopy, conventional transmission electron microscopy (TEM) and energy filtered TEM. The onset of iron mineralization within the teeth, initiated at row 13, is associated with a number of dramatic changes in the ultrastructure of the apical cusp cell epithelium. Specifically, the presence of ferritin containing siderosomes, the position and number of mitochondria, and the structure of the cell microvilli are each linked to aspects of the mineralization process. These changes in tissue development are discussed in context with their influence over the physiological conditions within both the cells and extracellular compartment of the tooth at the onset of iron mineralization.