bluuebunny/crossref_metadata_2025 huggingface dataset:
Histopathology and computed tomography of age‐associated degeneration of the equine temporohyoid joint
Authors: NAYLOR R. J. , PERKINS J. D. , ALLEN S. , ALDRED J. , DRAPER E. , PATTERSON‐KANE J. , PIERCY R. J.
Published: March 2010

Reasons for performing study:The aetiology of temporohyoid osteoarthropathy (THO) is unknown; both primary infectious and degenerative causes have been suggested.

Hypothesis:There is a significant association between increasing age and severity of temporohyoid joint degeneration. To examine the histopathology of the temporohyoid articulation in aged horses and to compare the appearance of the joint with computed tomography (CT) and peripheral quantitative CT (pQCT).

Methods:pQCT scans of the temporohyoid articulations were obtained bilaterally from 31 horses (range age 1–44 years)post mortemand images were graded by 2 blinded observers on 2 occasions for the presence of osteophytes, irregularity of the joint surface and mineralisation. Eight heads had been examined previously by CT, with the images similarly graded for the shape and density of the proximal stylohyoid bones, bone proliferation surrounding the joint, mineralisation of the tympanohyoid cartilage and the relationship of the petrous temporal bone to the stylohyoid bone. Sixteen temporohyoid joints were then evaluated histologically.

Results:There was significant association between the mean pQCT degeneration score and age (rho = 0.75; P<0.0001), between the pQCT and CT score (rho = 0.63; P = 0.01) and between the degenerative changes identified within each temporohyoid joint within each horse (rho = 0.81; P<0.0001). Age‐associated changes included the development of a club shape by the proximal stylohyoid bone, rounding of the synostosis with the petrous temporal bone and extension of osteophytes from the petrous temporal bone to envelope the stylohyoid head and bridge the joint. In no horse was there any evidence of osteomyelitis within the petrous temporal bone, stylohyoid bone or tympanohyoid cartilage.

Conclusions:This study provides evidence that age is associated with increasing severity of degenerative changes in the equine temporohyoid joint and that similar changes are commonly found bilaterally.

Potential relevance:The changes identified appear similar, albeit milder to the changes reported in horses with THO, suggesting that degenerative, rather than infectious causes may underlie the aetiology of THO. Future work should be directed at examining the histopathology of clinical THO cases.
On Cox rings of K3 surfaces
Authors: Artebani Michela , Hausen Jürgen , Laface Antonio
Published: March 2010

We study Cox rings of K3 surfaces. A first result is that a K3 surface has a finitely generated Cox ring if and only if its effective cone is rational polyhedral. Moreover, we investigate degrees of generators and relations for Cox rings of K3 surfaces of Picard number two, and explicitly compute the Cox rings of generic K3 surfaces with a non-symplectic involution that have Picard number 2 to 5 or occur as double covers of del Pezzo surfaces.
Highly piezoelectric AlN thin films grown on amorphous, insulating substrates
Authors: Artieda Alvaro , Sandu Cosmin , Muralt Paul
Published: March 2010

AlN thin films were grown by reactive sputtering on amorphous SiO2 thin films. Film texture, x-ray rocking curve width, mechanical stress, and the clamped piezoelectric constant d33,f were studied as a function of rf bias power and substrate roughness. A high d33,f of 5.0 pm/V was achieved at low substrate roughness and low mechanical AlN film stress. Increasing substrate roughness and stress leads to a deterioration of d33,f, which is correlated with a higher density of opposite polarity grains detected by piezoresponse force microscopy. Extrapolating to 100% uniform polarity, a d33,f of 6.1 pm/V is derived as highest possible value, probably corresponding to the d33,f=e33/c33E of perfect single crystalline material. Growth mechanisms are proposed and underlined by high resolution transmission electron microscopy to explain the observed phenomena.
Efficient Annealing of Radiation Damage Near Grain Boundaries via Interstitial Emission
Authors: Bai Xian-Ming , Voter Arthur F. , Hoagland Richard G. , Nastasi Michael , Uberuaga Blas P.
Published: March 2010

Preventing Radiation Damage

Inside a nuclear reactor, long-term exposure to radiation causes structural damage and limits the lifetimes of the reactor components.

Bai
et al.

(p.
1631
; see the Perspective by

Ackland

) now show, using three simulation methods able to cover a wide range of time and length scales, that grain boundaries in copper can act as sinks for radiation-induced defects. The boundaries are able to store up defects, in the form of interstitials, which subsequently annihilate with vacancies in the bulk. This recombination mechanism has a lower energy barrier than the bulk equivalent, and so provides a lower-cost route for the copper to self-heal.
Nonepitaxial Growth of Hybrid Core-Shell Nanostructures with Large Lattice Mismatches
Authors: Zhang Jiatao , Tang Yun , Lee Kwan , Ouyang Min
Published: March 2010

Perfect Mismatch

Heteroepitaxy, or the overgrowth of one crystalline material onto a second crystalline material, is a key fabrication method for making thin films and nanoparticles. But if the lattice mismatch between the two materials is too large or messy, fractured interfaces result.

Zhang
et al.

(p.
1634
) describe a synthesis strategy to obtain spherical nanoparticles with a core-shell architecture that does not depend on heteroepitaxy. Silver was deposited and converted to various semiconductors through a series of chemical transformations to yield structurally perfect single-crystal semiconductor shells on a gold core, despite mismatches approaching 50%.
Loss of Rap1 Induces Telomere Recombination in the Absence of NHEJ or a DNA Damage Signal
Authors: Sfeir Agnel , Kabir Shaheen , van Overbeek Megan , Celli Giulia B. , de Lange Titia
Published: March 2010

Shelterin the Ends

The ends of linear chromosomes suffer two problems: They cannot be replicated to their termini, resulting in loss of terminal sequences; and they can be mistakenly sensed as DNA double-strand breaks, activating DNA repair pathways that can result in serious genome derangement. These problems are solved by the addition of telomeres, repeat sequences at the ends of chromosomes, which are shielded by a protein complex called shelterin.

Sfeir
et al.

(p.
1657
) show that the mouse Rap1 protein, which is part of the shelterin complex and which binds to a second shelterin protein called TRF2, helps prevent telomeres undergoing unscheduled homologous recombination. Such recombination could threaten telomere integrity by generating sequence exchanges between sister telomeres resulting in critically shortened telomeres.
History as a Laboratory

Natural Experiments of History
Jared Diamond and James A. Robinson, Eds.

Harvard University Press, Cambridge, MA, 2010. 286 pp. $29.95, £22.95, €27. ISBN 9780674035577.
Authors: Mahoney James
Published: March 2010

To demonstrate the fruitfulness of comparative methodology, the contributors present eight case studies drawn from anthropology, archaeology, history, political science, and sociology.
A Green or a Prickly World?
Authors: Hambäck Peter A.
Published: March 2010

The evolution of plant traits shapes complex interactions with herbivores and their predators.
For Solutions That Will Work
The Essential Engineer
Why Science Alone Will Not Solve Our Global Problems

by Henry Petroski

Knopf, New York, 2010. 286 pp. $26.95, C$33, £17.89. ISBN 9780307272454.
Authors: Nye David E.
Published: March 2010

Petroski argues that engineers will play an essential role in solving the pressing problems humans currently face.
Health Bill Backs Evidence-Based Medicine, New Drug Studies
Authors: Kaiser Jocelyn
Published: March 2010

Buried within the 2400 pages of the landmark health care reform bill passed by the House of Representatives this week and signed by President Barack Obama are several provisions that touch on clinical research.
Ancient DNA From Siberia Fingers a Possible New Human Lineage
Authors: Balter Michael
Published: March 2010

Evolutionary geneticists analyzing a sample of a 40,000-year-old human finger bone from a Siberian cave have apparently identified a new lineage of ancient human, the first time that this has been done using ancient DNA and not fossil bones.
Science Meets Politics Off California's Coast
Authors: Stokstad Erik
Published: March 2010

Protecting marine resources involves a mix of cutting-edge science and political compromise, as California officials have learned.
Nations Move to Head Off Shortages of Rare Earths
Authors: Service Robert F.
Published: March 2010

Looming scarcities of a handful of essential elements could shake the electronics industry, unless manufacturers and mining companies develop more sources soon.
Nitrides Race Beyond the Light
Authors: Service Robert F.
Published: March 2010

Long prized for their optical properties, nitrogen-based semiconductors may take electronic devices into realms where silicon cannot tread.
Interlaboratory Comparison of Three Multiplexed Bead-Based Immunoassays for Measuring Serum Antibodies to Pneumococcal Polysaccharides
Authors: Whaley Melissa J. , Rose Charles , Martinez Joseph , Laher Gouri , Sammons Deborah L. , Smith Jerry P. , Snawder John E. , Borrow Ray , Biagini Raymond E. , Plikaytis Brian , Carlone George M. , Romero-Steiner Sandra
Published: March 2010

Serotype-specific IgG, as quantified by a standardized WHO enzyme-linked immunosorbent assay (ELISA), is a serologic end point used to evaluate pneumococcal polysaccharide-based vaccine immunogenicity. Antibodies to each vaccine polysaccharide in licensed multivalent vaccines are quantified separately; this is laborious and consumes serum. We compared three bead-based immunoassays: a commercial assay (xMAP Pneumo14; Luminex) and two in-house assays (of the Health Protection Agency [HPA] and Centers for Disease Control and Prevention [CDC]), using the WHO-recommended standard reference and reference sera (
n
= 11) from vaccinated adults. Multiple comparisons of the IgG concentrations for seven conjugate vaccine serotypes were performed by sample (percent error), serotype (equivalency testing), and laboratory (concordance correlation coefficient [CCC]). When comparing concentrations by sample, bead-based immunoassays generally yielded higher antibody concentrations than the ELISA and had higher variability for serotypes 6B, 18C, and 23F. None of the three assays met the current WHO recommendation of 75% of sera falling within 40% of the assigned antibody concentrations for all seven serotypes. When compared by serotype, the CDC and HPA tests were equivalent for five of seven serotypes, whereas the Luminex assay was equivalent for four of seven serotypes. When overall mean IgG concentrations were compared by laboratory, a higher level of agreement (CCC close to 1) was found among bead-based immunoassays than between the assays and WHO assignments. When compared to WHO assignments, the HPA assay outperformed the other assays (
r
= 0.920; CCC = 0.894; coefficient of accuracy = 0.972). Additional testing with sera from immunogenicity studies should demonstrate the applicability of this methodology for vaccine evaluation.
High Levels of β-
d
-Glucan in Immunocompromised Children with Proven Invasive Fungal Disease
Authors: Mularoni Alessandra , Furfaro Elisa , Faraci Maura , Franceschi Alessia , Mezzano Paola , Bandettini Roberto , Viscoli Claudio , Castagnola Elio
Published: March 2010

The plasmatic levels of 1,3-β-
d
-glucan (BDG) were >523 pg/ml in 4 children, 2 low-birth-weight neonates and 2 stem cell transplant recipients, with the following invasive fungal diseases (IFD) proven apart from this BDG test: 3 cases of
Candida parapsilosis
candidemias and 1 case of disseminated aspergillosis. The BDG test may be useful for identification of IFD in pediatrics.
Isolation and Phylogenetic Analysis of Sindbis Viruses from Mosquitoes in Germany
Authors: Jöst Hanna , Bialonski Alexandra , Storch Volker , Günther Stephan , Becker Norbert , Schmidt-Chanasit Jonas
Published: March 2010

A molecular survey of 16,057 mosquitoes captured in Southwest Germany during the summer of 2009 demonstrated the presence of Sindbis virus (SINV) in
Culex
spp. and
Anopheles maculipennis
sensu lato. Phylogenetic analysis of the German SINV strains linked them with Swedish SINV strains, the causative agent of Ockelbo disease in humans.
Characterization and Persistence of
Staphylococcus aureus
Strains Isolated from the Anterior Nares and Throats of Healthy Carriers in a Mexican Community
Authors: Hamdan-Partida Aída , Sainz-Espuñes Teresita , Bustos-Martínez Jaime
Published: March 2010

Healthy carriers of
Staphylococcus aureus
strains have an important role in the dissemination of this bacterium. To investigate the presence of
S. aureus
in the throat and anterior nares, samples from 1,243 healthy volunteers in a Mexican community were examined. The percentage of healthy carriers was 59.8%. Results showed that colonization of the throat occurred more frequently than that of the nares (46.5% versus 37.1%,
P
< 0.0001). Of the
S. aureus
carriers, 22.2% were exclusive nasal carriers and 38% were exclusive throat carriers. A total of 1,039 strains were isolated; 12.6% were shown to be methicillin-resistant
S. aureus
(MRSA). Of MRSA strains, 32.1% were isolated from exclusive throat carriers. Most of the strains isolated from the anterior nares and throat of the same carriers were the same or related; however, some were different. Pulsed-field gel electrophoresis (PFGE) pattern analysis of the MRSA strains isolated from the exclusive nasal carriers or exclusive throat carriers showed that they belong to different clusters. A 6-year prospective study was performed to investigate the persistence of
S. aureus
in the throat. Results showed that 13% of subjects were persistent carriers. Most of them were colonized with the same clone of
S. aureus
throughout the time of the study, and just three had different clones. Antimicrobial susceptibility testing showed that 91.1% of the strains were penicillin resistant. The presence of
mecA
and
nucA
genes (in order to confirm methicillin resistance) and of thermostable nuclease of
S. aureus
was examined. This study showed that some strains of
S. aureus
regularly colonized the throats of healthy people and could persist for years.
Mathematical Modeling of Ultradeep Sequencing Data Reveals that Acute CD8
+
T-Lymphocyte Responses Exert Strong Selective Pressure in Simian Immunodeficiency Virus-Infected Macaques but Still Fail To Clear Founder Epitope Sequences
Authors: Love Tanzy M. T. , Thurston Sally W. , Keefer Michael C. , Dewhurst Stephen , Lee Ha Youn
Published: March 2010

The prominent role of antiviral cytotoxic CD8
+
T-lymphocytes (CD8-TL) in containing the acute viremia of human and simian immunodeficiency viruses (HIV-1 and SIV) has rationalized the development of T-cell-based vaccines. However, the presence of escape mutations in the acute stage of infection has raised a concern that accelerated escape from vaccine-induced CD8-TL responses might undermine vaccine efficacy. We reanalyzed previously published data of 101,822 viral genomes of three CD8-TL epitopes, Nef
103-111
RM9 (RM9), Tat
28-35
SL8 (SL8), and Gag
181-189
CM9 (CM9), sampled by ultradeep pyrosequencing from eight macaques. Multiple epitope variants appeared during the resolution of acute viremia, followed by the predominance of a single mutant epitope. By fitting a mathematical model, we estimated the first acute escape rate as 0.36 day
−1
within escape-prone epitopes, RM9 and SL8, and the chronic escape rate as 0.014 day
−1
within the CM9 epitope. Our estimate of SIV acute escape rates was found to be comparable to very early HIV-1 escape rates. The timing of the first escape was more highly correlated with the timing of the peak CD8-TL response than with the magnitude of the CD8-TL response. The transmitted epitope decayed more than 400 times faster during the acute viral decline stage than predicted by a neutral evolution model. However, the founder epitope persisted as a minor population even at the viral set point; in contrast, the majority of acute escape epitopes were completely cleared. Our results suggest that a reservoir of SIV infection is preferentially formed by virus with the transmitted epitope.
Geographical Spread of Highly Pathogenic Avian Influenza Virus H5N1 during the 2006 Outbreak in Austria
Authors: Fink Maria , Fernández Sandra Revilla , Schobesberger Hermann , Koefer Josef
Published: March 2010

In spring 2006, highly pathogenic avian influenza virus (HPAIV) of subtype H5N1 was detected in Austria in 119 dead wild birds. The hemagglutinin cleavage site showed that the amino acid sequence motif was identical to that of the Qinghai lineage. For detailed analysis, the hemagglutinin (HA) and neuraminidase (NA) genes of 27 selected Austrian H5N1 viruses originating from different regions and wild bird species were analyzed phylogenetically, which revealed two clearly separated Austrian subclusters, both belonging to European cluster EMA-1. Subcluster
South
(
SCS
) contains virus isolates from the south of Austria as well as from Slovenia, Turkey, Egypt, and Nigeria. The second subcluster,
Northwest
(
SCN
), covered a larger group of viruses originating from different locations and wild bird species in the northern and very western parts of Austria, as well as from Bavaria and Switzerland. Surprisingly, virus isolates originating from two mute swans and one wild duck found on the north side of the Alps did not cluster with
SCN
but with
SCS
. Together with isolates from Bavarian, the Czech Republic, Italy, and Slovakia, they form a genuine subgroup, named subgroup
Bavaria
(
SGB
). This subgroup forms a link to
SCN
, indicating a spread of the virus from south to north. There has been a general assumption that the generic HPAI introduction route into Europe was from Russia to north Germany, introducing cluster EMA-2 into Europe. Interestingly, our findings support the assumption of an alternative introduction of the HPAI H5N1 virus from Turkey to central Europe, where it spread as cluster EMA-1 during the outbreak of 2006.
Rotaviruses Associate with Cellular Lipid Droplet Components To Replicate in Viroplasms, and Compounds Disrupting or Blocking Lipid Droplets Inhibit Viroplasm Formation and Viral Replication
Authors: Cheung Winsome , Gill Michael , Esposito Alessandro , Kaminski Clemens F. , Courousse Nathalie , Chwetzoff Serge , Trugnan Germain , Keshavan Nandita , Lever Andrew , Desselberger Ulrich
Published: March 2010

Rotaviruses are a major cause of acute gastroenteritis in children worldwide. Early stages of rotavirus assembly in infected cells occur in viroplasms. Confocal microscopy demonstrated that viroplasms associate with lipids and proteins (perilipin A, ADRP) characteristic of lipid droplets (LDs). LD-associated proteins were also found to colocalize with viroplasms containing a rotaviral NSP5-enhanced green fluorescent protein (EGFP) fusion protein and with viroplasm-like structures in uninfected cells coexpressing viral NSP2 and NSP5. Close spatial proximity of NSP5-EGFP and cellular perilipin A was confirmed by fluorescence resonance energy transfer. Viroplasms appear to recruit LD components during the time course of rotavirus infection. NSP5-specific siRNA blocked association of perilipin A with NSP5 in viroplasms. Viral double-stranded RNA (dsRNA), NSP5, and perilipin A cosedimented in low-density gradient fractions of rotavirus-infected cell extracts. Chemical compounds interfering with LD formation (isoproterenol plus isobutylmethylxanthine; triacsin C) decreased the number of viroplasms and inhibited dsRNA replication and the production of infectious progeny virus; this effect correlated with significant protection of cells from virus-associated cytopathicity. Rotaviruses represent a genus of another virus family utilizing LD components for replication, pointing at novel therapeutic targets for these pathogens.
Interleukin-15 Is Critical in the Pathogenesis of Influenza A Virus-Induced Acute Lung Injury
Authors: Nakamura Risa , Maeda Naoyoshi , Shibata Kensuke , Yamada Hisakata , Kase Tetsuo , Yoshikai Yasunobu
Published: March 2010

Highly pathogenic influenza A viruses cause acute severe pneumonia to which the occurrence of “cytokine storm” has been proposed to contribute. Here we show that interleukin-15 (IL-15) knockout (KO) mice exhibited reduced mortality after infection with influenza virus A/FM/1/47 (H1N1, a mouse-adapted strain) albeit the viral titers of these mice showed no difference from those of control mice. There were significantly fewer antigen-specific CD44
+
CD8
+
T cells in the lungs of infected IL-15 KO mice, and adoptive transfer of the CD8
+
T cells caused reduced survival of IL-15 KO mice following influenza virus infection. Mice deficient in β
2
-microglobulin by gene targeting and those depleted of CD8
+
T cells by
in vivo
administration of anti-CD8 monoclonal antibody displayed a reduced mortality rate after infection. These results indicate that IL-15-dependent CD8
+
T cells are at least partly responsible for the pathogenesis of acute pneumonia caused by influenza A virus.
Enhanced Anti-HIV Functional Activity Associated with Gag-Specific CD8 T-Cell Responses
Authors: Julg B. , Williams K. L. , Reddy S. , Bishop K. , Qi Y. , Carrington M. , Goulder P. J. , Ndung'u T. , Walker B. D.
Published: March 2010

Effective HIV-specific T-cell immunity requires the ability to inhibit virus replication in the infected host, but the functional characteristics of cells able to mediate this effect are not well defined. Since Gag-specific CD8 T cells have repeatedly been associated with lower viremia, we examined the influence of Gag specificity on the ability of unstimulated CD8 T cells from chronically infected persons to inhibit virus replication in autologous CD4 T cells. Persons with broad (≥6;
n
= 13) or narrow (≤1;
n
= 13) Gag-specific responses, as assessed by gamma interferon enzyme-linked immunospot assay, were selected from 288 highly active antiretroviral therapy (HAART)-naive HIV-1 clade C-infected South Africans, matching groups for total magnitude of HIV-specific CD8 T-cell responses and CD4 T-cell counts. CD8 T cells from high Gag responders suppressed
in vitro
replication of a heterologous HIV strain in autologous CD4 cells more potently than did those from low Gag responders (
P
< 0.003) and were associated with lower viral loads
in vivo
(
P
< 0.002). As previously shown in subjects with low viremia, CD8 T cells from high Gag responders exhibited a more polyfunctional cytokine profile and a stronger ability to proliferate in response to HIV stimulation than did low Gag responders, which mainly exhibited monofunctional CD8 T-cell responses. Furthermore, increased polyfunctionality was significantly correlated with greater inhibition of viral replication
in vitro
. These data indicate that enhanced suppression of HIV replication is associated with broader targeting of Gag. We conclude that it is not the overall magnitude but rather the breadth, magnitude, and functional capacity of CD8 T-cell responses to certain conserved proteins, like Gag, which predict effective antiviral HIV-specific CD8 T-cell function.
Bocavirus Infection Induces Mitochondrion-Mediated Apoptosis and Cell Cycle Arrest at G2/M Phase
Authors: Chen Aaron Yun , Luo Yong , Cheng Fang , Sun Yuning , Qiu Jianming
Published: March 2010

Bocavirusis a newly classified genus of the familyParvovirinae. Infection withBocavirusminute virus of canines (MVC) produces a strong cytopathic effect in permissive Walter Reed/3873D (WRD) canine cells. We have systematically characterized the MVC infection-produced cytopathic effect in WRD cells, namely, the cell death and cell cycle arrest, and carefully examined how MVC infection induces the cytopathic effect. We found that MVC infection induces an apoptotic cell death characterized by Bax translocalization to the mitochondrial outer membrane, disruption of the mitochondrial outer membrane potential, and caspase activation. Moreover, we observed that the activation of caspases occurred only when the MVC genome was replicating, suggesting that replication of the MVC genome induces apoptosis. MVC infection also induced a gradual cell cycle arrest from the S phase in early infection to the G2/M phase at a later stage, which was confirmed by the upregulation of cyclin B1 and phosphorylation of cdc2. Cell cycle arrest at the G2/M phase was reproduced by transfection of a nonreplicative NS1 knockout mutant of the MVC infectious clone, as well as by inoculation of UV-irradiated MVC. In contrast with other parvoviruses, only expression of the MVC proteins by transfection did not induce apoptosis or cell cycle arrest. Taken together, our results demonstrate that MVC infection induces a mitochondrion-mediated apoptosis that is dependent on the replication of the viral genome, and the MVC genomeper seis able to arrest the cell cycle at the G2/M phase. Our results may shed light on the molecular pathogenesis ofBocavirusinfection in general.
Efficient Generation of Mucosal and Systemic Antigen-Specific CD8+T-Cell Responses following Pulmonary DNA Immunization
Authors: Bivas-Benita Maytal , Bar Liat , Gillard Geoffrey O. , Kaufman David R. , Simmons Nathaniel L. , Hovav Avi-Hai , Letvin Norman L.
Published: March 2010

Although mucosal CD8+T-cell responses are important in combating mucosal infections, the generation of such immune responses by vaccination remains problematic. In the present study, we evaluated the ability of plasmid DNA to induce local and systemic antigen-specific CD8+T-cell responses after pulmonary administration. We show that the pulmonary delivery of plasmid DNA formulated with polyethyleneimine (PEI-DNA) induced robust systemic CD8+T-cell responses that were comparable in magnitude to those generated by intramuscular (i.m.) immunization. Most importantly, we observed that the pulmonary delivery of PEI-DNA elicited a 10-fold-greater antigen-specific CD8+T-cell response in lungs and draining lymph nodes of mice than that of i.m. immunization. The functional evaluation of these pulmonary CD8+T cells revealed that they produced type I cytokines, and pulmonary immunization with PEI-DNA induced lung-associated antigen-specific CD4+T cells that produced higher levels of interleukin-2 than those induced by i.m. immunization. Pulmonary PEI-DNA immunization also induced CD8+T-cell responses in the gut and vaginal mucosa. Finally, pulmonary, but not i.m., plasmid DNA vaccination protected mice from a lethal recombinant vaccinia virus challenge. These findings suggest that pulmonary PEI-DNA immunization might be a useful approach for immunizing against pulmonary pathogens and might also protect against infections initiated at other mucosal sites.
Translational ethics? The theory–practice gap in medical ethics
Authors: Cribb Alan
Published: March 2010

Translational research is now a critically important current in academic medicine. Researchers in all health-related fields are being encouraged not only to demonstrate the potential benefits of their research but also to help identify the steps through which their research might be ‘made practical’. This paper considers the prospects of a corresponding movement of ‘translational ethics’. Some of the advantages and disadvantages of focusing upon the translation of ethical scholarship are reviewed. While emphasising the difficulties of crossing the gap between scholarship and practice, the paper concludes that a debate about the business of translation would be useful for medical ethics.
Children in health research: a matter of trust
Authors: Woodgate Roberta L , Edwards Marie
Published: March 2010

Background

Central to the involvement of children in health research is the notion of risk. In this paper we present one of the factors, a matter of trust, that shaped Canadian parents' and children's perceptions and assessments of risk in child health research.

Participants and methods

Part of a larger qualitative research study, 82 parents took part an in-depth qualitative interview, with 51 parents having children who had participated in health research and 31 having children with no research history. 51 children ranging from 6 to 19 years of age were also interviewed, with 28 having a history of participation in child health research and 23 having no history. Children also took part in 3 focus groups interviews. Themes emerged through a grounded theory analysis of coded interview transcripts.

Findings

The presence or absence of trust was not only perceived by parents and children as a contributing factor to involving children in health research, but also shaped their perceptions and assessments of risk. Three interrelated subthemes identified were: (1) relationships of trust; (2) placing trust in symbols of authority; and (3) the continuum of trust.

Conclusions

Our study reinforces that trust is an important factor when parents assess risk in child health research and shows that children use the language of trust in relation to risk. More discussion regarding trust in training researchers is warranted given the trust in researchers and institutions evident in this study. We also recommend further study of the continuum of trust in child health research.
Ethics committees for biomedical research in some African emerging countries: which establishment for which independence? A comparison with the USA and Canada
Authors: Rwabihama Jean-Paul , Girre Catherine , Duguet Anne-Marie
Published: March 2010

Context

The conduct of medical research led by Northern countries in developing countries raises ethical questions. The assessment of research protocols has to be twofold, with a first reading in the country of origin and a second one in the country where the research takes place. This reading should benefit from an independent local ethical review of protocols. Consequently, ethics committees for medical research are evolving in Africa.

Objective

To investigate the process of establishing ethics committees and their independence.

Method

Descriptive study of 25 African countries and two North American countries. Data were recorded by questionnaire and interviews. Two visits of ethics committee meetings were conducted on the ground: over a period of 3 months in Kigali (Rwanda) and 2 months in Washington DC (USA).

Results

22 countries participated in this study, 20 from Africa and two from North America. The response rate was 80%. 75% of local African committees developed into national ethics committees. During the last 5 years, these national committees have grown on a structural level. The circumstances of creation and the general context of underdevelopment remain the major challenges in Africa. Their independence could not be ensured without continuous training and efficient funding mechanisms. Institutional ethics committees are well established in USA and in Canada, whereas ethics committees in North America are weakened by the institutional affiliation of their members.

Conclusion

The process of establishing ethics committees could affect their functioning and compromise their independence in some African countries and in North America.
Consent agreements for cryopreserved embryos: the case for choice
Authors: Sozou Peter D , Sheldon Sally , Hartshorne Geraldine M
Published: March 2010

Under current UK law, an embryo cannot be transferred to a woman's uterus without the consent of both of its genetic parents, that is both of the people from whose gametes the embryo was created. This consent can be withdrawn at any time before the embryo transfer procedure. Withdrawal of consent by one genetic parent can result in the other genetic parent losing the opportunity to have their own genetic children. We argue that offering couples only one type of consent agreement, as happens at present, is too restrictive. An alternative form of agreement, in which one genetic parent agrees to forego the right to future withdrawal of consent, should be available alongside the current form of agreement. Giving couples such a choice will better enable them to store embryos under a consent agreement that is appropriate for their circumstances. Allowing such a choice, with robust procedures in place to ensure the validity of consent, is the best way to respect patient autonomy.
AN ATLAS OF ROBUST, STABLE, HIGH-DIMENSIONAL LIMIT CYCLES
Authors: WILDS ROY , GLASS LEON
Published: March 2010

We present a method for constructing dynamical systems with robust, stable limit cycles in arbitrary dimensions. Our approach is based on a correspondence between dynamics in a class of differential equations and directed graphs on the n-dimensional hypercube (n-cube). When the directed graph contains a certain type of cycle, called a cyclic attractor, then a stable limit cycle solution of the differential equations exists. A novel method for constructing regulatory systems that we call minimal regulatory networks from directed graphs facilitates investigation of limit cycles in arbitrarily high dimensions.

We identify two families of cyclic attractors that are present for all dimensions n ≥ 3: cyclic negative feedback and sequential disinhibition. For each, we obtain explicit representations for the differential equations in arbitrary dimension. We also provide a complete listing of minimal regulatory networks, a representative differential equation, and a bifurcation analysis for each cyclic attractor in dimensions 3–5. This work joins discrete concepts of symmetry and classification with analysis of differential equations useful for understanding dynamics in complex biological control networks.
EXPERIMENTAL REALIZATION OF STRANGE NONCHAOTIC ATTRACTORS IN A NONLINEAR SERIES LCR CIRCUIT WITH NONSINUSOIDAL FORCE
Authors: SRINIVASAN K. , SENTHILKUMAR D. V. , SURESH R. , THAMILMARAN K. , LAKSHMANAN M.
Published: March 2010

We have identified several prominent routes, namely, fractalization, fractalization followed by intermittency, intermittency and Heagy–Hammel routes, for the birth of strange nonchaotic attractors (SNAs) in a quasiperiodically forced electronic system with nonsinusoidal (square wave) force as one of the quasiperiodic forces [Senthilkumar et al., 2008]. In addition, a new bubbling route has also been identified in this circuit. Although some of these prominent routes have been reported experimentally [Thamilmaran et al., 2006] in a quasiperiodically forced electronic circuit with both the forcings as sinusoidal forces, experimental identification of all these routes is reported here in a quasiperiodically forced electronic circuit with one of the forcings as a nonsinusoidal (square wave) force. The birth of SNAs by these routes are characterized from both the experimental and numerical data by the maximal Lyapunov exponents and their variance, Poincaré maps, Fourier amplitude spectra, spectral distribution functions and the distribution of finite-time Lyapunov exponents.
TOPOLOGICAL TRANSITIVITY AND CHAOS OF GROUP ACTIONS ON DENDRITES
Authors: WANG SUHUA , SHI ENHUI , ZHOU LIZHEN , SU XUNLI
Published: March 2010

We show that each weakly mixing group action on a dendrite must have a ping-pong game, and has positive geometric entropy when the acting group is finitely generated. As a corollary, we prove that no nilpotent group action on a dendrite is weakly mixing. At last, we show that each dendrite admits no chaotic group actions.
CHAOTIC COMMUNICATION SYSTEM USING CHUA'S OSCILLATORS REALIZED WITH CCII+s
Authors: TREJO-GUERRA R. , TLELO-CUAUTLE E. , CRUZ-HERNÁNDEZ C. , SÁNCHEZ–LÓPEZ C.
Published: March 2010

This work shows the experimental implementation of a chaotic communication system based on two Chua's oscillators which are synchronized by Hamiltonian forms and observer approach. The chaotic communication scheme is realized by using the commercially available positive-type second generation current conveyor (CCII+), which is included into the AD844 device. As a result, experimental measurements are provided to demonstrate the suitability of the CCII+ to implement chaotic communication systems.
SEARCH-BASED CHAOTIC PSEUDORANDOM BIT GENERATOR
Authors: KANSO ALI
Published: March 2010

This paper proposes the construction of a new chaotic pseudorandom bit generator, which forms the main building block of a chaotic stream cipher. The design of the algorithm is based on a single chaotic map whose numerical orbit indirectly contributes towards the generation of the keystream. The latter is produced from the numerical orbit by applying a technique that searches for iterates in specific intervals [a,b], for some real numbers a and b, and outputs 0 or 1 based on the iterate preceding the targeted iterate. The generator suggested here is built up from a quadratic map. We analyze the cycle length of the keystreams and investigate the resistance of the generator to well-known cryptanalytic attacks. Furthermore, the statistic characteristics of the keystreams are examined numerically using the NIST statistical test suite. The numerical and theoretical results demonstrate that the proposed technique results in generating keystreams possessing very good cryptographic properties and high level of security against existing cryptanalytic attacks. Empirical results show that the search technique leads to the generation of keystreams possessing good randomness properties when applied to any chaotic map whose orbits have good randomness properties such as the quadratic map, tent map and sawtooth map.
A NONLINEAR DYNAMICS PERSPECTIVE OF WOLFRAM'S NEW KIND OF SCIENCE PART XII: PERIOD-3, PERIOD-6, AND PERMUTIVE RULES
Authors: CHUA LEON O. , PAZIENZA GIOVANNI E.
Published: March 2010

This 12th part of our Nonlinear Dynamics Perspective of Cellular Automata concludes a series of three articles devoted to CA local rules having robust periodic ω-limit orbits. Here, we consider only the two rules, [Formula: see text] and [Formula: see text], constituting the third of the six groups in which we classified the 1D binary Cellular Automata. Among the numerous theoretical results contained in this article, we emphasize the complete characterization of the ω-limit orbits, both robust and nonrobust, of these two rules and the proof that period-3 and period-6 ω-limit orbits are dense for [Formula: see text] and [Formula: see text], respectively. Furthermore, we will also introduce the fundamental concepts of perfect period-T orbitsets and riddled basins, and see how they emerge in rule [Formula: see text].

As stated in the title, we also focus on permutive rules, which have been introduced in a previous installment of our series but never thoroughly studied. Indeed, we will review some of the well-known properties of such rules, like the surjectivity, examining their implications for finite and bi-infinite Cellular Automata.

Finally, we propose a new list of the 88 globally-independent local rules, which is slightly different from the one we have used so far but has the great advantage of being selected via a rigorous methodology and not an arbitrary choice. For the sake of completeness, we display in the appendix the basin tree diagrams and the portraits of the ω-limit orbits of the rules from this refined table which have not yet been reported in our previous articles.
CHAOS AT SCHOOL: CHUA'S CIRCUIT FOR STUDENTS IN JUNIOR AND SENIOR HIGH SCHOOL
Authors: BILOTTA ELEONORA , BOSSIO EUGENIA , PANTANO PIETRO
Published: March 2010

Chua's circuit is a nonlinear dynamic circuit that has assumed a paradigmatic role in mathematical, physical and experimental demonstrations of chaos. Yet even today, complexity and chaos are seen as challenging topics reserved for specialists. Is it possible for young people in junior and senior high school to acquire a difficult concept such as chaos? In order to study this issue, we developed a four-step teaching/learning method in which two groups of students (one from junior and one from senior high school) manually built Chua's circuit and used it as a source for extraordinary images and music. All this allowed students to interact with strange attractors, discovering their fascination and beauty. Both groups of students created 3-D models of attractors, modified the control parameters, explored the sound and music of chaos and, during the process, discovered the connection between science and art. Briefly, they learned through engaging activities, which allowed them to acquire physical and mathematical knowledge of chaos through various modalities. The results show that manipulation of the circuit and related artistic activities can provide a new, creative and enjoyable approach to science learning.
ON THE MULTIPLE SHOOTING CONTINUATION OF PERIODIC ORBITS BY NEWTON–KRYLOV METHODS
Authors: SÁNCHEZ JUAN , NET MARTA
Published: March 2010

The application of the multiple shooting method to the continuation of periodic orbits in large-scale dissipative systems is analyzed. A preconditioner for the linear systems which appear in the application of Newton's method is presented. It is based on the knowledge of invariant subspaces of the Jacobians at nearby solutions. The possibility of speeding up the process by using parallelism is studied for the thermal convection of a binary mixture of fluids in a rectangular domain, with positive results.
MULTISCALE COMPUTATIONS ON NEURAL NETWORKS: FROM THE INDIVIDUAL NEURON INTERACTIONS TO THE MACROSCOPIC-LEVEL ANALYSIS
Authors: SPILIOTIS KONSTANTINOS G. , SIETTOS CONSTANTINOS I.
Published: March 2010

We show how the Equation-Free approach for multiscale computations can be exploited to systematically study the dynamics of neural interactions on a random regular connected graph under a pairwise representation perspective. Using an individual-based microscopic simulator as a black box coarse-grained timestepper and with the aid of Simulated Annealing we compute the coarse-grained equilibrium bifurcation diagram and analyze the stability of the stationary states, sidestepping the necessity of obtaining explicit closures at the macroscopic level. We also exploit the scheme to perform a rare-events analysis by estimating an effective Fokker–Planck equation describing the evolving probability density function of the corresponding coarse-grained observables.
REGULAR AND CHAOTIC DYNAMICS OF THE LORENZ–STENFLO SYSTEM
Authors: XAVIER JOÃO C. , RECH PAULO C.
Published: March 2010

We analytically investigate the dynamics of the generalized Lorenz equations obtained by Stenflo for acoustic gravity waves. By using Descartes' Rule of Signs and Routh–Hurwitz Test, we decide on the stability of the fixed points of the Lorenz–Stenflo system, although without explicit solution of the eigenvalue equation. We determine the precise location where pitchfork and Hopf bifurcation of fixed points occur, as a function of the parameters of the system. Parameter-space plots, Lyapunov exponents, and bifurcation diagrams are used to numerically characterize periodic and chaotic attractors.
A COOPERATIVE MOBILE ROBOT TASK ASSIGNMENT AND COVERAGE PLANNING BASED ON CHAOS SYNCHRONIZATION
Authors: FALLAHI KIA , LEUNG HENRY
Published: March 2010

In this paper, we propose a cooperative task assignment and coverage planning for mobile robots based on chaos synchronization. The chaotic mobile robot implies that the robot controller that drives a chaotic motion is characterized by topological transitivity and sensitive dependence on initial conditions. Due to the topological transitivity, the chaotic mobile robot is guaranteed to scan a workspace completely and the robot requires neither a map of the workspace nor a global motion plan. Chen and Lorenz systems are used to generate chaotic motion in this work. Cooperative multirobot systems can operate faster with higher efficiency and better reliability than a single robot system. By synchronizing the chaotic robot controllers, effective cooperation can be achieved. The performance of the cooperative chaotic mobile robots can be attributed to the use of deterministic dynamical systems and extended Kalman filter for chaos synchronization. Computer simulations illustrate the effectiveness of the proposed approach.
ON THE MATHEMATICAL MODELING OF SOLITON-MEDIATED LONG-RANGE ELECTRON TRANSFER
Authors: VELARDE MANUEL G. , CHETVERIKOV ALEXANDER P. , EBELING WERNER , HENNIG DIRK , KOZAK JOHN J.
Published: March 2010

We discuss here possible models for long-range electron transfer (ET) between a donor (D) and an acceptor (A) along an anharmonic (Morse–Toda) one-dimensional (1d)-lattice. First, it is shown that the electron may form bound states (solectrons) with externally, mechanically excited solitons in the lattice thus leading to one form of soliton-mediated transport. These solectrons generally move with supersonic velocity. Then, in a thermally excited lattice, it is shown that solitons can also trap electrons, forming similar solectron bound states; here, we find that ET based on hopping can be modeled as a diffusion-like process involving not just one but several solitons. It is shown that either of these two soliton-assisted modes of transport can facilitate ET over quite long distances.
MICROHYDRATION OF HYDRONIUM ION AND ZÜNDEL ION: A MANY-BODY ANALYSIS APPROACH
Authors: CHAUDHARI AJAY , LEE SHYI-LONG
Published: March 2010

Studying the solvation of an extra proton is important for understanding the proton transfer mechanism in polymer electrolyte membrane fuel cell. We study the interaction of hydronium ion and Zündel ion with water molecules in their first solvation shell using density functional method. A many-body analysis approach has been used to know the contribution of many-body energies to the binding energy of the hydronium ion–(water)3 and Zündel ion–(water)4 hydrogen bonded complex. It was observed that not only two-body energies but three-body and four-body energies also contribute significantly to the binding energy of the hydronium ion–(water)3 and Zündel ion–(water)4 complexes. The binding energy for the former is -32.14 kcal/mol whereas that for the latter is -48.48 kcal/mol. The percentage contributions of the many-body energies to the binding energies for these complexes are reported. The contribution from the relaxation energy to the binding energy of hydronium ion–(water)3 and Zündel ion–(water)4 complexes is 6% and 4.58%, respectively.
REEXAMINATION OF LOW ENERGY STRUCTURES OF ${\rm Au}_{4}^{-}$ AND Au4
Authors: GAO YI , ZHAO YU , ZENG X. C.
Published: March 2010

Low energy isomers of [Formula: see text] and Au4 were reexamined using the hybrid density functional B3LYP method and the couple-cluster method with the aug-cc-pVDZ-PP and aug-cc-pVTZ-PP basis sets. For [Formula: see text], the B3LYP method favors the zigzag isomer and the second order Moller–Plesset perturbation (MP2) total energy calculation favors the D2h rhombus isomer, whereas the couple-cluster singles and doubles with perturbative triples [CCSD(T)] level of theory favors the Y-shaped C2v isomer. The pyramid isomer is much higher in energy and could be easily excluded. The Gibbs free energy correction based on harmonic approximation suggests that the zigzag isomer is lower in free energy than the D2h rhombus isomer at 298.15 K. These results confirm that the Y-shaped C2v isomer is the global minimum at both 0 K and room temperature and is thus the major isomer to account for the experimental photoelectron spectrum. The zigzag isomer is suggested, as a minor isomer, to account for the weak second peak at 3.40 eV in the experimental photoelectron spectrum. For neutral Au4 , the zigzag isomer is more stable than D2h rhombus isomer at the B3LYP level and the D2h rhombus isomer is the global minimum on basis of all post Hartree–Fock levels of theory.