bluuebunny/crossref_metadata_2025 huggingface dataset:
Limits to sustained energy intake XII: is the poor relation between resting metabolic rate and reproductive performance because resting metabolism is not a repeatable trait?
Authors: Duarte L. C. , Vaanholt L. M. , Sinclair R. E. , Gamo Y. , Speakman J. R.
Published: December 2009

Many studies have investigated the consequences of individual variation in resting metabolic rate at thermoneutrality (RMRt) on reproductive performance. Despite strong theoretical reasons for expecting such an association, results have generally been disappointing. A fundamental assumption of these studies is that RMRt is a repeatable trait. We examined repeatability of RMRt in female MF1 mice over short (15 days apart; N=238) and long intervals (110 days apart; N=33). In the long-term experiment, after the first RMRt measurement, females were separated in two groups: the first was kept virgin (N=16); the second was allowed to breed (N=17) and measured 15 days after they had weaned their pups. We also examined the association between RMRt and reproduction. We used Pearson's correlation (r) and intraclass correlation coefficients (ρ) to estimate repeatability. There was a strong effect of body mass on RMRt for all measurements. Over the short interval, repeatability was significant for body mass (r=0.86; ρ=0.86), RMRt (r=0.68; ρ=0.68,) and residual-RMRt (r=0.58; ρ=0.58). Over long intervals, repeatability of residual-RMRt was high in virgin females (r=0.59; ρ=0.60), but not in the breeders (r=0.38; ρ=0.39); body mass was repeatable only for non-breeders measured by r (r=0.55). There was no significant correlation between RMRt or residual-RMRt and litter size or litter mass. In conclusion, RMRt and residual-RMRt are highly repeatable traits in virgin MF1 female mice. The lack of association between non-reproductive RMRt and reproductive performance in MF1 mice does not come about because of its poor repeatability.
Eating chemically defended prey: alkaloid metabolism in an invasive ladybird predator of other ladybirds (Coleoptera: Coccinellidae)
Authors: Sloggett J. J. , Davis A. J.
Published: December 2009

By comparison with studies of herbivore physiological adaptation to plant allelochemicals, work on predator physiological adaptation to potentially toxic prey has been very limited. Such studies are important in understanding how evolution could shape predator diets. An interesting question is the specificity of predator adaptation to prey allelochemicals, given that many predators consume diverse prey with different chemical defences. The ladybird Harmonia axyridis, an invasive species in America, Europe and Africa, is considered a significant predatory threat to native invertebrates, particularly other aphid-eating ladybirds of which it is a strong intraguild predator. Although ladybirds possess species-specific alkaloid defences, H. axyridis exhibits high tolerance for allospecific ladybird prey alkaloids. Nonetheless, it performs poorly on species with novel alkaloids not commonly occurring within its natural range. We examined alkaloid fate in H. axyridis larvae after consumption of two other ladybird species, one containing an alkaloid historically occurring within the predator's native range (isopropyleine) and one containing a novel alkaloid that does not (adaline). Our results indicate that H. axyridis rapidly chemically modifies the alkaloid to which it has been historically exposed to render it less harmful: this probably occurs outside of the gut. The novel, more toxic alkaloid persists in the body unchanged for longer. Our results suggest metabolic alkaloid specialisation, in spite of the diversity of chemically defended prey that the predator consumes. Physiological adaptations appear to have made H. axyridis a successful predator of other ladybirds; however, limitations are imposed by its physiology when it eats prey with novel alkaloids.
The moment before touchdown: landing manoeuvres of the honeybee Apis mellifera
Authors: Evangelista C. , Kraft P. , Dacke M. , Reinhard J. , Srinivasan M. V.
Published: December 2009

Although landing is a crucial part of insect flight, it has attracted relatively little study. Here, we investigate, for the first time, the final moments of a honeybee's (Apis mellifera) landing manoeuvre. Using high-speed video recordings, we analyse the behaviour of bees as they approach and land on surfaces of various orientations. The bees enter a stable hover phase, immediately prior to touchdown. We have quantified behaviour during this hover phase and examined whether it changes as the tilt of the landing surface is varied from horizontal (floor), through sloped (uphill) and vertical (wall), to inverted (ceiling). The bees hover at a remarkably constant distance from the surface, irrespective of its tilt. Body inclination increases progressively as the tilt of the surface is increased, and is accompanied by an elevation of the antennae. The tight correlation between the tilt of the surface, and the orientation of the body and the antennae, indicates that the bee's visual system is capable of inferring the tilt of the surface, and pointing the antennae toward it. Touchdown is initiated by extending the appendage closest to the surface, namely, the hind legs when landing on horizontal or sloping surfaces, and the front legs or antennae when landing on vertical surfaces. Touchdown on inverted surfaces is most likely triggered by a mechanosensory signal from the antennae. Evidently, bees use a landing strategy that is flexibly tailored to the varying topography of the terrain.
Cellular mechanisms of acid secretion in the posterior midgut of the larval mosquito (Aedes aegypti)
Authors: Jagadeshwaran U. , Onken H. , Hardy M. , Moffett S. B. , Moffett D. F.
Published: December 2009

The gut contents of larval mosquitoes are alkalinized by the anterior midgut and reacidified by the posterior midgut. In the present study the cellular mechanisms of reacidification were studied in isolated, perfused posterior midgut by measuring the transepithelial voltage (Vte) and the rate of acid secretion as indicated by the color change of m-cresol purple during intervals of perfusion stop. The lumen-positive Vte and reacidification were significantly increased by serotonin (0.2 μmol l−1). The V-type H+-ATPase inhibitor concanamycin A (10 μmol l−1) on the luminal side inhibited acidification and decreased Vte. On the hemolymph side the carbonic anhydrase (CA) inhibitor acetazolamide (1 mmol l−1) almost abolished Vte, but had no effect on acidification. Similarly, hemolymph-side DIDS (0.1 mmol l−1), DPC (0.5 mmol l−1), amiloride (1 mmol l−1) and ouabain (2.5 mmol l−1) significantly reduced Vte, whereas Ba2+ (5 mmol l−1) was without effect. DPC and amiloride also reduced Vte when applied to the luminal side of the epithelium. Unilateral substitution of gluconate for Cl− affected Vte in a way consistent with a greater permeability for Cl−versus Na+. Cl− replacement in the lumen decreased Vte, whereas replacement on the hemolymph side increased it. Bilateral replacement left the control voltage unaffected. Na+ replacement on either side of the tissue reduced Vte to different degrees. Omission of luminal amino acids was followed by a significant decrease in Vte. Except for concanamycin A, none of the above manipulations impaired acidification, indicating that acidification requires only the apical proton pump. However, the chemical source of secreted H+ is still unknown and needs to be investigated.
Responses of alkaline phosphatase activity to phosphorus stress in Daphnia magna
Authors: McCarthy S. D. S. , Rafferty S. P. , Frost P. C.
Published: December 2009

We examined how alkaline phosphatase (AP) activity within the bodies and in the materials released by the crustacean Daphnia magna responds to variable algal food phosphorus (P)-content. We found that Daphnia eating P-poor food (C:P∼700) had significantly higher AP activity in their bodies on a mass-specific basis compared with individuals eating P-rich food (C:P∼100). This dietary P effect on AP activity was not altered by Daphnia starvation but was partially related to differences in the P concentration of animal body homogenates. By contrast, poor P-nutrition of Daphnia lowered AP activity in released materials compared with that measured from their P-sufficient conspecifics. Moreover, AP activity in Daphnia release was lowest in animals consuming P-poor food for longer time periods. Our results support the hypothesis that AP activity increases inside P-limited Daphnia as a mechanism to increase P-acquisition and retention from ingested algae in these nutritionally stressed animals. The lower level of AP activity present in the water of P-deprived animals could reflect a change from largely free to membrane-bound AP isotypes in the digestive tracts of P-starved animals or a decrease in the shedding of membrane-anchored AP from their intestinal lining. These results supplement accumulating evidence that P-poor algal food reduces the dietary mineral P available to Daphnia. In addition, animal body AP activity measurements, with some refinement, may prove useful as an in situ indicator of P-stress in aquatic consumers.
Application of a few necking criteria in predicting the forming limit of unwelded and tailor-welded blanks
Authors: Srinivas Naik B , Janaki Ramulu P , Ganesh Narayanan R
Published: December 2009

The limiting value of strain describing necking/failure during a sheet stamping operation is quantified, predicted by the forming limit curve (FLC). The main aim of the present work is to analyse the applicability of the few existing necking criteria, namely the effective strain rate based criterion (ESRC – RC1), major strain rate based criterion (MSRC – RC2), thickness strain rate based criterion (TSRC – RC3), and thickness gradient based criterion (TGNC – RC4), in predicting the forming limit of unwelded and tailor-welded blanks. In the case of unwelded blanks, dry ( μ = 0.12) and low-friction ( μ = 0.02) conditions are simulated and forming limit results are predicted. In the case of tailor-welded blanks, the forming limits of laser-welded steel blanks and friction-stir-welded blanks made of aluminium alloy are predicted using the chosen necking criteria and then compared with results in the literature. The influence of friction on the whole forming limit curve and the non-linearity of strain paths in the stretching side of the forming limit diagram (FLD) are also predicted and discussed. It is found that the FLCs predicted by ESRC, MSRC, TSRC, and TGNC are comparable with experimental FLCs. The predictions are accurate in the low-friction condition, indicating that the necking criteria are also valid under changing friction conditions. Moreover, the overall FLC does not change much with changing friction conditions. The strain paths are non-linear in the dry friction condition, but they become linear in the low-friction condition. In the case of laser-welded blanks, the original strain rate based criteria defined for unwelded blanks underestimate limit strains on the stretching side of the FLD, where failure near the weld region is witnessed. Hence they are modified as RC1 ≥ 25, RC2 ≥ 32, and RC3 ≥ 32, which show a better prediction level compared with the original criteria. The original and modified limit strain criteria show better correlation with results in the literature and the TGNC in the case of friction-stir-welded blanks modelled using the Hollomon and Swift strain-hardening laws.
Synchrotron X-ray analysis of microstructure and microdeformation in a recast AA6063 aluminium alloy
Authors: Korsunsky A M , Hofmann F , Abbey B , Gaucherin G
Published: December 2009

Aluminium alloy AA6063 has been processed by re-casting to produce polycrystalline ingots containing large grains. The microstructure and deformation behaviour of this material was studied by different techniques, including scanning electron microscopy, synchrotron X-ray micro-tomography, and synchrotron X-ray diffraction. The relationship between the dislocation cell-wall structure and reciprocal space maps obtained by diffraction was explored with the help of a dislocation model. The combination of different methods provides improved insight into the relationship between microstructure and deformation.
A novel method for the dynamic synthesis of cam mechanisms with an imposed driving force profile
Authors: Erdelyi H , Talaba D
Published: December 2009

In the car industry, the ergonomic and haptic properties of controls are gaining high priority. The cam mechanisms of switches and knobs, such as those of car turn switches, are usually required to comply with a certain user force profile, according to human physical limitations and ergonomic requirements. In order to fine-tune the force input and the function performed by the mechanism, the cam profile is normally subjected to a detailed synthesis having as input the desired user force profile. Nevertheless, conventional cam synthesis and analysis methods do not provide an adequate tool for designing the cam profile based on the required driving effort. In this article, an energy-based method is proposed for designing a cam mechanism able to accurately replicate the desired profile of the driving effort. According to the proposed method, the cam profile is determined as a finite series of points and takes into consideration all contact forces between the cam and the follower, including friction. The method is non-linear, considering a combined Stribeck—Therfall friction model as well as the damping of the system. Numerical validation is provided considering the case of the cam mechanism of a conventional car turn switch.
A database of finite element models and simulation systems for transporting sheets of paper
Authors: Cheng H , Yoshida K , Noro S , Tamamoto J , Asada M
Published: December 2009

Machines used for handling flexible sheets of paper may easily undergo jams due to the existence of irregular conditional sheets. However, most of the studies on handling behaviours have only been done for general sheets of paper transported with some simple guides. Establishing an efficient calculation method and analysis system that can predict all kinds of sheets whether or not there is jam in transport guides becomes more and more important. In this article, based on an analysis of the transport of a head-folded sheet in a V-type guide both in the experi-ment and finite-element (FE) simulation, the method of building the database of FE models for conditional sheets is established. A simulation system that directly connects the computer-aided design tools and the established database is also developed. Some simulated examples of sheet handling behaviours are demonstrated. It is shown that the developed system is useful for designing any transport guide.
A Fully Photoreversible Supramolecular Polymer Having a Diarylethene Photoswitch
Authors: Takeshita Michinori , Hayashi Miyuki , Miyazaki Takashi
Published: December 2009

The particle size of a supramolecular polymer composed of a diarylethene photoswitch and two quadruple hydrogen-bonding sites having C17 chain changes photoreversibly in tetrahydrofuran at room temperature, while that in a CHCl3 solution is not photoreversible but is reversible with the assistance of heat.
Covalent Modification of DNA with Azetidinium Lipids
Authors: Yonamine Yusuke , Kawasaki Takayoshi , Okahata Yoshio
Published: December 2009

We studied covalent bond formation of an ion complex of phosphate and azetidinium and applied the reaction to preparation of DNA which was elaborated at the phosphate units with azetidinium lipids.
Designing Chiral Quaternary Ammonium Polymers: Novel Type of Polymeric Catalyst for Asymmetric Alkylation Reaction
Authors: Itsuno Shinichi , Paul Devproshad K , Ishimoto Mikiya , Haraguchi Naoki
Published: December 2009

Optically active polymers containing chiral quaternary ammonium salt structure in their main chain have been prepared by simple polycondensation reaction. These polymers were used as catalyst for asymmetric alkylation of N-diphenylmethylidene glycine tert-butyl ester.
Highly Sensitive Detection of N1,N12-Diacetylspermine Based on Electrochemical Charge Accumulation
Authors: Yasukawa Tomoyuki , Inadumi Shingo , Harada Rie , Shinagawa Shingo , Nose Hiroshi , Mizutani Fumio
Published: December 2009

A novel immunosensor is presented based on a charge accumulation system using an electrode modified with a polymer containing [osmium(4,4′-dimethyl-2,2′-bipyridine)2chloride]+/2+ and horseradish peroxidase (Os/HRP polymer) to detect N1,N12-diacetylspermine (DiAcSpm). Glucose oxidase (GOx)-labeled antibody captured with immunoreaction on Os/HRP polymer catalyzed the production of hydrogen peroxide, which oxidizes [Os(bpy)2Cl]+ in polymer with HRP. [Os(bpy)2Cl]2+ was gradually accumulated in the polymer and reduced back to [Os(bpy)2Cl]+ by applying −0.1 V. This accumulation system of redox species allows enhancement of the response.
Electrochemical Formation of Mg–Li–Yb Alloys at Solid Magnesium Electrode from LiCl–KCl–YbCl3 Melts at Low Temperature
Authors: Ye Ke , Chen Ye , Zhang Milin , Han Wei , Yan Yongde , Wei Shuquan
Published: December 2009

This work presents a novel study on electrochemical preparation of Mg–Li–Yb alloys at a magnesium electrode in LiCl–KCl–YbCl3 melts at 743 K. Cyclic voltammograms showed that the reduction of ytterbium(III) ions is a stepwise reaction. The codeposition of Yb and Li takes place at magnesium electrode when the current intensity exceeds 60 mA in LiCl–KCl melts containing 2 wt % YbCl3. α, α + β, and β phases. Mg–Li–Yb alloys with different lithium contents were obtained by potentiostatic electrolysis at a magnesium electrode from LiCl–KCl melts with different concentrations YbCl3.
Manipulation of Single DNA Using a Micronanobubble Formed by Local Laser Heating on a Au-coated Surface
Authors: Fujii Sho , Kobayashi Katsuaki , Kanaizuka Katsuhiko , Okamoto Tetsuaki , Toyabe Shoichi , Muneyuki Eiro , Haga Masa-aki
Published: December 2009

We report a method for manipulating sequential single DNA strands by using a micronanobubble formed by local laser heating on a Au surface. DNA strands near the laser focal point were quickly pulled toward the focal point. This DNA pull-in phenomenon can be explained by Marangoni convection due to a micronanobubble generated by laser heating on the Au surface. The thickness of Au film plays a crucial role for absorbing the IR laser light.
MnIII Salen-type Single-molecule Magnet Fixed in a Two-dimensional Network
Authors: Kachi-Terajima Chihiro , Mori Erina , Eiba Tasuku , Saito Toshiaki , Kanadani Chikahide , Kitazawa Takafumi , Miyasaka Hitoshi
Published: December 2009

A two-dimensional network compound, [{Mn(saltmen)}4{Co(CN)6}](ClO4)·9H2O (2) (saltmen2− = N,N′-(1,1,2,2-tetramethylethylene)bis(salicylideneiminate)), was synthesized. Magnetic measurements characterized the [Mn2(saltmen)2]2+ subunit as a single-molecule magnet with an ST = 4 spin ground state, indicating that the MnIII dimer is magnetically isolated not only by the diamagnetic [Co(CN)6]3− unit but also by the space between the layers.
Preparation of Ester-group Substituted Allylic Zinc by Palladium-catalyzed Umpolung of γ-Acyloxy-α,β-unsaturated Ester by Bis(iodozincio)methane
Authors: Ueno Shizue , Sada Mutsumi , Matsubara Seijiro
Published: December 2009

Treatment of γ-acyloxy-α,β-unsaturated ester with bis(iodozincio)methane in the presence of palladium catalyst gave an allylic zinc carrying an ester group; the allylic zinc, which is prepared by this umpolung process, reacts with ketones regioselectively.
A Novel Synthesis of Mesoporous Nickel Oxide with Excellent Cycling Stability Used in Supercapacitors
Authors: Ni Wenbin , Wang Dengchao , Zhao Zhenzhen , Huang Zhongjie , Zhao Jianwei
Published: December 2009

Mesoporous nickel oxide is synthesized by a novel method by calcining a nickel–organic coordination complex precursor in this work. The prepared NiO has a uniform pore distribution evidenced by TEM and N2 adsorption–desorption tests. The NiO electrode presents a high specific capacitance of 143 F g−1, excellent rate capability (54.2% capacity retention at 100 mV s−1) and long cycling stability (no decrease in 1000 charge–discharge cycles), indicating a promising electrode material for supercapacitors.
Accommodation of tmRNA–SmpB into stalled ribosomes: A cryo-EM study
Authors: Weis Felix , Bron Patrick , Rolland Jean-Paul , Thomas Daniel , Felden Brice , Gillet Reynald
Published: December 2009

In eubacteria, translation of defective messenger RNAs (mRNAs) produces truncated polypeptides that stall on the ribosome. A quality control mechanism referred to as trans-translation is performed by transfer-messenger RNA (tmRNA), a specialized RNA acting as both a tRNA and an mRNA, associated with small protein B (SmpB). So far, a clear view of the structural movements of both the protein and RNA necessary to perform accommodation is still lacking. By using a construct containing the tRNA-like domain as well as the extended helix H2 of tmRNA, we present a cryo-electron microscopy study of the process of accommodation. The structure suggests how tmRNA and SmpB move into the ribosome decoding site after the release of EF-Tu·GDP. While two SmpB molecules are bound per ribosome in a preaccommodated state, our results show that during accommodation the SmpB protein interacting with the small subunit decoding site stays in place while the one interacting with the large subunit moves away. Relative to canonical translation, an additional movement is observed due to the rotation of H2. This suggests that the larger movement required to resume translation on a tmRNA internal open reading frame starts during accommodation.
Editorial Notes
Authors: Sambamurthy Vallabh
Published: December 2009

The performance of the journal is reviewed and metrics for 2009 are presented. In addition, key editorial transitions are highlighted.
Newborn Screening for Cystic Fibrosis by Use of a Multiplex Immunoassay
Authors: Lindau-Shepard Barbara A , Pass Kenneth A
Published: December 2009

Background: Since its beginnings, newborn screening for cystic fibrosis (CF) using an assay for immunoreactive trypsinogen (IRT) has been plagued by a high rate of false-positive results (screen positive, diagnosis negative), despite attempts to reduce this rate by use of altered cutoffs and second-tier DNA testing. IRT exists as 2 isoforms: IRT1 and IRT2, with IRT2 being more closely aligned with pancreatic disease, including CF. Assay standardization between programs is a continuing problem because the IRT assays currently in use variously recognize either 1 or both isoforms. Here we report the development of a multiplexed assay for both forms of IRT simultaneously.

Methods: Using 2 different Luminex bead sets, we developed assays for each IRT isoform separately and then combined them. Using the sum of IRT1 and IRT2 values (IRT1+IRT2), we compared the results with a CF kit currently in use.

Results: In a sample set consisting of 16 cases confirmed positive for CF, we established a cutoff at >97 μg/L total IRT. Seven of 8 carriers with 1 CF mutation screen-positive by the standard method were also screen-positive by IRT1+IRT2. Of 32 cases screen-positive by standard IRT, 11 were screen-negative by IRT1+IRT2. None of these 11 cases had CF mutations identified by the screening program.

Conclusions: These data indicate that the multiplex method with specificity for 2 isoforms of IRT has performance comparable to that of a standard IRT method and the advantage of improved standardization by detection of the 2 isoforms.
Alternative Splicing Modulates Ubx Protein Function inDrosophila melanogaster
Authors: Reed Hilary C , Hoare Tim , Thomsen Stefan , Weaver Thomas A , White Robert A H , Akam Michael , Alonso Claudio R
Published: December 2009

The Drosophila Hox gene Ultrabithorax (Ubx) produces a family of protein isoforms through alternative splicing. Isoforms differ from one another by the presence of optional segments—encoded by individual exons—that modify the distance between the homeodomain and a cofactor-interaction module termed the “YPWM” motif. To investigate the functional implications of Ubx alternative splicing, here we analyze the in vivo effects of the individual Ubx isoforms on the activation of a natural Ubx molecular target, the decapentaplegic (dpp) gene, within the embryonic mesoderm. These experiments show that the Ubx isoforms differ in their abilities to activate dpp in mesodermal tissues during embryogenesis. Furthermore, using a Ubx mutant that reduces the full Ubx protein repertoire to just one single isoform, we obtain specific anomalies affecting the patterning of anterior abdominal muscles, demonstrating that Ubx isoforms are not functionally interchangeable during embryonic mesoderm development. Finally, a series of experiments in vitro reveals that Ubx isoforms also vary in their capacity to bind DNA in presence of the cofactor Extradenticle (Exd). Altogether, our results indicate that the structural changes produced by alternative splicing have functional implications for Ubx protein function in vivo and in vitro. Since other Hox genes also produce splicing isoforms affecting similar protein domains, we suggest that alternative splicing may represent an underestimated regulatory system modulating Hox gene specificity during fly development.
Fabrication of Nanomodified Anodes for Power Density Enhancement of Microbial Fuel Cells
Authors: Schaller Rebecca , Fan Yanzhen , Xu Shoutao , Fern Alan , Chaplen Frank , Liu Hong , Jiao Jun
Published: December 2009

Microbial fuel cells (MFCs) use microorganisms to simultaneously break down organic materials and generate electricity. One of the greatest challenges in the practical application of MFCs is to sufficiently increase their power generation. Nanomodified graphite carbon anodes were prepared for use in MFCs to enhance the electron transport from the microbes to the electrode. Nanomodification to the anodes included growth of nanoparticles and multi-walled carbon nanotubes (MWCNTs). Nanoparticles of various metals, including Au, Ni, Pd, and Fe, were synthesized through thermal annealing and Fe catalyzed MWCNTs were synthesized through chemical vapor deposition. Power density was measured in MFCs for each type of nanomodified electrodes. Significant increase in power density was observed for the MFC with anodes decorated with MWCNTs (with 50-100nm diameters).
Tunneling and anisotropic-tunneling magnetoresistance in iron nanoconstrictions fabricated by focused-ion-beam
Authors: Fernandez-Pacheco Amalio , De Teresa Jose M , Cordoba Rosa , Ibarra Ricardo
Published: December 2009

We report the magnetoresistance (MR) measurements in a nanoconstriction fabricated by focused-ion-beam (FIB) in the tunneling regime of conductance. The resistance of the contact was controlled during the fabrication process, being stable in the metallic regime, near the conductance quantum, and under high vacuum conditions. The metallic contact was deteriorated when exposed to atmosphere, resulting in a conduction mechanism by tunneling. The TMR was found to be of 3% at 24 K. The anisotropic tunneling magnetoresistance (TAMR) was around 2% for low temperatures, with a field angle dependence more abrupt than in bulk Fe. This preliminary result is promising for the application of this technique to fabricate stable ferromagnetic constrictions near the atomic regime of conductance, where high MR values are expected.
Simulation of Ion-beam Induced Etching and Deposition Using a Non-local Recoil-based Algorithm
Authors: Ebm Christoph , Hobler Gerhard
Published: December 2009

Ion-beam induced etching and deposition rates are proportional to the flux of recoils reaching the surface. Based on this finding we propose an improved algorithm for etching and deposition simulations. In this algorithm the recoil flux at each point on the surface is calculated by summing up the recoil fluxes originating from ions impinging on any other surface point. The latter are determined by interpolation in tables calculated by binary collision simulations. For concave surfaces a correction to this algorithm is proposed. Fluxes calculated by this model are in good agreement with binary collision simulations of collision cascades in the same 2-d structure. Consistent with experimental findings, the model predicts that deposited pillars are broader than the ion beam, while etched trenches do not show such broadening. The pillar broadening is related to the lateral straggling of the recoils.
My Modeling Nanocluster Formation During Ion Beam Synthesis
Authors: Yuan Chun-Wei , Yi Diana O. , Sharp Ian D. , Shin Swanee J. , Liao Christopher Y. , Guzman Julian , Ager Joel , Haller Eugene , Chrzan Daryl
Published: December 2009

Ion beam synthesis of nanoclusters is studied via both kinetic Monte Carlo simulations and the self-consistent mean-field solution to a set of coupled rate equations. Both approaches predict a steady-state shape for the cluster size distribution that depends only on a characteristic length determined by the ratio of the effective diffusion coefficient times the effective solubility to the ion flux. The average cluster size in the steady state regime is determined by the implanted species/matrix interface energy.
Quantum and Classical Molecular Dynamics Studies of the Threshold Displacement Energy in Si Bulk and Nanowires
Authors: Holmström Eero , Krasheninnikov Arkady , Nordlund Kai
Published: December 2009

Using quantum mechanical and classical molecular dynamics computer simulations, we study the full three-dimensional threshold displacement energy surface in Si. We show that the SIESTA density-functional theory method gives a minimum threshold energy of 13 eV that agrees very well with experiments, and predicts an average threshold displacement energy of 36 eV. Using the quantum mechanical result as a baseline, we discuss the reliability of the classical potentials with respect to their description of the threshold energies. We also examine the threshold energies for sputtering in a nanowire, and find that this threshold depends surprisingly strongly on which layer the atom is in.
Low-energy Ion Beam Biotechnology at Chiang Mai University
Authors: Yu Liangdeng , Anuntalabhochai S.
Published: December 2009

MeV-ion beam has long been applied to biology research and applications for many decades as highly energetic ions are undoubtedly able to interact directly with biology molecules to cause changes in biology. However, low-energy ion beam at tens of keV and even lower has also been found to have significant biological effects on living materials. The finding has led to applications of ion-beam induced mutation and gene transfer. From the theoretical point of view, the low-energy ion beam effects on biology are difficult to understand since the ion range is so short that the ions can hardly directly interact with the key biological molecules for the changes. This talk introduces interesting aspects of low-energy ion beam biology, including basis of ion beam biotechnology and recent developments achieved in Chiang Mai University in relevant applications such as mutation and gene transfer and investigations on mechanisms involved in the low-energy ion interaction with biological matter such as eV-keV ion beam bombardments of naked DNA and the cell envelopes.
Low-energy ion induced sputtering of pre-patterned fused silica surfaces
Authors: Völlner Jens , Ziberi Bashkim , Frost Frank , Rauschenbach Bernd
Published: December 2009

Ripple formation and smoothing of pre-patterned fused silica surfaces by low-energy ion beam erosion have been investigated. As pre-pattern ripple surfaces produced by low-energy Ar+ ion beam erosion were used. In addition to the enhanced ripple formation on the pre-patterned surfaces also the smoothing characteristics of surface is changed. Due to the anisotropic surface roughness of the ripple pattern the irradiation direction with respect to the pre-pattern becomes important. It is suggested that all of these effects are related to surface gradient dependent sputtering and therefore it is an important mechanisms also in the low-energy ion beam erosion of fused silica surfaces.
Subjective Sleep Quality Alterations at High Altitude
Authors: Szymczak Robert K. , Sitek Emilia J. , Sławek Jarosław W. , Basiński Andrzej , Siemiński Mariusz , Wieczorek Dariusz
Published: December 2009

Objective

Sleep pattern at high altitude has been studied, mainly with the use of polysomnography. This study aimed to analyze subjective sleep quality at high altitude using the following standardized scales: the Pittsburgh Sleep Quality Index (PSQI) and the Athens Insomnia Scale (AIS-8).

Methods

Thirty-two members of 2 expeditions—28 males and 4 females (mean age 31 years)—participated in this study conducted in Nepal, Himalayas (Lobuche East, 6119 m above sea level [masl]), Kyrgyzstan, Pamirs (Lenin Peak, 7134 masl), and Poland (sea level). The scales were administered twice, at high altitude (mean altitude 4524 masl) and at sea level.

Results

Both measures showed a decrease in sleep quality at high altitude (statistical significance, P < .001). Sleep problems affected general sleep quality and sleep induction. Sleep disturbances due to awakenings during the night, temperature-related discomfort, and breathing difficulties were reported. High altitude had no statistically significant effect on sleep duration or daytime dysfunction as measured by PSQI.

Conclusions

The overall results of PSQI and AIS-8 confirm the data based on the climbers’ subjective accounts and polysomnographic results reported in previous studies. The introduction of standardized methods of subjective sleep quality assessment might resolve the problem of being able to perform precise evaluations and research in the field of sleep disturbances at high altitude.
Determinants of Summiting Success and Acute Mountain Sickness on Mt Kilimanjaro (5895 m)
Authors: Davies Andrew J. , Kalson Nicholas S. , Stokes Suzy , Earl Mark D. , Whitehead Adam G. , Frost Hannah , Tyrell-Marsh Ian , Naylor Jon
Published: December 2009

Objective

To determine the incidence of acute mountain sickness (AMS), the frequency of summiting success, and the factors that affect these in trekkers on Kilimanjaro, one of the world's most summitted high-altitude peaks.

Methods

The study group comprised 312 trekkers attempting Mt Kilimanjaro summit by the Marango Route. Trekkers ascended over 4 or 5 days along a fixed ascent profile, stopping at 3 huts on ascent (2700 m, 3700 m, and 4700 m) before attempting the summit. Researchers were stationed at each hut for 16 days. Each night we measured heart rate, respiratory rate, blood pressure, oxygen saturation, and Lake Louise Score. We recorded the highest altitude that trekkers reached on the mountain.

Results

Of 181 complete sets of data, 111 (61%) trekkers reached the summit, and 139 (77%) developed AMS. Physiological results were not related to summit success. The incidence of AMS and summiting success were similar in those on the 4- or 5-day route. Trekkers on the 5-day route who used acetazolamide were less likely to develop AMS and more likely to summit than were those not taking acetazolamide ( P = <.05); this difference was not present with trekkers on the 4-day route.

Conclusions

The risk of developing AMS is high on Mt Kilimanjaro. Although taking an extra day to acclimatize with the use of acetazolamide did provide some protection against AMS, ideally trekkers need a more gradual route profile for climbing this mountain.
Injury and Illness Encountered in Shenandoah National Park
Authors: Forrester Joseph D. , Holstege Christopher P.
Published: December 2009

Objective

There have been no studies to date exploring the nature of injuries and illness experienced by individuals in a National Park in the southeastern United States. The purpose of this study was to determine the incidence of such illnesses and injuries to visitors in Shenandoah National Park.

Methods

This study was a retrospective review of the case incident reports from Shenandoah National Park from 2003 to 2007. Data obtained included age, sex, time and date report was received, medical symptoms, trauma type, location of injury, mechanism of injury, level of care, time to patient, time to disposition, disposition type, location, and activity at time of event.

Results

There were 159 total cases, corresponding to a reported incident rate of 2.7 persons reported injured or ill per 100 000 visitors to Shenandoah National Park. A total of 23.3% of all reported injuries occurred in persons less than 18 years of age. The most common reported adult injury was soft tissue injury, with the most common anatomical location being the distal lower extremity. The most common activity in which adults were involved at the time of the injury was hiking. Of the pediatric trauma cases, the most common mechanism of injury was a fall. Of the adult medical illnesses, the most common complaint was chest pain.

Conclusions

The pattern of adult and pediatric trauma is consistent among several geographically different National Parks in the United States and represents an injury pattern that all wilderness/outdoor care providers need to be competent to treat. Among adult visitors, the most common medical complaint was chest pain, a complaint more prevalent at Shenandoah National Park compared to other parks. Knowing that trauma injury patterns are relatively similar to those of other parks but that medical illness is more locale specific can help health care providers tailor their resource allotment and health management protocols.
Injuries and Medical Conditions Among Kayakers Paddling in the Sea Environment
Authors: Powell Colin
Published: December 2009

Objective

Directly experienced health impacts and the perception of health impacts affecting the wider community kayaking in the sea environment were assessed.

Methods

Four hundred questionnaires were distributed at coastal launch sites in West Wales. One hundred and seventy-eight questionnaires were returned.

Results

The majority of respondents had not received injuries or developed medical conditions as a result of kayaking in the sea. Among those who had directly encountered health impacts, problems with joints, tendons, and muscles were the most frequently reported injury. When asked what were the most common health impacts in general among those who kayak in the sea, ‘sprains and pulled muscles’ and ‘cuts and abrasions’ were the most frequently cited factors. The rank order of the ‘most common injury or medical condition’ and the ‘most commonly injured part of the body’ varied according to type of boat used and activity undertaken. This variation was evident in relation to direct experience of health impacts and the perception of injuries and medical conditions affecting other kayakers. Most respondents regarded injuries and medical conditions as uncommon and not serious and reported positive health effects from kayaking.

Conclusions

Health impacts encountered by those kayaking in the sea reflect many of those identified in literature focusing upon other aspects of kayaking. Responses to questions regarding the most common injury or medical condition and the most common injury site vary according to type of boat used and activity undertaken. It is concluded that while there may be common demands placed upon paddlers using a variety of boats and participating in differing activities, it cannot be assumed that they are a homogeneous group. This has implications for the development of incident prevention strategies.
Recreational Surfing Injuries in Cornwall, United Kingdom
Authors: Hay Christopher S.M. , Barton Sue , Sulkin Tom
Published: December 2009

Objective

To analyze the nature of surfing injuries in Cornwall in order to identify trends and inform clinical management.

Methods

The details of patients presenting (with injuries sustained while surfboard/bodyboard riding) to the Emergency Department (ED) of the Royal Cornwall Hospital, Truro (UK), from September 2004 until August 2006 were recorded prospectively. The notes were then retrospectively reviewed by a senior ED physician. The records of each visit were scrutinized for date, age, sex, injury type, and injury severity and outcome; in addition, the patient's residential status (Cornish resident or visitor) was recorded.

Results

A total of 212 patient episodes were collected. Male patients represented 80% of injuries. The average age was 27 years (range, 11–66 years). Nonresident surfers represented 57% (121) of the patients, and 43% (91) of patients were local Cornwall residents. Of the total injuries, 90% ( n = 190) were injuries that were minor/moderate (allowing for discharge after treatment). Lacerations accounted for 38% ( n = 73) of injuries, and bruising and laceration to the head represented 37% ( n = 71) of injuries in this group. Sprains to the neck and back represented 53% (21/40) of all sprains. Fractures of the facial bones represented 6 of the 8 fractures to the head region; the other 2 fractures involved teeth. Fractures to the upper and lower limbs were equally frequent (6 cases of each). Anterior shoulder dislocations accounted for 10% ( n = 19) of injuries not requiring hospital admission. Injuries requiring hospital admission represented 10% ( n = 22). These injuries were a more disparate group, with fractures of the cervical spine and skull accounting for 32% ( n = 7) and fractures of the lower limb 27% ( n = 6) of the total. A total of 77% ( n = 168) of all injuries presented in the summer months (April through September). The greatest number of presentations occurred in August, with 33% ( n = 69) of the total surf-related injuries for the year.

Conclusions

Surfing injuries were most common in young adult men. Most injuries presenting to the ED were minor/moderate injuries and did not require hospital admission. The overall pattern of injuries was similar to those found in studies from other countries where surfing is popular; however, there was a higher-than-expected incidence of shoulder dislocation. The trends identified in this study could be used to inform education focused on prevention of the most common injuries. Increased use of protective headwear should be considered.
Attack Upon a Bather by a Swordfish: A Case Report
Authors: Haddad Vidal , Lima de Figueiredo José
Published: December 2009

We report a case of a bather injured by a swordfish in shallow water off the coast of southern Brazil. The victim suffered multiple injuries from the fish's bill, including a puncture wound of his left knee and the tip of the bill remaining as a foreign body. The victim made a full recovery after field management and conservative care. The potential factors leading to this most unusual attack are discussed.
A Long-Duration (118-day) Backpacking Trip (2669 km) Normalizes Lipids Without Medication: A Case Study
Authors: DeVoe Dale , Israel Richard Gay , Lipsey Tiffany , Voyles Wyatt
Published: December 2009

Objective

To evaluate the effects of a long-distance backpacking trip on body composition, weight, blood lipids, and lipoproteins.

Methods

Single-subject (male, aged 49 years) study of an experienced backpacker who hiked 118 days on the Appalachian Trail. Outcome measures that were assessed pre-hike and post-hike included body fat (%) by hydrostatic weighing and skinfold assessment, height and weight, body mass index (BMI), circumference measurements (umbilicus, anterior suprailiac, maximum hip, greater trochanter, minimum waist, umbilicus/anterior suprailiac ratio), and blood pressure (systolic and diastolic at rest and peak). Dietary analyses (total kilocalories, protein, carbohydrate, fat, cholesterol, saturated fat, monounsaturated fat, polyunsaturated fat, dietary fiber) were conducted pre-hike, on days 54 through 56, and on days 98 through 100. Blood lipids and lipoproteins (triglycerides, high-density lipoprotein, low-density lipoprotein) were measured pre-hike, on day 89, and post-hike.

Results

Pre-post differences showed decreases in body weight, from 85.3 kg to 73.9 kg (−11.4 [−13.4%]); percent body fat, hydrostatic weighing, from 25.18 to 14.31 (−10.87 [−43.2%]); percent body fat, skinfolds (7-site), from 23.79 to 11.61 (12.18 [−51.2%]); and BMI, from 29.37 to 25.46 (−3.91 [−13.3%]). Pre-post differences in blood lipid changes over the course of 118 days were as follows: triglycerides (mg·dL−1) fell from 319 to 79 (−240 [−75%]); total cholesterol (mg·dL−1) fell from 276 to 196 (−80 [−29%]); high-density lipoprotein (HDL) (mg·dL−1) rose from 46 to 63 (+17 [+37%]); low-density lipoprotein (LDL) (mg·dL−1) fell from 167 to 118 (−49 [−29%]); LDL/HDL ratio fell from 3.63 to 1.87 (−1.76 [−48%]); and total cholesterol/HDL ratio fell from 6.00 to 3.11 (−2.89 [−48%]).

Conclusion

The physical activity and diet associated with an extended backpacking adventure can considerably reduce and clinically normalize blood lipids and lipoproteins without medication and can very positively affect body composition and weight.
Changes in Plasma Bradykinin Concentration and Citric Acid Cough Threshold at High Altitude
Authors: Mason Nicholas P. , Petersen Merete , Mélot Christian , Kim Elena V. , Aldashev Almaz , Sarybaev Akpay , Mirrakhimov Mirsaid M. , Naeije Robert
Published: December 2009

Objective

Altitude-related cough is a troublesome condition of unknown etiology. Inhaled tussive agents are used to quantify cough, and the citric acid cough threshold has been shown to fall on ascent to altitude. Cough can occur in patients taking angiotensin-converting enzyme inhibitors due to stimulation of airway sensory receptors by increased levels of bradykinin. We hypothesized that increased levels of bradykinin could be responsible for the decrease in citric acid cough threshold on exposure to altitude and a possible etiologic factor in altitude-related cough.

Methods

Twenty healthy volunteers underwent baseline tests at 700 m before a 2-week stay at 3800 m. Angiotensin-converting enzyme activity and plasma bradykinin were measured at baseline and altitude. Citric acid cough threshold and nocturnal cough frequency were measured at baseline and throughout the 2 weeks at altitude.

Results

Citric acid cough threshold fell from 3.7 g/dL at baseline to 2.1 g/dL on the second day at 3800 m (geometric mean difference 1.8, 95% CIs 1.0–5.0, P = .025) and remained reduced throughout the stay at altitude. Nocturnal cough frequency was unchanged compared to baseline. Plasma bradykinin fell from 0.43 ng/mL at baseline to 0.08 ng/mL at altitude (geometric mean difference 5.7, 95% CIs 2.1–15.5, P = .002), but angiotensin-converting enzyme activity was unchanged (mean difference 0.06, 95% CIs –2.7–2.8, P = .97). There was no correlation between plasma bradykinin and citric acid cough threshold.

Conclusions

Increased levels of bradykinin are unlikely to be a significant factor in the increased sensitivity to citric acid seen in hypobaric hypoxia. Further studies are required to elucidate the etiology of altitude-related cough.