bluuebunny/crossref_metadata_2025 huggingface dataset:
Do Voluntary Programs Reduce Pollution? ExaminingISO14001's Effectiveness across Countries
Authors: Potoski Matthew , Prakash Aseem
Published: May 2013

Voluntary environmental programs have emerged as important instruments of environmental policy. Despite considerable scholarly scrutiny, there remain debates about whether they reduce pollution among participants, and their overall impact at the country level. We present a cross‐national analysis of the efficacy ofISO14001, the most widely adopted voluntary environmental program in the world. While several single country studies have explored the effect ofISO14001 participation on pollution reduction at the facility level, this is the first article to assess (i) national level pollution reduction effects ofISO14001 participation levels, (ii) across a large number of countries, and (iii) across two pollutants. We examine whether all else equal, the national level uptakes ofISO14001 are associated with reductions in air emissions (sulfur dioxide,SO2) and water pollution (biochemical oxygen demand,BOD). Because firms, regulators, and environmental groups tend to focus more on visible types of pollution than less visible ones, we hypothesize thatISO14001 uptake will be associated with more pronounced reductions in air pollution (visible) in relation to water pollution (less visible). Our analyses of pollution levels for a panel of 138 (72 forBOD) countries for the 1991–2005 period suggest that a 1 percent increase in aggregate levels ofISO14001 adoption is associated with about a 0.064 percent reduction inSO2emissions, all else equal. In contrast, we do not find a statistically significant relationship betweenISO14001 adoption levels and changes in water pollution (BOD).
The President, the Fed, and the Financial Crisis
Authors: Weatherford M. Stephen
Published: May 2013

The active role of the Federal Reserve (Fed) in responding to the financial crisis has provoked questions not only about its policies' economic wisdom but also about the political significance of the Fed's exercise of expanded power. This article places the Fed's actions into perspective, framing three counterfactuals that yield different vantage points on the key question: Have the Fed's actions in the financial crisis and beyond amounted to a “power play” intended to marginalize elected authorities in the management of the national economy? I begin with an overview of the relationship over the postwar period between the Fed and the presidency, and then employ this historical baseline in analyzing three key episodes: the response to the crisis as it emerged during the final years of the Bush administration, the surprising decision by the Obama administration to continue the policy trajectory set by the actions of the Fed and his Republican predecessor, and the stabilization policies implemented by the Fed since the onset of the financial crisis. I find no strong evidence that the Fed's actions exceeded the rubric expected on the basis of its evolving responsibility to meet emergencies in a financial marketplace where the pace of innovation is high and in the context of political party polarization that has stalemated fiscal policy.
Unilateral Presidential Policy Making and the Impact of Crises
Authors: Young Laura
Published: May 2013

Scholars interested in the power of the presidency often overlook the importance of a crisis. The right kind of event, however, has characteristics that create a window of opportunity for a president to exert or expand his unilateral power. Failure to explore this relationship leaves a gap in our knowledge regarding presidential power, which this article addresses. The results show foreign policy crises provide the largest window for a president to increase his authority. Economic crises and most natural disasters have little to no impact on unilateral power. Epidemic outbreaks are the exception, though compared to a foreign policy crisis, the impact is relatively small. Finally, the findings suggest a president suffering from institutional constraints or lacking in skill and will has the ability to increase his power whenever a foreign policy crisis occurs.
To be or not to be Angolosaurus: a multilocus perspective on the phylogenetic position of Africa's desert plated lizard (Gerrhosauridae)
Authors: Lamb Trip , Bauer Aaron M.
Published: May 2013

The Desert Plated Lizard is a Namib sand dune specialist whose distinct morphological habitus has elicited differing taxonomic interpretations. Originally described as Gerrhosaurus skoogi, the species was later placed in a monotypic genus, Angolosaurus, to emphasize its endemic status and psammophilous condition. Distinct views exist regarding its phylogenetic position as well. General morphological and cranial osteological analyses, respectively, identify the species as either the sister taxon to the remaining African gerrhosaurids or sister taxon to all (African + Madagascan) gerrhosaurids. Alternatively, a mitochondrial DNA phylogeny places the species within the genus Gerrhosaurus. Given these conflicting topologies, we revisit the systematic status of the Desert Plated Lizard, presenting here the first multilocus phylogeny for the African gerrhosaurids. Bayesian inference and maximum‐likelihood analyses depict the Desert Plated Lizard as being nested within a clade containing four species of Gerrhosaurus. This strongly supported clade, recovered in mitochondrial, nuclear and combined gene analyses, corroborates the previous mitochondrial phylogeny. Alternative topologies – in which the species was constrained to correspond to morphological phylogenetic placements – differ significantly from our multilocus topology. Thus, we reiterate and conclude that Angolosaurus is a junior synonym of Gerrhosaurus.
Ozone priming of patterned carbon nanotube forests for subsequent atomic layer deposition-like deposition of SiO2 for the preparation of microfabricated thin layer chromatography plates
Authors: Jensen David S. , Kanyal Supriya S. , Madaan Nitesh , Miles Andrew J. , Davis Robert C. , Vanfleet Richard , Vail Michael A. , Dadson Andrew E. , Linford Matthew R.
Published: May 2013

The authors report the ozonation of patterned, vertically aligned carbon nanotube (CNT) forests as a method of priming them for subsequent pseudo atomic layer deposition (ψ-ALD) (alternating layer deposition) of silica to produce microfabricated, CNT-templated thin layer chromatography (TLC) plates. Gas phase ozonation simplifies our deposition scheme by replacing two steps in our previous fabrication process: chemical vapor deposition of carbon and ALD of Al2O3, with this much more straightforward priming step. As shown by x-ray photoelectron spectroscopy (XPS), ozonation appears to prime/increase the number of nucleation sites on the CNTs by oxidizing them, thereby facilitating conformal growth of silica by ψ-ALD, where some form of priming appears to be necessary for this growth. (As shown previously, ψ-ALD of SiO2 onto unprimed CNTs is ineffective and leads to poor quality depositions.) In conjunction with a discussion of the challenges of good peak fitting of complex C 1s XPS narrow scans, the authors present an analysis of their C 1s data that suggests an increase in oxidized carbon, particularly the C=O group, with increasing oxygen content of the CNT forests. After coating with SiO2, the CNTs are removed by elevated temperature air oxidation, the SiO2 is rehydrated, and the plates are coated with 3-aminopropyltriethoxysilane (APTES). The resulting APTES-coated plates separate various fluorescent dyes giving results that are generally at least as good as those the authors reported previously with their more complicated fabrication/priming scheme. TLC plates with different geometries are microfabricated, where plates with narrower channels show longer run times (lower mobile phase velocities) and plates with narrower features appear to give higher efficiencies.
Modified knife-edge method for current density distribution measurements in e-beam writers
Authors: Bok Jan , Kolařík Vladimír , Horáček Miroslav , Matějka Milan , Matějka František
Published: May 2013

In this paper, the authors present a modified knife-edge method for two-dimensional current density mapping in electron-beam writing systems. This method is applicable in rectangular and in variable-shaped e-beam writers with a fixed mutual position of the e-beam and the 1st shutter during exposure. In contrast to other methods, the modified knife-edge method uses only native parts of the e-beam writer, giving it the advantage of easy implementation. The measurement error of our method is analyzed and the trade-off between the result accuracy, the current density resolution and the measurement duration is discussed. The presented method is demonstrated by adjusting an electron emitter in order to select a homogeneous e-beam pattern.
Determination of transit dose profile for a 192Ir HDR source
Authors: Fonseca G. P. , Rubo R. A. , Minamisawa R. A. , dos Santos G. R. , Antunes P. C. G. , Yoriyaz H.
Published: May 2013

Purpose:

Several studies have reported methodologies to calculate and correct the transit dose component of the moving radiation source for high dose rate (HDR) brachytherapy planning systems. However, most of these works employ the average source speed, which varies significantly with the measurement technique used, and does not represent a realistic speed profile, therefore, providing an inaccurate dose determination. In this work, the authors quantified the transit dose component of a HDR unit based on the measurement of the instantaneous source speed to produce more accurate dose values.

Methods:

The Nucletron microSelectron‐HDR Ir‐192 source was characterized considering the Task Group 43 (TG‐43U1) specifications. The transit dose component was considered through the calculation of the dose distribution using a Monte Carlo particle transport code, MCNP5, for each source position and correcting it by the source speed. The instantaneous source speed measurements were performed in a previous work using two optical fibers connected to a photomultiplier and an oscilloscope. Calculated doses were validated by comparing relative dose profiles with those obtained experimentally using radiochromic films.

Results:

TG‐43U1 source parameters were calculated to validate the Monte Carlo simulations. These agreed with the literature, with differences below 1% for the majority of the points. Calculated dose profiles without transit dose were also validated by comparison with ONCENTRA® Brachy v. 3.3 dose values, yielding differences within 1.5%. Dose profiles obtained with MCNP5 corrected using the instantaneous source speed profile showed differences near dwell positions of up to 800% in comparison to values corrected using the average source speed, but they are in good agreement with the experimental data, showing a maximum discrepancy of approximately 3% of the maximum dose. Near a dwell position the transit dose is about 22% of the dwell dose delivered by the source dwelling 1 s and reached 104.0 cGy per irradiation in a hypothetical clinical case studied in this work.

Conclusions:

The present work demonstrated that the transit dose correction based on average source speed fails to accurately correct the dose, indicating that the correct speed profile should be considered. The impact on total dose due to the transit dose correction near the dwell positions is significant and should be considered more carefully in treatments with high dose rate, several catheters, multiple dwell positions, small dwell times, and several fractions.
Toward correcting drift in target position during radiotherapy via computer‐controlled couch adjustments on a programmable Linac
Authors: McNamara Joseph E. , Regmi Rajesh , Michael Lovelock D. , Yorke Ellen D. , Goodman Karyn A. , Rimner Andreas , Mostafavi Hassan , Mageras Gig S.
Published: May 2013

Purpose:

Real‐time tracking of respiratory target motion during radiation therapy is technically challenging, owing to rapid and possibly irregular breathing variations. The authors report on a method to predict and correct respiration‐averaged drift in target position by means of couch adjustments on an accelerator equipped with such capability.

Methods:

Dose delivery is broken up into a sequence of 10 s field segments, each followed by a couch adjustment based on analysis of breathing motion from an external monitor as a surrogate of internal target motion. Signal averaging over three respiratory cycles yields a baseline representing target drift. A Kalman filter predicts the baseline position 5 s in advance, for determination of the couch correction. The method's feasibility is tested with a motion phantom programmed according to previously recorded patient signals. Computed couch corrections are preprogrammed into a research mode of an accelerator capable of computer‐controlled couch translations synchronized with the motion phantom. The method's performance is evaluated with five cases recorded during hypofractionated treatment and five from respiration‐correlated CT simulation, using a root‐mean‐squared deviation (RMSD) of the baseline from the treatment planned position.

Results:

RMSD is reduced in all 10 cases, from a mean of 4.9 mm (range 2.7–9.4 mm) before correction to 1.7 mm (range 0.7–2.3 mm) after correction. Treatment time is increased ∼5% relative to that for no corrections.

Conclusions:

This work illustrates the potential for reduction in baseline respiratory drift with periodic adjustments in couch position during treatment. Future treatment machine capabilities will enable the use of “on‐the‐fly” couch adjustments during treatment.
R-Loop Stabilization Represses Antisense Transcription at the
Arabidopsis FLC
Locus
Authors: Sun Qianwen , Csorba Tibor , Skourti-Stathaki Konstantina , Proudfoot Nicholas J. , Dean Caroline
Published: May 2013

Making Antisense of Flowering

The recent discovery of biological roles for long noncoding RNAs raises important questions as to how they are themselves regulated.

Sun
et al.

(p.
619
) adopted a genetic approach to identify regulators of
COOLAIR
—a set of antisense transcripts from the locus encoding the major
Arabidopsis
floral repressor,
FLC
. Analysis of a mutant misregulating
COOLAIR
revealed a homeodomain protein that repressed
COOLAIR
expression via an R-loop covering the
COOLAIR
promoter. Thus, R-loop stabilization is an integral part of
COOLAIR
regulation,
FLC
expression, and flowering time.
Global Research Integrity Training
Authors: Steneck Nicholas H.
Published: May 2013

Globalization of responsible conduct of research training should be grounded on shared professional standards.
Silencing a Metabolic Oncogene
Authors: Kim Jiyeon , DeBerardinis Ralph J.
Published: May 2013

Small molecules inhibit a mutant enzyme confined to tumors, supporting therapeutic approaches that can reprogram metabolism in cancer.

[Also see Reports by

Wang
et al.

and

Rohle
et al.

]
Scientists Clash Swords Over Future of GM Food Crops in India
Authors: Bagla Pallava , Stone Richard
Published: May 2013

Science
sought to shed light on the future of GM food crops in India by bringing together two prominent scientific voices in a debate.
Development of an Internally Controlled Real-Time Reverse Transcriptase PCR Assay for Pan-Dengue Virus Detection and Comparison of Four Molecular Dengue Virus Detection Assays
Authors: Waggoner Jesse J. , Abeynayake Janaki , Sahoo Malaya K. , Gresh Lionel , Tellez Yolanda , Gonzalez Karla , Ballesteros Gabriela , Balmaseda Angel , Karunaratne Kumudu , Harris Eva , Pinsky Benjamin A.
Published: May 2013

A number of diagnostic tests are available for dengue virus (DENV) detection, including a variety of nucleic acid amplification tests (NAATs). However, reports describing a direct comparison of different NAATs have been limited. In this study, we report the design of an internally controlled real-time reverse transcriptase PCR (rRT-PCR) that detects all four DENV serotypes but does not distinguish between them (the pan-DENV assay). Two hundred clinical samples were then tested using four different DENV RT-PCR assays: the pan-DENV assay, a commercially produced, internally controlled DENV rRT-PCR (the Altona assay), a widely used heminested RT-PCR, and a serotype-specific multiplex rRT-PCR assay. The pan-DENV assay had a linear range extending from 1.0 to 7.0 log
10
cDNA equivalents/μl and a lower limit of 95% detection ranging from 1.7 to 7.6 cDNA equivalents/μl, depending on the serotype. When measured against a composite reference standard, the pan-DENV assay proved to be more clinically sensitive than either the Altona or heminested assays, with a sensitivity of 98.0% compared to 72.3% and 78.8%, respectively (
P
≤ 0.0001 for both comparisons). The pan-DENV assay detected DENV in significantly more samples collected on or after day 5 of illness and in a subgroup of patients with detectable anti-DENV IgM at presentation. No significant difference in sensitivity was observed between the pan-DENV assay and the multiplex rRT-PCR, despite the presence of an internal control in the former. The detection of DENV RNA late in the course of clinical illness should serve to lengthen the period during which a confirmed molecular diagnosis of DENV infection can be provided.
Development and Evaluation of a Next-Generation Digital PCR Diagnostic Assay for Ocular Chlamydia trachomatis Infections
Authors: Roberts Chrissy h. , Last Anna , Molina-Gonzalez Sandra , Cassama Eunice , Butcher Robert , Nabicassa Meno , McCarthy Elizabeth , Burr Sarah E. , Mabey David C. , Bailey Robin L. , Holland Martin J.
Published: May 2013

Droplet digital PCR (ddPCR) is an emulsion PCR process that performs absolute quantitation of nucleic acids. We developed a ddPCR assay for
Chlamydia trachomatis
infections and found it to be accurate and precise. Using PCR mixtures containing plasmids engineered to include the PCR target sequences, we were able to quantify with a dynamic range between 0.07 and 3,160 targets/μl (
r
2
= 0.9927) with >95% confidence. Using 1,509 clinical conjunctival swab samples from a population in which trachoma is endemic in Guinea Bissau, we evaluated the specificity and sensitivity of the quantitative ddPCR assay in diagnosing ocular
C. trachomatis
infections by comparing the performances of ddPCR and the Roche Amplicor CT/NG test. We defined ddPCR tests as positive when we had ≥95% confidence in a nonzero estimate of target load. The sensitivity of ddPCR against Amplicor was 73.3% (95% confidence interval [CI], 67.9 to 78.7%), and specificity was 99.1% (95% CI, 98.6 to 99.6%). Negative and positive predictive values were 94.6% (95% CI, 93.4 to 95.8%) and 94.5% (95% CI, 91.3 to 97.7%), respectively. Based on Amplicor CT/NG testing, the estimated population prevalence of
C. trachomatis
ocular infection was ∼17.5%. Receiver-operator curve analysis was used to select critical cutoff values for use in clinical settings in which a balance between higher sensitivity and specificity is required. We concluded that ddPCR is an effective diagnostic technology suitable for both research and clinical use in diagnosing ocular
C. trachomatis
infections.
Epidemiological and Clinical Complexity of Amoxicillin-Clavulanate-Resistant Escherichia coli
Authors: Rodríguez-Baño Jesús , Oteo Jesús , Ortega Adriana , Villar Macarena , Conejo M. Carmen , Bou Germán , Aranzamendi-Zaldumbide Maitane , Cercenado Emilia , Gurguí Mercè , Martínez-Martínez Luis , Merino María , Rivera Alba , Oliver Antonio , Weber Irene , Pascual Alvaro , Bartolomé Rosa M. , Gónzalez-López Juan José , Campos José
Published: May 2013

Two hundred twelve patients with colonization/infection due to amoxicillin-clavulanate (AMC)-resistant
Escherichia coli
were studied. OXA-1- and inhibitor-resistant TEM (IRT)-producing strains were associated with urinary tract infections, while OXA-1 producers and chromosomal AmpC hyperproducers were associated with bacteremic infections. AMC resistance in
E. coli
is a complex phenomenon with heterogeneous clinical implications.
Interleukin-21 Is a Critical Cytokine for the Generation of Virus-Specific Long-Lived Plasma Cells
Authors: Rasheed Mohammed Ata Ur , Latner Donald R. , Aubert Rachael D. , Gourley Tania , Spolski Rosanne , Davis Carl W. , Langley William A. , Ha Sang-Jun , Ye Lilin , Sarkar Surojit , Kalia Vandana , Konieczny Bogumila T. , Leonard Warren J. , Ahmed Rafi
Published: May 2013

Long-lived plasma cells that reside in the bone marrow constitutively produce antibody in the absence of antigen and are the cellular basis of durable humoral immunity. The generation of these long-lived plasma cells depends upon a series of highly orchestrated interactions between antigen-specific CD4 T cells and B cells and the formation of germinal centers (GCs). In this study, we have examined the role of the cytokine interleukin-21 (IL-21) in regulating humoral immunity during acute viral infections. Using IL-21 receptor-deficient (IL-21R−/−) mice, we found that virus-specific CD4 T cells were generated after infection with lymphocytic choriomeningitis virus (LCMV) and that these CD4 T cells differentiated into T follicular helper (TFH)-like cells in the absence of IL-21 signaling. There was also no defect in the formation of GCs, although after day 15 these GCs disappeared faster in IL-21R−/−mice than in wild-type mice. Isotype switching and the initial LCMV-specific IgG response were normal in IL-21R−/−mice. However, these mice exhibited a profound defect in generating long-lived plasma cells and in sustaining antibody levels over time. Similar results were seen after infection of IL-21R−/−mice with vesicular stomatitis virus and influenza virus. Using chimeric mice containing wild-type or IL-21R−/−CD4 T cells and B cells, we showed that both B and CD4 T cells need IL-21 signaling for generating long-term humoral immunity. Taken together, our results highlight the importance of IL-21 in humoral immunity to viruses.
Immature and Mature Dengue Serotype 1 Virus Structures Provide Insight into the Maturation Process
Authors: Kostyuchenko Victor A. , Zhang Qian , Tan Joanne L. , Ng Thiam-Seng , Lok Shee-Mei
Published: May 2013

Dengue virus is a major human pathogen that has four serotypes (DENV1 to -4). Here we report the cryoelectron microscopy (cryo-EM) structures of immature and mature DENV1 at 6- and 4.5-Å resolution, respectively. The subnanometer-resolution maps allow accurate placement of all of the surface proteins. Although the immature and mature viruses showed vastly different surface protein organizations, the envelope protein transmembrane (E-TM) regions remain in similar positions. The pivotal role of the E-TM regions leads to the identification of the start and end positions of all surface proteins during maturation.
The Cellular Interactome of the Coronavirus Infectious Bronchitis Virus Nucleocapsid Protein and Functional Implications for Virus Biology
Authors: Emmott Edward , Munday Diane , Bickerton Erica , Britton Paul , Rodgers Mark A. , Whitehouse Adrian , Zhou En-Min , Hiscox Julian A.
Published: May 2013

The coronavirus nucleocapsid (N) protein plays a multifunctional role in the virus life cycle, from regulation of replication and transcription and genome packaging to modulation of host cell processes. These functions are likely to be facilitated by interactions with host cell proteins. The potential interactome of the infectious bronchitis virus (IBV) N protein was mapped using stable isotope labeling with amino acids in cell culture (SILAC) coupled to a green fluorescent protein-nanotrap pulldown methodology and liquid chromatography-tandem mass spectrometry. The addition of the SILAC label allowed discrimination of proteins that were likely to specifically bind to the N protein over background binding. Overall, 142 cellular proteins were selected as potentially binding to the N protein, many as part of larger possible complexes. These included ribosomal proteins, nucleolar proteins, translation initiation factors, helicases, and hnRNPs. The association of selected cellular proteins with IBV N protein was confirmed by immunoblotting, cosedimentation, and confocal microscopy. Further, the localization of selected proteins in IBV-infected cells as well as their activity during virus infection was assessed by small interfering RNA-mediated depletion, demonstrating the functional importance of cellular proteins in the biology of IBV. This interactome not only confirms previous observations made with other coronavirus and IBV N proteins with both overexpressed proteins and infectious virus but also provides novel data that can be exploited to understand the interaction between the virus and the host cell.
Intranasal Administration of Antibody-Bound Respiratory Syncytial Virus Particles Efficiently Primes Virus-Specific Immune Responses in Mice
Authors: Kruijsen Debby , Einarsdottir Helga K. , Schijf Marcel A. , Coenjaerts Frank E. , van der Schoot Ellen C. , Vidarsson Gestur , van Bleek Grada M.
Published: May 2013

Infants are protected from a severe respiratory syncytial virus (RSV) infection in the first months of life by maternal antibodies or by prophylactically administered neutralizing antibodies. Efforts are under way to produce RSV-specific antibodies with increased neutralizing capacity compared to the currently licensed palivizumab. While clearly beneficial during primary infections, preexisting antibodies might affect the onset of adaptive immune responses and the ability to resist subsequent RSV infections. Therefore, we addressed the question of how virus neutralizing antibodies influence the priming of subsequent adaptive immune responses. To test a possible role of the neonatal Fc receptor (FcRn) in this process, we compared the responses in C57BL/6 wild-type (WT) and FcRn−/−mice. We observed substantial virus-specific T-cell priming and B-cell responses in mice primed with RSV IgG immune complexes resulting in predominantly Th1-type CD4+T-cell and IgG2c antibody responses upon live-virus challenge. RSV-specific CD8+T cells were primed as well. Activation of these adaptive immune responses was independent of FcRn. Thus, neutralizing antibodies that localize to the airways and prevent infection-related routes of antigen processing can still facilitate antigen presentation of neutralized virus particles and initiate adaptive immune responses against RSV.
Antigenic Characterization of H3N2 Influenza A Viruses from Ohio Agricultural Fairs
Authors: Feng Zhixin , Gomez Janet , Bowman Andrew S. , Ye Jianqiang , Long Li-Ping , Nelson Sarah W. , Yang Jialiang , Martin Brigitte , Jia Kun , Nolting Jacqueline M. , Cunningham Fred , Cardona Carol , Zhang Jianqiang , Yoon Kyoung-Jin , Slemons Richard D. , Wan Xiu-Feng
Published: May 2013

The demonstrated link between the emergence of H3N2 variant (H3N2v) influenza A viruses (IAVs) and swine exposure at agricultural fairs has raised concerns about the human health risk posed by IAV-infected swine. Understanding the antigenic profiles of IAVs circulating in pigs at agricultural fairs is critical to developing effective prevention and control strategies. Here, 68 H3N2 IAV isolates recovered from pigs at Ohio fairs (2009 to 2011) were antigenically characterized. These isolates were compared with other H3 IAVs recovered from commercial swine, wild birds, and canines, along with human seasonal and variant H3N2 IAVs. Antigenic cartography demonstrated that H3N2 IAV isolates from Ohio fairs could be divided into two antigenic groups: (i) the 2009 fair isolates and (ii) the 2010 and 2011 fair isolates. These same two antigenic clusters have also been observed in commercial swine populations in recent years. Human H3N2v isolates from 2010 and 2011 are antigenically clustered with swine-origin IAVs from the same time period. The isolates recovered from pigs at fairs did not cross-react with ferret antisera produced against the human seasonal H3N2 IAVs circulating during the past decade, raising the question of the degree of immunity that the human population has to swine-origin H3N2 IAVs. Our results demonstrate that H3N2 IAVs infecting pigs at fairs and H3N2v isolates were antigenically similar to the IAVs circulating in commercial swine, demonstrating that exhibition swine can function as a bridge between commercial swine and the human population.
Human Cytomegalovirus-Induced NKG2ChiCD57hiNatural Killer Cells Are Effectors Dependent on Humoral Antiviral Immunity
Authors: Wu Zeguang , Sinzger Christian , Frascaroli Giada , Reichel Johanna , Bayer Carina , Wang Li , Schirmbeck Reinhold , Mertens Thomas
Published: May 2013

Recent studies indicate that expansion of NKG2C-positive natural killer (NK) cells is associated with human cytomegalovirus (HCMV); however, their activity in response to HCMV-infected cells remains unclear. We show that NKG2ChiCD57hiNK cells gated on CD3negCD56dimcells can be phenotypically identified as HCMV-induced NK cells that can be activated by HCMV-infected cells. Using HCMV-infected autologous macrophages as targets, we were able to show that these NKG2ChiCD57hiNK cells are highly responsive to HCMV-infected macrophages only in the presence of HCMV-specific antibodies, whereas they are functionally poor effectors of natural cytotoxicity. We further demonstrate that NKG2ChiCD57hiNK cells are intrinsically responsive to signaling through CD16 cross-linking. Our findings show that the activity of pathogen-induced innate immune cells can be enhanced by adaptive humoral immunity. Understanding the activity of NKG2ChiCD57hiNK cells against HCMV-infected cells will be of relevance for the further development of adoptive immunotherapy.
Structures of the Procapsid and Mature Virion of Enterovirus 71 Strain 1095
Authors: Cifuente Javier O. , Lee Hyunwook , Yoder Joshua D. , Shingler Kristin L. , Carnegie Michael S. , Yoder Jennifer L. , Ashley Robert E. , Makhov Alexander M. , Conway James F. , Hafenstein Susan
Published: May 2013

Enterovirus 71 (EV71) is an important emerging human pathogen with a global distribution and presents a disease pattern resembling poliomyelitis with seasonal epidemics that include cases of severe neurological complications, such as acute flaccid paralysis. EV71 is a member of thePicornaviridaefamily, which consists of icosahedral, nonenveloped, single-stranded RNA viruses. Here we report structures derived from X-ray crystallography and cryoelectron microscopy (cryo-EM) for the 1095 strain of EV71, including a putative precursor in virus assembly, the procapsid, and the mature virus capsid. The cryo-EM map of the procapsid provides new structural information on portions of the capsid proteins VP0 and VP1 that are disordered in the higher-resolution crystal structures. Our structures solved from virus particles in solution are largely in agreement with those from prior X-ray crystallographic studies; however, we observe small but significant structural differences for the 1095 procapsid compared to a structure solved in a previous study (X. Wang, W. Peng, J. Ren, Z. Hu, J. Xu, Z. Lou, X. Li, W. Yin, X. Shen, C. Porta, T. S. Walter, G. Evans, D. Axford, R. Owen, D. J. Rowlands, J. Wang, D. I. Stuart, E. E. Fry, and Z. Rao, Nat. Struct. Mol. Biol. 19:424–429, 2012) for a different strain of EV71. For both EV71 strains, the procapsid is significantly larger in diameter than the mature capsid, unlike in any other picornavirus. Nonetheless, our results demonstrate that picornavirus capsid expansion is possible without RNA encapsidation and that picornavirus assembly may involve an inward radial collapse of the procapsid to yield the native virion.
Citations of scientific results and conflicts of interest: the case of mammography screening
Authors: Rasmussen Kristine , Jørgensen Karsten Juhl , Gøtzsche Peter C
Published: May 2013

Introduction

In 2001, a Cochrane review of mammography screening questioned whether screening reduces breast cancer mortality, and a more comprehensive review inLancet, also in 2001, reported considerable overdiagnosis and overtreatment. This led to a heated debate and a recent review of the evidence by UK experts intended to be independent.

Objective

To explore if general medical and specialty journals differed in accepting the results and methods of three Cochrane reviews on mammography screening.

Methods

We identified articles citing theLancetreview from 2001 or updated versions of the Cochrane review (last search 20 April 2012). We explored which results were quoted, whether the methods and results were accepted (explicit agreement or quoted without caveats), differences between general and specialty journals, and change over time.

Results

We included 171 articles. The results for overdiagnosis were not quoted in 87% (148/171) of included articles and the results for breast cancer mortality were not quoted in 53% (91/171) of articles. 11% (7/63) of articles in general medical journals accepted the results for overdiagnosis compared with 3% (3/108) in specialty journals (p=0.05). 14% (9/63) of articles in general medical journals accepted the methods of the review compared with 1% (1/108) in specialty journals (p=0.001). Specialty journals were more likely to explicitly reject the estimated effect on breast cancer mortality 26% (28/108), compared with 8% (5/63) in general medical journals, p=0.02.

Conclusions

Articles in specialty journals were more likely to explicitly reject results from the Cochrane reviews, and less likely to accept the results and methods, than articles in general medical journals. Several specialty journals are published by interest groups and some authors have vested interests in mammography screening.
SCATTERING STATES OF HULTHÉN INTERACTION IN MINIMAL LENGTH QUANTUM MECHANICS
Authors: HASSANABADI H. , ZARRINKAMAR S. , MAGHSOODI E.
Published: May 2013

We first revisit the nonrelativistic minimal length quantum mechanics and reveal an interesting symmetry of the problem. In fact, we will show that the cumbersome problem can be cast into the ordinary Schrödinger equation with a new effective potential. Next, as a typical example, we show the minimal length Schrödinger equation in the presence of a nonminimal Hulthén vector interaction. The transmission and reflection coefficients are reported as well.
FRAME TRANSFORMATIONS OF GRAVITATIONAL THEORIES
Authors: CALMET XAVIER , YANG TING-CHENG
Published: May 2013

We show how to map gravitational theories formulated in the Jordan frame to the Einstein frame at the quantum field theoretical level considering quantum fields in curved space–time. As an example, we consider gravitational theories in the Jordan frame of the type F(ϕ, R) = f(ϕ)R-V(ϕ) and perform the map to the Einstein frame. Our results can easily be extended to any gravitational theory. We consider the Higgs inflation model as an application of our results.
ELECTRONIC AND OPTICAL PROPERTIES OF NITROGEN DOPED SiC NANOCRYSTALS: FIRST PRINCIPLES STUDY
Authors: JAVAN MASOUD BEZI
Published: May 2013

A typical nitrogen doped spherical SiC nanocrystal with a diameter of 1.2 nm ( Si 43 C 44 H 76) using linear combination atomic orbital (LCAO) in combination with pseudopotential density functional calculation have been studied. Our selected SiC nanocrystal has been modeled taking all the cubic bulk SiC atoms contained within a sphere of a given radius and terminating the surface dangling bonds with hydrogen atoms. We have examined nine possible situations in which nitrogen has a high probability for replacement in the lattice or placed between atoms in the nanocrystal. We have found that the silicone can substitute with a nitrogen atom in each layer as the constructed nanocrystals remain thermodynamically stable. Also the nitrogen atom can be placed between the free atomic spaces as the more thermodynamically stable position of the nitrogen is between the topmost layers. Also the optical absorption and refractive index energy dispersions of the pure and various stable doped SiC nanocrystals were studied.
THE QUANTUM REFRIGERATOR IN A TWO-QUBIT XXZ HEISENBERG MODEL
Authors: ALBAYRAK ERHAN
Published: May 2013

The four-level entangled quantum refrigerator (QR) is studied in the XXZ Heisenberg model for the two-qubits. The Hamiltonian of the problem includes the exchange parameters Jx = Jy = J and Jz = αJ along the x-, y- and z-directions, respectively, and constant external magnetic field B in the z-direction. The parameter α is introduced into the model which controls the strength of the exchange parameter Jz in comparison to Jx and Jy, thus, our investigation of QR includes the XX (α = 0.0), XXX (α = 1.0) and XXZ (for other α's) Heisenberg models. The two-qubits are assumed to be in contact with two heat reservoirs at different temperatures. The concurrences for a two-qubit are used as a measure of entanglement and then the expressions for the amount of heat transferred, the work performed and the efficiency are derived. The contour, i.e., the isoline maps, and some two-dimensional plots of the above mentioned thermodynamic quantities are illustrated.
A NEW METHOD FOR DETERMINING SUBENDOCARDIAL VIABILITY RATIO FROM RADIAL ARTERY PRESSURE WAVES
Authors: MA ZU-CHANG , ZHANG YONG-LIANG , NI CHAO-MING , HE ZI-JUN , CAO QING-QING , SUN YI-NING
Published: May 2013

Aortic subendocardial viability ratio (SEVR), an index of myocardial oxygen demand relative to supply, has been used for the early detection of hemodynamic changes. We aimed to validate a new method for determining SEVR directly from radial pressures. Hemodynamic parameters were measured in 231 outpatients (108 males and 123 females) for physical examination, aged from 20–77 years (45.9 ± 17.3 years), including 210 healthy and 21 hypertensive subjects. Aortic SEVR was obtained using a validated device (SphygmoCor; AtCor Medical, Sydney, Australia), and radial SEVR was obtained using a portable vascular testing device (IIM-2010A; Institute and Intelligent of Machines, Hefei, China). Radial SEVR was strongly related to aortic SEVR (r = 0.824, p < 0.01), with approximately 15.7% lower value. Aortic and radial SEVR had similar independent predictors, including diastolic time fraction (DTF), systolic blood pressure, diastolic blood pressure, age, and height. DTF exerted the most influence on both of them. In healthy subjects, there were significant changes in aortic and radial SEVR between age groups in both males and females (p < 0.05 for both ). Changes in aortic and radial SEVR with aging were parallel though the differences between them increased. These results suggested that the simple and easily obtainable radial SEVR could provide equivalent information to aortic SEVR, and has potential for the primary prevention of cardiovascular disease in health screening.
SIZE-DEPENDENT PIEZOELECTRICITY AND ELASTICITY DUE TO THE ELECTRIC FIELD-STRAIN GRADIENT COUPLING AND STRAIN GRADIENT ELASTICITY
Authors: XU LIANG , SHEN SHENGPING
Published: May 2013

A size-dependent nonclassical Bernoulli–Euler beam model based on the strain gradient elasticity is proposed for piezoelectric nanowires. The governing equations and the corresponding boundary conditions are naturally derived from the variational principle. Different from the classical piezoelectric beam theory, the electric field–strain gradient coupling and the strain gradient elasticity are both taken into account. Static bending problem of a cantilever piezoelectric nanobeam is solved to illustrate the effect of strain gradient. The present model contains material length scale parameters and can capture the size dependent piezoelectricity and elasticity for nanoscale piezoelectric structures. The numerical results reveal that the deflections predicted by the present model are smaller than that by the classical beam theory and the effective electromechanical coupling coefficient is dramatic enhanced by the electric field–strain gradient coupling effect. However, the differences in both the deflections and effective EMC coefficient between the two models are very significant when the beam thickness is very small; they are diminishing with the increase of the beam thickness. This model is helpful for understanding the electromechanically coupling mechanism and in designing piezoelectric nanowires based devices.
(Invited) Rethinking High-Performance CVD Graphene Nanoelectronics on Oxidized Silicon
Authors: Akinwande Deji , Tao Li
Published: May 2013

In this paper, substantial recent progress on graphene synthesis on standard substrates and the high-performance electronic properties arising from the synthesized monolayer will be highlighted. Nearly defect-free monolayer graphene can now be synthesized by CVD at wafer-scales with material quality comparable to ex-foliated natural flakes. Fabricated transistor devices from CVD graphene on oxidized silicon now readily afford mobilities over 10,000 cm2/V-s with 10x on/off current ratio while maintaining the intrinsic electron-hole symmetry. Linear and non-linear circuits such as amplifiers and low-loss doublers have also been achieved.
(Invited) Graphene Transistors for Ambipolar Mixing at Microwave Frequencies
Authors: Madan Himanshu , Hollander Matthew J , Robinson Joshua A. , Datta Suman
Published: May 2013

This work presents a detailed study of the graphene RF mixer in the ambipolar configuration, using quasi-free-standing epitaxial graphene on SiC. Record high conversion gain is achieved through use of optimized growth and synthesis techniques, metal contact formation, and dielectric materials integration. Hydrogen intercalation is utilized to isolate the graphene from the underlying SiC substrate and improve transport properties. Low contact resistances at the metal-graphene interface are realized using an oxygen plasma pre-treatment, while dielectric seeding is achieved using a direct deposited layer of HfO2 before ALD film growth. Output characteristics of the graphene transistor are analyzed and the effects on mixer performance are explained. A graphene RF transistor is designed with gate length 750 nm, width 20 μm, and equivalent oxide thickness ~2.5 nm in order to achieve record high conversion gain of -14 and -16 dB at LO power 0 dBm at 4.2 and 10 GHz, respectively, 100x higher than previously reported ambipolar mixing.
Effect of Gate Dielectric on Ballistic Transport of Cylindrical Carbon Nanotube MOSFET
Authors: Hossain Md. Shafayat , Khan Saeed Uz Zaman , Aziz Ahmedullah , Rahman Mohammad Wahidur , Arafat Muhammad Abdullah
Published: May 2013

Carbon NanoTube (CNT) channel promises near ballistic transport and is examined extensively for potential application in next-generation Nano-scale transistor. Cylindrical gate-all-around CNT field effect transistor (CNTFET) with semiconducting CNT S/D contacts and Schottky barrier CNTFET (SBCNTFET) are modeled numerically based on self-consistent solution of Poisson-Schrödinger equation with open boundary conditions within Non-Equilibrium Green’s Function formalism considering coaxial symmetry. The effect of dielectric constant (κ) and physical thickness of gate dielectric on transport characteristics of CNTFET and SBCNTFET are examined in this work. Gate capacitance, carrier injection velocity, current and therefore speed increases significantly with the inclusion of high κ dielectric and decrease in thickness. SBCNTFET also shows better performance with thin high κ dielectric layer. High trans-conductance and much lower Sub-threshold swing is visible with the inclusion of high κ gate stack.
Effect of Different Patterns Epitaxial Lift-Off Process by Finite Element Method
Authors: Horng Ray-Hua , Wu Fan-Lei , Ou Sin-Liang , Liu Fang-Ching , Lin Ming-Tzer , Lu C. H. , Kao Yu-Cheng , Wuu Dong-Sing
Published: May 2013

In this study, using the finite element method analyzes stress and strain of device structure on different patterns epitaxial lift-off process. Design copper substrate bears stress 28.3 MPa and to simulate the change of the sacrificial layer in the epitaxial lift-off process, which setting the sacrificial layer etching amount for 10%, 30%, 50%, 70%, 90%. Besides, the stress and strain distribution of device structure analyzes on various sacrificial layer etching amount. Copper substrate is subject to tensile stress and its corner exist the maximum of stress and strain. Moreover, the stress distribution of epilayer concentrates in the upper and lower interface of sacrificial layer. The stress is larger sacrificial layer etching to 10% than etching to 90%. The structures 3 stress is relatively lower, which the stress reduces approximately half on etching amount 50%. Therefore, the GaAs epilayer not only reduce subjected to stress but also decrease the occurrence of defects.
Application of an Extended Unified Schottky-Poole-Frenkel Model to High-k Capacitor Structures Used in Analog Integrated Circuit Technology
Authors: Lau Wai Shing
Published: May 2013

In this paper, the author points out that the Poole-Frenkel (P-F) and Schottky emission mechanisms actually can happen simultaneously and a unified Schottky-Poole-Frenkel model can be used to explain a lot of existing experimental data. However, sometimes, the basic unified Schottky-Poole-Frenkel model fails and an extended unified Schottky-Poole-Frenkel model is required to explain experimental data. In this paper, an example of using the basic unified Schottky-Poole-Frenkel model to explain the I-V characteristics of high-k capacitor structures used in analog integrated circuit technology will be presented. Then an example of high-k capacitor structures used in analog integrated circuit technology which require the extended unified Schottky-Poole-Frenkel model will also be provided.
Confocal Microscopy and TRPL Spectroscopy Study on Spatial Variation of PL in Blue-Emitting InGaN/GaN MQWs
Authors: Li Cheng , Stokes E. B. , Hefti Ryan , Moyer Patrick J , Arif Ronald A , Byrnes Dan , Lee Soo Min , Armour Eric
Published: May 2013

Confocal laser scanning microscopy (CLSM) and time-resolved photoluminescence (TRPL) spectroscopy were used to study blue-emitting indium gallium nitride (InGaN)/gallium nitride (GaN) multi-quantum wells grown on c-plane sapphire substrate by metal-organic chemical vapor deposition under different growth conditions. Spatial and spectral variations of photoluminescence (PL) were observed in sub-micrometer scale. Spectrum measurement showed that the bright regions have higher PL intensity as well as smaller PL peak energy than the dark regions. The brightness of CLSM images is related with the PL peak energy difference between bright region and dark region: the larger the energy difference is, the brighter the CLSM image is. TRPL measurement and calculation showed that the effective PL lifetime at bright regions is longer than that at dark regions, and brightness of CLSM images increases with the increment of bright region effective PL lifetime.
Improving the Current Density and the Coulombic Efficiency by a Cascade Reaction of Glucose Oxidizing Enzymes
Authors: Zafar Muhammad Nadeem , Shao Minling , Ludwig Roland , Leech Dónal , Schuhmann Wolfgang , Gorton Lo
Published: May 2013

Improvements in current density and coulombic efficiency of a glucose oxidizing electrode were realized by a combination of pyranose dehydrogenase from Agaricus meleagris (AmPDH) with glucose dehydrogenase from Glomerella cingulata (GcGDH). The mixed enzyme electrode oxidizes glucose in several combinations at the C-1, C-2 and C-3 positions of the pyranose ring. This concerted action of enzymes increases (i) the coulombic efficiency by extracting more than 2e- per substrate molecule and (ii) the current density of the electrode when the mass-transfer of substrates becomes rate limiting. The electrodes were investigated with flow injection analysis (FIA) using different substrates under physiological conditions (pH 7.4). These investigations showed that the product of one enzyme can be used as substrate for the other enzyme and maximally 6e- can be gained from the oxidation of one glucose molecule using mixed enzyme electrode AmPDH/GcGDH/Os-polymer. We propose a bioanode for use in biofuel cells with an increased current density and coulombic efficiency obtained by a cascade reaction catalyzed by redox enzymes with a different site-specificity for glucose.