bluuebunny/crossref_metadata_2025 huggingface dataset:
Concord grape juice supplementation improves memory function in older adults with mild cognitive impairment
Authors: Krikorian Robert , Nash Tiffany A. , Shidler Marcelle D. , Shukitt-Hale Barbara , Joseph James A.
Published: December 2009

Concord grape juice contains polyphenol compounds, which have antioxidant and anti-inflammatory properties and influence neuronal signalling. Concord grape juice supplementation has been shown to reduce inflammation, blood pressure and vascular pathology in individuals with CVD, and consumption of such flavonoid-containing foods is associated with a reduced risk for dementia. In addition, preliminary animal data have indicated improvement in memory and motor function with grape juice supplementation, suggesting potential for cognitive benefit in ageing humans. In this initial investigation of neurocognitive effects, we enrolled twelve older adults with memory decline but not dementia in a randomised, placebo-controlled, double-blind trial with Concord grape juice supplementation for 12 weeks. We observed significant improvement in a measure of verbal learning and non-significant enhancement of verbal and spatial recall. There was no appreciable effect of the intervention on depressive symptoms and no effect on weight or waist circumference. A small increase in fasting insulin was observed for those consuming grape juice. These preliminary findings suggest that supplementation with Concord grape juice may enhance cognitive function for older adults with early memory decline and establish a basis for more comprehensive investigations to evaluate potential benefit and assess mechanisms of action.
Maximum intensity of rarefaction shock waves for dense gases
Authors: GUARDONE ALBERTO , ZAMFIRESCU CALIN , COLONNA PIERO
Published: December 2009

Modern thermodynamic models indicate that fluids consisting of complex molecules may display non-classical gasdynamic phenomena such as rarefaction shock waves (RSWs) in the vapour phase. Since the thermodynamic region in which non-classical phenomena are physically admissible is finite in terms of pressure, density and temperature intervals, the intensity of RSWs is expected to exhibit a maximum for any given fluid. The identification of the operating conditions leading to the RSW with maximum intensity is of paramount importance for the experimental verification of the existence of non-classical phenomena in the vapour phase and for technical applications taking advantage of the peculiarities of the non-classical regime. This study investigates the conditions resulting in an RSW with maximum intensity in terms of pressure jump, wave Mach number and shock strength. The upstream state of the RSW with maximum pressure drop is found to be located along the double-sonic locus formed by the thermodynamic states associated with an RSW having both pre- and post-shock sonic conditions. Correspondingly, the maximum-Mach thermodynamic and maximum-strength loci locate the pre-shock states from which the RSW with the maximum wave Mach number and shock strength can originate. The qualitative results obtained with the simple van der Waals model are confirmed with the more complex Stryjek–Vera–Peng–Robinson, Martin–Hou and Span–Wagner equations of state for selected siloxane and perfluorocarbon fluids. Among siloxanes, which are arguably the best fluids for experiments aimed at the generation and measurement of an RSW, the state-of-the-art Span–Wagner multi-parameter equation of state predicts a maximum wave Mach number close to 1.026 for D6 (dodecamethylcyclohexasiloxane, [O-Si-(CH3)2]6). Such value is well within the capacity of the measurement system of a newly built experimental set-up aimed at the first-ever demonstration of the existence of RSWs in dense vapours.
Effect of confinement on three-dimensional stability in the wake of a circular cylinder
Authors: CAMARRI SIMONE , GIANNETTI FLAVIO
Published: December 2009

This paper investigates the three-dimensional stability of the wake behind a symmetrically confined circular cylinder by a linear stability analysis. Emphasis has been placed on discussing analogies and differences with the unconfined case to highlight the role of the inversion of the von Kármán street in the nature of the three-dimensional transition. Indeed, in this flow, the vortices of opposite sign that are alternately shed from the body into the wake cross the symmetry line further downstream and they assume a final configuration which is inverted with respect to the unconfined case. It is shown that the transition to a three-dimensional state has the same space–time symmetries of the unconfined case, although the shape of the linearly unstable modes is affected by the inversion of the wake vortices. A possible interpretation of this result is given here.
Indonesia's Salafist Sufis
Authors: HOWELL JULIA DAY
Published: December 2009

Islam's devotional and mystical tradition, Sufism (tasawwuf), is commonly cast as antithetical to Salafi Islam. Self-identified ‘Salafis’, with their ideological roots in anti-liberal strands of twentieth-century modernist Islam, do commonly view Sufis as heretics propagating practices wrongly introduced into Islam centuries after the time of the pious ancestors (the Salaf). Yet reformist zeal that fixes on the singular importance of the Salaf (particularly the Prophet Muhammad and his principal companions) as models for correct piety can also be found amongst Sufis. This paper calls attention to the Salafist colouration of Sufism in two areas of popular culture: television preaching and the popular religious ‘how-to’ books and DVDs that make the preachers’ messages available for purchase. It reprises the teachings of two of the best known Indonesian Muslim televangelists, ‘Hamka’ (b. 1908, d. 1981) and M. Arifin Ilham (b. 1969), both of whom also happen to be champions of Sufism, and analyses the different rhetorical uses each has made of references to the ‘Salaf’ and the notion of ‘Salafist’ Islam.
Multilocus phylogenetic analyses reveal that habitat selection drives the speciation of Didymozoidae (Digenea) parasitizing Pacific and Atlantic bluefin tunas
Authors: MLADINEO I. , BOTT N. J. , NOWAK B. F. , BLOCK B. A.
Published: December 2009

Parasite communities of wild and reared bluefin tuna display remarkable diversity. Among these, the most prevalent and abundant are the Didymozoidae (Monticelli, 1888) (Trematoda, Digenea), considered one of the most taxonomically complex digenean families. The aim of this study was to evaluate phylogenetic structure of Didymozoidae occurring in Pacific (Thunnus orientalis) and Atlantic bluefin tuna (T. thynnus) in order to increase our knowledge of didymozoid zoogeography and identify species that could successfully be employed as biological tags for stock assessment studies. For the present analyses we used 2 nuclear ribosomal DNA loci, part of the 28S gene and the second internal transcribed spacer (ITS-2) as well as a portion of the mitochondrial cytochromecoxidase subunit 1 gene (cox1). In most parasitic groups, morphology is the primary factor in the structuring of phylogenetic relationships. In rare examples, however, habitat has been suggested as a primary factor affecting parasite evolution. During their evolution, didymozoids have spread and inhabited a remarkable number of different sites in their hosts, colonizing exterior as well as strictly interior niches. Our data suggest that habitat selection has been the leading force in shaping didymozoid phylogenetic relationships. For 2 didymozoid species (D. wedliandD. palati),cox1sequences indicate intraspecific differences between Mexican and Adriatic populations.
Cerebral malaria: why experimental murine models are required to understand the pathogenesis of disease
Authors: BRIAN de SOUZA J. , HAFALLA JULIUS C. R. , RILEY ELEANOR M. , COUPER KEVIN N.
Published: December 2009

Cerebral malaria is a life-threatening complication of malaria infection. The pathogenesis of cerebral malaria is poorly defined and progress in understanding the condition is severely hampered by the inability to study in detail,ante-mortem, the parasitological and immunological events within the brain that lead to the onset of clinical symptoms. Experimental murine models have been used to investigate the sequence of events that lead to cerebral malaria, but there is significant debate on the merits of these models and whether their study is relevant to human disease. Here we review the current understanding of the parasitological and immunological events leading to human and experimental cerebral malaria, and explain why we believe that studies with experimental models of CM are crucial to define the pathogenesis of the condition.
Trypanosomiasis and the brain
Authors: RODGERS JEAN
Published: December 2009

Neurological involvement following trypanosome infection has been recognised for over a century. However, there are still many unanswered questions concerning the mechanisms used by the parasite to gain entry to the CNS and the pathogenesis of the resulting neuroinflammatory reaction. There is a paucity of material from human cases of the disease therefore the majority of current research relies on the use of animal models of trypanosome infection. This review reports contemporary knowledge, from both animal models and human samples, regarding parasite invasion of the CNS and the neuropathological changes that accompany trypanosome infection and disease progression. The effects of trypanosomes on the blood-brain barrier are discussed and possible key molecules in parasite penetration of the barrier highlighted. Changes in the balance of CNS cytokines and chemokines are also described. The article closes by summarising the effects of trypanosome infection on the circadian sleep-wake cycle, and sleep structure, in relation to neuroinflammation and parasite location within the CNS. Although a great deal of progress has been made in recent years, the advent and application of sophisticated analysis techniques, to decipher the complexities of HAT pathogenesis, herald an exciting and rewarding period for advances in trypanosome research.
Analysis of typical locomotion of a symmetric hexapod robot
Authors: Wang Z.-Y. , Ding X.-L. , Rovetta A.
Published: December 2009

In recent years hexagonal hexapod robots gained the interest of international research community. The aim of this paper is twofold. First, after summarizing all known gaits of such robots, we introduce some improvements both for normal conditions and for fault tolerance. Then we show the advantages of hexagonal hexapod robots over rectangular ones by comparing different gaits from theoretical and experimental points of view. Stability, fault tolerance, turning ability, and terrain adaptability are analyzed. For reaching these aims we also introduce a robot kinematics that considers at the same time supporting and transferring legs. The trajectories of feet are described as well. Finally, single leg stride selection is studied for side wave and for kick-off gaits to optimize walking ability and energy management.

The theoretical results presented herein have been validated with experiments conducted on a prototype of the Novel Robotics System for Planetary Exploration (Rovetta et al., “New Robot Concepts for Mars Soil Exploration: Mechanics and Functionality,” ASTRA 2004, Eighth ESA Workshop on Advanced Space Technologies for Robotics and Automatian, Nordwijk, The Netherlands Nov. 2–4, 2004) (NOROS), developed by Politecnico di Milano and Beijing University of Astronautics and Aeronautics, and the results are summarized in this paper.
Testing the HTA Core Model: Experiences from two pilot projects
Authors: Pasternack Iris , Anttila Heidi , Mäkelä Marjukka , Ikonen Tuija , Räsänen Pirjo , Lampe Kristian , van Brabandt Hans , Cleemput Irina , de Laet Chris , Marchetti Marco , Refolo Pietro , Sacchini Dario , Kunz Regina , Nordmann Alain , Lühmann Dagmar , Freyschuss Bo
Published: December 2009

Objectives: The aim of this study was to analyze and describe process and outcomes of two pilot assessments based on the HTA Core Model, discuss the applicability of the model, and explore areas of development.

Methods: Data were gathered from HTA Core Model and pilot Core HTA documents, their validation feedback, questionnaires to investigators, meeting minutes, emails, and discussions in the coordinating team meetings in the Finnish Office for Health Technology Assessment (FINOHTA).

Results: The elementary structure of the HTA Core Model proved useful in preparing HTAs. Clear scoping and good coordination in timing and distribution of work would probably help improve applicability and avoid duplication of work.

Conclusions: The HTA Core Model can be developed into a platform that enables and encourages true HTA collaboration in terms of distribution of work and maximum utilization of a common pool of structured HTA information for national HTA reports.
The adaptation of health technology assessment reports: Identification of the need for, and development of, a toolkit to aid the process
Authors: Turner Sheila , Chase Deborah L. , Milne Ruairidh , Cook Andrew , Hicks Nicholas J. , Rosten Claire , Payne Liz , Coles Suzanne , Bell Eleanor
Published: December 2009

Objectives: Europe has many health technology assessment (HTA) agencies, each producing their own HTA reports. Adapting HTA reports for different contexts could reduce the need for multiple reports on the same health technology with resultant saving of time and resources. This study aims to examine and understand the process of adaptation, and to develop a toolkit that would help the adaptation of reports produced by other countries.

Methods: The methods used were a review of the literature; a survey of twenty-nine European HTA organizations, two rounds of a Delphi survey, a face-to-face meeting of twenty-one European network for Health Technology Assessment (EUnetHTA) representatives, iterative rounds of review, and two rounds of quality assurance testing (termed applicability testing).

Results: Descriptions of previous examples of adaptation in the literature are sparse. Most respondents had previous experience in adapting reports, and all believed that adaptation was useful, and there was the ability to benefit from the use of a toolkit to aid in the process. EUnetHTA Partners developed and tested an adaptation toolkit. The toolkit is composed of a series of checklists and resources that identify or clarify the relevance, reliability, and transferability of data and information from existing reports.

Conclusions: Consensus of opinion from twenty-nine European organizations/networks has indicated that the adaptation of HTA reports would be desirable and beneficial. A toolkit was developed to help with the adaptation of HTA reports produced in other settings. This collection of resources is available for use by all HTA agencies and can be accessed at: http://www.eunethta.net/upload/WP5/EUnetHTA_HTA_Adaptation_Toolkit_October08.pdf.
Information service on new and emerging health technologies: Identification and prioritization processes for a European Union–wide newsletter
Authors: Wild Claudia , Simpson Sue , Douw Karla , Geiger-Gritsch Sabine , Mathis Stefan , Langer Thomas
Published: December 2009

Objectives: EUnetHTA WP 7 (Strand B) aimed to promote sharing information on new and emerging technologies. The task was to develop a prototype of a newsletter and pilot the processes of production.

Methods: The EuroScan database served as information source on pertinent technologies. To prioritize, a set of criteria for scoring the potential impact and for selecting the technologies for articles was applied and a pilot newsletter was produced.

Results: Being objective and transparent about the content of a newsletter required a method for prioritizing health technologies. Using significance criteria, members of the prioritization panel selected twelve technologies for articles of different length and depth. Potential recipients, surveyed on relevance, content, timeliness, and readability responded mostly positive, but requested more information on cost effectiveness and criticized timeliness.

Conclusions: Dissemination of an EU-wide newsletter would be feasible, but time-consuming. Although a newsletter appears to fulfill a need for information on emerging and new health technologies, it is not considered the right tool to avoid duplication of effort in the present international constellation of horizon scanning for new health technologies. Other options will be pursued as part of future collaborative actions, for example, a core set of early awareness information, or an on-demand electronic information system.
Involving stakeholders and developing a policy for stakeholder involvement in the European network for Health Technology Assessment, EUnetHTA
Authors: Nielsen Camilla Palmhøj , Lauritsen Sarah Wadmann , Kristensen Finn Børlum , Bistrup Marie Louise , Cecchetti Americo , Turk Eva
Published: December 2009

Objectives: This article explains how the issue of stakeholder involvement was addressed in the European network for Health Technology Assessment (EUnetHTA) Project and describes the structures of future stakeholder involvement in the EUnetHTA Collaboration.

Methods: Initiatives led to a dialogue with stakeholders and exchanging views and expectations on health technology assessment (HTA) processes and the future development of EUnetHTA. The methods of involving different stakeholder groups in EUnetHTA included general information to stakeholders about EUnetHTA, targeted information on a Web site, analysis of stakeholder opinions on HTA and EUnetHTA, and development of a draft stakeholder policy.

Results: First steps were taken to organize processes to consolidate the legitimacy of EUnetHTA and its products and encourage the representation of interests, thus contributing to promoting the utilization of HTA in national/regional policy making. A stakeholder Web site, analyses of stakeholder opinions on HTA and EUnetHTA in a discussion topic catalog, and a draft stakeholder policy resulted from the work.

Conclusions: Stakeholder involvement in EUnetHTA is necessary to ensure the legitimacy and prospects for utilization of EUnetHTA and its products. The described activities and results create the foundation for a continued dialogue with, and involvement of, stakeholders. The EUnetHTA stakeholder meeting can be considered as a successful experience of dialogue between EUnetHTA and stakeholders, which should be continued. Our experience shows the challenge of obtaining balanced stakeholder representation across the identified stakeholder groups. Continued attention should be given to achieving balanced stakeholder representation.
Report on the International Conference on Human Rights and the Environment (Tehran, May 13–14, 2009) and its Tehran Declaration
Authors: Blake Janet
Published: December 2009

The International Conference on Human Rights and the Environment took place in Tehran in May 2009 and was attended by around 150 participants, including 10 international and five Iranian speakers. It was conceived as an opportunity to bring together leading international experts in this field to seek greater clarity on the important but, as yet, under-conceptualised question of the nexus between human rights and the environment. Both in the papers presented and in the resulting Declaration text, cultural heritage was seen as a key element in both aspects of this nexus and as fundamental to achieving a suitable accommodation between the two.
High‐speed impacts by ash particles in the 1982 eruption of El Chichón, Mexico
Authors: Scolamacchia Teresa , Schouwenaars Rafael
Published: December 2009

A steel basketball pole was the only object left standing 3.5 km from the crater in Esquípula Guayabal, one of the villages that were completely buried by pyroclastic fallouts and density currents deposits during the 1982 eruption of El Chichón (Mexico). A close observation of its surface revealed the presence of small surface marks. Low‐magnification microscopic inspection indicated that most were corrosion pits. Metallographic observation in a SEM revealed the presence of submillimetric impact craters with encrusted ash particles and characterized by a plastically deformed zone. Particle velocity was calculated by equating the kinetic energy of the particles to the work needed to form the crater, using the classical Bishop‐Hill‐Mott formula for penetration, and calibrating the model to data in the literature. This method yields values between 710 and 980 m/s for the fragments embedded in the steel surface. Such speeds exceed those normally reported for gravitational acceleration in pyroclastic density currents (PDCs) and resemble values obtained both theoretically and numerically for shock waves accompanying volcanic eruptions. Source mechanisms for these phenomena include either a sudden decompression of the magmatic system or the mechanical rupture of the melt due to magma‐water interaction. Nevertheless, shock waves could have been developed independently from source conditions, inside PDCs that can reach supersonic speeds depending upon their mass loading. This study indicates that direct damage from air shock cannot be neglected in hazard assessment of explosive eruptions.
Space radiation environment forecast for EGYPTSAT‐2 satellite
Authors: Samwel S. W. , Hady A. A.
Published: December 2009

The space environment provides an assortment of hazards whose ill effects can range from degraded performance up to catastrophic loss of a spacecraft. The radiation environment is believed to be the most significant in terms of spacecraft failures. Hence, the present work provides a radiation analysis for the EGYPTSAT‐2 which is supposed to be launched in 2012 as a low Earth orbit satellite in order to assist the EGYPTSAT‐2 instrument team with adequate planning decisions. AE‐8, AP‐8, Jet Propulsion Laboratory (JPL) model, and the cosmic ray effects in microelectronic (CREME86) code are used to estimate the fluences of the trapped electrons and protons, solar protons, and galactic cosmic protons, respectively. SHIELDOSE‐2 code is used for space‐shielding radiation dose calculations, and the nonionizing energy loss function is used to estimate the nonionizing dose of space radiation. Finally, the end‐of‐life solar cell performance is evaluated using the displacement damage dose (DDD) method. The slowed down spectra emerging from the shielding material is obtained using the Multilayered Shielding Simulation Software (MULASSIS) code. It has been found that the radiation environment will not impede the sensitivity of EGYPTSAT‐2 materials over the course of the baseline mission lifetime. For 1.5 mm aluminum shielding thickness, total ionizing dose is 2.65 × 104 rads (Si) and DDD is 7.75 × 107 MeV/g(Si) for 5 years mission length, which are less than critical thresholds. Also, a flat glass of SiO2 sheet of thickness 0.5 mm is enough to resist the damage effect of the solar array cells.
Height of faceted spurs, a proxy for determining long‐term throw rates on normal faults: Evidence from the North Baikal Rift System, Siberia
Authors: Petit Carole , Meyer Bertrand , Gunnell Yanni , Jolivet Marc , San'kov Vladimir , Strak Vincent , Gonga‐Saholiariliva Nahossio
Published: December 2009

We present new results on the long‐term throw rates of active normal faults in the North Baikal Rift (NBR), eastern Siberia, based on a statistical analysis of triangular faceted scarps. Fault‐bounded ridges in the NBR display typical morphologies with several contiguous facets separated by fault‐perpendicular catchments. Over a range of 20 fault segments analyzed, triangular facet heights vary from ∼200 to >900 m. As fault scarps have been developing under similar long‐term climatic conditions, we infer that the scatter in mean facet height arises from long‐term differences in fault throw rate. We compare the morphology of NBR facets with results obtained in a previously published numerical model of facet growth. Using facet height as an input, model results provide estimates of the long‐term fault throw rate. NBR throw rates vary between 0.2 and 1.2 mm yr−1. The throw rates are then compared with the cumulated throw, which has been constrained by geophysical and stratigraphic data in the basins. This provides an estimate of the age of fault and basin initiation. We show that the modern stage of basin development started circa 3 Myr ago, except for the North Baikal basin (∼8 Ma). Our results also suggest that a proportion of the observed throw is inherited from an earlier tectonic stage.
The missing link
Authors: Hunter Philip
Published: December 2009

Viruses exceed the potential of all other organisms to adapt and evolve rapidly. Philip Hunter explores the evidence that these oft‐maligned pathogens might have also contributed some of their adaptability to human evolution.
Progress in ionic organic-inorganic composite membranes for fuelcell applications
Authors: Nagarale R. K. , Shin Woonsup , Singh Pramod K.
Published: December 2009

This review addresses the basic route used to synthesize composite membrane materials. The main emphasis has been given to the preparation procedures of inorganic materials, their modifications and composites with perfluorinated and hydrocarbon polymers. The properties are addressed with respect to fuel cell applications.
The N-terminal RASSF family: a new group of Ras-association-domaincontaining proteins, with emerging links to cancer formation
Authors: Sherwood Victoria , Recino Asha , Jeffries Alex , Ward Andrew , Chalmers Andrew D.
Published: December 2009

The RASSF (Ras-association domain family) has recently gained several new members and now contains ten proteins (RASSF1–10), several of which are potential tumour suppressors. The family can be split into two groups, the classical RASSF proteins (RASSF1–6) and the four recently added N-terminal RASSF proteins (RASSF7–10). The N-terminal RASSF proteins have a number of differences from the classical RASSF members and represent a newly defined set of potential Ras effectors. They have been linked to key biological processes, including cell death, proliferation, microtubule stability, promoter methylation, vesicle trafficking and response to hypoxia. Two members of the N-terminal RASSF family have also been highlighted as potential tumour suppressors. The present review will summarize what is known about the N-terminal RASSF proteins, addressing their function and possible links to cancer formation. It will also compare the N-terminal RASSF proteins with the classical RASSF proteins and ask whether the N-terminal RASSF proteins should be considered as genuine members or imposters in the RASSF family.
Towards the molecular mechanism of respiratory complex I
Authors: Hirst Judy
Published: December 2009

Complex I (NADH:quinone oxidoreductase) is crucial to respiration in many aerobic organisms. In mitochondria, it oxidizes NADH (to regenerate NAD+ for the tricarboxylic acid cycle and fatty-acid oxidation), reduces ubiquinone (the electrons are ultimately used to reduce oxygen to water) and transports protons across the mitochondrial inner membrane (to produce and sustain the protonmotive force that supports ATP synthesis and transport processes). Complex I is also a major contributor to reactive oxygen species production in the cell. Understanding the mechanisms of energy transduction and reactive oxygen species production by complex I is not only a significant intellectual challenge, but also a prerequisite for understanding the roles of complex I in disease, and for the development of effective therapies. One approach to defining a complicated reaction mechanism is to break it down into manageable parts that can be tackled individually, before being recombined and integrated to produce the complete picture. Thus energy transduction by complex I comprises NADH oxidation by a flavin mononucleotide, intramolecular electron transfer from the flavin to bound quinone along a chain of iron–sulfur clusters, quinone reduction and proton translocation. More simply, molecular oxygen is reduced by the flavin, to form the reactive oxygen species superoxide and hydrogen peroxide. The present review summarizes and evaluates experimental data that pertain to the reaction mechanisms of complex I, and describes and discusses contemporary mechanistic hypotheses, proposals and models.
Redox-mediated interactions of VHb (Vitreoscilla haemoglobin) with OxyR: novel regulation of VHb biosynthesis under oxidative stress
Authors: Anand Arvind , Duk Brian T. , Singh Sandeep , Akbas Meltem Y. , Webster Dale A. , Stark Benjamin C. , Dikshit Kanak L.
Published: December 2009

The bacterial haemoglobin from Vitreoscilla, VHb, displays several unusual properties that are unique among the globin family. When the gene encoding VHb, vgb, is expressed from its natural promoter in either Vitreoscilla or Escherichia coli, the level of VHb increases more than 50-fold under hypoxic conditions and decreases significantly during oxidative stress, suggesting similar functioning of the vgb promoter in both organisms. In the present study we show that expression of VHb in E. coli induced the antioxidant genes katG (catalase–peroxidase G) and sodA (superoxide dismutase A) and conferred significant protection from oxidative stress. In contrast, when vgb was expressed in an oxyR mutant of E. coli, VHb levels increased and the strain showed high sensitivity to oxidative stress without induction of antioxidant genes; this indicates the involvement of the oxidative stress regulator OxyR in mediating the protective effect of VHb under oxidative stress. A putative OxyR-binding site was identified within the vgb promoter and a gel-shift assay confirmed its interaction with oxidized OxyR, an interaction which was disrupted by the reduced form of the transcriptional activator Fnr (fumurate and nitrate reductase). This suggested that the redox state of OxyR and Fnr modulates their interaction with the vgb promoter. VHb associated with reduced OxyR in two-hybrid screen experiments and in vitro, converting it into an oxidized state in the presence of NADH, a condition where VHb is known to generate H2O2. These observations unveil a novel mechanism by which VHb may transmit signals to OxyR to autoregulate its own biosynthesis, simultaneously activating oxidative stress functions. The activation of OxyR via VHb, reported in the present paper for the first time, suggests the involvement of VHb in transcriptional control of many other genes as well.
Cupredoxin-like domains in haemocyanins
Authors: Jaenicke Elmar , Büchler Kay , Markl Jürgen , Decker Heinz , Barends Thomas R. M.
Published: December 2009

Haemocyanins are multimeric oxygen transport proteins, which bind oxygen to type 3 copper sites. Arthropod haemocyanins contain 75-kDa subunits, whereas molluscan haemocyanins contain 350–400-kDa subunits comprising seven or eight different 50 kDa FUs (functional units) designated FU-a to FU-h, each with an active site. FU-h possesses a tail of 100 amino acids not present in the other FUs. In the present study we show by X-ray crystallography that in FU-h of KLH1 (keyhole-limpet-haemocyanin isoform 1) the structure of the tail domain is cupredoxin-like but contains no copper. The copper-free domain 3 in arthropod haemocyanin subunits has also recently been reinterpreted as being cupredoxin-like. We propose that the cupredoxin-like domain in both haemocyanin types once served to upload copper to the active site of the oxygen-binding domain.
Mitochondrial peroxiredoxin involvement in antioxidant defence and redox signalling
Authors: Cox Andrew G. , Winterbourn Christine C. , Hampton Mark B.
Published: December 2009

Prxs (peroxiredoxins) are a family of proteins that are extremely effective at scavenging peroxides. The Prxs exhibit a number of intriguing properties that distinguish them from conventional antioxidants, including a susceptibility to inactivation by hyperoxidation in the presence of excess peroxide and the ability to form complex oligomeric structures. These properties, combined with a high cellular abundance and reactivity with hydrogen peroxide, have led to speculation that the Prxs function as redox sensors that transmit signals as part of the cellular response to oxidative stress. Multicellular organisms express several different Prxs that can be categorized by their subcellular distribution. In mammals, Prx 3 and Prx 5 are targeted to the mitochondrial matrix. Mitochondria are a major source of hydrogen peroxide, and this oxidant is implicated in the damage associated with aging and a number of pathologies. Hydrogen peroxide can also act as a second messenger, and is linked with signalling events in mitochondria, including the induction of apoptosis. A simple kinetic competition analysis estimates that Prx 3 will be the target for up to 90% of hydrogen peroxide generated in the matrix. Therefore, mitochondrial Prxs have the potential to play a major role in mitochondrial redox signalling, but the extent of this role and the mechanisms involved are currently unclear.
Antifungal curcumin induces reactive oxygen species and triggers an early apoptosis but prevents hyphae development by targeting the global repressorTUP1inCandida albicans
Authors: Sharma Monika , Manoharlal Raman , Puri Nidhi , Prasad Rajendra
Published: December 2009

In the present study, we have investigated the antifungal effects of a natural polyphenol, CUR (curcumin), against albicans and non-albicans species of Candida and have shown its ability to inhibit the growth of all the tested strains. The inhibitory effects of CUR were independent of the status of the multidrug efflux pump proteins belonging to either ABC transporter (ATP-binding cassette transporter) or MFS (major facilitator) superfamilies of transporters. By using a systemic murine model of infection, we established that CUR and piperine, when administered together, caused a significant fungal load reduction (1.4log10) in kidneys of Swiss mice. Additionally, CUR raised the levels of ROS (reactive oxygen species), which, as revealed by annexin V–FITC labelling, triggered early apoptosis in Candida cells. Coincident with the raised ROS levels, mRNAs of tested oxidative stress-related genes [CAP1 (Candida albicans AP-1), CaIPF7817 (putative NADH-dependent flavin oxidoreductase), SOD2 (superoxide dismutase 2), GRP2 (NADPH-dependent methyl glyoxal reductase) and CAT1 (catalase 1)] were also elevated. The growth inhibitory effects of CUR could be reversed by the addition of natural and synthetic antioxidants. Notably, independent of ROS status, polyphenol CUR prevented hyphae development in both liquid and solid hypha-inducing media by targeting the global suppressor TUP1 (thymidine uptake 1). Taken together, our results provide the first evidence that CUR acts as an antifungal agent, via generation of oxidative stress, and inhibits hyphae development by targeting TUP1.
Growth and survival signalling in B16F10 melanoma cells in 3D culture
Authors: Goundiam Oumou , Nagel Marie‐Danielle , Vayssade Muriel
Published: December 2009

The two‐way communication between the ECM (extracellular matrix) and the cytoplasm via the integrins has many functions in cancer cells, including the suppression of apoptosis. As cells in a 3D (three‐dimensional) architecture resemble the in vivo situation more closely than do cells in more conventional 2D cultures, we have employed a substratum that prevents cell adhesion and induces cell aggregation to determine why highly metastatic B16F10 melanoma cells resist anoikis. We compared the behaviour of B16F10 cells in 2D [on tPS (tissue culture polystyrene)] and 3D culture {on polyHEMA [poly(2‐hydroxyethylmethacrylate)]} configurations. For this, we analysed cell morphology, proliferation, apoptosis and the activation status of several proteins involved in cell proliferation and survival [RhoA, FAK (focal adhesion kinase), Akt, ERK1/2 (extracellular‐signal‐regulated kinase 1/2)]. B16F10 cells in 3D architecture were able to proliferate as cell aggregates for 3 days, after which the number of cells decreased. The normal Swiss 3T3 cells used as an anoikis‐sensitive control did not proliferate on the anti‐adhesive substratum. Rho A was activated in B16F10 aggregates throughout their time in culture, whereas it was not in Swiss 3T3 aggregates. An absence of apoptotic activity was correlated with the proliferation of B16F10 cells in aggregates: caspase 3 was significantly activated only after 3 days in culture on polyHEMA. FAK and Akt were transiently activated, and their inactivation was correlated with the induction of apoptosis. ERK1/2 were activated throughout the 3D culture. No survival protein was activated in Swiss 3T3 aggregates. Data obtained from cells in 3D culture suggest that B16F10 cells are resistant to anoikis through the activation of the FAK and Akt signalling pathways.
Quantum group connections
Authors: Lewandowski Jerzy , Okołów Andrzej
Published: December 2009

The Ahtekar–Isham C*-algebra known from loop quantum gravity is the algebra of continuous functions on the space of (generalized) connections with a compact structure Lie group. The algebra can be constructed by some inductive techniques from the C*-algebra of continuous functions on the group and a family of graphs embedded in the manifold underlying the connections. We generalize the latter construction replacing the commutative C*-algebra of continuous functions on the group by a noncommutative C*-algebra defining a compact quantum group.
Hybrid states of Tamm plasmons and exciton polaritons
Authors: Kaliteevski M. , Brand S. , Abram R. A. , Iorsh I. , Kavokin A. V. , Shelykh I. A.
Published: December 2009

Channeling of exciton polaritons in the plane of semiconductor microcavities can be achieved by the deposition of metallic mesas on the top of the semiconductor structure. We show theoretically that the regime of strong coupling between cavity polaritons and Tamm surface plasmons is possible in such structures. The effect is favorable for the spatial confinement of polaritons and the formation of hybrid one-dimensional plasmon-polariton modes.
Axial x-ray backlighting of wire-array Z-pinches using X pinches
Authors: Blesener I. C. , Greenly J. B. , Pikuz S. A. , Shelkovenko T. A. , Vishniakou S. , Hammer D. A. , Kusse B. R.
Published: December 2009

For the first time, a geometry has been developed to allow for an axial imaging system for wire-array Z-pinch experiments that produce high-resolution x-ray images. The new geometry required a significant redesign of the electrode hardware. Calibrated areal density measurements of the Z-pinch plasma including wire cores, coronal plasma, streaming plasma, and the precursor were obtained. The system used eight-wire molybdenum (Mo) X pinches in series with and directly below the Z-pinch axis to provide micron-scale x-rays sources for point-projection radiography. The images formed on the x-ray sensitive film had a 15 mm diameter field of view at the center height of the array and a magnification of about 7.5:1. Titanium (Ti) filters in front of the film transmitted radiation in the spectral range of 3–5 keV. For calibration, a separate film with the same thickness Ti filter was placed the same distance from the X pinch. This film had an unobstructed path that bypasses the Z-pinch but included step wedges for calibration of the Z-pinch plasma. The step wedges had thicknesses of tungsten (W) ranging from 0.015 to 1.1 μm to obtain areal density measurements of the W plasma from the wire-array. Images had subnanosecond temporal resolution and about 10 μm spatial resolution.
In-plane uniaxial anisotropy induced by two-phase stripelike magnetic hybrid structure
Authors: Lin Min , Fan Xiaolong , Zhang Zhengmei , Guo Dangwei , Xue Desheng
Published: December 2009

The in-plane magnetic anisotropy induced by the two-phase stripelike magnetic hybrid structures is studied via object oriented micromagnetic framework. Our theory and simulation prove that the nature of the induced anisotropy is a kind of shape anisotropy caused by the dipole-dipole interaction between the two phases with different saturation magnetizations. The magnitude of such anisotropy, which depends on the difference in the saturation magnetizations of the two-phase and the geometry of the systems, has been systematically simulated.
Scanning magnetic microscopy model analysis of circular flaws in thin metallic plates
Authors: Adamo M. , Calvano F. , Nappi C. , Sarnelli E.
Published: December 2009

We studied the eddy currents excited by a time varying external magnetic field in thin metallic plates in the presence of a circular hole piercing the plate. The value of the normal component of the magnetic field over the circular defect is analytically calculated and a complete scanning magnetic operation along a line crossing the defect is simulated. The analytical solution is then tested against a direct numerical simulation with good results. The aim is the reconstruction and interpretation of magnetic signatures due to structural defects in nondestructive evaluation made by superconducting quantum interference device microscopy measurements.
Anomalous wear-out phenomena of europium-implanted light emitters based on a metal-oxide-semiconductor structure
Authors: Rebohle L. , Lehmann J. , Prucnal S. , Nazarov A. , Tyagulskii I. , Tyagulskii S. , Kanjilal A. , Voelskow M. , Grambole D. , Skorupa W. , Helm M.
Published: December 2009

The anomalous wear-out phenomena of Eu-implanted metal-oxide-semiconductor devices were investigated. It will be shown that in contrast to other rare earth elements the electroluminescence (EL) intensity of Eu-implanted SiO2 layers can rise under constant current injection before the known EL quenching will start. Under certain circumstances, this rise may amount up to two orders of magnitude. The EL behavior will be correlated with the microstructural and electrical properties of the devices. Transmission electron microscopy and Rutherford backscattering spectroscopy were applied to trace the development of Eu/Eu oxide clusters and the diffusion of Eu to the interfaces of the gate oxide layer. The hydrogen profile within the SiO2–SiON interface region was determined by nuclear reaction analysis. Current-voltage characteristics, EL decay times, and the progression of the voltage and the EL spectrum with increasing charge injection were measured to study charge and trapping phenomena in the oxide layer to reveal details of the EL excitation mechanism. A first qualitative model for the anomalous life time behavior is proposed.
Morphological and microstructural evolution in the two-step growth of nonpolar a-plane GaN on r-plane sapphire
Authors: Sun Qian , Kong Bo Hyun , Yerino Christopher D. , Ko Tsung-Shine , Leung Benjamin , Cho Hyung Koun , Han Jung
Published: December 2009

In this paper, we report a detailed study on the evolution of surface morphology and microstructure of nonpolar a-plane GaN (a-GaN) through controlled growth interruptions. Microscopy imaging shows that the two-step a-GaN growth went through a roughening-recovery process. The first-step growth (under high V/III and high pressure) produced a rough surface with tall mesas separated by voids. The second-step growth (under low V/III and low pressure) promoted the lateral growth and filled up the voids. Striations that formed during the island coalescence persisted throughout the second-step growth, but could be relieved by an additional third-step growth. The morphological evolution was explained according to the kinetic Wulff plots. The microstructure of the a-GaN films was investigated by transmission electron microscopy (TEM) and x-ray rocking curve analysis. Most of the extended defects observed in the plan-view TEM images were I1 type basal-plane stacking faults (BSFs) and their associated partial dislocations (PDs). It is found that the bending of PDs (at the inclined/vertical growth fronts) within the basal plane toward the m-axes was responsible for the substantial reduction in threading PDs and the increase in BSF dimension. Based on a careful correlation between the morphological evolution and the microstructure development, we proposed a model explaining the possible mechanisms for the great reduction in defect density during the two-step growth process.
Demonstration on GaN-based light-emitting diodes grown on 3C-SiC/Si(111)
Authors: Zhu Y. H. , Zhang J. C. , Chen Z. T. , Egawa T.
Published: December 2009

GaN-based light-emitting diodes (LEDs) grown on template of 3C-SiC/Si(111) were demonstrated. The structural properties have been investigated systematically by means of atomic force microscopy, x-ray diffraction, and transmission electron microscopy. It is found that the intermediate layer (IL) of 3C-SiC leads to not only a significant improvement in the crystalline quality of GaN, but also better interfaces between the buffer layer and the initial layers of strained-layer superlattice. The device properties were also evaluated using the measurements of current-voltage, electroluminescence, and light output power-current. Compared to conventional LEDs that do not contain 3C-SiC IL, the device with IL exhibits enhanced output power by more than 200% at an injection current of 20 mA, and the operating voltage is slightly increased from 3.7 to 3.9 V. These results indicate that using 3C-SiC as IL is one of the promising approaches to improve the performance of LEDs on silicon.
Enhanced shot noise in carbon nanotube field-effect transistors
Authors: Betti A. , Fiori G. , Iannaccone G.
Published: December 2009

We predict shot noise enhancement in defect-free carbon nanotube field-effect transistors through a numerical investigation based on the self-consistent solution of the Poisson and Schrödinger equations within the nonequilibrium Green’s functions formalism, and on a Monte Carlo approach to reproduce injection statistics. Noise enhancement is due to the correlation between trapping of holes from the drain into quasibound states in the channel and thermionic injection of electrons from the source, and can lead to an appreciable Fano factor of 1.22 at room temperature.
A programmable microvalve-based microfluidic array for characterization of neurotoxin-induced responses of individual C. elegans
Authors: Ma Hui , Jiang Lei , Shi Weiwei , Qin Jianhua , Lin Bingcheng
Published: December 2009

The soil dwelling nematode Caenorhabditis elegans (C. elegans) is an excellent model organism for the study of numerous disease including neurodegenerative disease. In this study, a programmable microvalve-based microfluidic array for real-time and long-term monitoring of the neurotoxin-induced responses of the individual C. elegans was developed. The device consisted of a flow layer and a control layer, which were used for worm manipulation. By activating the programmable microvalves in the control layer, mutiple worms could be individually captured and intermittently immobilized in parallel channels. Thus the mobility behavior, together with the corresponding dopaminergic neuron features of the worms in response to neurotoxin, could be investigated simultaneously. It was found that the neurotoxin MPP+ enabled to induce mobility defects and dopaminergic neurons loss in worms. The established system is easy and fast to operate, which offers not only the controllable microenvironment for analyzing the individual worms in parallel, monitoring the same worm over time, but also the capability to characterize the mobility behavior and neuron features in response to stimuli simultaneously. In addition, the device enabled to sustain the worm culture over most of their adult lifespan without any harm to worm, providing a potential platform for lifespan and aging research.
The radio-frequency impedance of individual intrinsic Josephson junctions
Authors: Leiner Johannes , Saleem Sajid , Fenton J. C. , Yamamoto Takashi , Kadowaki Kazuo , Warburton P. A.
Published: December 2009

We have measured the response of an array of Bi2Sr2CaCu2O8+δ intrinsic Josephson junctions to irradiation at 3 GHz. By measuring the dependence of the switching current upon the radio-frequency current for five of the junctions in the array we show quantitatively that the junctions have identical impedances at 3 GHz, this impedance being given by the inverse of the slope of the current-voltage characteristics.