bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial correlation in the ambient core noise field of a turbofan engine
Authors: Miles Jeffrey Hilton
Published: June 2012

An acoustic transfer function relating combustion noise and turbine exit noise in the presence of enclosed ambient core noise is investigated using a dynamic system model and an acoustic system model for the particular turbofan engine studied and for a range of operating conditions. Measurements of cross-spectra magnitude and phase between the combustor and turbine exit and auto-spectra at the turbine exit and combustor are used to show the presence of indirect and direct combustion noise over the frequency range of 0–400 Hz. The procedure used evaluates the ratio of direct to indirect combustion noise. The procedure used also evaluates the post-combustion residence time in the combustor which is a factor in the formation of thermal NOx and soot in this region. These measurements are masked by the ambient core noise sound field in this frequency range which is observable since the transducers are situated within an acoustic wavelength of one another. An ambient core noise field model based on one and two dimensional spatial correlation functions is used to replicate the spatially correlated response of the pair of transducers. The spatial correlation function increases measured attenuation due to destructive interference and masks the true attenuation of the turbine.
Quantitative acoustic analysis of the vocal repertoire of the golden rocket frog (Anomaloglossus beebei)
Authors: Pettitt Beth A. , Bourne Godfrey R. , Bee Mark A.
Published: June 2012

This study describes the vocal repertoire of the Guyanan golden rocket frog, Anomaloglossus beebei, a bromeliad specialist with biparental care. Using multivariate analyses of nine call properties, as well as the occurrence of nonlinear phenomena, three signal types were distinguished—advertisement, courtship, and aggressive calls. Although all three call types were composed of a short series of rapidly repeated pulses, advertisement calls were produced at higher amplitudes and had longer pulse durations than both courtship calls and aggressive calls. Courtship calls exhibited lower dominant frequencies than both advertisement and aggressive calls, which had similar dominant frequencies. Aggressive calls had more pulses per call, had longer intervals between calls, and occasionally contained one or two introductory pulses preceding the pulsed call. Several acoustic properties predicted aspects of the signaler’s body size and condition. Our study demonstrates the reliability of human observers to differentiate the multiple call types of A. beebei based on hearing calls and observing the social context in which they are produced under field conditions.
Clutter from non-discrete seabed structures
Authors: Holland Charles W. , Ellis Dale D.
Published: June 2012

Clutter, or discrete target-like returns, is the most significant problem in the employment of active sonar. It is well understood that discrete objects, which are of the same spatial scale as the target and which possess a significant impedance contrast to the surrounding ocean, can lead to clutter. Here a somewhat counter-intuitive result is shown: that discrete target-like returns can occur from slowly varying seabed structures. The range dependence of the seabed can be weak and smooth—due to changes in layer thicknesses, sound speed, or both. Thus, this clutter mechanism may be a viable hypothesis for areas in which seabed clutter has been observed, but no discrete features, buried or proud, could be found. By using a broadband source, the time-frequency evolution of this clutter could be a useful way to discriminate against other kinds of clutter; e.g., that due to discrete objects.
The Functions of Biological Diversity in an Age of Extinction
Authors: Naeem Shahid , Duffy J. Emmett , Zavaleta Erika
Published: June 2012

Environmental Determinism?

Earth's millions of species influence a wide range of environmental processes, including elemental cycling, the stability of ecosystems, and the goods and services they provide.

Naeem
et al.

(p.
1401
) review recent advances in the young and evolving field of biodiversity and ecosystem functioning, explore the extent to which the field is becoming a predictive science, and indicate how the field needs to develop in order to aid worldwide efforts to achieve environmental sustainability in the face of rising rates of extinction.
Spin-Orbit Echo
Authors: Sugimoto N. , Nagaosa N.
Published: June 2012

Spin Recovery

Spin-orbit interactions present in many semiconductors are used to manipulate the spin of an electron in spin-based electronics. However, this same interaction is also responsible for the loss of information contained in a spin when it changes its direction during the scattering off of impurities.
Sugimoto and Nagaosa
(p.
1413
) describe a new quantity, twisted spin, which, unlike regular spin, survives the scatterings; moreover, because the spin-orbit interaction is turned off adiabatically, the lost spin information is retrieved.
Continental-Scale Effects of Nutrient Pollution on Stream Ecosystem Functioning
Authors: Woodward Guy , Gessner Mark O. , Giller Paul S. , Gulis Vladislav , Hladyz Sally , Lecerf Antoine , Malmqvist Björn , McKie Brendan G. , Tiegs Scott D. , Cariss Helen , Dobson Mike , Elosegi Arturo , Ferreira Verónica , Graça Manuel A.S. , Fleituch Tadeusz , Lacoursière Jean O. , Nistorescu Marius , Pozo Jesús , Risnoveanu Geta , Schindler Markus , Vadineanu Angheluta , Vought Lena B.-M. , Chauvet Eric
Published: June 2012

Reading the Leaves

Excess inputs of nutrients—a type of pollution known as eutrophication—threatens biodiversity and water quality in rivers and streams.

Woodward
et al.

(p.
1438
; see the Perspective by

Palmer and Febria

) studied how one key ecosystem process—leaf-litter decomposition—responds to eutrophication across a large nutrient pollution gradient in 100 European streams. Leaf breakdown was stimulated by low to moderate nutrient concentrations but was inhibited at high rates of nutrient loading.
U-Series Dating of Paleolithic Art in 11 Caves in Spain
Authors: Pike A. W. G. , Hoffmann D. L. , García-Diez M. , Pettitt P. B. , Alcolea J. , De Balbín R. , González-Sainz C. , de las Heras C. , Lasheras J. A. , Montes R. , Zilhão J.
Published: June 2012

Dating Cave Paintings

A number of caves in Europe contain exquisite ancient art. Most of the art has been thought to be produced during the time of last glaciation by recently arrived modern humans, but dating of the art has been problematic because the art contains only minimal amounts of carbon for radiocarbon dating.

Pike
et al.

(p.
1409
; see the cover; see the Perspective by

Hellstrom

) have now obtained U-series dates on the calcite crusts that formed over the art from 11 caves in northwestern Spain. The ages from three caves are older than 35,000 years ago, and one dates to nearly 41,000 years ago. The earliest art used primarily red and was relatively formless; animal depictions appeared later. This dating is near the time of the arrival of modern humans and, because Neandertals were also present, complicates identifying the artists.
A Three-Stage Symbiosis Forms the Foundation of Seagrass Ecosystems
Authors: van der Heide Tjisse , Govers Laura L. , de Fouw Jimmy , Olff Han , van der Geest Matthijs , van Katwijk Marieke M. , Piersma Theunis , van de Koppel Johan , Silliman Brian R. , Smolders Alfons J. P. , van Gils Jan A.
Published: June 2012

Ancient Associations

Submarine seagrass meadows are critical to fisheries and coastline protection and provide feeding grounds for many endangered species, including dugongs and turtles, and serve as a nursery for coral reef fish. The persistence and maintenance of seagrass ecosystems have been mysterious, because accumulation of organic matter in the beds should rapidly lead to toxic sulphide levels in the sediment. Using a meta-analysis and a field study,van der Heideet al.(p.1432) atttribute the 100-million-year success of seagrasses to a three-stage symbiosis. Seagrass beds worldwide contain high densities of small lucinid bivalves that have symbiotic sulphide-oxidizing bacteria in their gills. This association appears to relieve any sulphide stress for seagrasses, while the lucinids and their symbionts profit from the accumulation of degradable organic matter and oxygen release from seagrass roots.
Reticulated Nanoporous Polymers by Controlled Polymerization-Induced Microphase Separation
Authors: Seo Myungeun , Hillmyer Marc A.
Published: June 2012

Porous Blocks

Porous materials are widely used in separation processes and catalysis.
Seo and Hillmyer
(p.
1422
) used block copolymers that naturally separate into domains to achieve a continuous network of pores. A chain transfer agent was used to direct the copolymerization of the two materials in situ to generate a structure with a percolating porous structure with pore sizes of a few nanometers and with tunable control over the polymer properties and extent of cross-linking.
Segregation of Axonal and Somatic Activity During Fast Network Oscillations
Authors: Dugladze Tamar , Schmitz Dietmar , Whittington Miles A. , Vida Imre , Gloveli Tengis
Published: June 2012

Controlling the Axon

The cellular mechanisms and circuits involved in gamma oscillations in the brain are not fully understood.

Dugladze
et al.

(p.
1458
) simultaneously performed patch-clamp recordings in the soma and axon of hippocampal pyramidal neurons during gamma oscillations in brain slices. Under these conditions, pyramidal cells were divided into two electrogenic compartments: the soma fired at low frequency, whereas, in the axon, ectopic action potentials were generated at higher frequencies. This functional separation was maintained by highly active axoaxonic interneurons. Powerful inhibition of the axon initial segment by these axoaxonic cells prevented the backpropagation of ectopic action potentials to the somatodendritic compartment. However, when the overall excitatory drive to pyramidal cells was high, normal orthodromic action potentials were generated.
Cancer and Telomeres—An ALTernative to Telomerase
Authors: Shay Jerry W. , Reddel Roger R. , Wright Woodring E.
Published: June 2012

Finding ways to target the alternative (ALT) telomere lengthening pathway found in some cancer cells could complement telomerase inhibitors currently in clinical trials.
All Packed Up and Ready to Go
Authors: Jacob Yannick , Martienssen Rob
Published: June 2012

Gene silencing depends on the higher-order structure of heterochromatin as well as repressive biochemical modifications.
UNsustainable?
Authors: Nobre Carlos A.
Published: June 2012

Next week, thousands of participants from governments, the private sector, nongovernmental organizations, and other stakeholders will gather in Brazil at a United Nations (UN) summit to secure political and economic commitments for sustainable development and to address new and emerging challenges. These objectives recall the 1992 UN Conference on Environment and Development, also held in Rio de Janeiro. Although political progress toward these goals has stagnated, in the intervening 20 years science and technology have moved on. The “Rio+20” meeting should be framed by these new developments.
Social Scientists Hope for Reprieve From the Senate
Authors: Mervis Jeffrey
Published: June 2012

The U.S. House of Representatives voted last month to prohibit the National Science Foundation from funding political science research and to eliminate the American Community Survey.
Seagrasses Partner With Clams to Stay Healthy
Authors: Pennisi Elizabeth
Published: June 2012

In this week's issue of
Science
, marine ecologists describe a partnership among seagrasses, lucinid clams, and bacteria living in the clams that likely keeps toxic sediments from building up and killing the seagrass.
Microbial Survey of Human Body Reveals Extensive Variation
Authors: Pennisi Elizabeth
Published: June 2012

This week, investigators from a variety of disciplines describe more than a dozen microscopic communities as part of the most thorough look ever at the microbial world on and within us.
How Do You Count the Dead?
Authors: Vogel Gretchen
Published: June 2012

Scientists agree they need better estimates for the death toll from the world's major killers. But they fiercely disagree on how to go about it.
Enhanced Bovine Herpesvirus Type 1 Neutralization by Multimerized Single-Chain Variable Antibody Fragments Regardless of Differential Glycosylation
Authors: Pasman Yfke , Nagy Eva , Kaushik Azad K.
Published: June 2012

Single-chain variable antibody fragments (scFvs) with a 2-amino-acid linker capable of multimerization as di-, tri-, or tetrabodies that neutralize bovine herpesvirus type 1 (BoHV-1)in vitrowere constructed and expressed inPichia pastoris. In contrast to the monomeric form, multimeric scFvs had a higher virus neutralization potency, as evidenced by a 2-fold increase in their ability to neutralize BoHV-1 due to avidity effects. Mass spectrum (quadrupole time of flight [Q-TOF]) analyses of multimeric scFv demonstrated extensive heterogeneity due to differential cleavage, variable glycosylation (1 to 9 mannose residues), and the incorporation of minor unidentified adducts. Regardless of the differential glycosylation patterns, the scFvs recognized non-gB or -gE target viral epitopes in the BoHV-1 envelope fraction in a Western blot and also neutralized BoHV-1 in infected Madin-Darby kidney (MDBK) cellsin vitro. Indirect evidence for the noncovalent multimerization of scFv was the presence of a major peak of multimerized scFv without a His tag (due to differential cleavage) in the Q-TOF profile, unlike monomeric scFv, which copurified with normally His-tagged scFv and recognized the target antigen. Overall, differentially glycosylated recombinant scFvs against BoHV-1 with a short linker (2 amino acids) are capable of assembly into functional multimers that confer high avidity, resulting in increased virus neutralizationin vitrocompared to that of monovalent scFv with a long (18-amino-acid) flexible linker. Overall, recombinant multimerized scFv5-2L potentially provides a high-potency therapeutic and immunodiagnostic reagent against BoHV-1, which is suitable for passive immunization and topical application.
IL23R(Arg381Gln) Functional Polymorphism Is Associated with Active Pulmonary Tuberculosis Severity
Authors: Ben-Selma Walid , Boukadida Jalel
Published: June 2012

The purpose of our study was to investigate the association between a functional single nucleotide polymorphism (SNP) in the interleukin-23 receptor gene (IL23R; rs11209026, 1142 Gwild type→ Areduced function, Arg381Gln) and disease severity outcome in pulmonary tuberculosis (TB) in the Tunisian population. SNP was investigated in a population of 168 patients with active pulmonary TB (cases were stratified into patients with minimal/moderate lung involvement, i.e., patients with minimal/moderate disease [Pmd], and patients with extensive lung involvement, i.e., patients with active disease [Pad]) and 150 healthy subjects. Genotype analyses were carried out using the PCR-restriction fragment length polymorphism method. We have found that theIL23Rreduced-function allele 1142A and genotypes AA and AG were overrepresented, especially in the Pad subgroup compared with the control group (51% versus 18% [P= 10−8], 33% versus 5% [P= 10−8], and 36% versus 26% [P= 5 × 10−3], respectively). Additionally, comparison of the Pad and the Pmd groups showed that the A allele and AA genotype seemed to be associated with 2.79-fold (P= 4 × 10−5) and 7.74-fold (P= 10−5) increased risks of TB with minimal/moderate lung involvement, respectively. Our results demonstrate that the reduced-function polymorphism 1142G → A encoded byIL23Rinfluences the outcome of disease severity of active pulmonary TB in Tunisian patients.
Evaluation of Recombinant Proteins of Burkholderia mallei for Serodiagnosis of Glanders
Authors: Pal Vijai , Kumar Subodh , Malik Praveen , Rai Ganga Prasad
Published: June 2012

Glanders is a contagious disease caused by the Gram-negative bacillusBurkholderia mallei. The number of equine glanders outbreaks has increased steadily during the last decade. The disease must be reported to the Office International des Epizooties, Paris, France. Glanders serodiagnosis is hampered by the considerable number of false positives and negatives of the internationally prescribed tests. The major problem leading to the low sensitivity and specificity of the complement fixation test (CFT) and enzyme-linked immunosorbent assay (ELISA) has been linked to the test antigens currently used, i.e., crude preparations of whole cells. False-positive results obtained from other diagnostic tests utilizing crude antigens lead to financial losses to animal owners, and false-negative results can turn a risk into a possible threat. In this study, we report on the identification of diagnostic targets using bioinformatics tools for serodiagnosis of glanders. The identified gene sequences were cloned and expressed as recombinant proteins. The purified recombinant proteins ofB. malleiwere used in an indirect ELISA format for serodiagnosis of glanders. Two recombinant proteins, 0375H and 0375TH, exhibited 100% sensitivity and specificity for glanders diagnosis. The proteins also did not cross-react with sera from patients with the closely related disease melioidosis. The results of this investigation highlight the potential of recombinant 0375H and 0375TH proteins in specific and sensitive diagnosis of glanders.
Field Application of Serodiagnostics To Identify Elephants with Tuberculosis prior to Case Confirmation by Culture
Authors: Lyashchenko Konstantin P. , Greenwald Rena , Esfandiari Javan , Mikota Susan , Miller Michele , Moller Torsten , Vogelnest Larry , Gairhe Kamal P. , Robbe-Austerman Suelee , Gai Jackie , Waters W. Ray
Published: June 2012

Three serologic methods for antibody detection in elephant tuberculosis (TB), the multiantigen print immunoassay (MAPIA), ElephantTB STAT-PAK kit, and DPP VetTB test, were evaluated using serial serum samples from 14 captive elephants infected withMycobacterium tuberculosisin 5 countries. In all cases, serological testing was performed prior to the diagnosis of TB by mycobacterial culture of trunk wash or tissue samples collected at necropsy. All elephants produced antibody responses toM. tuberculosisantigens, with 13/14 recognizing ESAT-6 and/or CFP10 proteins. The findings supported the high serodiagnostic test accuracy in detecting infections months to years beforeM. tuberculosiscould be isolated from elephants. The MAPIA and/or DPP VetTB assay demonstrated the potential for monitoring antimycobacterial therapy and predicting TB relapse in treated elephants when continuously used in the posttreatment period. History of exposure to TB and past treatment information should be taken into consideration for proper interpretation of the antibody test results. Data suggest that the more frequent trunk wash culture testing of seropositive elephants may enhance the efficiency of the TB diagnostic algorithm, leading to earlier treatment with improved outcomes.
Evaluation of the Efficacy of an Attenuated Live Vaccine against Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus in Young Pigs
Authors: Leng Xue , Li Zhenguang , Xia Mingqi , He Yanliang , Wu Hua
Published: June 2012

Highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) is characterized by high fever and high mortality in pigs of all ages and has severely affected the pork industry of China in the last few years. An attenuated HP-PRRSV strain, TJM, was obtained by passaging HP-PRRSV strain TJ on MARC-145 cells for 92 passages. Porcine reproductive and respiratory syndrome virus (PRRSV)- and antibody-free pigs were inoculated intramuscularly with TJM (105.050% tissue culture infective doses [TCID50]) and challenged at 28, 60, 120, and 180 days postimmunization (dpi). The results showed that 5/5, 5/5, 5/5, and 4/5 immunized pigs were protected from the lethal challenge and did not develop fever and clinical diseases at each challenge, respectively. Compared to control pigs, vaccinated pigs showed much milder pathological lesions and gained significantly more weight (P< 0.01). Sequence analysis of different passages of strain TJ showed that the attenuation resulted in a deletion of a continuous 120 amino acids (aa), in addition to the discontinuous 30-aa deletion in the nsp2 region. The analysis also demonstrated that the 120-aa deletion was genetically stablein vivo. These results suggested that HP-PRRSV TJM was efficacious against a lethal challenge with a virulent HP-PRRSV strain, and effective protection could last at least 4 months. Therefore, strain TJM is a good candidate for an efficacious modified live virus vaccine as well as a useful molecular marker vaccine against HP-PRRSV.
Increased Antibody Affinity Confers Broad
In Vitro
Protection against Escape Mutants of Severe Acute Respiratory Syndrome Coronavirus
Authors: Rani Mridula , Bolles Meagan , Donaldson Eric F. , Van Blarcom Thomas , Baric Ralph , Iverson Brent , Georgiou George
Published: June 2012

Even though the effect of antibody affinity on neutralization potency is well documented, surprisingly, its impact on neutralization breadth and escape has not been systematically determined. Here, random mutagenesis and DNA shuffling of the single-chain variable fragment of the neutralizing antibody 80R followed by bacterial display screening using anchored periplasmic expression (APEx) were used to generate a number of higher-affinity variants of the severe acute respiratory syndrome coronavirus (SARS-CoV)-neutralizing antibody 80R with equilibrium dissociation constants (

K
D

) as low as 37 pM, a >270-fold improvement relative to that of the parental 80R single-chain variable fragment (scFv). As expected, antigen affinity was shown to correlate directly with neutralization potency toward the icUrbani strain of SARS-CoV. Additionally, the highest-affinity antibody fragment displayed 10-fold-increased broad neutralization
in vitro
and completely protected against several SARS-CoV strains containing substitutions associated with antibody escape. Importantly, higher affinity also led to the suppression of viral escape mutants
in vitro
. Escape from the highest-affinity variant required reduced selective pressure and multiple substitutions in the binding epitope. Collectively, these results support the hypothesis that engineered antibodies with picomolar dissociation constants for a neutralizing epitope can confer escape-resistant protection.
Safer, Silencing-Resistant Lentiviral Vectors: Optimization of the Ubiquitous Chromatin-Opening Element through Elimination of Aberrant Splicing
Authors: Knight Sean , Zhang Fang , Mueller-Kuller Uta , Bokhoven Marieke , Gupta Abhinav , Broughton Thomas , Sha Sha , Antoniou Michael N. , Brendel Christian , Grez Manuel , Thrasher Adrian J. , Collins Mary , Takeuchi Yasuhiro
Published: June 2012

Gammaretroviral and lentiviral vectors have been used successfully in several clinical gene therapy trials, although powerful enhancer elements have caused insertional mutagenesis and clonal dysregulation. Self-inactivating vectors with internal heterologous regulatory elements have been developed as potentially safer and more effective alternatives. Lentiviral vectors containing a ubiquitous chromatin opening element from the human
HNRPA2B1-CBX3
locus (A2UCOE), which allows position-independent, long-term transgene expression, are particularly promising. In a recently described assay, aberrantly spliced mRNA transcripts initiated in the vector A2UCOE sequence were found to lead to upregulation of growth hormone receptor gene (
Ghr
) expression in transduced murine Bcl-15 cells. Aberrant hybrid mRNA species formed between A2UCOE and a number of other cellular genes were also detected in transduced human PLB-985 myelomonocytic cells. Modification of the A2UCOE by mutation or deletion of recognized and potential cryptic splice donor sites was able to abrogate these splicing events and hybrid mRNA formation in Bcl-15 cells. This modification did not compromise A2UCOE regulatory activity in terms of resistance to CpG methylation and gene silencing in murine P19 embryonic carcinoma cells. These refined A2UCOE regulatory elements are likely to improve intrinsic biosafety and may be particularly useful for a number of clinical applications where robust gene expression is desirable.
Live-Attenuated Lentivirus Immunization Modulates Innate Immunity and Inflammation while Protecting Rhesus Macaques from Vaginal Simian Immunodeficiency Virus Challenge
Authors: Genescà Meritxell , Ma Zhong-Min , Wang Yichuan , Assaf Basel , Qureshi Huma , Fritts Linda , Huang Ying , McChesney Michael B. , Miller Christopher J.
Published: June 2012

Immunization with attenuated lentiviruses is the only reliable method of protecting rhesus macaques (RM) from vaginal challenge with pathogenic simian immunodeficiency virus (SIV). CD8
+
lymphocyte depletion prior to SIVmac239 vaginal challenge demonstrated that a modest, Gag-specific CD8
+
T cell response induced by immunization with simian-human immunodeficiency virus 89.6 (SHIV89.6) protects RM. Although CD8
+
T cells are required for protection, there is no anamnestic expansion of SIV-specific CD8
+
T cells in any tissues except the vagina after challenge. Further, SHIV immunization increased the number of viral target cells in the vagina and cervix, suggesting that the ratio of target cells to antiviral CD8
+
T cells was not a determinant of protection. We hypothesized that persistent replication of the attenuated vaccine virus modulates inflammatory responses and limits T cell activation and expansion by inducing immunoregulatory T cell populations. We found that attenuated SHIV infection decreased the number of circulating plasmacytoid dendritic cells, suppressed T cell activation, decreased mRNA levels of proinflammatory mediators, and increased mRNA levels of immunoregulatory molecules. Three days after SIV vaginal challenge, SHIV-immunized RM had significantly more T regulatory cells in the vagina than the unimmunized RM. By day 14 postchallenge, immune activation and inflammation were characteristic of unimmunized RM but were minimal in SHIV-immunized RM. Thus, a modest vaccine-induced CD8
+
T cell response in the context of immunoregulatory suppression of T cell activation may protect against vaginal HIV transmission.
Detailed Mapping of Determinants within the Porcine Endogenous Retrovirus Envelope Surface Unit Identifies Critical Residues for Human Cell Infection within the Proline-Rich Region
Authors: Argaw Takele , Wilson Carolyn A.
Published: June 2012

Replication-competent porcine endogenous retroviruses (PERVs) are either human cell tropic (PERV-A and PERV-B) or non-human cell tropic (PERV-C). We previously demonstrated that PERV
in vitro
cell tropism is modulated by 2 residues within the C terminus of SU and that the PERV receptor binding domain (RBD) extends beyond the variable regions A and B (VRA and VRB, respectively), to include the proline rich-region (PRR) of SU (M. Gemeniano et al., Virology 346:108–117, 2000; T. Argaw et al., J. Virol. 82:7483–7489, 2008). The present study aimed to identify the specific elements within the PERV RBD that interact with the C-terminal elements of SU to facilitate human cell infection. We constructed a series of chimeric and mutated envelopes between PERV-A and PERV-C and using pseudotyped retroviral vectors to map the human cell tropism-determining sequences within the PERV RBD. We show that the PRR from PERV-A is both necessary and sufficient to allow human cell infection when substituted into the homologous region of the PERV-C envelope carrying two C-terminal amino acid substitutions shown to influence human cell tropism, Q374R and I412V (PERV-Crv). Furthermore, substitution of a single amino acid residue in the PRR of the non-human-tropic PERV-Crv envelope allows vectors carrying this envelope to infect human cells. Receptor interference assays showed that these modified PERV-C envelopes do not bind either of the human PERV-A receptors, suggesting the presence of a distinct human PERV-C receptor. Finally, vectors carrying these modified PERV-C envelopes infect primary human endothelial cells, a cell type likely to be exposed to PERV in clinical use of certain porcine xenotransplantation products.
HMGB1 Protein Binds to Influenza Virus Nucleoprotein and Promotes Viral Replication
Authors: Moisy Dorothée , Avilov Sergiy V. , Jacob Yves , Laoide Brid M. , Ge Xingyi , Baudin Florence , Naffakh Nadia , Jestin Jean-Luc
Published: June 2012

Influenza virus has evolved replication strategies that hijack host cell pathways. To uncover interactions between viral macromolecules and host proteins, we applied a phage display strategy. A library of human cDNA expression products displayed on filamentous phages was submitted to affinity selection for influenza viral ribonucleoproteins (vRNPs). High-mobility-group box (HMGB) proteins were found to bind to the nucleoprotein (NP) component of vRNPs. HMGB1 and HMGB2 bind directly to the purified NP in the absence of viral RNA, and the HMG box A domain is sufficient to bind the NP. We show that HMGB1 associates with the viral NP in the nuclei of infected cells, promotes viral growth, and enhances the activity of the viral polymerase. The presence of a functional HMGB1 DNA-binding site is required to enhance influenza virus replication. Glycyrrhizin, which reduces HMGB1 binding to DNA, inhibits influenza virus polymerase activity. Our data show that the HMGB1 protein can play a significant role in intranuclear replication of influenza viruses, thus extending previous findings on the bornavirus and on a number of DNA viruses.
Bats Worldwide Carry Hepatitis E Virus-Related Viruses That Form a Putative Novel Genus within the Family Hepeviridae
Authors: Drexler Jan Felix , Seelen Annika , Corman Victor Max , Fumie Tateno Adriana , Cottontail Veronika , Melim Zerbinati Rodrigo , Gloza-Rausch Florian , Klose Stefan M. , Adu-Sarkodie Yaw , Oppong Samuel K. , Kalko Elisabeth K. V. , Osterman Andreas , Rasche Andrea , Adam Alexander , Müller Marcel A. , Ulrich Rainer G. , Leroy Eric M. , Lukashev Alexander N. , Drosten Christian
Published: June 2012

Hepatitis E virus (HEV) is one of the most common causes of acute hepatitis in tropical and temperate climates. Tropical genotypes 1 and 2 are associated with food-borne and waterborne transmission. Zoonotic reservoirs (mainly pigs, wild boar, and deer) are considered for genotypes 3 and 4, which exist in temperate climates. In view of the association of several zoonotic viruses with bats, we analyzed 3,869 bat specimens from 85 different species and from five continents for hepevirus RNA. HEVs were detected in African, Central American, and European bats, forming a novel phylogenetic clade in the familyHepeviridae. Bat hepeviruses were highly diversified and comparable to human HEV in sequence variation. No evidence for the transmission of bat hepeviruses to humans was found in over 90,000 human blood donations and individual patient sera. Full-genome analysis of one representative virus confirmed formal classification within the familyHepeviridae. Sequence- and distance-based taxonomic evaluations suggested that bat hepeviruses constitute a distinct genus within the familyHepeviridaeand that at least three other genera comprising human, rodent, and avian hepeviruses can be designated. This may imply that hepeviruses invaded mammalian hosts nonrecently and underwent speciation according to their host restrictions. Human HEV-related viruses in farmed and peridomestic animals might represent secondary acquisitions of human viruses, rather than animal precursors causally involved in the evolution of human HEV.
Andes Virus Infection of Lymphatic Endothelial Cells Causes Giant Cell and Enhanced Permeability Responses That Are Rapamycin and Vascular Endothelial Growth Factor C Sensitive
Authors: Gavrilovskaya Irina N. , Gorbunova Elena E. , Mackow Erich R.
Published: June 2012

Hantaviruses primarily infect endothelial cells (ECs) and nonlytically cause vascular changes that result in hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). Acute pulmonary edema during HPS may be caused by capillary leakage and failure of lymphatic vessels to clear fluids. Uniquely regulated lymphatic ECs (LECs) control fluid clearance, although roles for lymphatics in hantavirus disease remain undetermined. Here we report that hantaviruses productively infect LECs and that LEC infection by HPS causing Andes virus (ANDV) and HFRS causing Hantaan virus (HTNV) are inhibited by α
v
β
3
integrin antibodies. Although α
v
β
3
integrins regulate permeabilizing responses directed by vascular endothelial growth factor receptor 2 (VEGFR2), we found that only ANDV-infected LECs were hyperpermeabilized by the addition of VEGF-A. However, VEGF-C activation of LEC-specific VEGFR3 receptors blocked ANDV- and VEGF-A-induced LEC permeability. In addition, ∼75% of ANDV-infected LECs became viable mononuclear giant cells, >4 times larger than normal, in response to VEGF-A. Giant cells are associated with constitutive mammalian target of rapamycin (mTOR) activation, and we found that both giant LECs and LEC permeability were sensitive to rapamycin, an mTOR inhibitor, and VEGF-C addition. These findings indicate that ANDV uniquely alters VEGFR2-mTOR signaling responses of LECs, resulting in giant cell and LEC permeability responses. This suggests that ANDV infection alters normal LEC and lymphatic vessel functions which may contribute to edematous fluid accumulation during HPS. Moreover, the ability of VEGF-C and rapamycin to normalize LEC responses suggests a potential therapeutic approach for reducing pulmonary edema and the severity of HPS following ANDV infection.
Sequential Evolution and Escape from Neutralization of Simian Immunodeficiency Virus SIVsmE660 Clones in Rhesus Macaques
Authors: Wu Fan , Ourmanov Ilnour , Kuwata Takeo , Goeken Robert , Brown Charles R. , Buckler-White Alicia , Iyengar Ranjini , Plishka Ronald , Aoki Scott T. , Hirsch Vanessa M.
Published: June 2012

Simian immunodeficiency virus (SIV) infection of rhesus macaques has become an important surrogate model for evaluating HIV vaccine strategies. The extreme resistance to neutralizing antibody (NAb) of many commonly used strains, such as SIVmac251/239 and SIVsmE543-3, limits their potential relevance for evaluating the role of NAb in vaccine protection. In contrast, SIVsmE660 is an uncloned virus that appears to be more sensitive to neutralizing antibody. To evaluate the role of NAb in this model, we generated full-length neutralization-sensitive molecular clones of SIVsmE660 and evaluated two of these by intravenous inoculation of rhesus macaques. All animals became infected and maintained persistent viremia that was accompanied by a decline in memory CD4
+
T cells in blood and bronchoalveolar lavage fluid. High titers of autologous NAb developed by 4 weeks postinoculation but were not associated with control of viremia, and neutralization escape variants were detected concurrently with the generation of NAb. Neutralization escape was associated with substitutions and insertion/deletion polymorphisms in the V1 and V4 domains of envelope. Analysis of representative variants revealed that escape variants also induced NAbs within a few weeks of their appearance in plasma, in a pattern that is reminiscent of the escape of human immunodeficiency virus type 1 (HIV-1) isolates in humans. Although early variants maintained a neutralization-sensitive phenotype, viruses obtained later in infection were significantly less sensitive to neutralization than the parental viruses. These results indicate that NAbs exert selective pressure that drives the evolution of the SIV envelope and that this model will be useful for evaluating the role of NAb in vaccine-mediated protection.
Diversity and Relationships of Cocirculating Modern Human Rotaviruses Revealed Using Large-Scale Comparative Genomics
Authors: McDonald Sarah M. , McKell Allison O. , Rippinger Christine M. , McAllen John K. , Akopov Asmik , Kirkness Ewen F. , Payne Daniel C. , Edwards Kathryn M. , Chappell James D. , Patton John T.
Published: June 2012

Group A rotaviruses (RVs) are 11-segmented, double-stranded RNA viruses and are primary causes of gastroenteritis in young children. Despite their medical relevance, the genetic diversity of modern human RVs is poorly understood, and the impact of vaccine use on circulating strains remains unknown. In this study, we report the complete genome sequence analysis of 58 RVs isolated from children with severe diarrhea and/or vomiting at Vanderbilt University Medical Center (VUMC) in Nashville, TN, during the years spanning community vaccine implementation (2005 to 2009). The RVs analyzed include 36 G1P[8], 18 G3P[8], and 4 G12P[8] Wa-like genogroup 1 strains with VP6-VP1-VP2-VP3-NSP1-NSP2-NSP3-NSP4-NSP5/6 genotype constellations of I1-R1-C1-M1-A1-N1-T1-E1-H1. By constructing phylogenetic trees, we identified 2 to 5 subgenotype alleles for each gene. The results show evidence of intragenogroup gene reassortment among the cocirculating strains. However, several isolates from different seasons maintained identical allele constellations, consistent with the notion that certain RV clades persisted in the community. By comparing the genes of VUMC RVs to those of other archival and contemporary RV strains for which sequences are available, we defined phylogenetic lineages and verified that the diversity of the strains analyzed in this study reflects that seen in other regions of the world. Importantly, the VP4 and VP7 proteins encoded by VUMC RVs and other contemporary strains show amino acid changes in or near neutralization domains, which might reflect antigenic drift of the virus. Thus, this large-scale, comparative genomic study of modern human RVs provides significant insight into how this pathogen evolves during its spread in the community.
COMPLEX DYNAMICS OF THE ELEMENTARY CELLULAR AUTOMATON RULE 54
Authors: GUAN JUNBIAO
Published: June 2012

This work deals with a discussion of complex dynamics of the elementary cellular automaton rule 54. An equation which shows some degree of self-similarity is obtained. It is shown that rule 54 exhibits Bernoulli shift and is topologically mixing on its closed invariant subsystem. Finally, many complex Bernoulli shifts are explored for the finite symbolic sequences with periodic boundary conditions.
IMPACT OF SUPERSYMMETRY ON EMERGENT GEOMETRY IN YANG–MILLS MATRIX MODELS II
Authors: YDRI BADIS
Published: June 2012

We present a study of D = 4 supersymmetric Yang–Mills matrix models with SO(3) mass terms based on the Monte Carlo method. In the bosonic models we show the existence of an exotic first-/second-order transition from a phase with a well defined background geometry (the fuzzy sphere) to a phase with commuting matrices with no geometry in the sense of Connes. At the transition point the sphere expands abruptly to infinite size then it evaporates as we increase the temperature (the gauge coupling constant). The transition looks first-order due to the discontinuity in the action whereas it looks second-order due to the divergent peak in the specific heat. The fuzzy sphere is stable for the supersymmetric models in the sense that the bosonic phase transition is turned into a very slow crossover transition. The transition point is found to scale to zero with N. We conjecture that the transition from the background sphere to the phase of commuting matrices is associated with spontaneous supersymmetry breaking. The eigenvalues distribution of any of the bosonic matrices in the matrix phase is found to be given by a nonpolynomial law obtained from the fact that the joint probability distribution of the four matrices is uniform inside a solid ball with radius R. The eigenvalues of the gauge field on the background geometry are also found to be distributed according to this nonpolynomial law.
SINGLE CHARGED TOP-PION PRODUCTION AT THE LHeC IN γp COLLISION
Authors: BI YAN-PING , LIU YAO-BEI , CAO JUN
Published: June 2012

In the context of the topcolor-assisted technicolor (TC2) model, we study the productions of the charged top-pion associated with single top, charm or bottom quark in γp collision, which proceed via the subprocesses [Formula: see text], [Formula: see text] and [Formula: see text]. With the electron energy Ee = 50 GeV and photon energy Ep = 7 TeV , we find that the production rates can reach the level of several tens fb for [Formula: see text] production, and hundreds of fb for [Formula: see text] (or [Formula: see text]) productions. So one can expect that enough signals could be produced in the large part of the parameter space. Furthermore, these flavor-changing (FC) productions are extremely suppressed in the standard model (SM). With a large number of events and the clean background, the charged top-pion should be observable at the Large Hadron electron Collider (LHeC) based γp colliders. Thus, such charged top-pion production processes may offer a useful way to test the TC2 model.
WARPED SELF-GRAVITATING U(1) GAUGE COSMIC STRINGS IN 5D
Authors: SLAGTER REINOUD JAN , MASSELINK DERK
Published: June 2012

We present the "classical" Nielsen–Olesen vortex solution on a warped 5-dimensional spacetime, where we solved the effective 4-dimensional equations from the 5-dimensional equations together with the junction and boundary conditions. 4-dimensional cosmic strings show some serious problems concerning the mechanism of string smoothing related to the string mass per unit length, Gμ ≤ 10-6. Moreover, there is no observational evidence of axially symmetric lensing effect caused by cosmic strings. Also super-massive cosmic strings (Gμ ≳ 1), predicted by superstring theory, possess some problems. They are studied because the universe may have undergone phase transitions at scales much higher than the GUT scale. But Gμ ≳ 1 is far above observational bounds, so one needs an inflationary scenario to smooth them out. Further, it is believed that these super-massive strings never extended to macroscopic size. Brane world models could overcome these problems. Gμ could be warped down to GUT scale, even if its value was at the Planck scale.

In our warped cosmic string model, where the string mass per unit length in the bulk can be of order of the Planck scale, we find that the 4-dimensional brane spacetime is exponential warped down. Moreover, asymptotically the induced 4-dimensional spacetime does not show conical behavior. So there is no angle deficit compared to its value in the bulk and the spacetime seems to be unphysical, at least under fairly weak assumptions on the stress–energy tensor and without a positive brane tension. The results are confirmed by numerical solutions of the field equations.
NATURAL CUBIC SPLINE COALESCENCE HIDDEN VARIABLE FRACTAL INTERPOLATION SURFACES
Authors: CHAND A. K. B.
Published: June 2012

Fractal interpolation functions provide a new light to the natural deterministic approximation and modeling of complex phenomena. The present paper proposes construction of natural cubic spline coalescence hidden variable fractal interpolation surfaces (CHFISs) over a rectangular grid [Formula: see text] through the tensor product of univariate bases of cardinal natural cubic spline coalescence hidden variable fractal interpolation functions (CHFIFs). Natural cubic CHFISs are self-affine or non-self-affine in nature depending on the IFS parameters of univariate natural cubic spline CHFIFs. An upper bound of the error between the natural cubic spline blended coalescence fractal interpolant and the original function is deduced. Convergence of the natural cubic CHFIS to the original function [Formula: see text], and their derivatives are deduced. The effects free variables, constrained free variables and hidden variables are discussed on the natural cubic spline CHFIS with suitably chosen examples.
A CLASSIFICATION OF FINITE p-GROUPS WHOSE PROPER SUBGROUPS ARE OF CLASS ≤ 2 (I)
Authors: LI PUJIN
Published: June 2012

A finite group G is said to be a minimal non-[Formula: see text] group if G is not a group of class ≤ n whose proper subgroups are of class ≤ n. In this paper, we give a complete classification of p-groups H of odd order with d(H) = 2 and c(H) = 2. Based on the classification of H, minimal non-[Formula: see text]p-groups G are classified for p > 3. If p > 3, then we have G3 ≅ Cp or G3 ≅ Cp × Cp. In this paper, we deal with the case when G3 ≅ Cp. In another paper [A classification of finite p-groups whose proper subgroups are of class ≤ 2(II), accepted] we deal with the case when G3 ≅ Cp × Cp.
A GENERALIZED FIXED-POINT-FREE ACTION
Authors: GÜLOĞLU İSMAİL Ş. , ERCAN GÜLİN
Published: June 2012

In this paper we study the structure of a finite group G admitting a solvable group A of automorphisms of coprime order so that for any x ∈ CG(A) of prime order or of order 4, every conjugate of x in G is also contained in CG(A). Under this hypothesis it is proven that the subgroup [G, A] is solvable. Also an upper bound for the nilpotent height of [G, A] in terms of the number of primes dividing the order of A is obtained in the case where A is abelian.
ON THE COZERO-DIVISOR GRAPHS AND COMAXIMAL GRAPHS OF COMMUTATIVE RINGS
Authors: AFKHAMI MOJGAN , KHASHYARMANESH KAZEM
Published: June 2012

Let R be a commutative ring with non-zero identity. The cozero-divisor graph of R, denoted by Γ′(R), is a graph with vertices in W*(R), which is the set of all non-zero and non-unit elements of R, and two distinct vertices a and b in W*(R) are adjacent if and only if a ∉ bR and b ∉ aR. Also the comaximal graph is a graph with vertices all elements of R and two distinct vertices a and b are adjacent if and only if aR + bR = R. We denote the subgraph of the comaximal graph with vertex-set W*(R), by Γ2(R). In this note, we study the relations between two graphs Γ′(R) and Γ2(R). Also, we investigate the cozero-divisor graphs of idealizations of commutative rings.
METABOLIC INVOLUTIONS AND QUADRATIC RADICAL EXTENSIONS
Authors: DOLPHIN ANDREW
Published: June 2012

In this paper we characterize involutions that become metabolic over a quadratic field extension attained by adjoining a square root.
EVOLUTION OF WIKIPEDIA'S CATEGORY STRUCTURE
Authors: SUCHECKI KRZYSZTOF , SALAH ALKIM ALMILA AKDAG , GAO CHENG , SCHARNHORST ANDREA
Published: June 2012

Wikipedia, as a social phenomenon of collaborative knowledge creation, has been studied extensively from various points of view. The category system of Wikipedia, introduced in 2004, has attracted relatively little attention. In this study, we focus on the documentation of knowledge, and the transformation of this documentation with time. We take Wikipedia as a sample of knowledge in general and its category system as an aspect of the structure of this knowledge. We investigate the evolution of the category structure of the English Wikipedia from its birth in 2004 to 2008. We treat the category system as if it is a hierarchical Knowledge Organization System, capturing the changes in the distributions of the top categories. We investigate how the clustering of articles, defined by the category system, matches the direct link network between the articles and show how it changes over time. We find the Wikipedia category network mostly stable, but with occasional reorganization. We show that the clustering matches the link structure quite well, except short periods preceding the reorganizations.
STABILITY OF J*-DERIVATIONS
Authors: PARK CHOONKIL , LEE JUNG RYE , SHIN DONG YUN
Published: June 2012

Gordji et al. proved the Hyers–Ulam stability and the superstability of J*-derivations in J*-algebras for the generalized Jensen type functional equation [Formula: see text] by using direct method and by fixed point method. They only proved the theorems for the case r > 1. In this paper, we prove the Hyers–Ulam stability and the superstability of J*-derivations in J*-algebras for the case r ≠ 0 of the above generalized Jensen type functional equation by using direct method and by fixed point method under slightly different conditions.