bluuebunny/crossref_metadata_2025 huggingface dataset:
Intravitreal ranibizumab treatment of retinal angiomatous proliferation
Authors: Kramann Christina A. , Schöpfer Kilian , Lorenz Katrin , Zwiener Isabella , Stoffelns Bernhard M. , Pfeiffer Norbert
Published: June 2010

Purpose:  To determine the efficacy of intravitreal injections of ranibizumab in the treatment of retinal angiomatous proliferation (RAP) in neovascular age‐related macular degeneration.

Methods:  Retrospective, consecutive case series of 26 eyes (26 patients) treated with intravitreal injections of 0.5 mg ranibizumab for RAP. Patients received intravitreal injections at monthly intervals during upload phase for a 3‐month period.

Results:  Mean visual acuity before treatment was 0.75 ± 0.38logMAR (mean ± SD, n = 26). In the upload phase, mean visual acuity improved 4 weeks after the initial injection to 0.6 ± 0.37logMAR (n = 26) and to 0.53 ± 0.34logMAR (n = 26) 4 weeks after the third monthly intravitreal injection of ranibizumab. The mean optical coherence tomography (OCT) central foveal thickness reduced from 345 ± 55 μm at baseline to 215 ± 87 μm at 3 months. In the maintenance phase, mean visual acuity after 6 months was 0.66 ± 0.38logMAR (n = 12) and 0.7 ± 0.37logMAR after 9 months (n = 6). The mean OCT central foveal thickness was 259 ± 59 μm (n = 13) at 6 months and 280 ± 127 μm (n = 6) at nine‐month follow‐up.

Conclusion:  Intravitreal ranibizumab resulted in an improvement of visual acuity 4 weeks after the first injection but was more pronounced after 3 months. A reduction in leakage and OCT central foveal thickness was seen 3 months after the commencement of treatment.
Dynamic Modeling and Analysis of Shield TBM Cutterhead Driving System
Authors: Li Xian Hong , Yu Hai Bin , Yuan Ming Zhe , Wang Jin , Yin Yuan
Published: June 2010

In this paper, a generalized nonlinear time-varying dynamic model is established for the cutterhead driving system of a shield tunnel boring machine. A nonlinear multiple input and multiple output state-space dynamic model is also proposed. The dynamic model is simulated to analyze the driving system and the effects of system parameters such as gear backlash and transmission error, larger gear inertia, and load torque on the dynamic response of driving system are investigated as well. A preliminary approach is proposed to restrain speed oscillation and reduce steady-state speed ripple. Through modeling and studying the dynamic model, we refine some important issues that should be given closer attention.
Heat Transfer Analysis of a Novel Pressurized Air Receiver for Concentrated Solar Power via Combined Cycles
Authors: Hischier I. , Hess D. , Lipiński W. , Modest M. , Steinfeld A.
Published: June 2010

A novel design of a high-temperature pressurized solar air receiver for power generation via combined Brayton–Rankine cycles is proposed. It consists of an annular reticulate porous ceramic (RPC) bounded by two concentric cylinders. The inner cylinder, which serves as the solar absorber, has a cavity-type configuration and a small aperture for the access of concentrated solar radiation. Absorbed heat is transferred by conduction, radiation, and convection to the pressurized air flowing across the RPC. A 2D steady-state energy conservation equation coupling the three modes of heat transfer is formulated and solved by the finite volume technique and by applying the Rosseland diffusion, P1, and Monte Carlo radiation methods. Key results include the temperature distribution and thermal efficiency as a function of the geometrical and operational parameters. For a solar concentration ratio of 3000 suns, the outlet air temperature reaches 1000°C at 10 bars, yielding a thermal efficiency of 78%.
Principles of Nonequal Channel Angular Pressing
Authors: Hasani Arman , Tóth László S. , Beausir Benoît
Published: June 2010

A variant of the equal channel angular pressing (ECAP) process is examined in this paper where the channels are of rectangular shape with different thicknesses while the widths of the channels are the same. The process is named nonequal channel angular pressing and it is similar to the earlier introduced dissimilar channel angular pressing (DCAP) process. In DCAP, however, the diameters are near values, with the exit channel being slightly larger, while in NECAP, the exit channel is much smaller attributing several advantages to nonequal channel angular pressing (NECAP) with respect to ECAP. In this work an analysis is performed to determine the strain mode in a 90 deg NECAP die. A new flow line function is also presented to better describe the deformation field. The proposed flow line function is validated using finite element simulations. A comparison is made between ECAP and NECAP. Finally, texture predictions are presented for NECAP of fcc polycrystals. The advantages of this severe plastic deformation process are the following: (i) significantly larger strains can be obtained in one pass with respect to the classical ECAP process, (ii) grains become more elongated that enhances their fragmentation, and (iii) large hydrostatic stresses develop that improve the stability of the deformation process for difficult-to-work materials. The results obtained concerning the deformation field are also applicable in the machining process for the plastic strains that imparted into the chips.
Experimental and Numerical Determination of Limiting Drawing Ratio of Al3105-Polypropylene-Al3105 Sandwich Sheets
Authors: Parsa M. H. , Ettehad M. , Matin P. H. , Al Ahkami S. Nasher
Published: June 2010

Sandwich structures are gaining wide applications in aeronautical, marine, automotive, and civil engineering. Since such sheets can be subjected to stamping processes, it is crucial to characterize their forming behavior before trying out any conventional forming process. To achieve this goal, sandwich sheets of Al 3105/polymer/Al 3105 were prepared using thin film hot melt adheres. Different sandwich specimens with different thickness ratios (of polymer core to aluminum face sheet) were prepared. Throughout an experimental effort, the limiting drawing ratios (LDRs) of the sandwich sheets were determined. Besides, the LDR of the sandwich sheets were predicted using finite element analysis simulations by considering Gurson–Tvergaard–Needleman damage model. The results show the capability of the damage model to predict the LDR and the location of damaged zone in a workpiece during a forming operation.
Robust Fault-Tolerant Control for a Class of Nonlinear Stochastic Systems With Variance Constraints
Authors: Ma Lifeng , Wang Zidong , Bo Yuming , Guo Zhi
Published: June 2010

This paper is concerned with the variance-constrained controller design problem for a class of uncertain nonlinear stochastic systems with possible actuator faults. The stochastic nonlinearities described by statistical means are quite general that include several well-studied classes of nonlinearities as special cases. A model of actuator failures is adopted, which is more practical than the traditional outage one. A linear matrix inequality (LMI) approach is proposed to solve the multiobjective fault-tolerant controller design problem, where both the exponential stability and the steady-state state variance indices are simultaneously guaranteed. Within the developed LMI framework, a sufficient condition for the solvability of the robust control problem is obtained. The explicit expression of the desired controllers is also parameterized and a single degree-of-freedom model is used to demonstrate the effectiveness and applicability of the proposed design approach.
The Relation of the Vickers Hardness With the Loading Stiffness of Instrumented Vickers Indentation of Metal Substrates
Authors: Baxevani E. A. , Giannakopoulos A. E.
Published: June 2010

The present paper presents a relation between the vickers hardness HV and the loading stiffness C of instrumented vickers indentation of metal substrates. The relation is based on the fact that the nonaxisymmetry of the plastic deformation of the vickers indenter leaves the corners of the indentation imprint at the surface of metal substrates after complete unloading. This relation can transform available HV data for metals to C data. It is also shown that the strain hardening details are important in the estimation of material properties and investigators should be cautions when using power-law strain hardening in all cases.
Dynamic Optimization of Reactionless Four-Bar Linkages
Authors: Jiang Qimi , Gosselin Clément M.
Published: June 2010

Reactionless mechanisms have many important applications because of their zero reaction forces and moments at the base. However, in most cases, these mechanisms consume more energy than their unbalanced counterparts. This paper focuses on analyzing the relationship between the needed input torque and the dynamic parameters of reactionless four-bar linkages. The objective is to minimize the needed input torque by optimizing the relevant dynamic parameters. The dynamic analysis shows that the needed input torque mainly depends on the mass of the link, which needs to be balanced. The results obtained can be applied to the design optimization and dynamic control of the devices such as parallel manipulators composed of reactionless four-bar linkages.
Prediction of Elastic-Plastic Boundary Around Cold-Expanded Holes Using Elastic Strain Measurement
Authors: Dutta Nripendu , Rasty Jahan
Published: June 2010

The cold-expansion process is used routinely for improving the fatigue life of holes in a variety of components. The expansion process involves drawing a slightly oversized tapered mandrel through the hole. Upon expansion, the material near the hole deforms plastically while material away from the hole undergoes elastic deformation. Upon removal of the mandrel, the ensuing elastic recovery of the surrounding material results in the development of a compressive residual stress field around the hole. Since the magnitude of plastic deformation sustained by the material near the hole depends on the severity of the expansion, the elastic-plastic boundary radius (EPBR) during the expansion process can be used to characterize the extent of cold expansion. The elastic-plastic boundary is an important parameter in characterizing the residual stress distribution around cold-expanded holes, as well as in determining required spacing between successively expanded holes. This paper presents a new method for determining the EPBR using strain measurements within the elastic region. Analytical equations are developed relating elastic strains measured away from the hole to EPBR. A methodology is presented for employing strain data (obtained via miniature resistance strain gauges located away from the hole and within the elastic region) to be used as an input variable into the developed equations for determining EPBR. Using the method described in this paper, an average normalized EPBR of 2.38 (normalized with respect to the initial hole radius) was calculated utilizing elastic strain measurements during 4.0% cold expansion of a set of 4.826 mm thick 7075-T6 aluminum specimens containing a 6.0 mm diameter hole. The results showed excellent agreement with numerical simulations using a nonlinear elastic-plastic finite element code (ABAQUS). The deviation between the average EPBR determined by the analytical-experimental method and the finite element analysis was about 4.0%. The proposed method for using elastic strain measurements away from the hole provides improvement over earlier methods that rely on fringe observations or strain measurements within the relatively narrow plastic zone that has an uneven surface near the hole.
Polycrystal Plasticity Modeling of Cyclic Residual Stress Relaxation in Shot Peened Martensitic Gear Steel
Authors: Prasannavenkatesan Rajesh , McDowell David L.
Published: June 2010

Using a three-dimensional crystal plasticity model for cyclic deformation of lath martensitic steel, a simplified scheme is adopted to simulate the effects of shot peening on inducing initial compressive residual stresses. The model is utilized to investigate the subsequent cyclic relaxation of compressive residual stresses in shot peened lath martensitic gear steel in the high cycle fatigue (HCF) regime. A strategy is identified to model both shot peening and cyclic loading processes for polycrystalline ensembles. The relaxation of residual stress field during cyclic bending is analyzed for strain ratios Rε=0 and −1 for multiple realizations of polycrystalline microstructure. Cyclic microplasticity in favorably oriented martensite grains is the primary driver for the relaxation of residual stresses in HCF. For the case of Rε=−1, the cyclic plasticity occurs throughout the microstructure (macroplasticity) during the first loading cycle, resulting in substantial relaxation of compressive residual stresses at the surface and certain subsurface depths. The initial magnitude of residual stress is observed to influence the degree (percentage) of relaxation. Describing the differential intergranular yielding is necessary to capture the experimentally observed residual stress relaxation trends.
Adaptive Control of Mechanical Gas Face Seals With Rotor Runout and Static Stator Misalignment
Authors: Zhang Haojiong , Landers Robert G. , Miller Brad A.
Published: June 2010

This paper presents a control methodology that utilizes a robust model reference adaptive control technique to regulate the dynamic behavior of a coned mechanical gas face seal system in a flexibly mounted stator configuration. Individual adaptive controllers are designed for the three stator rigid body degrees of freedom based on the linear portions of their respective equations of motion. The force and moments generated within the gas film are estimated using Kalman filter-based estimators and directly cancelled in the control algorithm using offset control signals. The estimation errors are considered as bounded disturbances to the seal system and are taken into account by the robust adaptive controllers. Simulation results show that the controllers effectively stabilize the stator motion and control the stator tilts to synchronously track the rotor runout with near-zero relative misalignment magnitude and phase shift, thus, minimizing gas leakage.
An Adjustable Model Reference Adaptive Control for a Flexible Launch Vehicle
Authors: Khoshnood A. M. , Roshanian J. , Jafari A. A. , Khaki-Sedigh A.
Published: June 2010

Flexibility and aeroelastic behaviors in large space structures can lead to degradation of control system stability and performance. The model reference adaptive notch filter is an effective methodology used and implemented for reducing such effects. In this approach, designing a model reference for adaptive control algorithm in a flight device such as a launch vehicle is very important. In this way, the vibrations resulting from the structure flexibility mostly affects the pitch channel, and its influences on the yaw channel are negligible. This property is used and also the symmetrical behavior of the yaw and pitch channels. In this paper, by using this property and also the symmetrical behavior of the yaw and pitch channels, a new model reference using identification on the yaw channel is proposed. This model behaves very similar to the rigid body dynamic of the pitch channel and can be used as a model reference to control the vibrational effects. Simulation results illustrated applies the proposed algorithm and considerably reduces the vibrations in the pitch channel. Moreover, the main advantage of this new method is the online tuning of the model reference against unforeseen variations in the parameters of the rigid launch vehicle, which has not been considered in the previous works. Finally, robustness of the new control system in the presence of asymmetric behavior is investigated.
Two-Level Nonlinear Model Predictive Control for Lean NOx Trap Regenerations
Authors: Hsieh Ming-Feng , Wang Junmin , Canova Marcello
Published: June 2010

This paper describes a two-level nonlinear model predictive control (NMPC) scheme for diesel engine lean NOx trap (LNT) regeneration control. Based on the physical insights into the LNT operational characteristics, a two-level NMPC architecture with the higher-level for the regeneration timing control and the lower-level for the regeneration air to fuel ratio profile control is proposed. A physically based and experimentally validated nonlinear LNT dynamic model is employed to construct the NMPC control algorithms. The control objective is to minimize the fuel penalty induced by LNT regenerations while keeping the tailpipe NOx emissions below the regulations. Based on the physical insights into the LNT system dynamics, different choices of cost function were examined in terms of the impacts on fuel penalty and tailpipe NOx slip amount. The designed control system was evaluated on an experimentally validated vehicle simulator, cX-Emissions, with a 1.9 l diesel engine model through the FTP75 driving cycle. Compared with a conventional LNT control strategy, 31.9% of regeneration fuel penalty reduction was observed during a single regeneration. For the entire cold-start FTP75 test cycle, a 28.1% of tailpipe NOx reduction and 40.9% of fuel penalty reduction were achieved.
H
∞

Control for Continuous-Time Switched Linear Systems
Authors: Deaecto Grace S. , Geromel José C.
Published: June 2010

This paper deals with the output feedback H∞ control design problem for continuous-time switched linear systems. More specifically, the main goal is to design a switching rule together with a dynamic full order linear controller to satisfy a prespecified H∞ level defined by the L2 gain from the input to the output signal. Initially, the state feedback version of this problem is solved in order to put in evidence the main difficulties we have to face toward the solution of the output feedback control design problem. The results reported in this paper are based on the so called Lyapunov–Metzler inequalities, which express a sufficient condition for switched linear systems global stability. The solution of the previously mentioned output feedback control design problem through a linear matrix inequality based method is the main contribution of the present paper. An academic example borrowed from literature is used for illustration.
Surface Roughness Effects on Flow Boiling in Microchannels
Authors: Jones Benjamin J. , Garimella Suresh V.
Published: June 2010

The influence of surface roughness on flow boiling heat transfer and pressure drop in microchannels is experimentally explored. The microchannel heat sink employed in the study consists of ten parallel, 25.4 mm long channels with nominal dimensions of 500×500 μm2. The channels were produced by saw-cutting. Two of the test piece surfaces were roughened to varying degrees with electrical discharge machining (EDM). The roughness average Ra varied from 1.4 μm for the as-fabricated, saw-cut surface to 3.9 μm and 6.7 μm for the two roughened EDM surfaces. Deionized water was used as the working fluid. The experiments indicate that the surface roughness has little influence on boiling incipience and only a minor impact on saturated boiling heat transfer coefficients at lower heat fluxes. For wall heat fluxes above 1500 kW/m2, the two EDM surfaces (3.9 μm and 6.7 μm) have similar heat transfer coefficients that were 20–35% higher than those measured for the saw-cut surface (1.4 μm). A modified Bertsch et al. [2009, “A Composite Heat Transfer Correlation for Saturated Flow Boiling in Small Channels,” Int. J. Heat Mass Transfer, 52, pp. 2110–2118] correlation was found to provide acceptable predictions of the flow boiling heat transfer coefficient over the range of conditions tested. Analysis of the pressure drop measurements indicates that only the roughest surface (6.7 μm) has an adverse effect on the two-phase pressure drop.
Glass Transition Dynamics and Surface Layer Mobility in Unentangled Polystyrene Films
Authors: Yang Zhaohui , Fujii Yoshihisa , Lee Fuk Kay , Lam Chi-Hang , Tsui Ophelia K. C.
Published: June 2010

Tangle-Free Polymer Dynamics

The dynamics of polymer chains at interfaces will differ from the dynamics in the bulk. While hard interfaces generally cause chain motions to slow down, at free surfaces the dynamics should generally speed up. A consequence is that for thin polymer films, there should be a reduction in the glass transition temperature (
T
g
), but a wide range of effects have been seen in different polymeric materials. Now,

Yang
et al.

(p.
1676
) show that for short, unentangled polystyrene polymers, there is a direct correlation between the viscosity and the glass transition temperature, and that the reduction in
T
g
is due to a surface mobile layer that dominates the behavior as the films decrease in thickness.
Dry Times Ahead
Authors: Overpeck Jonathan , Udall Bradley
Published: June 2010

The climate of the western United States could become much drier over the course of this century.
Transition to Addiction Is Associated with a Persistent Impairment in Synaptic Plasticity
Authors: Kasanetz Fernando , Deroche-Gamonet Véronique , Berson Nadège , Balado Eric , Lafourcade Mathieu , Manzoni Olivier , Piazza Pier Vincenzo
Published: June 2010

Addicts Lose Plasticity

What are the biological mechanisms associated with the transition from occasional drug use to addiction? In rats, like in humans, even after a prolonged period of drug intake, only a limited number of animals develop addiction-like behavior despite the amount of drug taken by all subjects being the same.

Kasanetz
et al.

(p.
1709
) compared the expression of
N
-methyl-
d
-aspartate (NMDA)–dependent long-term depression (NMDA-LTD) in the nucleus accumbens of addicted and nonaddicted rats. Initially, once drug self-administration had been learned and consolidated, but before the appearance of addiction-like behavior, LTD was suppressed in all animals independently of their vulnerability to addiction at a later stage. However, after 2 months, when addiction-like behavior appears, LTD was persistently lost in the addicted animals. In contrast, normal NMDA-LTD reappeared in animals that maintained a controlled drug intake without becoming addicted.
Increased Food and Ecosystem Security via Perennial Grains
Authors: Glover J. D. , Reganold J. P. , Bell L. W. , Borevitz J. , Brummer E. C. , Buckler E. S. , Cox C. M. , Cox T. S. , Crews T. E. , Culman S. W. , DeHaan L. R. , Eriksson D. , Gill B. S. , Holland J. , Hu F. , Hulke B. S. , Ibrahim A. M. H. , Jackson W. , Jones S. S. , Murray S. C. , Paterson A. H. , Ploschuk E. , Sacks E. J. , Snapp S. , Tao D. , Van Tassel D. L. , Wade L. J. , Wyse D. L. , Xu Y.
Published: June 2010

Perennial grains hold promise, especially for marginal landscapes or with limited resources where annual versions struggle.
Detection of Hydrated Silicates in Crustal Outcrops in the Northern Plains of Mars
Authors: Carter J. , Poulet F. , Bibring J.-P. , Murchie S.
Published: June 2010

Hydrated Minerals on Martian Northern Plains

The presence of hydrated minerals on the surface of Mars implies that the crust of the planet was once altered by the action of liquid water. This conclusion is well established for the ancient southern highlands of Mars, but the situation in the northern lowlands, which are thought to have been resurfaced by lava flows during the Hesperian period about 3 billion years ago, is not so clear.

Carter
et al.

(p.
1682
) report the detection of hydrated minerals in nine northern plain craters, which are thought to have exposed the ancient, pre-Hesperian crust. The results suggest that the degree of alteration of the ancient martian crust is more extensive than previously assumed.
Delay in Photoemission
Authors: Schultze M. , Fieß M. , Karpowicz N. , Gagnon J. , Korbman M. , Hofstetter M. , Neppl S. , Cavalieri A. L. , Komninos Y. , Mercouris Th. , Nicolaides C. A. , Pazourek R. , Nagele S. , Feist J. , Burgdörfer J. , Azzeer A. M. , Ernstorfer R. , Kienberger R. , Kleineberg U. , Goulielmakis E. , Krausz F. , Yakovlev V. S.
Published: June 2010

Defining Time-Zero

When a high-energy photon hits an atom and is absorbed, the result can be the excitation and emission of an electron. This photoemission, or photoelectric effect, is generally assumed to occur instantaneously, and represents the definition of “time-zero” in clocking such ultrafast events.

Schultze
et al.

(p.
1658
, see the cover; see the Perspective by

van der Hart

) use ultrafast spectroscopy, with light pulses on the time scale of several tens of attoseconds, to test this assumption directly. They excite neon atoms with 100 eV photons and find that there is a small (20-attosecond) time delay between the emission of electrons from the 2
s
and 2
p
orbitals of the atoms. These results should have implications in modeling electron dynamics occurring on ultrafast time scales.
Asking Why Who Is Where
Here Be Dragons
How the Study of Animal and Plant Distributions Revolutionized Our Views of Life and Earth

by Dennis McCarthy

Oxford University Press, Oxford, 2009. 242 pp. $29.95, £16.99. ISBN 9780199542468.
Authors: Bennu Devorah
Published: June 2010

McCarthy surveys the history and development of biogeography by discussing interesting and informative examples of the distributions of organisms in space and time.
The Palladium-Catalyzed Trifluoromethylation of Aryl Chlorides
Authors: Cho Eun Jin , Senecal Todd D. , Kinzel Tom , Zhang Yong , Watson Donald A. , Buchwald Stephen L.
Published: June 2010

Three Fluorines at Once

The trifluoromethyl (CF
3
) group is playing an increasingly important role in the design of pharmaceutical and agrochemical compounds. CF
3
is a powerful attractor of electron density within a given molecular framework, and recently fluorine-hydrocarbon interactions have emerged as a distinct complement to the more traditional hydrophilic/hydrophobic interplay that governs docking between small molecules and proteins.

Cho
et al.

(p.
1679
) now present an efficient method for appending CF
3
groups to a broad range of aryl substrates. A carefully optimized palladium catalyst was able to speed up a critical elimination step that has plagued previous efforts to realize a general solution to this synthetic challenge.
When Does Photoemission Begin?
Authors: van der Hart H. W.
Published: June 2010

Ultrafast spectroscopy and multielectron calculations reveal complex electron dynamics occurring just before an atom emits a photoelectron.
IgA Changes the Rules of Memory
Authors: Cerutti Andrea
Published: June 2010

Pathogens and bacteria that normally live in the gut induce different immune responses.
Membrane Protein Gymnastics
Authors: Tate Christopher G.
Published: June 2010

A bacterial protein could flip its orientation in the membrane to attain its correct topology.
The Royal Society's Wider Role
Authors: Rees Martin
Published: June 2010

The royal society is currently celebrating its 350th anniversary. In its earlier years, Christopher Wren, Robert Hooke, Robert Boyle, Samuel Pepys, and other “ingenious and curious gentlemen” met regularly in London. Their motto was to “accept nothing on authority.” They did experiments, peered through newly invented telescopes and microscopes, and dissected weird animals. But, as well as indulging their curiosity, they were immersed in the practical agenda of their era: improving navigation, exploring the New World, and rebuilding London after the Great Fire of 1666. Today, our horizons have hugely expanded. Earth no longer offers an open frontier but seems constricted and crowded—a “pale blue dot” in the immense cosmos. But the Royal Society's core values have enduring relevance. Today's scientists, like their forbears, probe nature and nature's laws by observation and experiment, but they should also engage broadly with the needs of society and with public affairs.
Amid War, Appraising the Mineral Wealth of Afghanistan
Authors: Bhattacharjee Yudhijit
Published: June 2010

Two geologists who have helped manage the survey of Afghanistan's mineral wealth spoke to
Science
last week about the past, present, and future of mineral exploration in the war-torn country.
Critics Are Far Less Prominent Than Supporters
Authors: Kintisch Eli
Published: June 2010

A new analysis of 1372 climate scientists who have participated in major climate science reviews or taken public positions on their main conclusions confirms that those who believe in anthropogenic climate change rank, on average, much higher in the scientific pecking order than do those who take issue with the idea.
Natural Gas From Shale Bursts Onto the Scene
Authors: Kerr Richard A.
Published: June 2010

New technologies have sparked a rush of drilling in the United States, but environmental concerns and economic unknowns could still keep shale gas from becoming a bridge to clean energy.
A WEIRD View of Human Nature Skews Psychologists' Studies
Authors: Jones Dan
Published: June 2010

Relying on undergraduates from developed nations as research subjects creates a false picture of human behavior, some psychologists argue.
Pushing DAISY
Authors: Reed Sarah
Published: June 2010

In his spare time, an entrepreneurial engineer-cum-entomologist is teaming up with a museum to develop an automated insect-identification computer program.
Recombinant Diabody-Based Immunocapture Enzyme-Linked Immunosorbent Assay for Quantification of Rabies Virus Glycoprotein
Authors: Nimmagadda Sridevi V. , Aavula Shukra M. , Biradhar Neelakantam , Rao Varaprasada Sankarasetty , Shanmugham Rajalakshmi , Chandran Dev , Thirumeni Nagarajan , Singanallur Nagendrakumar Balasubramanian , Villuppanoor Srinivasan Alwar
Published: June 2010

The potency of rabies vaccines, determined using the NIH mouse protection test, can be directly correlated to the amount of rabies virus glycoprotein (RV GP) present in the vaccine. In an effort to develop a simple and sensitive enzyme-linked immunosorbent assay (ELISA) using recombinant diabody for quantification of RV GP, the variable heavy (V
H
) and light chain (V
L
) domains of an RV GP-specific human monoclonal antibody (MAb) secreted by a human × mouse heterohybridoma (human MAb R16E5) was amplified, linked using splicing by overlap extension PCR (SOE PCR), and expressed as a recombinant diabody (D06) in the pET28a bacterial expression system. The diabody D06 was purified by immobilized metal affinity chromatography on a nickel-nitrilotriacetic acid (NTA) agarose column and characterized. The purified diabody was used in combination with a well-characterized RV GP-specific mouse MAb, M5B4, to develop an immunocapture ELISA (IC-ELISA) for the quantification of RV GP in human rabies vaccine preparations. The maximum detection limit of the IC-ELISA using the M5B4-D06 combination was up to 31.25 ng/ml of RV GP. The specificity of the diabody was established by its nonreactivity toward other human viral antigens as determined by ELISA and toward RV GP as determined by immunoblot transfer assay and competitive ELISA with the parent human MAb R16E5 and MAb M5B4. The adjusted
r
2
value obtained by the regression through the origin model was 0.902, and the equation for predicted potency values for M5B4-D06-based IC-ELISA and MAb M5B4 IC-ELISA were 0.5651
x
and 0.8044
x
, respectively, where
x
is the estimate of RV GP from the IC-ELISA in micrograms. Analysis of variance (ANOVA) results showed the estimates of the two methods differed significantly (
P
< 0.001), while the predicted potencies by the two tests did not differ significantly (
P
> 0.05). The IC-ELISA can be readily adapted to measure the RV GP content in purified antigen, and a vaccine can be formulated based on the estimated GP.
New Assessment of Bovine Tuberculosis Risk Factors in Belgium Based on Nationwide Molecular Epidemiology
Authors: Humblet M.-F. , Gilbert M. , Govaerts M. , Fauville-Dufaux M. , Walravens K. , Saegerman C.
Published: June 2010

This assessment aimed to elaborate a statistical nationwide model for analyzing the space-time dynamics of bovine tuberculosis in search of potential risk factors that could be used to better target surveillance measures. A database comprising
Mycobacterium bovis
molecular profiles from all isolates obtained from Belgian outbreaks during the 1995-to-2006 period (
n
= 415) allowed the identification of a predominant spoligotype (SB0162). Various databases compiling 49 parameters to be tested were queried using a multiple stepwise logistic regression to assess bovine tuberculosis risk factors. Two isolate datasets were analyzed: the first included all
Mycobacterium bovis
isolates, while the second included only data related to the SB0162 type strain. When all
Mycobacterium bovis
isolates were included in the model, several risk factors were identified: history of bovine tuberculosis in the herd (
P
< 0.001), proximity of an outbreak (
P
< 0.001), cattle density (
P
< 0.001), and annual amplitude of mean middle-infrared temperature (
P
< 0.001). The approach restricted to the predominant SB0162 type strain additionally highlighted the proportion of movements from an infected area during the current year as a main risk factor (
P
= 0.009). This study identified several risk factors for bovine tuberculosis in cattle, highlighted the usefulness of molecular typing in the study of bovine tuberculosis epidemiology, and suggests a difference of behavior for the predominant type strain. It also emphasizes the role of animals' movements in the transmission of the disease and supports the importance of controlling trade movements.
First Report of Septic Arthritis Caused by
Klebsiella oxytoca
Authors: Ménard Armelle , Harambat Jérome , Pereyre Sabine , Pontailler Jean-Roger , Mégraud Francis , Richer Olivier
Published: June 2010

Klebsiella oxytoca
is known to be a pathogen in immunodeficient adults and children. Here we report the first case of a
K. oxytoca
infection associated with spontaneous arthritis of the knee in a child with no history of immunosuppressive therapy or previous bacterial infections. Despite an initial antibiotic treatment failure, a second treatment led to a cure of the infection with no joint sequelae.
Higher Prevalence of Pharyngeal than Nasal
Staphylococcus aureus
Carriage in Pediatric Intensive Care Units
Authors: Nakamura Mari M. , McAdam Alexander J. , Sandora Thomas J. , Moreira Katharina R. , Lee Grace M.
Published: June 2010

Sensitive detection of
Staphylococcus aureus
colonization is important for epidemiologic studies, infection control, and decolonization measures. We examined the sensitivity of nasal and pharyngeal sampling for
S. aureus
colonization in 331 children admitted to intensive care units. Pharyngeal screening was more sensitive than nasal screening (92.6% versus 63.1%,
P
< 0.0001).
First Case of Postaneurysmal Prosthetic Vascular Infection Due to a Nonsuperantigenic
Yersinia pseudotuberculosis
Strain
Authors: Loïez Caroline , Carnoy Christophe , Decoene Christophe , Pradel Elizabeth , Fichel Caroline , Courcol René , Wallet Frédéric
Published: June 2010

Among
Yersinia
spp.,
Y. enterocolitica
is the species most frequently isolated from infected aneurysms. This report describes the first case of postaneurysmal prosthetic vascular infection due to a superantigen-negative
Yersinia pseudotuberculosis
strain, showing a potential affinity of this species for endovascular tissue.
Evaluation of the Roche Cobas AmpliPrep/Cobas TaqMan HIV-1 Test and Identification of Rare Polymorphisms Potentially Affecting Assay Performance
Authors: Pyne Michael T. , Brown Katherine L. , Hillyard David R.
Published: June 2010

We evaluated the FDA-approved Roche Cobas AmpliPrep/Cobas TaqMan (CAP/CTM) HIV-1 viral load assay for sensitivity, reproducibility, linearity, HIV-1 subtype detection, and correlation to the Roche Amplicor HIV-1 monitor test, version 1.5 (Amplicor). The limit of detection calculated by probit analysis was 23.8 copies/ml using the 2nd International WHO Standard and 30.8 copies/ml using Viral Quality Assurance (VQA) standard material. Serial dilutions of six patient samples were used to determine inter- and intra-assay reproducibility and linearity, which were very good (<8% coefficient of variation [CV]; between ∼1.7 and 7.0 log
10
copies/ml). Subtype detection was evaluated in the CAP/CTM, Amplicor, and Bayer Versant HIV-1 bDNA 3.0 (Versant) assays using a commercially available panel. Versant averaged 0.829 log
10
copies/ml lower than CAP/CTM and Amplicor averaged 0.427 log
10
copies/ml lower than CAP/CTM for the subtype panel. Correlation with samples previously tested by Amplicor was excellent (
R
2
= 0.884; average difference [Amplicor value minus CAP/CTM value], 0.008 log
10
copies/ml). Of the 305 HIV samples tested, 7 samples generated CAP/CTM titers between 1.0 and 2.75 log
10
copies/ml lower than those for Amplicor. Three of these samples revealed primer and probe mismatches that could account for the discrepancies. Otherwise, the CAP/CTM assay exhibits excellent sensitivity, dynamic range, reproducibility, and correlation with Amplicor in an automated format.
Human Astrovirus Infection in a Patient with New-Onset Celiac Disease
Authors: Smits Saskia L. , van Leeuwen Marije , van der Eijk Annemiek A. , Fraaij Pieter L. A. , Escher Johanna C. , Simon James H. , Osterhaus Albert D. M. E.
Published: June 2010

Many diseases with unknown etiology may be caused by unidentified viruses. Sequence-independent amplification revealed a new astrovirus, similar to VA1, in a 4-year-old male diagnosed with celiac disease. This expands the geographic range of this virus to include Europe and may associate astrovirus infection with the onset of celiac disease.
Utilization of the QuantiFERON-TB Gold Test in a Two-Step Process with the Tuberculin Skin Test To Evaluate Health Care Workers for Latent Tuberculosis
Authors: Abdalhamid Baha , Hinrichs Steven H. , Garrett Jodi L. , O'Neill Jean M. , Hansen-Cain Kristine M. , Armbrust Amy A. , Iwen Peter C.
Published: June 2010

A cost analysis of combining a tuberculin skin test (TST) and the QuantiFERON-TB Gold test (QFT-GT) to detect latent tuberculosis in newly hired health care workers was performed. An approximately 50% reduction in the cost of additional care was realized when workers with positive TST results were subsequently screened using the QFT-GT.
Myc Is Required for the Maintenance of Kaposi's Sarcoma-Associated Herpesvirus Latency
Authors: Li Xudong , Chen Shijia , Feng Jun , Deng Hongyu , Sun Ren
Published: June 2010

Myc is deregulated by Kaposi's sarcoma-associated herpesvirus (KSHV) latent proteins, but its role in KSHV latency is not clear. We found that Myc knockdown with RNA interference (RNAi) induced KSHV reactivation and increased the protein and mRNA levels of RTA, a key viral regulator of KSHV reactivation. Myc knockdown increased, whereas Myc overexpression inhibited, RTA promoter activity. KSHV reactivation and the activation of the RTA promoter induced by Myc depletion were inhibited by c-Jun N-terminal kinase (JNK) and p38 inhibitors but not by a MEK1 inhibitor. Myc knockdown inhibited primary effusion lymphoma (PEL) cell proliferation through inducing apoptosis and G
1
cell cycle arrest. Thus, Myc may be a key cellular node coupling cellular transformation and KSHV latency.
Baculovirus GP64 Disulfide Bonds: the Intermolecular Disulfide Bond of
Autographa californica
Multicapsid Nucleopolyhedrovirus GP64 Is Not Essential for Membrane Fusion and Virion Budding
Authors: Li Zhaofei , Blissard Gary W.
Published: June 2010

The GP64 envelope glycoprotein of the
Autographa californica
nucleopolyhedrovirus (AcMNPV) is a class III viral membrane fusion protein that is triggered by low pH during entry. Unlike most other viral fusion protein trimers, the monomers of GP64 are covalently linked to each other within the trimer by a single intermolecular disulfide bond (Cys24—Cys372). Single or paired alanine substitutions for Cys24 and Cys372 resulted in lower-efficiency transport of GP64 to the cell surface. Surprisingly, these mutated GP64s induced syncytium formation, and normalized fusion activities were approximately 30% of that from wild-type (WT) GP64. Heat treatment (37°C) did not further reduce fusion activity of GP64 constructs with a disrupted intermolecular disulfide bond, suggesting that the GP64 trimers were relatively thermostable in the absence of the intermolecular disulfide bond. In addition, analysis of binding by a conformation-specific monoclonal antibody (MAb) suggested that the low-pH-induced refolding of those GP64 constructs was generally similar to that of WT GP64. In addition to its critical role in membrane fusion, GP64 is also necessary for efficient budding. When GP64 constructs containing a disrupted intermolecular disulfide bond (Cys24—Cys372) were displayed at the cell surface at levels comparable to those of WT GP64, virion budding efficiency ranged from approximately 39 to 88%, indicating that the intermolecular disulfide bond is not required for virion budding. However, GP64 proteins with a disrupted intermolecular disulfide could not rescue a GP64-null bacmid. We also examined the 6 conserved intramolecular disulfide bonds using single and paired alanine substitution mutations. None of the GP64 constructs with disrupted intramolecular disulfide bonds were capable of mediating pH-triggered membrane fusion, indicating that the intramolecular disulfide bonds are all necessary for membrane fusion. Thus, while the intramolecular disulfide bonds of GP64 appear to serve critical roles in membrane fusion, the unusual intermolecular disulfide bond was not critical for membrane fusion or virion budding yet appears to play an unknown role in viral infectivity.
Distinct Molecular Pathways to X4 Tropism for a V3-Truncated Human Immunodeficiency Virus Type 1 Lead to Differential Coreceptor Interactions and Sensitivity to a CXCR4 Antagonist
Authors: Del Prete Gregory Q. , Leslie George J. , Haggarty Beth , Jordan Andrea P. O. , Romano Josephine , Hoxie James A.
Published: June 2010

During the course of infection, transmitted HIV-1 isolates that initially use CCR5 can acquire the ability to use CXCR4, which is associated with an accelerated progression to AIDS. Although this coreceptor switch is often associated with mutations in the stem of the viral envelope (Env) V3 loop, domains outside V3 can also play a role, and the underlying mechanisms and structural basis for how X4 tropism is acquired remain unknown. In this study we used a V3 truncated R5-tropic Env as a starting point to derive two X4-tropic Envs, termed ΔV3-X4A.c5 and ΔV3-X4B.c7, which took distinct molecular pathways for this change. The ΔV3-X4A.c5 Env clone acquired a 7-amino-acid insertion in V3 that included three positively charged residues, reestablishing an interaction with the CXCR4 extracellular loops (ECLs) and rendering it highly susceptible to the CXCR4 antagonist AMD3100. In contrast, the ΔV3-X4B.c7 Env maintained the V3 truncation but acquired mutations outside V3 that were critical for X4 tropism. In contrast to ΔV3-X4A.c5, ΔV3-X4B.c7 showed increased dependence on the CXCR4 N terminus (NT) and was completely resistant to AMD3100. These results indicate that HIV-1 X4 coreceptor switching can involve (i) V3 loop mutations that establish interactions with the CXCR4 ECLs, and/or (ii) mutations outside V3 that enhance interactions with the CXCR4 NT. The cooperative contributions of CXCR4 NT and ECL interactions with gp120 in acquiring X4 tropism likely impart flexibility on pathways for viral evolution and suggest novel approaches to isolate these interactions for drug discovery.
The Cellular RNA Helicase DDX1 Interacts with Coronavirus Nonstructural Protein 14 and Enhances Viral Replication
Authors: Xu Linghui , Khadijah Siti , Fang Shouguo , Wang Li , Tay Felicia P. L. , Liu Ding Xiang
Published: June 2010

The involvement of host proteins in the replication and transcription of viral RNA is a poorly understood area for many RNA viruses. For coronaviruses, it was long speculated that replication of the giant RNA genome and transcription of multiple subgenomic mRNA species by a unique discontinuous transcription mechanism may require host cofactors. To search for such cellular proteins, yeast two-hybrid screening was carried out by using the nonstructural protein 14 (nsp14) from the coronavirus infectious bronchitis virus (IBV) as a bait protein, leading to the identification of DDX1, a cellular RNA helicase in the DExD/H helicase family, as a potential interacting partner. This interaction was subsequently confirmed by coimmunoprecipitation assays with cells coexpressing the two proteins and with IBV-infected cells. Furthermore, the endogenous DDX1 protein was found to be relocated from the nucleus to the cytoplasm in IBV-infected cells. In addition to its interaction with IBV nsp14, DDX1 could also interact with the nsp14 protein from severe acute respiratory syndrome coronavirus (SARS-CoV), suggesting that interaction with DDX1 may be a general feature of coronavirus nsp14. The interacting domains were mapped to the C-terminal region of DDX1 containing motifs V and VI and to the N-terminal portion of nsp14. Manipulation of DDX1 expression, either by small interfering RNA-induced knockdown or by overexpression of a mutant DDX1 protein, confirmed that this interaction may enhance IBV replication. This study reveals that DDX1 contributes to efficient coronavirus replication in cell culture.
Distinct Intracellular Trafficking of Hepatitis C Virus in Myeloid and Plasmacytoid Dendritic Cells
Authors: Lambotin Mélanie , Baumert Thomas F. , Barth Heidi
Published: June 2010

Dendritic cells (DCs) are of pivotal importance for the initiation of immune responses to control and eliminate viral infections. The molecular mechanisms of hepatitis C virus (HCV) antigen uptake and processing by blood DCs are poorly defined. Here we show that human blood DC subsets acquire HCV independent of the classical HCV entry factors. Following HCV uptake, human plasmacytoid and myeloid DC subsets deliver HCV antigen into distinct endocytotic compartments, which are dedicated to presentation to CD4
+
or CD8
+
T cells. Our findings support a model of HCV antigen processing and presentation in which DC subsets fulfill distinct functions.