bluuebunny/crossref_metadata_2025 huggingface dataset:
Pitch angle distributions of electrons at dipolarization sites during geomagnetic activity: THEMIS observations
Authors: Wang Kaiti , Lin Ching‐Huei , Wang Lu‐Yin , Hada Tohru , Nishimura Yukitoshi , Turner Drew L. , Angelopoulos Vassilis
Published: November 2014

Changes in pitch angle distributions of electrons with energies from a few eV to 1 MeV at dipolarization sites in Earth's magnetotail are investigated statistically to determine the extent to which adiabatic acceleration may contribute to these changes. Forty‐two dipolarization events from 2008 and 2009 observed by Time History of Events and Macroscale Interactions during Substorms probes covering the inner plasma sheet from 8 RE to 12 RE during geomagnetic activity identified by the AL index are analyzed. The number of observed events with cigar‐type distributions (peaks at 0° and 180°) decreases sharply below 1 keV after dipolarization because in many of these events, electron distributions became more isotropized. From above 1 keV to a few tens of keV, however, the observed number of cigar‐type events increases after dipolarization and the number of isotropic events decreases. These changes can be related to the ineffectiveness of Fermi acceleration below 1 keV (at those energies, dipolarization time becomes comparable to electron bounce time). Model‐calculated pitch angle distributions after dipolarization with the effect of betatron and Fermi acceleration tested indicate that these adiabatic acceleration mechanisms can explain the observed patterns of event number changes over a large range of energies for cigar events and isotropic events. Other factors still need to be considered to assess the observed increase in cigar events around 2 keV. Indeed, preferential directional increase/loss of electron fluxes, which may contribute to the formation of cigar events, was observed. Nonadiabatic processes to accelerate electrons in a parallel direction may also be important for future study.
Southern Ocean wind‐driven entrainment enhances satellite chlorophyll‐a through the summer
Authors: Carranza Magdalena M. , Gille Sarah T.
Published: November 2014

Despite being the largest High Nitrate Low Chlorophyll (HNLC) region, the Southern Ocean sustains phytoplankton blooms through the summer, when presumably there is sufficient light, but nutrients in the euphotic zone have been depleted. Physical processes that can potentially supply nutrients from subsurface waters to the euphotic zone, and promote phytoplankton growth in the summer, have not been fully explored at the large scale. By means of a correlation analysis, this study combines high‐resolution satellite observations of ocean color, winds and sea surface temperature, surface heat fluxes from reanalysis and Argo mixed‐layer depth (MLD) estimates to explore the role of the atmospheric forcing (i.e., winds and surface heat fluxes) on upper ocean processes that may help sustain high satellite chlorophyll‐a (Chl‐a) through the summer. Two physical processes that can supply nutrients to the euphotic zone are: MLD deepening, caused by wind‐mixing and/or surface cooling, and Ekman pumping driven by the wind stress curl. We find that high winds correlate with high Chl‐a over broad open ocean areas, suggesting that transient MLD deepening through wind‐mixing (i.e., wind‐driven entrainment) helps sustain high Chl‐a. Wind‐driven entrainment plays a dominant role on time scales associated with atmospheric synoptic storms (i.e., <10 days) and has a larger influence on surface Chl‐a than storm scale local Ekman pumping. Based on our analysis of statistically significant correlation patterns, we identify regions in the Southern Ocean where wind‐induced entrainment may play a role in sustaining summer phytoplankton blooms.
Accuracy and precision in the calculation of phenology metrics
Authors: Ferreira A. Sofia , Visser Andre W. , MacKenzie Brian R. , Payne Mark R.
Published: November 2014

Phytoplankton phenology (the timing of seasonal events) is a commonly used indicator for evaluating responses of marine ecosystems to climate change. However, phenological metrics are vulnerable to observation‐(bloom amplitude, missing data, and observational noise) and analysis‐related (temporal resolution, preprocessing technique, and phenology metric) processes. Here we consider the impact of these processes on the robustness of four phenology metrics (timing of maximum, 5% above median, maximum growth rate, and 15% of cumulative distribution). We apply a simulation‐testing approach, where a phenology metric is first determined from a noise‐ and gap‐free time series, and again once it has been modified. We show that precision is a greater concern than accuracy for many of these metrics, an important point that has been hereto overlooked in the literature. The variability in precision between phenology metrics is substantial, but it can be improved by the use of preprocessing techniques (e.g., gap‐filling or smoothing). Furthermore, there are important differences in the inherent variability of the metrics that may be crucial in the interpretation of studies based upon them. Of the considered metrics, the 15% of cumulative distribution metric best satisfies the precision criteria. However, the 5% above median metric is comparable in terms of precision and exhibits more inherent variability. We emphasize that the choice of phenology metric should be determined by the specific nature of the question being asked. We believe these findings to be useful to the current discussion on phenology metrics of phytoplankton dynamics.
Total Synthesis and Structural Revision of (+)‐Uprolide G Acetate
Authors: Zhu Liangyu , Liu Yuan , Ma Renze , Tong Rongbiao
Published: November 2014

The first, asymmetric total synthesis of the proposed structure of (+)‐uprolide G acetate (UGA) is reported, and the spectral properties of the synthetic compound clearly differed from those reported for natural UGA. On the basis of comprehensive analysis of the NMR data, two possible structures for the natural UGA were proposed and their total synthesis achieved, thus leading to the identification and confirmation of the correct structure and absolute configuration of the natural UGA. This synthesis was enabled by development of a novel synthetic strategy, which revolved around three key cyclization reactions: an Achmatowicz rearrangement, Sharpless asymmetric dihydroxylation/lactonization, and ring‐closing metathesis. These synthetic studies pave the way for further studies on this class of structurally unusual cytotoxic cembranolides.
Synthesis, Molecular Modeling, and Biological Evaluation of Novel Chiral Thiosemicarbazone Derivatives as Potent Anticancer Agents
Authors: Taşdemir Demet , Karaküçük‐İyidoğan Ayşegül , Ulaşli Mustafa , Taşkin‐Tok Tuğba , Oruç‐Emre Emİne Elçİn , Bayram Hasan
Published: November 2014

A series of new chiral thiosemicarbazones derived from homochiral amines in both enantiomeric forms were synthesized and evaluated for their in vitro antiproliferative activity against A549 (human alveolar adenocarcinoma), MCF‐7 (human breast adenocarcinoma), HeLa (human cervical adenocarcinoma), and HGC‐27 (human stomach carcinoma) cell lines. Some of compounds showed inhibitory activities on the growth of cancer cell lines. Especially, compound17bexhibited the most potent activity (IC504.6 μM) against HGC‐27 as compared with the reference compound, sindaxel (IC5010.3 μM), and could be used as a lead compound to search new chiral thiosemicarbazone derivatives as antiproliferative agents.Chirality 27:177–188, 2015. © 2014 Wiley Periodicals, Inc.
The Early Diabetes Intervention Program – is early actually late?
Authors: Bergman Michael
Published: November 2014

This Commentary briefly reviews the background of prediabetes including its definition and pathophysiology and describes as well the natural course of glycemic deterioration as it follows a continuum. Research efforts in identifying glucose and other biomarkers for the early detection of high‐risk individuals are summarized.
Xhe2 is a member of the astacin family of metalloproteases that promotes Xenopus hatching
Authors: Hong Chang‐Soo , Saint‐Jeannet Jean‐Pierre
Published: November 2014

Transcription factors Pax3 and Zic1 are among the earliest genes activated at the neural plate border. In Xenopus, they are necessary and sufficient to promote the formation of multiple neural plate border cell types, including the neural crest, cranial placodes, and hatching gland. Pax3 is especially critical for the formation of the hatching gland, a group of cells that produce proteolytic enzymes essential to digest the egg vitelline envelope and jelly coat in order to release the tadpole into the environment. In a screen designed to identify downstream targets of Pax3, we isolated a member of the astacin family of metalloproteases, related to Xenopus hatching enzyme (Xhe), that we named Xhe2. Xhe2 is exclusively expressed in hatching gland cells as they first emerge at the lateral edge of the anterior neural plate, and persists in this tissue up to the tadpole stage. Knockdown experiments show that Xhe2 expression depends entirely on Pax3 function. Gain‐of‐function studies demonstrate that Pax3 can induce premature hatching through the upregulation of several proteolytic enzymes including Xhe2. Interestingly, Xhe2 overexpression is sufficient to induce early hatching, indicating that Xhe2 is one of the key components of the degradation mechanism responsible for breaking down the vitelline membrane. genesis 52:946–951, 2014. © 2014 Wiley Periodicals, Inc.
Disgust sensitivity predicts political ideology and policy attitudes in the Netherlands
Authors: Brenner Corinne J. , Inbar Yoel
Published: November 2014

Individual differences in disgust sensitivity have been linked to social attitudes and ideology, but the generalizability of this effect and the nature of the political issues implicated remain unclear. In two studies using large Dutch samples, we find that disgust sensitivity predicts political attitudes for issues in several domains related to physical/spiritual purity and pathogen risk. Sensitivity to disgust was significantly associated with attitudes for a general ‘physical and spiritual purity’ factor, as well as specific issue factors regarding sex and sexual minorities, immigration, and foreign outgroups. Additionally, disgust sensitivity was associated with greater likelihood of voting for the socially conservative “Freedom Party” (Partij Voor de Vrijheid). These results suggest that the tendency to experience disgust influences a specific subset of social and political attitudes across cultures. Copyright © 2014 John Wiley & Sons, Ltd.
Lithological controls on soft cliff planshape evolution under high and low sediment availability
Authors: Carpenter Natasha E. , Dickson Mark E. , Walkden Mike , Nicholls Robert J. , Powrie William
Published: November 2014

This paper addresses a series of geomorphic questions relating to large‐scale (> 1 km), long‐term (100 – 1,000 years) coastal planshape evolution. Previous research on soft‐cliff coasts has recognised the role of protective fronting beach volumes on reducing rates of cliff toe retreat. However, it is the maintenance of this critical threshold that ultimately determines two contrasting modes of shoreline behaviour: Mode A, in which there is little beach sediment and shoreline evolution is controlled by material strength; and, Mode B, when ample beach sediment means that shoreline evolution is controlled by longshore sediment transport. Here we use a numerical model (SCAPE) to investigate temporal and spatial changes in beach volume on a broader range of feedbacks than considered in previous models. The transition between Mode A and Mode B coasts is defined by relative sediment inputs to outputs and used to explore how these contrasting modes control the evolution of an initial linear frontage exhibiting longshore changes in cliff lithology (material resistance and the proportion of beach grade material in the eroded bedrock). Under Mode A, relative changes in material resistance result in long term heterogeneous rates of retreat, which result in the development of persistent headland and embayment features. However, under Mode B, feedbacks between coastal planshape, longshore sediment transport, beach volume and wave energy result in steady state retreat rates regardless of longshore variations in resistance. Results are compared and contrasted to previous simulations and site specific examples and a conceptual model of Mode A and Mode B interactions presented. Copyright © 2015 John Wiley & Sons, Ltd.
Review
Authors: White J. Peter
Published: November 2014

The Cambridge Encyclopaedia of Archaeology. Edited by A. Sherratt. Cambridge University Press, Cambridge, 1980. 495 pages, numerous plates, maps and diagrams. $39.95.
Review
Authors: Anderson Atholl
Published: November 2014

Archaeology as Human Ecology: Method and Theory for a Contextual Approach. By Karl W. Butzer. Cambridge, Cambridge University Press. 1982. ISBN 0 521 28877 0. Pp. xii + 364. Price $19.50.
Review
Authors: O'Connell James F.
Published: November 2014

Archaeology of the Dreamtime. By Josephine Flood. Collins, Sydney, 1983. ISBN 0 00 216444 2. Pp. 288. $24.95.
Review
Authors: Sullivan Hilary
Published: November 2014

Coastal Archaeology in South‐eastern Australia. Edited by P. J. F. Coutts. Records of the Victorian Archaeological Survey 14, 1984. ISBN 0158 9697 Pp. xvi + 347. Price $13.00.
Review
Authors: Hallam Sylvia J.
Published: November 2014

1000 years of gardening in New Zealand. By Helen Leach. A.H. and A.W. Reed Ltd., Wellington, 1984. ISBN 0 589 01488 9. Pp. x + 157. Price: $NZ24.95.
Review
Authors: Bonhomme T.
Published: November 2014

Archaeological Investigations in the Yap Islands, Micronesia, First Millennium B.C. to the Present Day By Michiko Intoh and Foss Leach BAR International Series 277, 1985. Pp x + 200. ISBN 0 86054 353 6. £UK14.
Review
Authors: Bowdler Sandra
Published: November 2014

The Palaeolithic Settlement of Europe. By Clive Gamble. Cambridge University Press, 1986. ISBN 0 521 24514 1 (cloth); 0 521 28764 2 (paper). Pp. xix + 471. $53.00 (paper)
Review
Authors: Allen Harry
Published: November 2014

Archaeology at ANZAAS, Canberra (1984). Edited by G.K. Ward. Canberra Archaeological Society, Canberra, 1986. ISBN 0 95886255 0 8. Pp. 264. $10.00
Prehistoric social landscapes of the Arawe Islands, West New Britain Province, Papua New Guinea
Authors: Gosden Chris
Published: November 2014

This paper lays out a theoretical framework for interpreting a regional archaeological record in terms of the social formations which produced it. The central idea is that of the social landscape. Past social groups are seen to operate in the landscape in order to provide and sustain a social system, rather than reacting to the structure of their environment. The idea of a social landscape is employed to examine how groups organise themselves on a local regional scale to meet social goals and to link these forms of organisation to the archaeological record they leave behind. The central social principle explored here is that of debt, which enjoins dispersal of materials and sets up landscapes which are non‐accumulative. Data from the Arawe island group on the south coast of West New Britain, Papua New Guinea are presented to illustrate these ideas.
New Guinea II Cave: A Pleistocene site on the Snowy River, Victoria
Authors: Ossa Paul , Marshall Brendan , Webb Cathie
Published: November 2014

New Guinea II Cave is a limestone shelter and cave complex on the Snowy River in Eastern Victoria. Human occupation has been intermittent for more than 20,000 radiocarbon years leaving behind a small but constant amount of lithic material and bone artefacts. Vertebrate faunal remains are abundant but mostly of non‐cultural origin. The character of the assemblage has similarities to Cloggs Cave in Buchan and together with Birrigai in the ACT they form a general signature for human use of the southeastern uplands during the Pleistocene. The signature shows non‐intensive use of caves and shelters and local faunal resources. In comparison, southwestern Tasmanian Pleistocene sites appear to have a different signature of cave occupation and the primacy of a single vertebrate resource.
Cyclical patterns in the Pleistocene human occupation of Southwest Tasmania
Authors: Holdaway Simon , Porch Nick
Published: November 2014

One hundred Pleistocene radiocarbon determinations from southwest Tasmanian archaeological sites are used to construct a moving sum of determinations every 500 years within periods spanning 1000 years. The resulting plot shows a cyclical pattern with an increasing amplitude through time. The cyclical pattern can be correlated with climatic indicators from Pulbeena Swamp (northwest Tasmania) and allows us to suggest that the archaeological sites were subject to relatively low levels of occupation during periods of cold and dry climate.
Faunal reduction at Puntutjarpa rockshelter, Warburton Ranges, Western Australia
Authors: Gould Richard A.
Published: November 2014

The Holocene faunal assemblage from Puntutjarpa Rockshelter in the Western Desert has always been problematic owing to the extreme fragmentation of bones and teeth there. This study examines alternative explanations for this fragmentation by looking closely at the Puntutjarpa material and also by controlled comparisons with late Holocene faunal materials from Intitjikula Rockshelter (James Range East), Northern Territory. The results of this analysis indicate that certain taphonomic factors probably account for extreme fragmentation of animal bones at both sites. But gross differences in fragmentation of macropod teeth at these two sites point to behavioral explanations related to dietary shortfalls of meat and meat‐related products resulting from variability in the biogeography of hunting in these two arid‐zone localities. An ethnographic‐behavioral model is proposed to account for differences in macropod tooth reduction at these two sites.
Sand tempers in indigenous Lapita and Lapitoid Polynesian Plainware and imported protohistoric Fijian pottery of Ha'apai (Tonga) and the question of Lapita tradeware
Authors: Dickinson William R. , Shutler Richard , Shortland Rob , Burley David V. , Dye Thomas S.
Published: November 2014

The Lapita site at Faleloa on Foa Island in the Ha'apai Group of central Tonga lies near the southeastern end of the belt of Lapita sites spread through island Melanesia and western Polynesia during the millennium 1500–500 BC. Temper sands in Faleloa Lapita sherds closely resemble modern placer sands on beaches of islands within Ha'apai, and document local manufacture without intrusion of tradeware. Other Lapita and Lapitoid (Polynesian Plainware) sherds from nearby islands in Ha'apai contain similar local tempers that differ only in reflecting lesser placer concentrations of ferromagnesian mineral grains. Imported protohistoric sherds from Fiji contain distinctly different temper sand clearly exotic to Tonga. Although suggestions that Lapita pottery was largely tradeware are not supported by available petrographic information, Lapita pottery transport should be tested further by additional study of sand tempers in other Lapita collections using systematic sampling strategies to select sherds for microscopic analysis. The varied geotectonic environment of different island groups within the Lapita region ensures that far‐travelled wares can be identified by temper analysis.
Small Aβ1–42 oligomer‐induced membrane depolarization of neuronal and microglial cells: Role of N‐methyl‐D‐aspartate receptors
Authors: Morkuniene Ramune , Cizas Paulius , Jankeviciute Silvija , Petrolis Robertas , Arandarcikaite Odeta , Krisciukaitis Algimantas , Borutaite Vilmante
Published: November 2014

Although it is well documented that soluble beta amyloid (Aβ) oligomers are critical factors in the pathogenesis of Alzheimer's disease (AD) by causing synaptic dysfunction and neuronal death, the primary mechanisms by which Aβ oligomers trigger neurodegeneration are not entirely understood. We sought to investigate whether toxic small Aβ1–42 oligomers induce changes in plasma membrane potential of cultured neurons and glial cells in rat cerebellar granule cell cultures leading to neuronal death and whether these effects are sensitive to the N‐methyl‐D‐aspartate receptor (NMDA‐R) antagonist MK801. We found that small Aβ1–42 oligomers induced rapid, protracted membrane depolarization of both neurons and microglia, whereas there was no change in membrane potential of astrocytes. MK801 did not modulate Aβ‐induced neuronal depolarization. In contrast, Aβ1−42 oligomer‐induced decrease in plasma membrane potential of microglia was prevented by MK801. Small Aβ1–42 oligomers significantly elevated extracellular glutamate and caused neuronal necrosis, and both were prevented by MK801. Also, small Aβ1–42 oligomers decreased resistance of isolated brain mitochondria to calcium‐induced opening of mitochondrial permeability transition pore. In conclusion, the results suggest that the primary effect of toxic small Aβ oligomers on neurons is rapid, NMDA‐R‐independent plasma membrane depolarization, which leads to neuronal death. Aβ oligomers‐induced depolarization of microglial cells is NMDA‐R dependent. © 2014 Wiley Periodicals, Inc.
Reconstruction of dynamic image series from undersampled MRI data using data‐driven model consistency condition (MOCCO)
Authors: Velikina Julia V. , Samsonov Alexey A.
Published: November 2014

Purpose

To accelerate dynamic MR imaging through development of a novel image reconstruction technique using low‐rank temporal signal models preestimated from training data.

Theory

We introduce the model consistency condition (MOCCO) technique, which utilizes temporal models to regularize reconstruction without constraining the solution to be low‐rank, as is performed in related techniques. This is achieved by using a data‐driven model to design a transform for compressed sensing‐type regularization. The enforcement of general compliance with the model without excessively penalizing deviating signal allows recovery of a full‐rank solution.

Methods

Our method was compared with a standard low‐rank approach utilizing model‐based dimensionality reduction in phantoms and patient examinations for time‐resolved contrast‐enhanced angiography (CE‐MRA) and cardiac CINE imaging. We studied the sensitivity of all methods to rank reduction and temporal subspace modeling errors.

Results

MOCCO demonstrated reduced sensitivity to modeling errors compared with the standard approach. Full‐rank MOCCO solutions showed significantly improved preservation of temporal fidelity and aliasing/noise suppression in highly accelerated CE‐MRA (acceleration up to 27) and cardiac CINE (acceleration up to 15) data.

Conclusions

MOCCO overcomes several important deficiencies of previously proposed methods based on pre‐estimated temporal models and allows high quality image restoration from highly undersampled CE‐MRA and cardiac CINE data. Magn Reson Med 74:1279–1290, 2015. © 2014 Wiley Periodicals, Inc.
Conservative management for female urinary incontinence and pelvic organ prolapse review 2013: Summary of the 5th International Consultation on Incontinence
Authors: Dumoulin Chantale , Hunter Kathleen F. , Moore Katherine , Bradley Catherine S. , Burgio Kathryn L. , Hagen S. , Imamura M. , Thakar R. , Williams K. , Chambers T.
Published: November 2014

Aims

The objective of the 5th International Consultation on Incontinence (ICI) chapter on Adult Conservative Management was to review and summarize the new evidence on conservative management of urinary incontinence (UI) and pelvic organ prolapse (POP) in order to compile a current reference source for clinicians, health researchers, and service planners. In this paper, we present the review highlights and new evidence on female conservative management.

Methods

Revision and updates of the 4th ICI Report using systematic review covering years 2008–2012.

Results

Each section begins with a brief definition and description of the intervention followed by a summary, where possible, of both the state and level of evidence for prevention and treatment, and ends with a “grade of recommendation.” The paper concludes with areas identified as requiring further research.

Conclusions

For UI, there are no prevention trials on lifestyle interventions. There are, however, few new intervention trials of lifestyle interventions involving weight loss and fluid intake with improved levels of evidence and grade of recommendation. Outside of pre‐ and post‐natal pelvic floor muscle training (PFMT) trials for the prevention of female UI, there is a dearth of PFMT prevention trials for women with UI. PFMT remains the first‐line treatment for female UI with high levels of evidence and grades of recommendation. Bladder training levels of evidence and grades of recommendation are maintained. For POP, new evidence supports the effectiveness of physiotherapy in the treatment of POP and there are now improved levels of evidence and grades of recommendation. Neurourol. Urodynam. 35:15–20, 2016. © 2014 Wiley Periodicals, Inc.
The natural history of monoamniotic twin pregnancies: a case series and systematic review of the literature
Authors: Prefumo Federico , Fichera Anna , Pagani Giorgio , Marella Daria , Valcamonico Adriana , Frusca Tiziana
Published: November 2014

Objective

To describe the natural history of monoamniotic twin pregnancies in contemporary practice.

Method

Cohort study of monochorionic monoamniotic twin pregnancies with two live fetuses diagnosed at less than 16 weeks and prospectively followed up between 2004 and 2013. A systematic review of the literature using Medline, Embase and Scopus to determine the perinatal mortality rate after 24 weeks of gestation in monoamniotic twins was also performed.

Results

Twenty pregnancies were analyzed. Four were terminated (in three cases as a result of fetal abnormalities). Another six miscarried spontaneously. Among ten pregnancies reaching viability, there was double intrauterine death in one, and both fetuses were alive at delivery in the other nine. There were no neonatal deaths. Overall survival for fetuses alive at the initial scan was 18/40 (45%; 95% CI 29 to 62%). At meta‐analysis of 13 studies (including the current series), the perinatal mortality rate after 24 weeks was 4.5% (95% CI 3.3 to 5.8%).

Conclusions

Despite early diagnosis and intensive monitoring, of those fetuses alive before 16 weeks less than half survive until the neonatal period. Most losses are attributable to fetal abnormalities and spontaneous miscarriage and are therefore unlikely to be reduced by further improvements in fetal assessment and monitoring. © 2014 John Wiley & Sons, Ltd.
State of the art of 2D DIGE
Authors: Arentz Georgia , Weiland Florian , Oehler Martin K. , Hoffmann Peter
Published: November 2014

Difference gel electrophoresis enables the accurate quantification of changes in the proteome including combinations of PTMs and protein isoform expression. Here, we review recent advances in study design, image acquisition, and statistical analysis. We also compare DIGE to established and emerging mass spectrometric analysis technologies. Despite these recent advances in MS and the still unsolved limitations of 2DE to map hydrophobic, high molecular weight proteins with extreme pIs, DIGE remains the most comprehensive top‐down method to study changes in abundance of intact proteins.
Potential generation and path‐integral Monte Carlo in study of microscopic superfluidity
Authors: Zeng Tao , Li Hui , Roy Pierre‐Nicholas
Published: November 2014

The idea of a macroscopic Andronikashvili experiment used to measure superfluid fraction of bulk liquid 4He can be ported into the realm of spectroscopic studies to measure the superfluid fraction of microscopic systems at the nanoscale. Theoretical studies are needed to fully unravel the superfluid information contained in such a microscopic Andronikashvili experiment. Two aspects of the theoretical studies, the generation of accurate and efficient potential energy surfaces, and the methodology of path‐integral Monte Carlo simulations are briefly introduced in this article. © 2014 Wiley Periodicals, Inc.
Hybridised extraordinary optical transmission in plasmonic cavity
Authors: Briscoe J.L. , Cho S.‐Y.
Published: November 2014

Modification of the spectral response of a periodically coupled metallic nanostructure is reported. A thin SU‐8 dielectric cavity was fabricated on a nanopatterned gold film. Additional resonance peaks are observed in the transmitted spectrum due to the interaction between excited surface plasmon polaritons (SPPs) and optical feedback provided by the dielectric cavity. A comparison with transmitted spectra from a planar gold/dielectric cavity configuration confirms the hybridisation of extraordinary optical transmission through interaction between SPPs and optical Fabry‐Pérot modes in the cavity.
Optimum modulation scheme for single‐band wireless biotelemetry system
Authors: Kim Jungsuk
Published: November 2014

The optimum modulation scheme for single‐band wireless telemetry which is utilised in high‐density biomedical implants is discussed. Hand‐wound induction coils are used for a single‐band inductive link, and an equivalent circuit of the link is modelled by adopting an impedance analyser to characterise the link features. Additionally, an optimum modulation scheme is found to maximise the power transfer efficiency over a single band by simulating the single‐band inductive link, this being demonstrated on a bench top.
Multi‐beam RF aperture using multiplierless FFT approximation
Authors: Suarez D. , Cintra R. J. , Bayer F. M. , Sengupta A. , Kulasekera S. , Madanayake A.
Published: November 2014

Multiple independent radio‐frequency (RF) beams find applications in communications, radio astronomy, radar and microwave imaging. An N‐point fast Fourier transform (FFT) applied spatially across an array of receiver antennas provides N‐independent RF beams at N/2 log2 N multiplier complexity. Here, a low‐complexity multiplierless approximation for the 8‐point FFT is presented for RF beamforming, using only 26 additions. The algorithm provides eight beams that closely resemble the antenna array patterns of the traditional FFT‐based beamformer albeit without using multipliers. The proposed FFT‐like algorithm was verified on‐chip using a Xilinx Virtex‐6 Lx240T field programmable gate array (FPGA) device. The FPGA implementation indicated bandwidth of 369 MHz for each of the independent receive‐mode RF beams.
Computer-Assisted Three-Dimensional Planning for Orbital Decompression
Authors: Mahoney Nicholas , Grant Michael P. , Susarla SrinivasMurthy , Merbs Shannath
Published: November 2014

Thyroid-associated orbitopathy is the most common cause of unilateral or bilateral proptosis in adults. A mainstay of surgical treatment is orbital decompression utilizing osteotomies to increase the size of the affected bony orbit to accommodate the larger soft tissue volume. Over the past several decades, numerous approaches have been described for orbital decompression. However, given the intricate osseous and soft tissue anatomy within the orbit, orbital decompression is a potentially hazardous intervention. With advances in three-dimensional imaging and virtual planning, extensive orbital decompressions can be performed safely and efficiently. In this report, we describe two cases of three-wall orbital decompressions using three-dimensional planning.
Finite Element Analysis of Patient-Specific Condyle Fracture Plates: A Preliminary Study
Authors: Aquilina Peter , Parr William C. H. , Chamoli Uphar , Wroe Stephen
Published: November 2014

Various patterns of internal fixation of mandibular condyle fractures have been proposed in the literature. This study investigates the stability of two patient-specific implants (PSIs) for the open reduction and internal fixation of a subcondylar fracture of the mandible. A subcondylar fracture of a mandible was simulated by a series of finite element models. These models contained approximately 1.2 million elements, were heterogeneous in bone material properties, and also modeled the muscles of mastication. Models were run assuming linear elasticity and isotropic material properties for bone. The stability and von Mises stresses of the simulated condylar fracture reduced with each of the PSIs were compared. The most stable of the plate configurations examined was PSI 1, which had comparable mechanical performance to a single 2.0 mm straight four-hole plate.
Reduction of scattering using thin all-dielectric shells designed by stochastic optimizer
Authors: Ladutenko Konstantin , Peña-Rodríguez Ovidio , Melchakova Irina , Yagupov Ilya , Belov Pavel
Published: November 2014

Adaptive differential evolution method has been used for optimization of all-dielectric multilayer coatings in order to reduce total scattering from spherical targets. The optimal refractive index profiles have been found for various sizes of targets and thicknesses of coatings. Few profile types that appear to be optimal for various geometrical parameters have been identified. Scattering of the target with diameter of 0.75 λ has been reduced by 85% using 0.16 λ thick coating formed by isotropic dielectric materials. For larger targets, scattering reduction becomes smaller, but it still reaches 50% for targets with the diameter of 1.5 λ. The obtained designs provide a route to implement cloaking without the use of magnetic and anisotropic metamaterials.
Gate-control efficiency and interface state density evaluated from capacitance-frequency-temperature mapping for GaN-based metal-insulator-semiconductor devices
Authors: Shih Hong-An , Kudo Masahiro , Suzuki Toshi-kazu
Published: November 2014

We present an analysis method for GaN-based metal-insulator-semiconductor (MIS) devices by using capacitance-frequency-temperature (C-f-T) mapping to evaluate the gate-control efficiency and the interface state density, both exhibiting correlations with the linear-region intrinsic transconductance. The effectiveness of the method was exemplified by application to AlN/AlGaN/GaN MIS devices to elucidate the properties of AlN-AlGaN interfaces depending on their formation processes. Using the C-f-T mapping, we extract the gate-bias-dependent activation energy with its derivative giving the gate-control efficiency, from which we evaluate the AlN-AlGaN interface state density through the Lehovec equivalent circuit in the DC limit. It is shown that the gate-control efficiency and the interface state density have correlations with the linear-region intrinsic transconductance, all depending on the interface formation processes. In addition, we give characterization of the AlN-AlGaN interfaces by using X-ray photoelectron spectroscopy, in relation with the results of the analysis.
Extended Fourier-transform spectroscopy studies and deperturbation analysis of the spin-orbit coupled A1Σ+ and b3Π states in RbCs
Authors: Kruzins A. , Alps K. , Docenko O. , Klincare I. , Tamanis M. , Ferber R. , Pazyuk E. A. , Stolyarov A. V.
Published: November 2014

The article presents a study of the strongly spin-orbit coupled singlet A1Σ+ and triplet b3Π states of the RbCs molecule, which provide an efficient optical path to transfer ultracold molecules to their rovibrational ground state. Fourier-transform A1Σ+ − b3Π → X1Σ+ and (4)1Σ+ → A1Σ+ − b3Π laser-induced fluorescence (LIF) spectra were recorded for the natural mixture of the 85Rb133Cs and 87Rb133Cs isotopologues produced in a heat pipe oven. Overall 8730 rovibronic term values of A1Σ+ and b3Π states were determined with an uncertainty of 0.01 cm−1 in the energy range [9012, 14087] cm−1, covering rotational quantum numbers J ∈ [6, 324]. An energy-based deperturbation analysis performed in the framework of the four A1Σ+ − b3ΠΩ = 0, 1, 2 coupled-channels approach reproduces 97% of the experimental term values of both isotopologues with a standard deviation of 0.0036 cm−1. The reliability of the deperturbed mass-invariant potentials and spin-orbit coupling functions of the interacting A1Σ+ and b3Π states is additionally proved by a good reproduction of the A − b → X and (4)1Σ+ → A − b relative intensity distributions. The achieved accuracy of the A − b complex description allowed us to use the latter to assign the observed (5)1Σ+ → A − b and (3)1Π → A − b transitions. As is demonstrated, LIF to the A − b complex becomes as informative as to the ground X1Σ+ state, which is confirmed by comparing the results of (4)1Σ+ state analysis based on (4)1Σ+ → A − b LIF with the data from V. Zuters et al. [Phys. Rev. A 87, 022504 (2013)] based on (4)1Σ+ → X LIF.
Photodissociation of OCS: Deviations between theory and experiment, and the importance of higher order correlation effects
Authors: Schmidt J. A. , Olsen J. M. H.
Published: November 2014

The photodissociation of carbonyl sulfide (OCS) was investigated theoretically in a series of studies by Schmidt and co-workers. Initial studies [J. A. Schmidt, M. S. Johnson, G. C. McBane, and R. Schinke, J. Chem. Phys. 136, 131101 (2012); J. A. Schmidt, M. S. Johnson, G. C. McBane, and R. Schinke, J. Chem. Phys. 137, 054313 (2012)] found photodissociation in the first UV-band to occur mainly by excitation of the 21A′ (A) excited state. However, in a later study [G. C. McBane, J. A. Schmidt, M. S. Johnson, and R. Schinke, J. Chem. Phys. 138, 094314 (2013)] it was found that a significant fraction of photodissociation must occur by excitation of 11A″ (B) excited state to explain the product angular distribution. The branching between excitation of the A and B excited states is determined by the magnitude of the transition dipole moment vectors in the Franck-Condon region. This study examines the sensitivity of these quantities to changes in the employed electronic structure methodology. This study benchmarks the methodology employed in previous studies against highly correlated electronic structure methods (CC3 and MRAQCC) and provide evidence in support of the picture of the OCS photodissociation process presented in [G. C. McBane, J. A. Schmidt, M. S. Johnson, and R. Schinke, J. Chem. Phys. 138, 094314 (2013)] showing that excitation of A and B electronic states both contribute significantly to the first UV absorption band of OCS. In addition, this study presents evidence in support of the assertion that the A state potential energy surface employed in previous studies underestimates the energy at highly bent geometries (γ ∼ 70°) leading to overestimated rotational energy in the product CO.
Model for analyzing the mechanical behavior of articular cartilage under creep indentation test
Authors: Elhamian Mohammad Mehdi , Karami Hossein , Alizadeh Mansour , Shokrieh Mahmood Mehrdad , Karimi Alireza
Published: November 2014

In this study, an innovative depth dependent biphasic transversely isotropic model (DBT) was proposed to study the mechanical behavior of Articular Cartilage (AC). To find a more precise model to address the mechanical behavior of AC, the vital role of collagen fibers in all zones of the AC has been taken into account and depth dependent elasticity mechanical properties of cartilage are calculated as a function of collagen fibers orientation and volume fraction. Material parameters of permeability function were calculated in such a way that the variations of indenter displacement with time predicted by Finite Element Method (FEM) simulation for creep indentation test of the AC sample based on DBT model. In addition, the test was simulated by an isotropic-biphasic model to compare the capabilities of these two models and difference in mechanical behaviors of biphasic-isotropic and depth dependent transversely isotropic materials. According to the calculations, the presence of collagen fibers triggers increasing of stresses in fibers direction and decreasing of stresses perpendicular to fiber direction in the superficial and deep zones of AC. The findings of this study may have implications not only for calculating stress distributions in AC components but also for developing progressive damage model of AC for predicting osteoarthritic cartilage behavior in different cartilage-related diseases.
Coexisting chaotic and multi-periodic dynamics in a model of cardiac alternans
Authors: Skardal Per Sebastian , Restrepo Juan G.
Published: November 2014

The spatiotemporal dynamics of cardiac tissue is an active area of research for biologists, physicists, and mathematicians. Of particular interest is the study of period-doubling bifurcations and chaos due to their link with cardiac arrhythmogenesis. In this paper, we study the spatiotemporal dynamics of a recently developed model for calcium-driven alternans in a one dimensional cable of tissue. In particular, we observe in the cable coexistence of regions with chaotic and multi-periodic dynamics over wide ranges of parameters. We study these dynamics using global and local Lyapunov exponents and spatial trajectory correlations. Interestingly, near nodes—or phase reversals—low-periodic dynamics prevail, while away from the nodes, the dynamics tend to be higher-periodic and eventually chaotic. Finally, we show that similar coexisting multi-periodic and chaotic dynamics can also be observed in a detailed ionic model.
Second harmonic detection in the electrochemical strain microscopy of Ag-ion conducting glass
Authors: Yang Sang Mo , Baris Okatan M. , Parans Paranthaman M. , Jesse Stephen , Noh Tae Won , Kalinin Sergei V.
Published: November 2014

The first and second harmonic electromechanical responses and their cross-correlation in Ag-ion conducting glass were investigated using band-excitation electrochemical strain microscopy (ESM). Consecutive ESM images with increasing magnitudes of the applied AC voltage allowed observation of not only reversible surface displacement but also irreversible silver nanoparticle formation above a certain threshold voltage. The second harmonic ESM response was anti-correlated with the first harmonic response in many local regions. Furthermore, the nucleation sites of silver nanoparticles were closely related to the anti-correlated regions, specifically, with low second harmonic and high first harmonic ESM responses. The possible origins of the second harmonic ESM response are discussed.
Uniform surface growth of copper oxide nanowires in radiofrequency plasma discharge and limiting factors
Authors: Filipič Gregor , Baranov Oleg , Mozetič Miran , Ostrikov Kostya (Ken) , Cvelbar Uroš
Published: November 2014

The uniform growth of copper oxide nanowires on the top of copper plate has been investigated during the exposure to radiofrequency plasma discharge in respect to plasma properties and its localization. The copper samples of 10 mm radius and 1 mm in thickness were exposed to argon-oxygen plasma created at discharge power of 150 W. After 10 min, almost uniform growth of nanowires was achieved over large surface. There were significant distortions in nanowire length and shape near the edges. Based on the experimental results, we developed a theoretical model, which took into account a balance in heat released at the flow of the current to the nanowire and rejected from the nanowire. This model established a dependence of the maximal length of the nanowire at dependence on the plasma parameters, where the limiting factor for nanowire growth and distortions in distribution are ballistic effects of ions and their local fluxes. In contrast, the plasma heating by potential interactions of species has very little influence on the length and smaller deviations in flux are allowed for uniformity of growth.
Guiding conductive heat flux through thermal metamaterials
Authors: Vemuri K. P. , Canbazoglu F. M. , Bandaru P. R.
Published: November 2014

Experimental evidence of the bending of heat to desired purpose, in analogy to that of light, through designed placement and orientation of nominally isotropic material is presented. This was done by inducing anisotropy in an effective thermal medium through off-diagonal components in the thermal conductivity tensor. An upward or downward heat flux bending of up to ± 26°, in close agreement with theoretical estimates, was obtained in a metamaterial constituted from thin, stacked layers of copper and stainless steel. Transient observations of heat flow indicate anisotropic energy transport hinging on the relative differences between the elements of the thermal diffusivity tensor.
Biphilic nanoporous surfaces enabled exceptional drag reduction and capillary evaporation enhancement
Authors: Dai Xianming , Yang Fanghao , Yang Ronggui , Huang Xinyu , Rigdon William A. , Li Xiaodong , Li Chen
Published: November 2014

Simultaneously achieving drag reduction and capillary evaporation enhancement is highly desired but challenging because of the trade-off between two distinct hydrophobic and hydrophilic wettabilities. Here, we report a strategy to synthesize nanoscale biphilic surfaces to endow exceptional drag reduction through creating a unique slip boundary condition and fast capillary wetting by inducing nanoscopic hydrophilic areas. The biphilic nanoporous surfaces are synthesized by decorating hydrophilic functional groups on hydrophobic pristine multiwalled carbon nanotubes. We demonstrate that the carbon nanotube-enabled biphilic nanoporous surfaces lead to a 63.1% reduction of the friction coefficient, a 61.7% wetting speed improvement, and up to 158.6% enhancement of capillary evaporation heat transfer coefficient. A peak evaporation heat transfer coefficient of 21.2 W/(cm2·K) is achieved on the biphilic surfaces in a vertical direction.
High-output microwave detector using voltage-induced ferromagnetic resonance
Authors: Shiota Yoichi , Miwa Shinji , Tamaru Shingo , Nozaki Takayuki , Kubota Hitoshi , Fukushima Akio , Suzuki Yoshishige , Yuasa Shinji
Published: November 2014

We investigated the voltage-induced ferromagnetic resonance (FMR) with various DC bias voltage and input RF power in magnetic tunnel junctions. We found that the DC bias monotonically increases the homodyne detection voltage due to the nonlinear FMR originating in an asymmetric magnetization-potential in the free layer. In addition, the linear increase of an output voltage to the input RF power in the voltage-induced FMR is more robust than that in spin-torque FMR. These characteristics enable us to obtain an output voltage more than ten times than that of microwave detectors using spin-transfer torque.
Highly featured amorphous silicon nanorod arrays for high-performance lithium-ion batteries
Authors: Soleimani-Amiri Samaneh , Safiabadi Tali Seied Ali , Azimi Soheil , Sanaee Zeinab , Mohajerzadeh Shamsoddin
Published: November 2014

High aspect-ratio vertical structures of amorphous silicon have been realized using hydrogen-assisted low-density plasma reactive ion etching. Amorphous silicon layers with the thicknesses ranging from 0.5 to 10 μm were deposited using radio frequency plasma enhanced chemical vapor deposition technique. Standard photolithography and nanosphere colloidal lithography were employed to realize ultra-small features of the amorphous silicon. The performance of the patterned amorphous silicon structures as a lithium-ion battery electrode was investigated using galvanostatic charge-discharge tests. The patterned structures showed a superior Li-ion battery performance compared to planar amorphous silicon. Such structures are suitable for high current Li-ion battery applications such as electric vehicles.