bluuebunny/crossref_metadata_2025 huggingface dataset:
3D CFD Investigation of Air Flow Behind a Porous Fence Using Different Turbulence Models
Authors: Xu Yizhong , Mustafa Mohamad Y. , Polanco Geanette
Published: October 2014

Even after many years of the application of numerical CFD techniques to flow through porous fences, still there is disagreement between researchers regarding the best turbulence model to be implemented in this field. Moreover, different sources claim to have achieved good agreement between numerical results and experimental data; however, it is not always possible to compare numerical and experimental results due to the lack of information or variations in test conditions. In this paper, five different turbulence models namely; K-ε models (standard, RNG and Realizable) and K-ω models (Standard and SST), have been applied through a 3D CFD model to investigate air flow behind a porous panel, under the same conditions (boundary conditions and numerical schemes). Results are compared with wind tunnel experiments. Comparison is based on the vertical velocity profile at a location 925 mm downstream of the fence along its center line. All models were capable of reproducing the velocity profile, however, some turbulence models over-predicted the reduction of velocity while it was under-predicted by other models, however, discrepancy between CFD modelling and experimental results was kept around 20%. Comprehensive description of the turbulence structure and the streamlines highlight the fact that the criterion for selecting the best turbulence model cannot rely only on the velocity comparison at one location, it must also include other variables.
Residual Life Estimation Under Low-Cycle and Thermo-Mechanical Fatigue Conditions: Proposal of a Dedicated Numerical Code
Authors: Delprete Cristiana , Rosso Carlo
Published: October 2014

A brief description of the main guidelines of the most common literature damage models is reported; in particular two uniaxial and five multi-axial damage models have been individuated from literature, which can be all used determining five parameters only, with a decisive advantage in terms of experimental effort. A Matlab®-based fatigue code has been purposely developed with the aim to receive in input the stress-strain data obtained by finite element analysis or experimentation and the constitutive parameters of the damage models, providing as output directly the residual fatigue life of the component under investigation. The paper presents the pivotal features of a numerical code, named FAST-Life, purposely developed to make the usage of these literature damage models easy and fast, and summarizes the predictions achieved with respect the estimation of the residual life of a commercial exhaust manifold made by ductile Si-Mo-Cr cast iron.
On Application of Second Order Sliding Mode Control to Electro-Hydraulic Systems
Authors: Schmidt Lasse , Andersen Torben O. , Pedersen Henrik C.
Published: October 2014

This paper discusses the application of second order mode controls to hydraulic valve-cylinder drives with a special focus on the limitations resulting from nonlinear dynamic effects in flow control valves. Second order sliding mode algorithms appear highly attractive in the successive implementation of sliding mode control, achieving continuous control inputs, while maintaining the main properties of sliding modes. Under certain model assumptions, some of these controllers may even be applied as output feedback controllers. However, intrinsic nonlinear dynamic effects of hydraulic valves such as slew rates and time delays arising in the amplification stages, limits the applicability of such methods, and may lead to partial losses of robustness and limit cycles. These properties are analyzed and experimentally verified, and compensation methods are proposed. The application of the second order sliding algorithm known as the super twisting controller is considered for output feedback control and compared with conventional first order sliding mode control. The controllers under consideration are applied for position tracking control of a hydraulic valve-cylinder drive exhibiting strong variations in inertia- and gravitational loads. Results demonstrate that the super twisting algorithm may be successfully applied for output feedback control of hydraulic valve-cylinder drives, with modifications guaranteeing robust control performance in a small vicinity of the control target.
Second Law Analysis Optimal Design of a Mixer for Sanitary Water
Authors: Sciacovelli Adriano , Verda Vittorio , Mauro Stefano
Published: October 2014

In this work, entropy generation analysis is used in the search for the optimal design of a mixer for sanitary water. An innovative design of the device is considered: hot water and cold water enter a manifold from five orifices, which opening is controlled by actuators, depending on the requested mass flow rate and average temperature. The design variables are the position of the various orifices, which are modified in order to minimize the mixing length and response time of the device, as well as the global pressure losses. Analysis is conducted using a thermofluid dynamic model which includes continuity, momentum and energy equations, that are solved using a commercial code. Results are then used to calculate the entropy generation distribution, in order to properly consider the various sources of irreversibilities, some of which are necessary (thermal mixing) and some undesired (pressure losses).
Pregnant Occupant Model Including a Fetus for Vehicle Safety Investigations
Authors: Acar B. Serpil , Moustafa M. , Esat Volkan , Acar Memis
Published: October 2014

Computational occupant modelling has an effective role to play in investigating road safety. Realistic representation of occupants is very important to make investigations in virtual environment. Pregnant occupant modelling can help investigating safety for unborn occupants (fetuses) however, existing pregnant occupant models are not very realistic. Most do not anthropometrically represent pregnant women and do not include a fetus model.

‘Expecting’, a computational pregnant occupant model, developed with a view to simulate the dynamic response to crash impacts is briefly explained in this paper. The model is validated through rigid bar impacts and belt loading tests and used to simulate a wide range of impacts. ‘Expecting’, possess the anthropometric properties of a 5th percentile female at around the 38th week of pregnancy. The model is complete with a finite element uterus and a realistic multibody fetus which is a novel feature in models of this kind.

In this paper, the effect of further developments to ‘Expecting’, by incorporating a finite element fetus head model is investigated. Further detailed anatomic geometry is used to generate deformable fetus head model. The model is used to simulate a range of frontal impacts with seatbelt and airbag, as well as no restraint cases. The strains developed in the utero-placental interface are used as the main criteria for fetus safety. The effect of incorporating a finite element fetus head in the pregnant occupant model is discussed.
Engineer Solutions Decreasing Seepage Losses From Enguri Pressure Tunnel
Authors: Kalabegishvili M.
Published: October 2014

The majority of pressure tunnels are designed with pervious concrete lining, considering limited parameters (quantity and opening) equidistributed cracks. In general, according to the requirements of building specifications admissible seepage losses from tunnel shall not exceed 1% of HPP design discharge. As shown by the operation of HPP’s the value of seepage losses is in reality much higher than the acceptable one.

The Inguri HPP pressure tunnel (15 km in length and 9.5 m in diameter) passes in complex geological conditions. The maximum value of pressure at the beginning and end of tunnel is, correspondingly, 110–175 m, while the water level variability in the reservoir is 90 m.

The main characteristic of the structure of diversion tunnel is that in the main part of its length it is represented as a single complex: concrete lining (0.5 m thick) with strengthened grouting zone (6 m deep). Such design decision replaced more traditional structures, e.g. strengthened concrete, combined or metal linings.

The internal pressure of tunnel is borne by the monolithic mass formed by reinforcement grouting. Thereby lining operation is completely dependent on the parameters characteristic for the zone of strengthened grouting (resilient backpressure and perviousness), which must satisfy design values. Thus reinforcement grouting, along with filling grouting are integral parts of pressure tunnel, without which the operation of structure is practically impossible.

At the initial stage of operation (in 1985, at the low level in the reservoir and under the impact of the increase of pressures from massif the loss of lining stability (of the wall and inverted arch) occurred. Presently, based on general assessment the seepage losses developed from tunnel reach up to 10 m3/sec, which thrice exceed the design ones.

As a result of rehabilitation works (massif grouting and shotcrete lining) conducted in 2006 in certain sections of tunnel seepage losses were temporarily reduced. Subsequently seepage losses increased again due to the development of erosive leakage processes in massif.

In the present work calculations were conducted of the seepage parameters and stress condition of the “tunnel-massif” system during filling and discharge of reservoir using a static-seepage coupled scheme, in which a complex geological structure of massif (anisotropy, presence of cracks), the deformation of massif and seepage body force developed in it are taken into consideration. The processes developed during operational period, including depression surface enlarged and the loss of concrete lining stability, are also analyzed.

Inguri HPP is Georgia’s powerful energy object (capacity – 1300 MW, design head – 450 m). Clearly the reduction of seepage losses has a great impact on power generation. In future the rehabilitation of tunnel is envisaged, as alternative options of which shotcrete lining is viewed, the same with strengthening grouting zone and stressed lining (with expanding cement). The present work presents part of the research.
Rotational Molding Applied to the Manufacturing of Blades of Small Wind Turbine
Authors: Marrero M. Dolores , Hernández Pedro , Suárez Luis , Pestana David , Benítez Antonio , Martín José , Rivero Silvia , Calero Estela
Published: October 2014

The small wind energy produces electric energy using power turbines below 100 kW. This technology allows the electrical supply in places isolated, generates energy of way distributed (distributed microgeneration) and permits to produce electricity in the points of consumption. The rotomoulding process is characterized to allow hollow plastics parts, with great surface quality, good homogeneity of thicknesses and suitable mechanical properties, all this with a great freedom of design and a wide variety of materials. The Department of Economy and Competitiveness from Government of Spain, inside the Subprogram INNPACTO 2012, resolved to grant the project of title Development of new blades made for rotational moulding for small wind generators (RotEos). The main purpose of this project is focused on getting a viable and cheaper process to manufacture the blades to small wind generators without reducing the efficiency of them, and trying to increase the competitiveness of these turbines. This research work presents the initial results obtained in the design of the blades, materials characterization and in the manufacturing process of these components.
Finite-Element Simulation of Temperature Fields and Residual Stresses in Butt Welded Joints and Comparison With Experimental Measurements
Authors: Armentani Enrico , Pozzi Angela , Sepe Raffaele
Published: October 2014

Welding is used in fabrication of structures ranging from small components to large and important structures. One of the important problems associated with welded structures is development of residual stresses and deformations due to welding temperature. In fact when structures are manufactured by welding, a non-uniform temperature distribution is produced. This distribution initially causes a rapid thermal expansion followed by a thermal contraction in the weld and surrounding areas, thus generating inhomogeneous plastic deformation and residual stresses in the weldment when it is cooled. High residual stresses in regions close to the weld may promote brittle fracture, fatigue, or stress corrosion cracking. Meanwhile, distortion in base plate may reduce the buckling strength of structural members. Therefore estimating the magnitude and distribution of welding residual stresses and distortion are necessary for achieving the safest design.

In the present work an elastic-plastic finite element model considering temperature dependent mechanical properties is used to evaluate residual stresses. In this study a parametric model is adopted and the elements birth and death are used in single-pass butt welded joint to simulate the weld filler variation with time. Then numerical results are compared with experimental data.
Near-Optimal Mixing Allocation for Traded Products and Prices
Authors: Agarwal Mukul
Published: October 2014

Modern flour mills continuously mix up to 80 intermediate flour streams into 3–6 final streams, whereby each intermediate stream can be allocated to only one final stream. All streams are characterized by several intensive properties and a yield. The decision for mixing allocation involves maximizing the total sale value of all final streams, such that each of them corresponds, with respect to its property ranges, to a flour that can be sold on the trade market. The decision must thereby respect any constraints on the allocation variable and on the yields of the final streams. In this work, a tool is developed that automatically performs the discrete optimization for the allocation problem and outputs the best mixing decision for the given situation. Using heuristics-based optimization, the tool respects all constraints, selects the most lucrative combination from all possible traded flours, and determines the allocation of each intermediate stream to one of the selected traded flours. The optimization method can accommodate nonlinear mixing rules. The tool can trivially be extended to other mixing allocation problems, e.g., to select input streams with minimal total cost to mix to a single output stream with specified property and yield ranges.
A Comparative 1D Analysis of PEM, SO and DB Fuel Cells
Authors: Perez-Raya Isaac , Ellis Michael W. , Hernandez-Guerrero Abel , Elizalde-Blancas Francisco , Gonzalez-Valle Carlos U. , Lorenzini-Gutierrez Luis D.
Published: October 2014

Although fuel cells represent an attractive alternative for electricity generation, different technical problems, such as the hydrogen storage, have not been solved, as yet. Nowadays direct sodium borohydride fuel cells are considered as a promising technology since NaBH4 (fuel) is a stable, nonflammable and nontoxic liquid solution. In the present study a one-dimensional numerical study of a proton exchange membrane, a solid oxide, and a direct sodium borohydride fuel cell is performed. The objective of this work is to compare qualitatively the fuel cell performance between these technologies. For proton exchange membrane and solid oxide fuel cells there are already established useful models and correlations widely known, and used, to predict the current density and the power generated. Direct Borohydride fuel cells, on the other hand, are still in their early developments; in the present paper DBFCs are analyzed using a novel model. This proposed model for DBFCs includes the prediction of the NaBH4 oxidation in the anode side, the H2O2 reduction in the cathode side and the effect of the solution concentration and temperature on the membrane. It is noteworthy mentioning that this last effect has not been integrated in any of the established models in the current technical literature.
Numerical Simulation of Tooth Surface Finish Effects on Gear Noise
Authors: Jolivet S. , Mezghani S. , El Mansori M. , Zahouani H.
Published: October 2014

Due to the rapid development of electric and hybrid motorisations, gear manufacturers have encountered an increasing need to create high level quality gear flanks. While the main goals are to increase the load-carrying capacity and the wear resistance, reducing gear noise has become more and more important. To answer this, macro- and micro-geometry defects have long been studied as well as their effect in amplifying the vibrations of gears. However, the impact of tooth flanks micro-scale roughness on gear noise has not well been studied and understood, even though the teeth surface contacts are essential in the gear mechanics.

This paper aimed to discriminate the influence of the tooth finishing process (grinding, powerhoning) on single stage spur gear noise. A two-dimensional finite-element simulation model of a one-stage gear system was hence developed. The transmission system was composed of two identical loaded gears with one degree of freedom. Topological features of teeth surfaces finished by grinding and powerhoning were measured with a three-dimensional white light interferometer. These real topographic profiles of the tooth surfaces were integrated in the model. The meshing stiffness was determined as an output of this dynamic model. It is a parameter directly linked to the acoustic behaviour of the gear. Results show that gear noise could be reduced by the right choice of the finishing process kinematic.
Numerical Simulation and Control of Rotating Stall in a Transonic Centrifugal Compressor
Authors: Halawa Taher , Alqaradawi Mohamed , Badr Osama , Gadala Mohamed S.
Published: October 2014

This study presents a numerical simulation of precursors and characteristics of rotating stall in a centrifugal compressor with vaned diffuser. The aim is to further understand the causes of stall inception, characteristics of stall process and to investigate reliable simulation of stall control methods and aid in their optimization. Initial numerical results show that the tip leakage flow and early separation in the impeller blades are causing weakness of radial velocity and deviation of fluid angle at impeller exit.

Also, results show that the vaneless region between impeller and diffuser near shroud surface is the key factor of developing radial velocity deficiency into stall cells leading to pressure fluctuations on impeller blades. The present study confirms that injection of air at the shroud surface of the vaneless region has an effect on modifying fluid angle entering diffuser and on delaying of stall inception to occur at lower mass flow rates.
Performance Comparison of Different Power Management Control Strategies for a Hybrid Fuel Cell/Battery Vehicle
Authors: Abu Mallouh M. , Surgenor B. W. , Salah M. , Abdelhafez E. , Hamdan A. , Hamdan M.
Published: October 2014

Power management systems are one of the most important components in modern hybrid vehicles. They are needed to optimize the operation of the hybrid system components. In this paper, a model for a fuel cell/battery vehicle is developed using PSAT and then tested with four power management control strategies utilizing the driving cycle of Amman city, the capital of Jordan. The main components of the hybrid vehicle are a PEM fuel cell, battery, and a brushless dc motor. PEM fuel cells are popular due to their good start up, high power density, and low operating temperature. The role of the battery in a hybrid system is to boost the system power during start-up and transient events in addition to storing the energy recovered from the braking process. The developed hybrid vehicle model is designed and configured so that it matches the power, acceleration, and maximum speed of a midsized vehicle powered by an internal combustion engine. The proposed control strategies are the thermostat strategy, fuel cell optimized strategy, load following strategy and fuzzy logic strategy. All four control strategies are implemented in simulation utilizing PSAT. The simulation results indicate that the best performance in terms of fuel economy is achieved by the load following control strategy.
Optimized Mechanical Performance of Cantilevered Vibration Energy Harvesters Using a Modal Approach
Authors: Xiong X. , Oyadiji S. O.
Published: October 2014

In order to improve the performance of cantilevered vibration energy harvesters, current methods normally vary their geometric dimensions and derive the maximum power outputs by running a full analysis. This paper attempts to optimize the structural performance of cantilevered vibration energy harvesters using a modal approach without carrying out full analysis. The effects of varying geometrical dimensions on the modal mechanical performance are analysed, which includes the analysis on rectangular cantilevered beams with and without extra mass, the convergent and divergent tapered cantilevered beams. The modal approach uses mass ratio and the modal electromechanical coupling coefficient to determine the electrical and mechanical modal performance of vibration energy harvesters. In particular, mass ratio depends on the modal participation factor, and it represents the influence of modal mechanical behaviour on the power density directly. The required modal parameters are derived using the finite element method and a distributed parameter electromechanical model is also used for comparison. The cantilevered beam designs using the modal approach can be used with different sizes with the power ranging from microwatts to milliwatts.
Measurement of Oil Film Thickness in Cylindrical Roller Bearing by Ultrasound
Authors: Zhang Kai , Meng Qingfeng , Zhao Wei
Published: October 2014

This paper describes the measurement of oil film thickness between rolling element and inner raceway in cylindrical roller bearing. A fine piezoelectric element is bonded on the inner surface of the inner ring to measure the reflection coefficient of oil between rolling element and inner raceway. The quasi-static spring model is used to calculate oil film thickness from the corrected reflection coefficient data. Experiments are described on a simplified cylindrical roller bearing configured by one cylindrical roller, 11ø, and an inner ring from a NU209EM bearing. Reasonable agreement is shown over several loads and speeds with predictions from elastohydrodynamic lubrication (EHL) theory.
Re-Conceptualizing Sport as a Sacred Phenomenon
Authors: Shilling Chris , Mellor Philip A.
Published: October 2014

Sociological studies of sport have established their subject matter as significant to a wide range of sociocultural concerns. Despite a broad consensus about its global importance, however, the reasons for the particular, even ‘extraordinary’, societal importance of sport today remain deeply contested. Most studies account for it by highlighting its entanglement within a range of secular phenomena including state building, rationalization, biopolitical regulation, and the ‘controlled-decontrolling’ of bodies and affects. Occupying a more marginal position within the discipline, others focus on the religious or quasi-religious characteristics of sport. Our paper suggests that neither of these positions, on their own, is best placed to capture the nature and implications of sport’s particular centrality to social life. Proposing a new theoretical approach to the subject that places competing conceptions of what we refer to as the ‘sporting sacred’ at the center of discussion, we outline, via a reconceptualization of the writings of two major classical theorists, Durkheim and Weber, a number of contrasting modalities through which sport is prized within contemporary society. These modalities, which embrace both secular and religious phenomena, can, we suggest, provide new insight into the divergent paths along which sports are being ‘pulled’ and steered in the modern era.
Coping With Growth in Adolescent Elite Sport
Authors: Schubring Astrid , Thiel Ansgar
Published: October 2014

Growing up in elite sport represents a challenging project. Young athletes must negotiate a career-defining transitional period while in the midst of adolescence. In this context, notably, the growth process can lead to health problems such as overloading and injuries. In this article, we investigate how adolescent elite athletes cope with problematic growth experiences. Taking a Bourdieusian perspective, we consider coping to be a socioculturally-located practice. Drawing on qualitative interviews and participant observation in German elite sport, our conversational analysis reveals five typical coping strategies among young athletes: (a) distancing, (b) rationalization, (c) active agency, (d) self-disciplining, and (e) responsibility transfer. We reflect on the health-compromising side effects of these strategies as well as the implications for the sporting community’s handling of growth problems.
Look After Yourself, or Look After One Another? An Analysis of Life Skills in Sport for Development and Peace HIV Prevention Curriculum
Authors: Forde Shawn D.
Published: October 2014

HIV/AIDS education and prevention are often described as one way that SDP can contribute to international development, yet there has been little critical analysis of how discourses legitimize particular conceptions of HIV/AIDS and constructions of life skills. Therefore, the purpose of this study was to conduct a critical discourse analysis, guided by the concept of biopedagogies, of the Live Safe Play Safe (LSPS) manual that Right to Play (RTP) has used to train facilitators for its HIV/AIDS prevention program. The findings demonstrate that discourses of risk, individualism, and deficiency constructed life skills in a way that aligned with neoliberal approaches to health promotion and development; emphasizing risk management and individual responsibility, while glossing over the broader social and political factors influencing HIV transmission.
A photoinduced metal-like phase of monoclinic VO
2
revealed by ultrafast electron diffraction
Authors: Morrison Vance R. , Chatelain Robert. P. , Tiwari Kunal L. , Hendaoui Ali , Bruhács Andrew , Chaker Mohamed , Siwick Bradley J.
Published: October 2014

How to make vanadium dioxide metallic

At about 70°C, the material vanadium dioxide (VO
2
) switches from being a semiconductor to a metal. The switch happens so fast that it may be useful in electronic devices, but it is not clear whether the switch is primarily caused by enhanced interactions between electrons or by a change in the crystal structure. Morrison
et al.
shone laser light on a sample of VO
2
, initially in a semiconducting state. They used electron diffraction to monitor the changes in the material's crystal structure and simultaneously measured its optical properties to monitor the electronic state. For certain laser powers, VO
2
switched to a long-lived metallic state even though it preserved its initial crystal structure.

Science
, this issue p.
445
Medial prefrontal activity during delay period contributes to learning of a working memory task
Authors: Liu Ding , Gu Xiaowei , Zhu Jia , Zhang Xiaoxing , Han Zhe , Yan Wenjun , Cheng Qi , Hao Jiang , Fan Hongmei , Hou Ruiqing , Chen Zhaoqin , Chen Yulei , Li Chengyu T.
Published: October 2014

Cognitive processes require working memory (WM) that involves a brief period of memory retention known as the delay period. Elevated delay-period activity in the medial prefrontal cortex (mPFC) has been observed, but its functional role in WM tasks remains unclear. We optogenetically suppressed or enhanced activity of pyramidal neurons in mouse mPFC during the delay period. Behavioral performance was impaired during the learning phase but not after the mice were well trained. Delay-period mPFC activity appeared to be more important in memory retention than in inhibitory control, decision-making, or motor selection. Furthermore, endogenous delay-period mPFC activity showed more prominent modulation that correlated with memory retention and behavioral performance. Thus, properly regulated mPFC delay-period activity is critical for information retention during learning of a WM task.
Rapid evolution of a native species following invasion by a congener
Authors: Stuart Y. E. , Campbell T. S. , Hohenlohe P. A. , Reynolds R. G. , Revell L. J. , Losos J. B.
Published: October 2014

Making adjustments for a new neighborhood

Competition between species drives the acquisition of diversity. Stuart
et al.
introduced a non-native anole lizard to natural experimental islands. In response, the original inhabitants adopted higher perches in the trees, where the larger invader was at a disadvantage. Within about 3 years—or 20 generations—the shift led to inherited morphological changes in the native lizards, including their growing larger toepads.

Science
, this issue p.
463
Influenza A virus uses the aggresome processing machinery for host cell entry
Authors: Banerjee Indranil , Miyake Yasuyuki , Nobs Samuel Philip , Schneider Christoph , Horvath Peter , Kopf Manfred , Matthias Patrick , Helenius Ari , Yamauchi Yohei
Published: October 2014

Flu mimics damaged proteins during entry

Viruses are master manipulators. The early stages of how flu viruses enter cells are very well understood, but Banerjee
et al.
describe a new wrinkle (see the Perspective by Rajsbaum and García-Sastre). It seems that the virus carries with it into the cell ubiquitin: a molecule involved in marking proteins for destruction. The virus then exploits host cell machinery involved in recognizing and dealing with damaged proteins to uncoat its own RNA genome, ready to continue its path toward successful infection.

Science
, this issue p.
473
; see also p.
427
Computational design of water-soluble α-helical barrels
Authors: Thomson Andrew R. , Wood Christopher W. , Burton Antony J. , Bartlett Gail J. , Sessions Richard B. , Brady R. Leo , Woolfson Derek N.
Published: October 2014

Building with alphahelical coiled coils

Understanding how proteins fold into well-defined three-dimensional structures has been a longstanding challenge. Increased understanding has led to increased success at designing proteins that mimic existing protein folds. This raises the possibility of custom design of proteins with structures not seen in nature. Thomson
et al.
describe the design of channelcontaining α-helical barrels, and Huang
et al.
designed hyperstable helical bundles. Both groups used rational and computational design to make new protein structures based on α-helical coiled coils but took different routes to reach different target structures.

Science
, this issue p.
485
, p.
481
Comment on “A Jurassic ornithischian dinosaur from Siberia with both feathers and scales”
Authors: Lingham-Soliar Theagarten
Published: October 2014

Godefroit
et al
. (Reports, 25 July 2014, p. 451) reported scales and feathers, including “basal plates,” in an ornithischian dinosaur. Their arguments against the filaments being collagen fibers are not supported because of a fundamental misinterpretation of such structures and underestimation of their size. The parsimonious explanation is that the filaments are support fibers in association with badly degraded scales and that they do not represent early feather stages.
Harnessing chirality for valleytronics
Authors: Lundeberg Mark B. , Folk Joshua A.
Published: October 2014

Artificial magnetic fields bend electron trajectories in gapped graphene

[Also see Report by

Gorbachev
et al.

]
Breathing the unbreathable
Authors: Edwards Elizabeth Anne
Published: October 2014

A crystal structure reveals how some bacteria break down organohalide pollutants

[Also see Report by

Bommer
et al.

]
Terminating the replisome
Authors: Bell Stephen P.
Published: October 2014

Multiple proteins modify and dismantle a key enzyme after DNA replication terminates

[Also see Research Article by

Maric
et al.

and Report by

Priego Moreno
et al.

]
Election stakes go beyond control of the Senate
Authors: Mervis Jeffrey
Published: October 2014

Funding, peer review, water rules, fusion, and other science issues on tap after the vote.
Show me the money
Authors: Hvistendahl Mara
Published: October 2014

A bitter dispute lays bare questionable practices in China's foreign-talent programs.
Innovations in light sheet microscopy: Strategies and new applications
Authors: Truong Thai , Pitrone Peter G. , Hanrahan Orla
Published: October 2014

Over the past 10 years, light sheet microscopy (or selective plane illumination microscopy, SPIM) has transformed the microscopy field, offering a faster, less phototoxic technique than conventional methods that can create true 3-D images. Ideal for observing living organisms and the cellular dynamics of biological systems, this method uses a unique illumination approach to achieve high penetration depths, fast imaging speeds, and subcellular-level resolution. Because a specimen is illuminated with a sheet of light rather than a focused laser beam, only regions directly exposed to light will fluoresce—creating minimal photo-induced tissue damage. In this webinar, the speakers will discuss their own uses of light sheet microscopy and provide insight into its different applications, including open source SPIM and the dynamic behavior of subcellular components within live specimens.
Metagenomic Analysis of Viruses in Feces from Unsolved Outbreaks of Gastroenteritis in Humans
Authors: Moore Nicole E. , Wang Jing , Hewitt Joanne , Croucher Dawn , Williamson Deborah A. , Paine Shevaun , Yen Seiha , Greening Gail E. , Hall Richard J.
Published: October 2014

The etiology of an outbreak of gastroenteritis in humans cannot always be determined, and ∼25% of outbreaks remain unsolved in New Zealand. It is hypothesized that novel viruses may account for a proportion of unsolved cases, and new unbiased high-throughput sequencing methods hold promise for their detection. Analysis of the fecal metagenome can reveal the presence of viruses, bacteria, and parasites which may have evaded routine diagnostic testing. Thirty-one fecal samples from 26 gastroenteritis outbreaks of unknown etiology occurring in New Zealand between 2011 and 2012 were selected for
de novo
metagenomic analysis. A total data set of 193 million sequence reads of 150 bp in length was produced on an Illumina MiSeq. The metagenomic data set was searched for virus and parasite sequences, with no evidence of novel pathogens found. Eight viruses and one parasite were detected, each already known to be associated with gastroenteritis, including adenovirus, rotavirus, sapovirus, and
Dientamoeba fragilis
. In addition, we also describe the first detection of human parechovirus 3 (HPeV3) in Australasia. Metagenomics may thus provide a useful audit tool when applied retrospectively to determine where routine diagnostic processes may have failed to detect a pathogen.
A Study of Genotyping for Management of Human Papillomavirus-Positive, Cytology-Negative Cervical Screening Results
Authors: Schiffman M. , Burk R. D. , Boyle S. , Raine-Bennett T. , Katki H. A. , Gage J. C. , Wentzensen N. , Kornegay J. R. , Aldrich C. , Tam T. , Erlich H. , Apple R. , Befano B. , Castle P. E.
Published: October 2014

The effective management of women with human papillomavirus (HPV)-positive, cytology-negative results is critical to the introduction of HPV testing into cervical screening. HPV typing has been recommended for colposcopy triage, but it is not clear which combinations of high-risk HPV types provide clinically useful information. This study included 18,810 women with Hybrid Capture 2 (HC2)-positive, cytology-negative results and who were age ≥30 years from Kaiser Permanente Northern California. The median follow-up was 475 days (interquartile range [IQR], 0 to 1,077 days; maximum, 2,217 days). The baseline specimens from 482 cases of cervical intraepithelial neoplasia grade 3 or cancer (CIN3+) and 3,517 random HC2-positive noncases were genotyped using 2 PCR-based methods. Using the case-control sampling fractions, the 3-year cumulative risks of CIN3+ were calculated for each individual high-risk HPV type. The 3-year cumulative risk of CIN3+ among all women with HC2-positive, cytology-negative results was 4.6%. HPV16 status conferred the greatest type-specific risk stratification; women with HC2-positive/HPV16-positive results had a 10.6% risk of CIN3+, while women with HC-2 positive/HPV16-negative results had a much lower risk of 2.4%. The next most informative HPV types and their risks in HPV-positive women were HPV33 (5.9%) and HPV18 (5.9%). With regard to the etiologic fraction, 20 of 71 cases of cervical adenocarcinoma
in situ
(AIS) and adenocarcinoma in the cohort were positive for HPV18. HPV16 genotyping provides risk stratification useful for guiding clinical management; the risk among HPV16-positive women clearly exceeds the U.S. consensus risk threshold for immediate colposcopy referral. HPV18 is of particular interest because of its association with difficult-to-detect glandular lesions. There is a less clear clinical value of distinguishing the other high-risk HPV types.
Development of an Efficient Entire-Capsid-Coding-Region Amplification Method for Direct Detection of Poliovirus from Stool Extracts
Authors: Arita Minetaro , Kilpatrick David R. , Nakamura Tomofumi , Burns Cara C. , Bukbuk David , Oderinde Soji B. , Oberste M. Steven , Kew Olen M. , Pallansch Mark A. , Shimizu Hiroyuki
Published: October 2014

Laboratory diagnosis has played a critical role in the Global Polio Eradication Initiative since 1988, by isolating and identifying poliovirus (PV) from stool specimens by using cell culture as a highly sensitive system to detect PV. In the present study, we aimed to develop a molecular method to detect PV directly from stool extracts, with a high efficiency comparable to that of cell culture. We developed a method to efficiently amplify the entire capsid coding region of human enteroviruses (EVs) including PV. cDNAs of the entire capsid coding region (3.9 kb) were obtained from as few as 50 copies of PV genomes. PV was detected from the cDNAs with an improved PV-specific real-time reverse transcription-PCR system and nucleotide sequence analysis of the VP1 coding region. For assay validation, we analyzed 84 stool extracts that were positive for PV in cell culture and detected PV genomes from 100% of the extracts (84/84 samples) with this method in combination with a PV-specific extraction method. PV could be detected in 2/4 stool extract samples that were negative for PV in cell culture. In PV-positive samples, EV species C viruses were also detected with high frequency (27% [23/86 samples]). This method would be useful for direct detection of PV from stool extracts without using cell culture.
Use of Whole-Genus Genome Sequence Data To Develop a Multilocus Sequence Typing Tool That Accurately Identifies Yersinia Isolates to the Species and Subspecies Levels
Authors: Hall Miquette , Chattaway Marie A. , Reuter Sandra , Savin Cyril , Strauch Eckhard , Carniel Elisabeth , Connor Thomas , Van Damme Inge , Rajakaruna Lakshani , Rajendram Dunstan , Jenkins Claire , Thomson Nicholas R. , McNally Alan
Published: October 2014

The genus
Yersinia
is a large and diverse bacterial genus consisting of human-pathogenic species, a fish-pathogenic species, and a large number of environmental species. Recently, the phylogenetic and population structure of the entire genus was elucidated through the genome sequence data of 241 strains encompassing every known species in the genus. Here we report the mining of this enormous data set to create a multilocus sequence typing-based scheme that can identify
Yersinia
strains to the species level to a level of resolution equal to that for whole-genome sequencing. Our assay is designed to be able to accurately subtype the important human-pathogenic species
Yersinia enterocolitica
to whole-genome resolution levels. We also report the validation of the scheme on 386 strains from reference laboratory collections across Europe. We propose that the scheme is an important molecular typing system to allow accurate and reproducible identification of
Yersinia
isolates to the species level, a process often inconsistent in nonspecialist laboratories. Additionally, our assay is the most phylogenetically informative typing scheme available for
Y. enterocolitica
.
Use of Transrenal DNA for the Diagnosis of Extrapulmonary Tuberculosis in Children: a Case of Tubercular Otitis Media
Authors: Petrucci Roberta , Lombardi Giulia , Corsini Ilaria , Visciotti Francesca , Pirodda Antonio , Cazzato Salvatore , Landini Maria Paola , Dal Monte Paola
Published: October 2014

The diagnosis of tuberculosis (TB) is difficult in children, especially for smear-negative pulmonary and extrapulmonary TB, which are common at this age. We report an 11-year-old girl with TB otitis media with negative smear microscopy and Xpert MTB/RIF but positive
Mycobacterium tuberculosis
-specific transrenal DNA (Tr-MTB-DNA) test results and culture for
M. tuberculosis
.
Unbiased Species-Level Identification of Clinical Isolates of Coagulase-Negative Staphylococci: Does It Change the Perspective on Staphylococcus lugdunensis?
Authors: Elamin Wael F. , Ball David , Millar Michael
Published: October 2014

Unbiased species-level identification of coagulase-negative staphylococci (CoNS) using matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) identified
Staphylococcus lugdunensis
to be a more commonly isolated CoNS in our laboratory than previously observed. It has also highlighted the possibility of vertical transmission.
Clonal Evolution of CD8+T Cell Responses against Latent Viruses: Relationship among Phenotype, Localization, and Function
Authors: Remmerswaal Ester B. M. , Klarenbeek Paul L. , Alves Nuno L. , Doorenspleet Marieke E. , van Schaik Barbera D. C. , Esveldt Rebecca E. E. , Idu Mirza M. , van Leeuwen Ester M. M. , van der Bom-Baylon Nelly , van Kampen Antoine H. C. , Koch Sven D. , Pircher Hanspeter , Bemelman Frederike J. , ten Brinke Anja , Baas Frank , ten Berge Ineke J. M. , van Lier Rene A.W. , de Vries Niek
Published: October 2014

Human cytomegalovirus (hCMV) infection is characterized by a vast expansion of resting effector-type virus-specific T cells in the circulation. In mice, interleukin-7 receptor α (IL-7Rα)-expressing cells contain the precursors for long-lived antigen-experienced CD8+T cells, but it is unclear if similar mechanisms operate to maintain these pools in humans. Here, we studied whether IL-7Rα-expressing cells obtained from peripheral blood (PB) or lymph nodes (LNs) sustain the circulating effector-type hCMV-specific pool. Using flow cytometry and functional assays, we found that the IL-7Rα+hCMV-specific T cell population comprises cells that have a memory phenotype and lack effector features. We used next-generation sequencing of the T cell receptor to compare the clonal repertoires of IL-7Rα+and IL-7Rα−subsets. We observed limited overlap of clones between these subsets during acute infection and after 1 year. When we compared the hCMV-specific repertoire between PB and paired LNs, we found many identical clones but also clones that were exclusively found in either compartment. New clones that were found in PB during antigenic recall were only rarely identical to the unique LN clones. Thus, although PB IL-7Rα-expressing and LN hCMV-specific CD8+T cells show typical traits of memory-type cells, these populations do not seem to contain the precursors for the novel hCMV-specific CD8+T cell pool during latency or upon antigen recall. IL-7Rα+PB and LN hCMV-specific memory cells form separate virus-specific compartments, and precursors for these novel PB hCMV-specific CD8+effector-type T cells are possibly located in other secondary lymphoid tissues or are being recruited from the naive CD8+T cell pool.

IMPORTANCEInsight into the self-renewal properties of long-lived memory CD8+T cells and their location is crucial for the development of both passive and active vaccination strategies. Human CMV infection is characterized by a vast expansion of resting effector-type cells. It is, however, not known how this population is maintained. We here investigated two possible compartments for effector-type cell precursors: circulating acute-phase IL-7Rα-expressing hCMV-specific CD8+T cells and lymph node (LN)-residing hCMV-specific (central) memory cells. We show that new clones that appear after primary hCMV infection or during hCMV reactivation seldom originate from either compartment. Thus, although identical clones may be maintained by either memory population, the precursors of the novel clones are probably located in other (secondary) lymphoid tissues or are recruited from the naive CD8+T cell pool.
Bindarit, an Inhibitor of Monocyte Chemotactic Protein Synthesis, Protects against Bone Loss Induced by Chikungunya Virus Infection
Authors: Chen Weiqiang , Foo Suan-Sin , Taylor Adam , Lulla Aleksei , Merits Andres , Hueston Linda , Forwood Mark R. , Walsh Nicole C. , Sims Natalie A. , Herrero Lara J. , Mahalingam Suresh
Published: October 2014

The recent global resurgence of arthritogenic alphaviruses, in particular chikungunya virus (CHIKV), highlights an urgent need for the development of therapeutic intervention strategies. While there has been significant progress in defining the pathophysiology of alphaviral disease, relatively little is known about the mechanisms involved in CHIKV-induced arthritis or potential therapeutic options to treat the severe arthritic symptoms associated with infection. Here, we used microcomputed tomographic (μCT) and histomorphometric analyses to provide previously undescribed evidence of reduced bone volume in the proximal tibial epiphysis of CHIKV-infected mice compared to the results for mock controls. This was associated with a significant increase in the receptor activator of nuclear factor-κB ligand/osteoprotegerin (RANKL/OPG) ratio in infected murine joints and in the serum of CHIKV patients. The expression levels of the monocyte chemoattractant proteins (MCPs), including MCP-1/CCL2, MCP-2/CCL8, and MCP-3/CCL7, were also highly elevated in joints of CHIKV-infected mice, accompanied by increased cellularity within the bone marrow in tibial epiphysis and ankle joints. Both this effect and CHIKV-induced bone loss were significantly reduced by treatment with the MCP inhibitor bindarit. Collectively, these findings demonstrate a unique role for MCPs in promoting CHIKV-induced osteoclastogenesis and bone loss during disease and suggest that inhibition of MCPs with bindarit may be an effective therapy for patients affected with alphavirus-induced bone loss.

IMPORTANCEArthritogenic alphaviruses, including chikungunya virus (CHIKV) and Ross River virus (RRV), cause worldwide outbreaks of polyarthritis, which can persist in patients for months following infection. Previous studies have shown that host proinflammatory soluble factors are associated with CHIKV disease severity. Furthermore, it is established that chemokine (C-C motif) ligand 2 (CCL2/MCP-1) is important in cellular recruitment and inducing bone-resorbing osteoclast (OC) formation. Here, we show that CHIKV replicates in bone and triggers bone loss by increasing the RANKL/OPG ratio. CHIKV infection results in MCP-induced cellular infiltration in the inflamed joints, and bone loss can be ameliorated by treatment with an MCP-inhibiting drug, bindarit. Taken together, our data reveal a previously undescribed role for MCPs in CHIKV-induced bone loss: one of recruiting monocytes/OC precursors to joint sites and thereby favoring a pro-osteoclastic microenvironment. This suggests that bindarit may be an effective treatment for alphavirus-induced bone loss and arthritis in humans.