bluuebunny/crossref_metadata_2025 huggingface dataset:
Observation of the single-electron regime in a highly tunable silicon quantum dot
Authors: Lim W. H. , Zwanenburg F. A. , Huebl H. , Möttönen M. , Chan K. W. , Morello A. , Dzurak A. S.
Published: December 2009

We report on low-temperature electronic transport measurements of a silicon metal-oxidesemiconductor quantum dot, with independent gate control of electron densities in the leads and the quantum dot island. This architecture allows the dot energy levels to be probed without affecting the electron density in the leads and vice versa. Appropriate gate biasing enables the dot occupancy to be reduced to the single-electron level, as evidenced by magnetospectroscopy measurements of the ground state of the first two charge transitions. Independent gate control of the electron reservoirs also enables discrimination between excited states of the dot and density of states modulations in the leads.
Fabrication of high efficiency III-V quantum nanostructures at low thermal budget on Si
Authors: Bietti S. , Somaschini C. , Sanguinetti S. , Koguchi N. , Isella G. , Chrastina D.
Published: December 2009

We fabricate high efficiency GaAs∕AlGaAs quantum nanostructure active layer for intersubband detectors and light emitting devices on a silicon substrate. The whole process of formation of the GaAs∕AlGaAs active layer was realized via droplet epitaxy and migration enhanced epitaxy maintaining the growth temperature ⩽350°C, thus resulting in a low thermal budget procedure compatible with back-end integration of the fabricated materials on integrated circuits. The realized quantum nanostructures show optical efficiencies comparable to those achievable with state of the art quantum dot materials grown on GaAs substrates.
Depth resolved luminescence from oriented ZnO nanowires
Authors: Rosenberg R. A. , Abu Haija M. , Vijayalakshmi K. , Zhou J. , Xu S. , Wang Z. L.
Published: December 2009

We have utilized the limited penetration depth of x-rays to study the near-surface properties of vertically aligned ZnO nanowires. For an energy of 600 eV the penetration depth varies between 3 and 132 nm as the incidence angle changes from 2° to 33°. Thus, by obtaining optical luminescence spectra as a function of incidence angle, it is possible to probe the near-surface region with nanometer-scale resolution. We will present angle dependent optical luminescence data from oriented ZnO nanowires. By fitting the results to a simple model, we extract a depth for the surface defect regions of ∼14 nm.
Real-time observation of the transition from transcription initiation to elongation of the RNA polymerase
Authors: Tang Guo-Qing , Roy Rahul , Bandwar Rajiv P. , Ha Taekjip , Patel Smita S.
Published: December 2009

The transition from initiation to elongation of the RNA polymerase (RNAP) is an important stage of transcription that often limits the production of the full-length RNA. Little is known about the RNAP transition kinetics and the steps that dictate the transition rate, because of the challenge in monitoring subpopulations of the transient and heterogeneous transcribing complexes in rapid and real time. Here, we have dissected the complete transcription initiation pathway of T7 RNAP by using kinetic modeling of RNA synthesis and by determining the initiation (IC) to elongation (EC) transition kinetics at each RNA polymerization step using single-molecule and stopped-flow FRET methods. We show that the conversion of IC to EC in T7 RNAP consensus promoter occurs only after 8- to 12-nt synthesis, and the 12-nt synthesis represents a critical juncture in the transcriptional initiation pathway when EC formation is most efficient. We show that the slow steps of transcription initiation, including DNA scrunching/RNAP–promoter rotational changes during 5- to 8-nt synthesis, not the major conformational changes, dictate the overall rate of EC formation in T7 RNAP and represent key steps that regulate the synthesis of full-length RNA.
The electronic structure of the primary electron donor of reaction centers of purple bacteria at atomic resolution as observed by photo-CIDNP
13
C NMR
Authors: Daviso Eugenio , Prakash Shipra , Alia A. , Gast Peter , Neugebauer Johannes , Jeschke Gunnar , Matysik Jörg
Published: December 2009

Composed of the two bacteriochlorophyll cofactors, P
L
and P
M
, the special pair functions as the primary electron donor in bacterial reaction centers of purple bacteria of
Rhodobacter sphaeroides
. Under light absorption, an electron is transferred to a bacteriopheophytin and a radical pair is produced. The occurrence of the radical pair is linked to the production of enhanced nuclear polarization called photochemically induced dynamic nuclear polarization (photo-CIDNP). This effect can be used to study the electronic structure of the special pair at atomic resolution by detection of the strongly enhanced nuclear polarization with laser-flash photo-CIDNP magic-angle spinning NMR on the carotenoid-less mutant R26. In the electronic ground state, P
L
is strongly disturbed, carrying a slightly negative charge. In the radical cation state, the ratio of total electron spin densities between P
L
and P
M
is 2:1, although it is 2.5:1 for the pyrrole carbons, 2.2:1 for all porphyrinic carbons, and 4:1 for the pyrrole nitrogen. It is shown that the symmetry break between the electronic structures in the electronic ground state and in the radical cation state is an intrinsic property of the special pair supermolecule, which is particularly attributable to a modification of the structure of P
L
. The significant difference in electron density distribution between the ground and radical cation states is explained by an electric polarization effect of the nearby histidine.
Activation of EGFR on monocytes is required for human cytomegalovirus entry and mediates cellular motility
Authors: Chan Gary , Nogalski Maciej T. , Yurochko Andrew D.
Published: December 2009

Human cytomegalovirus (HCMV) rapidly induces a mobile and functionally unique proinflammatory monocyte following infection that is proposed to mediate viral spread. The cellular pathways used by HCMV to initiate these biological changes remain unknown. Here, we document the expression of the epidermal growth factor receptor (EGFR) on the surface of human peripheral blood monocytes but not on other blood leukocyte populations. Inhibition of EGFR signaling abrogated viral entry into monocytes, indicating that EGFR can serve as a cellular tropism receptor. Moreover, HCMV-activated EGFR was required for the induction of monocyte motility and transendothelial migration, two biological events required for monocyte extravasation into peripheral tissue, and thus viral spread. Transcriptome analysis revealed that HCMV-mediated EGFR signaling up-regulated neural Wiskott–Aldrich syndrome protein (N-WASP), an actin nucleator whose expression and function are normally limited in leukocytes. Knockdown of N-WASP expression blocked HCMV-induced but not phorbol 12-myristate 13-acetate (PMA)-induced monocyte motility, suggesting that a switch to and/or the distinct use of a new actin nucleator controlling motility occurs during HCMV infection of monocytes. Together, these data provide evidence that EGFR plays an essential role in the immunopathobiology of HCMV by mediating viral entry into monocytes and stimulating the aberrant biological activity that promotes hematogenous dissemination.
Sigma-1 receptors regulate hippocampal dendritic spine formation via a free radical-sensitive mechanism involving Rac1·GTP pathway
Authors: Tsai Shang-Yi , Hayashi Teruo , Harvey Brandon K. , Wang Yun , Wu Wells W. , Shen Rong-Fong , Zhang Yongqing , Becker Kevin G. , Hoffer Barry J. , Su Tsung-Ping
Published: December 2009

Sigma-1 receptors (Sig-1Rs) are endoplasmic reticulum (ER)-resident proteins known to be involved in learning and memory. Dendritic spines in hippocampal neurons play important roles in neuroplasticity and learning and memory. This study tested the hypothesis that Sig-1Rs might regulate denritic spine formation in hippocampal neurons and examined potential mechanisms therein. In rat hippocampal primary neurons, the knockdown of Sig-1Rs by siRNAs causes a deficit in the formation of dendritic spines that is unrelated to ER Ca2+signaling or apoptosis, but correlates with the mitochondrial permeability transition and cytochromecrelease, followed by caspase-3 activation, Tiam1 cleavage, and a reduction in Rac1·GTP. Sig-1R-knockdown neurons contain higher levels of free radicals when compared to control neurons. The activation of superoxide dismutase or the application of the hydroxyl-free radical scavenger N-acetyl cysteine (NAC) to the Sig-1R-knockdown neurons rescues dendritic spines and mitochondria from the deficits caused by Sig-1R siRNA. Further, the caspase-3-resistant TIAM1 construct C1199DN, a stable guanine exchange factor able to constitutively activate Rac1 in the form of Rac1·GTP, also reverses the siRNA-induced dendritic spine deficits. In addition, constitutively active Rac1·GTP reverses this deficit. These results implicate Sig-1Rs as endogenous regulators of hippopcampal dendritic spine formation and suggest a free radical-sensitive ER-mitochondrion-Rac1·GTP pathway in the regulation of dendritic spine formation in the hippocampus.
Structural determinants of ion permeation in CRAC channels
Authors: McNally Beth A. , Yamashita Megumi , Engh Anita , Prakriya Murali
Published: December 2009

CRAC channels generate Ca
2+
signals critical for the activation of immune cells and exhibit an intriguing pore profile distinguished by extremely high Ca
2+
selectivity, low Cs
+
permeability, and small unitary conductance. To identify the ion conduction pathway and gain insight into the structural bases of these permeation characteristics, we introduced cysteine residues in the CRAC channel pore subunit, Orai1, and probed their accessibility to various thiol-reactive reagents. Our results indicate that the architecture of the ion conduction pathway is characterized by a flexible outer vestibule formed by the TM1-TM2 loop, which leads to a narrow pore flanked by residues of a helical TM1 segment. Residues in TM3, and specifically, E190, a residue considered important for ion selectivity, are not close to the pore. Moreover, the outer vestibule does not significantly contribute to ion selectivity, implying that Ca
2+
selectivity is conferred mainly by E106. The ion conduction pathway is sufficiently narrow along much of its length to permit stable coordination of Cd
2+
by several TM1 residues, which likely explains the slow flux of ions within the restrained geometry of the pore. These results provide a structural framework to understand the unique permeation properties of CRAC channels.
Expression of mutant huntingtin in mouse brain astrocytes causes age-dependent neurological symptoms
Authors: Bradford Jennifer , Shin Ji-Yeon , Roberts Meredith , Wang Chuan-En , Li Xiao-Jiang , Li Shihua
Published: December 2009

Huntington disease (HD) is an inherited neurological disorder caused by a polyglutamine expansion in the protein huntingtin and is characterized by selective neurodegeneration that preferentially occurs in striatal medium spiny neurons. Because the medium spiny neurons are innervated abundantly by glutamatergic axons from cortical neurons, the preferential degeneration in the striatal neurons supports the glutamate excitotoxicity theory for HD pathogenesis. Thus, glutamate uptake by glia may be particularly important for preventing glutamate excitotoxicity in HD. Although mutant huntingtin is expressed ubiquitously in various types of cells, it accumulates and forms aggregates in fewer glial cells than in neuronal cells. It remains largely unknown whether and how mutant huntingtin in glia can contribute to the neurological symptoms of HD. We generated transgenic mice that express N-terminal mutant huntingtin in astrocytes, a major type of glial cell that remove extracellular glutamate in the brain. Although transgenic mutant huntingtin in astrocytes is expressed below the endogenous level, it can cause age-dependent neurological phenotypes in transgenic mice. Mice expressing mutant huntingtin show body weight loss, have motor function deficits, and die earlier than wild-type or control transgenic mice. We also found that mutant huntingtin in astrocytes decreases the expression of glutamate transporter by increasing its binding to Sp1 and reducing the association of Sp1 with the promoter of glutamate transporter. These results imply an important role for glial mutant huntingtin in HD pathology and suggest possibilities for treatment.
Gangliosides play pivotal roles in the regulation of complement systems and in the maintenance of integrity in nerve tissues
Authors: Ohmi Yuhsuke , Tajima Orie , Ohkawa Yuki , Mori Atsushi , Sugiura Yasuo , Furukawa Keiko , Furukawa Koichi
Published: December 2009

Gangliosides are considered to be essential in the maintenance and repair of nervous tissues; however, the mechanisms for neurodegeneration caused by ganglioside defects are unknown. We examined gene expression profiles in double knockout (DKO) mice of GM2/GD2 synthase and GD3 synthase genes and showed that the majority of complement genes and their receptors were up-regulated in cerebellum in DKO mice. Inflammatory reactions were demonstrated in those tissues by measuring up-regulated inflammatory cytokines, indicating the presence of complement activation and inflammation as reported in Alzheimer's disease. Immunoblotting of fractionated membrane extracts by sucrose density gradient revealed that complement-regulatory molecules such as decay-accelerating factor and CD59 were dispersed from glycolipid-enriched microdomain/rafts in DKO cerebellum. Immunohistostaining of these molecules showed disordered membrane localization. These results suggested that dysfunction of complement-regulatory molecules may be due to abnormal glycolipid-enriched microdomain/rafts that triggered complement activation, subsequent inflammation, and neurodegeneration in DKO mice. Generation of the triple KO mice lacking complement activity in addition to the two glycosyltransferases suggested that complement activation is involved in the inflammatory reactions and neurodegeneration caused by the ganglioside deficiency.
Transcriptional response in the peripheral blood of patients infected with Salmonella enterica serovar Typhi
Authors: Thompson Lucinda J. , Dunstan Sarah J. , Dolecek Christiane , Perkins Tim , House Deborah , Dougan Gordon , Hue Nguyen Thi , Phi La Tran Thi , Du Doan Cong , Phuong Le Thi , Dung Nguyen Thi , Hien Tran Tinh , Farrar Jeremy J. , Monack Denise , Lynn David J. , Popper Stephen J. , Falkow Stanley
Published: December 2009

We used microarrays and transcriptional profiling of peripheral blood to investigate the host response of 29 individuals who contracted typhoid fever in the Mekong Delta region of Vietnam. Samples were taken over a nine month period encompassing acute disease, convalescence, and recovery. We found that typhoid fever induced a distinct and highly reproducible signature in the peripheral blood that changed during treatment and convalescence, returning in the majority of cases to the “normal” profile as measured in healthy uninfected controls. Unexpectedly, there was a strong, distinct signature of convalescence present at day 9 after infection that remained virtually unchanged one month after acute infection and in some cases persisted as long as nine months despite a complete clinical recovery in all patients. Patients who retain the convalescent signature may be genetically or temporarily incapable of developing an effective immune response and may be more susceptible to reinfection, relapse, or the establishment of a carrier state.
Yugoslavia in 1989 and after
Authors: Gagnon V.P. (Chip)
Published: December 2009

The year 1989 marked a turning point for the Socialist Federal Republic of Yugoslavia (SFRY). But unlike other places in the region, that year saw a turn towards growing political conflict which soon led to violent warfare. This paper identifies and discusses three processes that led to this outcome. The first process was the impetus towards reform of the Yugoslav federal state, its political and economic system. The second was the conflict over the future of the League of Communists of Yugoslavia (Savez komunista Jugoslavije – SKJ). The third was the shifting meanings of ethnic and nonethnic labels and the ways in which putative “national” and “ethnic” interests came to be aligned with specific political options. By the end of 1989 these three processes had come together to spell the end of the SKJ, of the SFRY, and of “Yugoslavism” as a political identity. In their places, ruling parties threatened by changes within their own societies, as well as by pressures created by the 1989 revolutions in the region, resorted to strategies of conflict and violence in an attempt to forestall the kinds of changes and elite turnovers seen in other socialist countries.
Howard's End: a narrative memoir of political contrivance, neoconservative ideology and the Australian history curriculum
Authors: Taylor Tony
Published: December 2009

In August 2006, Australia's conservative prime minister John Howard convened a history summit in Canberra. The purported goal of the summit was the framing of a nationally‐acceptable curriculum in Australian history. However, as this article suggests, Howard's hidden intention was to use the summit as a device for introducing a narrowly traditionalist syllabus that would be personally pleasing to the prime minister. As it happened, Howard's plan encountered resistance from members of the history education community and, after several diversions and alarms, was discarded when the conservative coalition government was defeated in the general election of November 2007. The author was closely involved in these proceedings and this article constitutes a contextualisd memoir of events.
History in the National Curriculum: a lesson in curriculum devolution
Authors: Jones Gareth Elwyn
Published: December 2009

This article will focus on an event in the educational history of Wales in the 1980s which still impacts both on school practice and on thinking about concepts of Welsh identity. That event was the creation of the History Committee for Wales which was charged with devising a history curriculum for Welsh schools in the wake of the 1988 Education Act. The story will be told largely by using evidence gleaned in elite interviews with the ministers, senior inspectors and civil servants most closely associated with the decision to support or accept the creation of this committee.

 The significance of the decision will be assessed by charting the progress of curriculum devolution in Wales from the beginnings of state education and the implications of this for ideas of Welshness. This background will be briefly sketched, as will the background to the 1988 Education Act on a wider canvas. General reaction to that act in the Welsh Office will be discussed before the detailed implications for the subject of history will be explored in detail.

 It will then be argued that wider discussions as to how schools should approach and reflect the history and culture of nations not only shed important light on devolutionary processes which were gathering pace at the time but also reflect the nature of Welshness as perceived by senior figures in the world of education policy‐making.
How history becomes a cross‐border matter: death foretold of a French–German–Swiss textbook
Authors: Dupeyron Bruno
Published: December 2009

The middle of the 1990s saw the creation of a French–German–Swiss history textbook supported by the European Commission. Disseminated to school instructors in the Upper Rhine, it received generally positive reviews, but ended up on the dusty shelves of school libraries. This result was due to several factors, which are analysed in this article. This acknowledgement of failure leads to the argument that European cross‐border cooperation is constrained by a key paradox, referred to as ‘low gravity’, i.e. the attraction of small projects toward the local and regional levels, while major projects are pushed up to the national level.
‘I think it's about the teacher feeding off our minds, instead of us learning off them, sort of like switching the process around’: pupils' perspectives on being consulted about classroom teaching and learning
Authors: Morgan Bethan
Published: December 2009

This article reports on selected findings from a doctoral study which investigated how teachers in an 11–16 secondary school in the UK consulted pupils about teaching and learning in their classrooms. It presents the views of pupils on the consultation practices and responses of their teachers. While interest in consulting pupils has increased over the last decade, there is little published research on pupils' perspectives on being consulted apart from Rudduck and McIntyre who themselves draw upon data from the study reported here. Qualitative case‐studies of four teachers were carried out over one academic year. Data were gathered through semi‐structured interviews (with the teachers, with 75 Year 8 pupils and with school management) and lesson observation. Analysis was guided by a systematic inductive approach aided by NVivo. Key findings were that pupils: (i) welcomed consultation; (ii) had much to say about its benefits; (iii) valued feedback from teachers post‐consultation; and (iv) had concerns clustered around issues of trust and anonymity. The article suggests there are implications for teachers, school management and policy‐makers if significant benefit is to be realised from teachers consulting pupils on teaching and learning in the classroom.
Ground rules for talk: the acceptable face of prescription
Authors: Lambirth Andrew
Published: December 2009

In this second article on the theory of ‘ground rules for talk’ I extend a debate between myself and Professor Neil Mercer over the introduction of ‘ground rules’ into classrooms. I critique ground rules through the use of sociological theory and argue that advocates of the ground rules perspective need to recognise the ideological nature of their theoretical position. In making this article a clear extension of my previous argument I introduce the work of Bernstein and Fairclough to support my new arguments. I use Bernstein's theory of pedagogy as cultural relay and Fairclough's appropriateness model of language variation to critique ‘ground rules perspectives’. In doing so, I draw out the political nature of educational theory and curriculum within the context of a specific socio‐economic society.
Integrating media education into liberal studies: a positive response to curriculum reform in Hong Kong
Authors: Cheung C.K.
Published: December 2009

Media education has been around for quite some time in the West (Bazalgette et al. 1990), but it only started to gain acceptance in Asia (Cheung 2005), particularly in Hong Kong, in the last decade. Recently, it has been gaining more attention in Hong Kong thanks to the curriculum reform in which liberal studies will become one of the four core subjects to be taken by students in the New Senior Secondary Curriculum and media is one of the six themes to be studied in the subject of liberal studies. This article argues for the need for teaching media education in liberal studies and shows the many connections between the two subjects that facilitate this integration.
Signs, symbols and metaphor: linking self with text in inquiry‐based learning
Authors: Crick Ruth Deakin , Grushka Kath
Published: December 2009

The focus in this article is on the role of symbol and metaphor in the development of student self‐awareness and engagement in the process of learning. It draws on a case‐study which explored the process of an inquiry‐based learning project in an Indigenous learning centre in a school in New South Wales, Australia. The data used for this article were taken from the first stage of the inquiry project – the construction of a shared language for learning. The article argues that developing a rich and local language for learning, that links to the collective consciousness of a community through metaphors and symbols, is a crucial prerequisite for inquiry‐based learning. It reveals how the naming of native Australian animals as icons for learning power, the co‐construction of a learning story and the creation of a self‐portrait as a learner collage provide mechanisms through which the students can performatively re‐represent and recall their identities as learners. The processes enable the students to make connections between self and the meanings carried in the pictorial texts to develop self‐awareness and responsibility for their own learning. It also provides the learners and their mentors with the necessary symbols and metaphors to scaffold the process of the inquiry in ways that allowed them to use the metaphors associated with the symbols to talk about change and to begin to engage with the formal requirements of the curriculum.
Inquiry‐based learning: personalisation or the rehabilitation of human value
Authors: Steed Chris
Published: December 2009

In this article I argue that the concept of personalisation is simply rhetorical unless it facilitates theory and practice which takes seriously and engages with the value of the human person. The idea of human value is a fundamental theme in social and cultural life and the motor behind many psychological and social processes. Traditionally, knowledge presented as abstract and top down, and education systems which are driven by targets and economic imperatives, can unwittingly contribute to human devaluation by marginalising the personal, the idiosyncratic and the particular. The model of inquiry‐based learning discussed here offers pedagogical strategies which attend to the self who is learning, as well as facilitating learners in engaging with the moral questions of human value embedded in processes of knowledge construction.
The Role of Working Memory in Information Acquisition and Decision Making: Lessons from the Binary Prediction Task
Authors: Rakow Tim , Newell Ben R. , Zougkou Konstantina
Published: December 2009

The effects of memory constraints upon information acquisition and decision making were examined in two experiments using binary prediction tasks, where participants observe outcomes for two options before deciding which one to bet upon. Our studies extend previous investigations to the case where participants learn the structure of the task through observation, but where information acquisition is separated from the task of prediction. Participants with higher cognitive capacity (larger memory span or higher intelligence) were more likely to adopt the “maximizing” strategy (always selecting the more frequent alternative). This finding conflicts with some recent investigations of similar tasks, a contrast that implies that the presence of feedback on choices may be important in determining the strategic actions of high-capacity individuals. Participants selecting the optimal strategy were in turn more efficient in their data acquisition. The behaviour of participants adopting suboptimal choice strategies was consistent with prediction based upon a “narrow window of experience”—that is, seeking to match the characteristics of small samples of observations.
Sex differences in the processing of flankers
Authors: Stoet Gijsbert
Published: December 2009

The study of sex differences in cognition has often focused on differences in spatial processing. Recently, sex differences in selective attention have been observed by Bayliss, di Pellegrino, and Tipper (2005), showing that women are more influenced than men by irrelevant spatial cues. The current study elaborates on this finding and tests whether sex differences in the processing of irrelevant information also occur in a simpler task, in which there is no need to redirect visual attention and no need to remember multiple spatial stimulus–response associations. Here, attention is studied using a novel combination of a go/no-go task and a flanker task. A total of 80 neurotypical participants were studied, and it was found that responses in women were more strongly affected by flanker information than were responses in men. This suggests that these sex differences were not due to difficulties with spatial reorientation, or remembering spatial stimulus–response relationships. The findings are discussed in the context of the hunter–gatherer theory of sex differences.
Polysaccharide of Radix Pseudostellariae Improves Chronic Fatigue Syndrome Induced by Poly I:C in Mice
Authors: Sheng Rong , Xu Xianxiang , Tang Qin , Bian Difei , Li Ying , Qian Cheng , He Xin , Gao Xinghua , Pan Rong , Wang Chong , Luo Yubin , Xia Yufeng , Dai Yue
Published: December 2009

Radix Pseudostellariae is used as a tonic drug in traditional Chinese medicine with immunomodulating and anti‐fatigue activities, and the polysaccharide is considered as the main active component. The purpose of this study is to examine the effect of the polysaccharide isolated from Radix Pseudostellariae (PRP) on mouse chronic fatigue syndrome (CFS) induced by intraperitoneal injection of polyriboinosinic:polyribocytidylic acid (poly I:C), a double‐stranded synthetic RNA. It has shown that the fatigue symptom of mice lasted at least 1 week as evaluated by forced swimming time. PRP (100, 200, 400 mg kg−1), orally administered 3 days before poly I:C injection, showed dose‐dependent anti‐fatigue effects. In addition, poly I:C led to evident alternations in neuroendocrine and immune systems of mice, such as reduced spontaneous activity and learning ability, declined serum level of corticosterone, increased weight indexes and T lymphocyte numbers in thymuses and spleens, and increased CD4+/CD8+ ratio but decreased proliferation ability of T lymphocytes in spleens. PRP alleviated the abnormalities caused by poly I:C, and restored the function of hosts to normal conditions. The findings suggest that PRP is beneficial to CFS, and the underlying mechanisms of action involve neuroendocrine and immune systems.
REC‐2006—A Fractionated Extract of Podophyllum hexandrum Protects Cellular DNA from Radiation‐Induced Damage by Reducing the Initial Damage and Enhancing Its Repair In Vivo
Authors: Chaudhary Pankaj , Shukla Sandeep Kumar , Sharma Rakesh Kumar
Published: December 2009

Podophyllum hexandrum, a perennial herb commonly known as the Himalayan May Apple, is well known in Indian and Chinese traditional systems of medicine. P. hexandrum has been widely used for the treatment of venereal warts, skin infections, bacterial and viral infections, and different cancers of the brain, lung and bladder. This study aimed at elucidating the effect of REC‐2006, a bioactive fractionated extract from the rhizome of P. hexandrum, on the kinetics of induction and repair of radiation‐induced DNA damage in murine thymocytes in vivo. We evaluated its effect on non‐specific radiation‐induced DNA damage by the alkaline halo assay in terms of relative nuclear spreading factor (RNSF) and gene‐specific radiation‐induced DNA damage via semi‐quantitative polymerase chain reaction. Whole body exposure of animals with gamma rays (10 Gy) caused a significant amount of DNA damage in thymocytes (RNSF values 17.7 ± 0.47, 12.96 ± 1.64 and 3.3 ± 0.014) and a reduction in the amplification of β‐globin gene to 0, 28 and 43% at 0, 15 and 60 min, respectively. Administrating REC‐2006 at a radioprotective concentration (15 mg kg−1 body weight) 1 h before irradiation resulted in time‐dependent reduction of DNA damage evident as a decrease in RNSF values 6.156 ± 0.576, 1.647 ± 0.534 and 0.496 ± 0.012, and an increase in β‐globin gene amplification 36, 95 and 99%, at 0, 15 and 60 min, respectively. REC‐2006 scavenged radiation‐induced hydroxyl radicals in a dose‐dependent manner stabilized DPPH free radicals and also inhibited superoxide anions. Various polyphenols and flavonoides present in REC‐2006 might contribute to scavenging of radiation‐induced free radicals, thereby preventing DNA damage and stimulating its repair.
Desargues maps and the Hirota–Miwa equation
Authors: Doliwa Adam
Published: December 2009

We study the Desargues maps, which generate lattices whose points are collinear with all their nearest (in positive directions) neighbours. The multi-dimensional compatibility of the map is equivalent to the Desargues theorem and its higher dimensional generalizations. The nonlinear counterpart of the map is the non-commutative (in general) Hirota–Miwa system. In the commutative case of the complex field we apply the non-local-dressing method to construct Desargues maps and the corresponding solutions of the system. In particular, we identify the Fredholm determinant of the integral equation inverting the non-local-dressing problem with theτ-function. Finally, we establish equivalence between the Desargues maps and quadrilateral lattices provided we take into consideration also their Laplace transforms.
A model of carbon dioxide dissolution and mineral carbonation kinetics
Authors: Mitchell Mark J. , Jensen Oliver E. , Cliffe K. Andrew , Maroto-Valer M. Mercedes
Published: December 2009

The kinetics of the dissolution of carbon dioxide in water and subsequent chemical reactions through to the formation of calcium carbonate, a system of reactions integral to carbon sequestration and anthropogenic ocean acidification, is mathematically modelled using the mass action law. This group of reactions is expressed as a system of five coupled nonlinear ordinary differential equations, with 14 independent parameters. The evolution of this system to equilibrium at 25
°
C and 1 atm, following an instantaneous injection of gaseous carbon dioxide, is simulated. An asymptotic analysis captures the leading-order behaviour of the system over six disparate time scales, yielding expressions for all species in each time scale. These approximations show excellent agreement with simulations of the full system, and give remarkably simple formulae for the equilibrium concentrations.
Rupture of thin films formed during droplet impact
Authors: Dhiman Rajeev , Chandra Sanjeev
Published: December 2009

Rupture of liquid films formed during droplet impact on a dry solid surface was studied experimentally. Water droplets (580±70 μm) were photographed as they hit a solid substrate at high velocities (10–30 m s
−1
). Droplet–substrate wettability was varied over a wide range, from hydrophilic to superhydrophobic, by changing the material of the substrate (glass, Plexiglas, wax and alkylketene dimer). Both smooth and rough wax surfaces were tested. Photographs of impact showed that as the impact velocity increased and the film thickness decreased, films became unstable and ruptured internally through the formation of holes. However, the impact velocity at which rupture occurred was found to first decrease and then increase with the liquid–solid contact angle, with wax showing rupture at all impact velocities tested. A thermodynamic stability analysis combined with a droplet spreading model predicted the rupture behaviour by showing that films would be stable at very small or at very large contact angles, but unstable in between. Film rupture was found to be greatly promoted by surface roughness.
Climate change and spring-fruiting fungi
Authors: Kauserud Håvard , Heegaard Einar , Semenov Mikhail A. , Boddy Lynne , Halvorsen Rune , Stige Leif Chr. , Sparks Tim H. , Gange Alan C. , Stenseth Nils Chr.
Published: December 2009

Most macrofungi produce ephemeral fruit bodies during autumn but some have adapted to spring fruiting. In this study, temporal changes in the time of spring fruiting in Norway and the UK during 1960–2007 have been investigated by statistical analyses of about 6000 herbarium and field records, covering 34 species. Nearly 30 per cent of the temporal variation in fruiting could be ascribed to spatial and species-specific effects. Correcting for these effects, linear trends towards progressively earlier fruiting were detected during the entire period in both Norway and the UK, with a change in average fruiting day of 18 days over the study period. Early fruiting was correlated with high winter temperatures in both countries, indicating that the observed phenological changes are likely due to earlier onset of spring. There were also significant correlations between climatic conditions in one year and timing of fruiting the following year, indicating that below-ground mycelia are influenced by climatic conditions over a longer time period before fruiting. Fruiting dates were, however, not strictly related to changes in vernal accumulated thermal time. Our results indicate that global warming has lead to progressively earlier fruiting of spring fungi in northwest Europe during the last half century.
Extending anticipation horizon of chaos synchronization schemes with time-delay coupling
Authors: Pyragas Kestutis , Pyragienė Tatjana
Published: December 2009

We analyse anticipating synchronization in chaotic systems with time-delay coupling. Two algorithms for extending the prediction horizon are considered. One of them is based on the design of a suitable coupling matrix compensating the phase lag in the time-delay feedback term of the slave system. The second algorithm extends the first by incorporating, in the coupling law, information from many previous states of the master and slave systems. We demonstrate the efficiency of both algorithms with the simple dynamical model of coupled unstable spirals, as well as with the coupled Rössler systems. The maximum prediction time attained for the Rössler system is equal to the characteristic period of chaotic oscillations.
Williamsia faeni sp. nov., an actinomycete isolated from a hay meadow
Authors: Jones Amanda L. , Payne Gail D. , Goodfellow Michael
Published: December 2009

The taxonomic status of an actinomycete isolated from soil collected from a hay meadow was determined using a polyphasic approach. The strain, designated N1350T, had morphological and chemotaxonomic properties consistent with its classification in the genus Williamsia and formed a distinct phyletic line within the clade comprising the type strains of species of the genus Williamsia in the 16S rRNA gene tree. Strain N1350T shared highest 16S rRNA gene sequence similarities with Williamsia marianensis MT8T (98.1 %) and Williamsia muralis MA140-96T (98.3 %). However, strain N1350T was readily distinguished from the type strains of Williamsia species using a combination of phenotypic properties. On the basis of these data, strain N1350T is considered to represent a novel species of the genus Williamsia. The name proposed for this taxon is Williamsia faeni sp. nov., with the type strain N1350T (=DSM 45372T =NCIMB 14575T =NRRL B-24794T).
Molecular systematics of marine gregarines (Apicomplexa) from North-eastern Pacific polychaetes and nemerteans, with descriptions of three novel species: Lecudina phyllochaetopteri sp. nov., Difficilina tubulani sp. nov. and Difficilina paranemertis sp. nov.
Authors: Rueckert Sonja , Chantangsi Chitchai , Leander Brian S.
Published: December 2009

Most eugregarine apicomplexans infecting the intestines of marine invertebrates have been described within the family Lecudinidae and the type genus Lecudina. The diversity of these parasites is vast and poorly understood and only a tiny number of species has been characterized at the molecular phylogenetic level. DNA sequences coupled with high-resolution micrographs of trophozoites provide an efficient and precise approach for delimiting gregarine lineages from one another and also facilitate our overall understanding of gregarine biodiversity. In this study, phylogenetic analyses of small subunit (SSU) rDNA sequences from five (uncultivated) gregarines isolated from polychaetes and nemerteans in the North-eastern Pacific Ocean are presented. Lecudina phyllochaetopteri sp. nov. was isolated from the intestines of the parchment tubeworm Phyllochaetopterus prolifica (Polychaeta). Lecudina longissima and Lecudina polymorpha were both isolated from the intestines of Lumbrineris japonica (Polychaeta). Difficilina tubulani sp. nov. was isolated from the nemertean Tubulanus polymorpha and Difficilina paranemertis sp. nov. was isolated from the nemertean Paranemertes peregrina. This is the first report of molecular sequence data from gregarines that infect nemerteans. The two novel species of the genus Difficilina described in this study formed a strongly supported clade in the phylogenetic analyses. This Difficilina clade formed the sister group to a robust subclade of lecudinids consisting of Lecudina longissima, Lecudina phyllochaetopteri sp. nov. (which lacked epicytic folds), Lecudina tuzetae, species of the genus Lankesteria and several sequences derived from previous environmental DNA surveys of marine biodiversity.
Mesorhizobium robiniae sp. nov., isolated from root nodules of Robinia pseudoacacia
Authors: Zhou Ping Fa , Chen Wei Min , Wei Ge Hong
Published: December 2009

Previously, five rhizobial strains isolated from root nodules of Robinia pseudoacacia were assigned to the same genospecies on the basis of identical 16S rRNA gene sequences and phylogenetic analyses of the nodA, nodC and nifH genes, in which the five isolates formed a well-supported group that excluded other sequences found in public databases. In this study, the 16S rRNA gene sequence similarities between the isolates and Mesorhizobium mediterraneum UPM-Ca36T and Mesorhizobium temperatum SDW018T were 99.5 and 99.6 %, respectively. The five isolates were also different from defined Mesorhizobium species using ERIC fingerprint profiles and they formed a novel Mesorhizobium lineage in phylogenetic analyses of recA and atpD gene sequences. DNA–DNA relatedness values between the representative strain, CCNWYC 115T, and type strains of defined Mesorhizobium species were found to be lower than 47.5 %. These results indicated that the isolates represented a novel genomic species. Therefore, a novel species, Mesorhizobium robiniae sp. nov., is proposed, with type strain CCNWYC 115T (=ACCC 14543T =HAMBI 3082T). Strain CCNWYC 115T can form effective nodules only on its original host.
Hydrophobin Fusions for High-Level Transient Protein Expression and Purification inNicotiana benthamiana
Authors: Joensuu Jussi J. , Conley Andrew J. , Lienemann Michael , Brandle Jim E. , Linder Markus B. , Menassa Rima
Published: December 2009

Insufficient accumulation levels of recombinant proteins in plants and the lack of efficient purification methods for recovering these valuable proteins have hindered the development of plant biotechnology applications. Hydrophobins are small and surface-active proteins derived from filamentous fungi that can be easily purified by a surfactant-based aqueous two-phase system. In this study, the hydrophobin HFBI sequence from Trichoderma reesei was fused to green fluorescent protein (GFP) and transiently expressed in Nicotiana benthamiana plants by Agrobacterium tumefaciens infiltration. The HFBI fusion significantly enhanced the accumulation of GFP, with the concentration of the fusion protein reaching 51% of total soluble protein, while also delaying necrosis of the infiltrated leaves. Furthermore, the endoplasmic reticulum-targeted GFP-HFBI fusion induced the formation of large novel protein bodies. A simple and scalable surfactant-based aqueous two-phase system was optimized to recover the HFBI fusion proteins from leaf extracts. The single-step phase separation was able to selectively recover up to 91% of the GFP-HFBI up to concentrations of 10 mg mL™1. HFBI fusions increased the expression levels of plant-made recombinant proteins while also providing a simple means for their subsequent purification. This hydrophobin fusion technology, when combined with the speed and posttranslational modification capabilities of plants, enhances the value of transient plant-based expression systems.
Aneuploidy Causes Tissue-Specific Qualitative Changes in Global Gene Expression Patterns in Maize
Authors: Makarevitch Irina , Harris Carolyn
Published: December 2009

Segmental aneuploidy refers to the relative excess or deficiency of specific chromosome regions. This condition results in gene dosage imbalance and often causes severe phenotypic alterations in plants and animals. The mechanisms by which gene dosage imbalance affects gene expression and phenotype are not completely clear. The effects of aneuploidy on the transcriptome may depend on the types of cells analyzed and on the developmental stage. We performed global gene expression profiling to determine the effects of segmental aneuploidy on gene expression levels in two different maize (Zea mays) tissues and a detailed analysis of expression of 30 genes affected by aneuploidy in multiple maize tissues. Different maize tissues varied in the frequency at which genes located outside of the aneuploid regions are positively or negatively regulated as well as in the degree of gene dosage compensation. Multiple genes demonstrated qualitative changes in gene expression due to aneuploidy, when the gene became ectopically expressed or completely silenced in aneuploids relative to wild-type plants. Our data strongly suggested that quantitative changes in gene expression at developmental transition points caused by variation in gene copy number progressed through tissue development and resulted in stable qualitative changes in gene expression patterns. Thus, aneuploidy in maize results in alterations of gene expression patterns that differ between tissues and developmental stages of maize seedlings.
Effectiveness of a smoking cessation intervention in Dutch pharmacies and general practices
Authors: Hoving Ciska , Mudde Aart N. , Dijk Froukje , de Vries Hein
Published: December 2009

Purpose

The purpose of this paper is to test the effectiveness of a computer‐tailored smoking cessation intervention, distributed through 75 Dutch general practices (GP) and 65 pharmacies (PH) in a randomised control trial.

Design/methodology/approach

Respondents receive a tailored letter or a thank you letter (control condition). Main outcome measures are a quit attempt, seven‐day abstinence and continued abstinence at follow‐up (PH: three and 12 months, GP: six months). Effect of use and appreciation of the tailored letter are also tested.

Findings

In total, 1,019 smokers are recruited (545 in PH study, 474 in GP study). At 12‐month follow‐up (PH), respondents receiving the tailored letter report quit attempts significantly more often. No main effects are found in the GP sample. However, reading the tailored letter more than once (GP) and talking with others about the tailored letter (PH) are borderline significant predictors of quitting and point prevalence abstinence.

Research limitations/implications

Positive effects of the intervention in a previous efficacy study are not repeated. The possible influence of power, social desirability and testing effect, extraneous events, the availability of the intervention outside the study and data entry issues are presented.

Practical implications

Possible explanations for the results found in the study and improvements of the intervention are discussed. This can guide researchers in future smoking cessation intervention development and testing.

Originality/value

The paper aims to replicate findings from a previously conducted efficacy study under real‐life circumstances.