bluuebunny/crossref_metadata_2025 huggingface dataset:
Capability of photoluminescence for characterization of multi-crystalline silicon
Authors: Mchedlidze T. , Seifert W. , Kittler M. , Blumenau A. T. , Birkmann B. , Mono T. , Müller M.
Published: April 2012

Application of various characterization methods for the investigation of photovoltaic materials allows fast progress in perfection of their quality. However, capabilities of the methods should be clearly understood and the methods should be applied in the correct manner to avoid false and/or unreliable interpretation of the results. We applied photoluminescence (PL) for characterization of multi-crystalline silicon (mc-Si) samples and compared the obtained results with carrier lifetime measurement data for the same samples. The analyses revealed strong influence of surface recombination and optical shadowing from grain boundaries on the interpretation of the PL results. Proper surface passivation allows application of defect-related luminescence for the characterization of mc-Si along with traditionally used band-to-band luminescence.
Local resistive switching of Nd doped BiFeO3 thin films
Authors: Shen Wan , Bell Andrew , Karimi Sarah , Reaney Ian M.
Published: April 2012

Local resistive switching behavior was investigated in Nd doped BiFeO3 thin film by conductive atomic force microscopy. The resistance of grains in Nd doped BiFeO3 thin films was reversibly switched between a low and high resistance state. When scanning a part of a grain interior, the whole grain eventually switched. Neighbouring grains, however, exhibited different values of conductance and remained unswitched. To explain this observation, it is proposed that the mobility of oxygen vacancies varies from grain to grain and that grain boundaries act as a barrier to their diffusion.
Aquatic ecosystems in inland Australia: tourism and recreational significance, ecological impacts and imperatives for management
Authors: Hadwen Wade L. , Boon Paul I. , Arthington Angela H.
Published: April 2012

The value of aquatic systems for biodiversity, agriculture, pastoralism and mining is widely recognised, whereas their significance for tourism and recreation is often poorly acknowledged. We surveyed protected-area managers, local governments and tour operators (river and general) to determine how aquatic systems were used in inland Australia for tourism and recreation and the perceived impacts of these uses. Inland waterbodies were reported by all respondent groups to be highly significant foci for visitors. Natural features were rated as more important to visitors than infrastructure by protected-area managers and river-tour operators, whereas all respondent groups identified water clarity, water quality and accessibility to water as important aspects of visitor appeal. Although >75% of respondents nominated visitors as being environmentally aware, visitors were reported to have a range of negative effects on the ecological condition of inland waterbodies, especially on water quality, and to also increase erosion and the loss of fringing vegetation. Managing the recreational use of inland waterbodies will become increasingly important as demand from all sectors intensifies and climate-change impacts become more severe. Management must take into account variations in perceptions by different stakeholder groups and the paradox of inappropriate visitor behaviour despite visitors’ apparent environmental awareness.
The biology of language and the epigenesis of recursive embedding
Authors: Jennings Ray E. , Thompson Joe J.
Published: April 2012

Theorists have oversold the usefulness of predicate logic and generative grammar to the study of language origins. They have searched for models that correspond to semantic properties, such as truth, when what is needed is an empirically testable model of evolution. Such a model is required if we are to explain the origins of linguistic properties by appealing to general properties of linguistic engendering, rather than to the advent of genotypes with the propensity to produce certain brain mechanisms. While the latter sort of explanation has a place, no theory can be considered an ‘evolutionary’ theory without the former. We introduce a general notion of engendering, whose primary virtue is its freedom from assumptions regarding the nature of colloquial change. We use it to frame a conjecture about the evolution of centre embedded clauses; one which makes the fewest possible assumptions about the neural requirements upon individual brains. Keywords: biology of language; epigenesis; engendering; evolution; mutation; population; recursion
A discourse analysis of power in relation to PSYCHLOPS (Psychological outcome profiles) in the context of CBT for psychosis
Authors: Kelly Vikki , Holttum Sue , Evans Chris , Shepherd Melanie
Published: April 2012

Aims: Outcome measures (OMs) and routine change measurement have developed dramatically in psychological therapies over the last two decades and some therapists have expressed concerns that this, depending on how it is handled by the parties involved, can markedly affect the therapy. However, little research has investigated this. It therefore seemed timely to explore discourses of OMs drawn upon by both parties in the therapy room. Method: PSYCHLOPS (Psychological Outcome Profiles) is a client‐centred measure which offered an opportunity to explore how therapists and clients receiving CBT for psychosis talked about OMs. A useful contrast was provided by the CORE‐OM (Clinical Outcomes in Routine Evaluation‐Outcome Measure). The discourses drawn upon by clients (n=4) and therapists (n=4) were analysed, informed by a Foucaultian framework. Results: OMs were constructed as empowering or disempowering of clients, as being able to do therapeutic work of engagement and containment, and as part of the apparatus of service power, positioning therapists as relatively powerless to question their use. Discussion: It is suggested that client‐centred measures like PSYCHLOPS, although partly aligned with a recovery framework, may become part of top‐down state and service power, and there is a need for more research into the different ways in which OMs are used in therapy and the impacts on therapists, clients and their relationships.
Actin polymerization stabilizes α4β1 integrin anchors that mediate monocyte adhesion
Authors: Rullo Jacob , Becker Henry , Hyduk Sharon J. , Wong Janice C. , Digby Genevieve , Arora Pamma D. , Cano Adrianet Puig , Hartwig John , McCulloch Christopher A. , Cybulsky Myron I.
Published: April 2012

Leukocytes arrested on inflamed endothelium via integrins are subjected to force imparted by flowing blood. How leukocytes respond to this force and resist detachment is poorly understood. Live-cell imaging with Lifeact-transfected U937 cells revealed that force triggers actin polymerization at upstream α4β1 integrin adhesion sites and the adjacent cortical cytoskeleton. Scanning electron microscopy revealed that this culminates in the formation of structures that anchor monocyte adhesion. Inhibition of actin polymerization resulted in cell deformation, displacement, and detachment. Transfection of dominant-negative constructs and inhibition of function or expression revealed key signaling steps required for upstream actin polymerization and adhesion stabilization. These included activation of Rap1, phosphoinositide 3-kinase γ isoform, and Rac but not Cdc42. Thus, rapid signaling and structural adaptations enable leukocytes to stabilize adhesion and resist detachment forces.
Ovastacin, a cortical granule protease, cleaves ZP2 in the zona pellucida to prevent polyspermy
Authors: Burkart Anna D. , Xiong Bo , Baibakov Boris , Jiménez-Movilla Maria , Dean Jurrien
Published: April 2012

The mouse zona pellucida is composed of three glycoproteins (ZP1, ZP2, and ZP3), of which ZP2 is proteolytically cleaved after gamete fusion to prevent polyspermy. This cleavage is associated with exocytosis of cortical granules that are peripherally located subcellular organelles unique to ovulated eggs. Based on the cleavage site of ZP2, ovastacin was selected as a candidate protease. Encoded by the single-copy Astl gene, ovastacin is an oocyte-specific member of the astacin family of metalloendoproteases. Using specific antiserum, ovastacin was detected in cortical granules before, but not after, fertilization. Recombinant ovastacin cleaved ZP2 in native zonae pellucidae, documenting that ZP2 was a direct substrate of this metalloendoprotease. Female mice lacking ovastacin did not cleave ZP2 after fertilization, and mouse sperm bound as well to Astl-null two-cell embryos as they did to normal eggs. Ovastacin is a pioneer component of mouse cortical granules and plays a definitive role in the postfertilization block to sperm binding that ensures monospermic fertilization and successful development.
Nuclear translation visualized by ribosome-bound nascent chain puromycylation
Authors: David Alexandre , Dolan Brian P. , Hickman Heather D. , Knowlton Jonathan J. , Clavarino Giovanna , Pierre Philippe , Bennink Jack R. , Yewdell Jonathan W.
Published: April 2012

Whether protein translation occurs in the nucleus is contentious. To address this question, we developed the ribopuromycylation method (RPM), which visualizes translation in cells via standard immunofluorescence microscopy. The RPM is based on ribosome-catalyzed puromycylation of nascent chains immobilized on ribosomes by antibiotic chain elongation inhibitors followed by detection of puromycylated ribosome-bound nascent chains with a puromycin (PMY)-specific monoclonal antibody in fixed and permeabilized cells. The RPM correlates localized translation with myriad processes in cells and can be applied to any cell whose translation is sensitive to PMY. In this paper, we use the RPM to provide evidence for translation in the nucleoplasm and nucleolus, which is regulated by infectious and chemical stress.
Mechanical unloading reverses transverse tubule remodelling and normalizes local Ca2+‐induced Ca2+release in a rodent model of heart failure
Authors: Ibrahim Michael , Navaratnarajah Manoraj , Siedlecka Urszula , Rao Christopher , Dias Priyanthi , Moshkov Alexey V. , Gorelik Julia , Yacoub Magdi H. , Terracciano Cesare M.
Published: April 2012

Aims

Ca2+‐induced Ca2+ release (CICR) is critical for contraction in cardiomyocytes. The transverse (t)‐tubule system guarantees the proximity of the triggers for Ca2+ release [L‐type Ca2+ channel, dihydropyridine receptors (DHPRs)] and the sarcoplasmic reticulum Ca2+ release channels [ryanodine receptors (RyRs)]. Transverse tubule disruption occurs early in heart failure (HF). Clinical studies of left ventricular assist devices in HF indicate that mechanical unloading induces reverse remodelling. We hypothesize that unloading of failing hearts normalizes t‐tubule structure and improves CICR.

Methods and results

Heart failure was induced in Lewis rats by left coronary artery ligation for 12 weeks; sham‐operated animals were used as controls. Failing hearts were mechanically unloaded for 4 weeks by heterotopic abdominal heart transplantation (HF‐UN). HF reduced the t‐tubule density measured by di‐8‐ANEPPS staining in isolated left ventricular myocytes, and this was reversed by unloading. The deterioration in the regularity of the t‐tubule system in HF was also reversed in HF‐UN. Scanning ion conductance microscopy showed the reappearance of normal surface striations in HF‐UN. Electron microscopy revealed recovery of normal t‐tubule microarchitecture in HF‐UN. L‐type Ca2+ current density, measured using whole‐cell patch clamping, was reduced in HF but unaffected by unloading. The variance of the time‐to‐peak of the Ca2+ transient, an index of CICR dyssynchrony, was increased in HF and normalized by unloading. The increased Ca2+ spark frequency observed in HF was reduced in HF‐UN. These results could be explained by the recoupling of orphaned RyRs in HF, as indicated by immunofluorescence.

Conclusions

Our data show that mechanical unloading of the failing heart reverses the pathological remodelling of the t‐tubule system and improves CICR.
Indo-Gangetic river systems, monsoon and malaria
Authors: Whitcombe Elizabeth
Published: April 2012

The history of the Indo-Gangetic river systems from the late nineteenth to the early twentieth centuries can be reconstructed from the meticulous official records of the survey, meteorological and medical departments of the British Government of India. In contrast with the grand sweep of the geological evidence, these records indicate a complex narrative of floods, droughts and channel shifts. Similarly, the cumulative growth of the Ganges–Brahmaputra and Indus deltas was overprinted by the effects of the annual monsoon cycle on precipitation, temperature and winds. Malaria, the principal vector-borne disease of the Indian subcontinent, and the deadliest, displayed epidemiological types that ranged between the extremes of stable–endemic to unstable–epidemic as defined in the classic theory of equilibrium of George Macdonald. Variations in its transmission, incidence and prevalence were closely tied to the different deltaic environments of the Bengal and Indus basins and to the short-sightedness of many irrigation and related engineering schemes.
River history and tectonics
Authors: Vita-Finzi C.
Published: April 2012

The analysis of crustal deformation by tectonic processes has gained much from the clues offered by drainage geometry and river behaviour, while the interpretation of channel patterns and sequences benefits from information on Earth movements before or during their development. The interplay between the two strands operates at many scales: themes which have already benefited from it include the possible role of mantle plumes in the breakup of Gondwana, the Cenozoic development of drainage systems in Africa and Australia, Himalayan uplift in response to erosion, alternating episodes of uplift and subsidence in the Mississippi delta, buckling of the Indian lithospheric plate, and changes in stream pattern and sinuosity along individual alluvial channels subject to localized deformation. Developments in remote sensing, isotopic dating and numerical modelling are starting to yield quantitative analyses of such effects, to the benefit of geodymamics as well as fluvial hydrology.
Rev-erbα and Rev-erbβ coordinately protect the circadian clock and normal metabolic function
Authors: Bugge Anne , Feng Dan , Everett Logan J. , Briggs Erika R. , Mullican Shannon E. , Wang Fenfen , Jager Jennifer , Lazar Mitchell A.
Published: April 2012

The nuclear receptor Rev-erbα regulates circadian rhythm and metabolism, but its effects are modest and it has been considered to be a secondary regulator of the cell-autonomous clock. Here we report that depletion of Rev-erbα together with closely related Rev-erbβ has dramatic effects on the cell-autonomous clock as well as hepatic lipid metabolism. Mouse embryonic fibroblasts were rendered arrhythmic by depletion of both Rev-erbs. In mouse livers, Rev-erbβ mRNA and protein levels oscillate with a diurnal pattern similar to that of Rev-erbα, and both Rev-erbs are recruited to a remarkably similar set of binding sites across the genome, enriched near metabolic genes. Depletion of both Rev-erbs in liver synergistically derepresses several metabolic genes as well as genes that control the positive limb of the molecular clock. Moreover, deficiency of both Rev-erbs causes marked hepatic steatosis, in contrast to relatively subtle changes upon loss of either subtype alone. These findings establish the two Rev-erbs as major regulators of both clock function and metabolism, displaying a level of subtype collaboration that is unusual among nuclear receptors but common among core clock proteins, protecting the organism from major perturbations in circadian and metabolic physiology.
Complexity in the signaling network: insights from the use of targeted inhibitors in cancer therapy
Authors: Logue Jeremy S. , Morrison Deborah K.
Published: April 2012

Cancer often arises when normal cellular growth goes awry due to defects in critical signal transduction pathways. A growing number of inhibitors that target specific components of these pathways are in clinical use, but the success of these agents has been limited by the resistance to inhibitor therapy that ultimately develops. Studies have now shown that cancer cells respond to chronic drug treatment by adapting their signaling circuitry, taking advantage of pathway redundancy and routes of feedback and cross-talk to maintain their function. This review focuses on the compensatory signaling mechanisms highlighted by the use of targeted inhibitors in cancer therapy.
Transmission Electron Microscopy of Thin Sections of Drosophila: High-Pressure Freezing and Freeze-Substitution
Authors: McDonald Kent L. , Sharp David J. , Rickoll Wayne
Published: April 2012

The state of the art in fine-structure preservation for thin sectioning can be achieved by using fast-freezing technology followed by freeze substitution and embedding in resin. Samples prepared by high-pressure freezing are estimated to be “fixed” in 20–50 msec. Fast freezing also freezes every cell component regardless of its chemistry. Once frozen, tissues can be processed in a variety of ways before viewing in the electron microscope; here we describe only freeze substitution. In freeze substitution, cells are dehydrated at very low temperatures and cell water is replaced with organic solvent at −80°C to −90°C. At this temperature, large molecules such as proteins are immobilized, yet smaller molecules such as water (ice) can be dissolved and replaced with organic solvents, e.g., acetone. The ideal way to do freeze substitution is with a dedicated freeze-substitution device such as the Leica AFS2 system. These devices allow programming of the times and temperatures needed. Alternatively, if this equipment is not available, freeze substitution can still be performed using items commonly found around the laboratory, as is described here. This protocol is useful for preparing thin sections of Drosophila when the best possible preservation of ultrastructure and antigenicity is required.
Transmission Electron Microscopy of Thin Sections of Drosophila: Conventional Chemical Fixation of Embryos Using Trialdehyde
Authors: McDonald Kent L. , Sharp David J. , Rickoll Wayne
Published: April 2012

High-pressure freezing (HPF) followed by freeze-substitution is a valuable method for specimen preservation for transmission electron microscopy (TEM) in Drosophila. However, not all projects require this level of precision. In addition, some tissues are too large to fit into the HPF specimen carriers, and some fly tissues such as eyes and ovaries do not freeze well. This protocol describes a trialdehyde fixation procedure for embryos, to be used in situations where optimal preservation is not required or when HPF is not an option. Because the vitelline membrane is impermeable to aqueous solvents, it is necessary to either mechanically disrupt it or render it permeable by treatment with organic solvents. Good ultrastructural preservation has been achieved by puncturing embryos immersed in fixative with extremely sharp tungsten needles, as described here.
Preparation of Vesicular Stomatitis Virus-G (VSV-G) Conjugate and Its Use in Gene Transfer
Authors: Miyanohara Atsushi
Published: April 2012

The fusiogenic envelope G glycoprotein of the vesicular stomatitis virus (VSV-G) that has been used to pseudotype retrovirus and lentivirus vectors can be used alone as an efficient vehicle for gene transfer. VSV-G protein is secreted into the culture medium as sendimentable vesicles from cells transfected with a VSV-G expression plasmid in the absence of other viral components. The VSV-G vesicles in the conditioned medium can be partially purified by pelleting through sucrose cushion ultracentrifugation. Protein–DNA complexes are formed by mixing the VSV-G vesicles with naked plasmid DNA. Such complexes show markedly enhanced transfection efficiency when added to the culture medium of recipient cells. The cell tropism of VSV-G–DNA complex-mediated gene transfer resembles that of VSV-G–pseudotyped retrovirus and lentivirus vectors, and the complex is therefore particularly useful for transfection of cells that are refractory to other methods. Still, some cells are refractory to VSV-G-mediated transfection. It should also be noted that overdose of VSV-G can be quite toxic to the recipient cells. The primitive complexes formed by mixing a viral fusiogenic envelope protein with naked DNA may represent a step toward fusing useful features of viral and nonviral vectors for safer and more efficient gene transfer. This protocol describes simple methods for preparation of VSV-G and for gene transfer with DNA–VSV-G complexes.
Microultrasound and Its Application to Longitudinal Studies of Mouse Eye Development and Disease
Authors: Foster F. Stuart , Brown Allison S.
Published: April 2012

Microultrasound imaging is a flexible high-resolution real-time in vivo imaging modality based on the transmission and the reception of ultrasound waves. Because of its high temporal (>250 Hz) and spatial (30–150 µm) resolutions and the noninvasive nature of ultrasound, microultrasound is used extensively in preclinical research to monitor functional and dynamic phenotypic changes in small animal models. Its ability to perform in vivo longitudinal monitoring of development, pathology, and therapeutic effectiveness is particularly advantageous. This article reviews the technology and the applications of high-frequency microultrasound for the study of mouse eye development from embryonic day E11.5 to postnatal day P16. Procedures for animal handling and scanning are given, and applications are described in the context of ocular development and disease. Quantitative analysis of the growth kinetics of the lens and the orbit is discussed. In addition, mouse models of retinoblastoma and glaucoma are followed as a function of disease progression to reveal their associated morphological and functional traits. Microultrasound is performed with high-frequency imaging equipment (from VisualSonics) operating at center frequencies between 15 and 50 MHz. These instruments provide both anatomical imaging as well as functional and molecular analyses of the living mouse.
Presynaptic Imaging of Projection Fibers by In Vivo Injection of Dextran-Conjugated Calcium Indicators
Authors: Brenowitz Stephan D. , Regehr Wade G.
Published: April 2012

Dextran-conjugated calcium indicators are stably retained within neurons. As a result, they are well suited to measuring presynaptic calcium at physiological temperatures. In addition, dextran indicators can be used to label neurons and their presynaptic boutons in vivo. This has allowed measurements of calcium in the presynaptic boutons of projection fibers that cannot be stably loaded with other types of indicators. This protocol describes a technique for in vivo loading of the climbing fiber projection to the cerebellum with dextran-conjugated indicators for subsequent presynaptic calcium imaging in brain slices. This technique is applicable to studies of projection fibers in many species from which brain slices can be prepared. The dextran indicator is injected into the inferior olive using a stereotaxic device. After a period of 1–3 d, cerebellar slices are prepared and presynaptic calcium transients are measured at physiological temperature in labeled climbing fibers. The protocol also discusses important considerations for using dextran-conjugated indicators to measure presynaptic calcium.
In Vivo Imaging of the Drosophila Larval Neuromuscular Junction
Authors: Andlauer Till F.M. , Sigrist Stephan J.
Published: April 2012

In the past decade, a significant number of proteins involved in the developmental assembly and maturation of synapses have been identified. However, detailed knowledge of the molecular processes underlying developmental synapse assembly is still sparse. We have developed an approach that makes extended in vivo imaging of selected proteins in live Drosophila larvae feasible at a single-synapse resolution. This protocol describes the repetitive, noninvasive imaging of the neuromuscular junction (NMJ) of a live, intact, anesthetized Drosophila larva over extended periods of time with confocal microscopy. Proteins of interest must be tagged with a fluorescent label and have to be expressed in transgenic fly strains. The method has proven highly useful for the study of synaptic assembly and the trafficking of proteins. These data contribute to our understanding of synaptic assembly under in vivo conditions.
Quantifying the Bicoid Morphogen Gradient in Living Fly Embryos
Authors: Morrison Alexander H. , Scheeler Martin , Dubuis Julien , Gregor Thomas
Published: April 2012

In multicellular organisms, patterns of gene expression are established in response to gradients of signaling molecules. During fly development in early Drosophila embryos, the Bicoid (Bcd) morphogen gradient is established within the first hour after fertilization. Bcd acts as a transcription factor, initiating the expression of a cascade of genes that determine the segmentation pattern of the embryo, which serves as a blueprint for the future adult organism. A robust understanding of the mechanisms that govern this segmentation cascade is still lacking, and a new generation of quantitative measurements of the spatiotemporal concentration dynamics of the individual players in this cascade is necessary for further progress. Here we describe a series of methods that represent the beginning of the use of Bcd as a quantification example. We describe the generation of a transgenic fly line expressing a Bcd-enhanced green fluorescent protein fusion protein. Using two-photon microscopy, we analyze the Bcd concentration dynamics and measure absolute Bcd expression levels in living fly embryos. These experiments have proven to be fruitful, generating new insights into the mechanisms that lead to the establishment and readout of the Bcd gradient. Generalization of these methods to other genes in the Drosophila segmentation cascade is straightforward and should further our understanding of the early patterning processes and the architecture of the underlying genetic network structure.
Hydraulic limits preceding mortality in a piñon–juniper woodland under experimental drought
Authors: PLAUT JENNIFER A. , YEPEZ ENRICO A. , HILL JUDSON , PANGLE ROBERT , SPERRY JOHN S. , POCKMAN WILLIAM T. , MCDOWELL NATE G.
Published: April 2012

Drought‐related tree mortality occurs globally and may increase in the future, but we lack sufficient mechanistic understanding to accurately predict it. Here we present the first field assessment of the physiological mechanisms leading to mortality in an ecosystem‐scale rainfall manipulation of a piñon–juniper (Pinus edulis–Juniperus monosperma) woodland. We measured transpiration (E) and modelled the transpiration rate initiating hydraulic failure (Ecrit). We predicted that isohydric piñon would experience mortality after prolonged periods of severely limited gas exchange as required to avoid hydraulic failure; anisohydric juniper would also avoid hydraulic failure, but sustain gas exchange due to its greater cavitation resistance. After 1 year of treatment, 67% of droughted mature piñon died with concomitant infestation by bark beetles (Ips confusus) and bluestain fungus (Ophiostoma spp.); no mortality occurred in juniper or in control piñon. As predicted, both species avoided hydraulic failure, but safety margins from Ecrit were much smaller in piñon, especially droughted piñon, which also experienced chronically low hydraulic conductance. The defining characteristic of trees that died was a 7 month period of near‐zero gas exchange, versus 2 months for surviving piñon. Hydraulic limits to gas exchange, not hydraulic failure per se, promoted drought‐related mortality in piñon pine.
Exploring the link between cognitive processes and learning from refutational text
Authors: McCrudden Matthew T. , Kendeou Panayiota
Published: April 2012

The purpose of this exploratory study was to investigate the cognitive processes used by individuals who read a refutational text about physics and demonstrated conceptual change learning. Four high school readers whose initial conceptions differed from the scientific conception of Newton's first law thought aloud while reading a refutational text. After reading, they completed a post‐test and participated in an in‐depth interview in which they were asked to provide interpretations of their think‐aloud comments. Qualitative analysis revealed that readers used a variety of cognitive processes during reading and their incorrect conceptions were revised to be more in line with the scientific conception explained in the text. The findings were consistent with the co‐activation hypothesis, which predicts that refutational texts can induce cognitive conflict and facilitate conceptual change learning.
Changes to financial incentives in English dentistry 2006–2009: a qualitative study
Authors: Mcdonald Ruth , Cheraghi‐Sohi Sudeh , Sanders Caroline , Tickle Martin
Published: April 2012

Objectives

To explore the views of NHS dentists in England regarding reforms, which changed their incentive and payment structure.

Methods

Semi‐structured interviews with 35 dentists, digitally recorded, transcribed verbatim and analysed using a constant comparative method.

Results

Dentists reported changing their behaviour in response to incentives in ways that were likely to have adverse impacts on patients. There was also a loss of trust in NHS paymasters, as well as a loss of faith in the ability to provide high quality care in NHS dentistry.

Conclusions

Responses suggest that many dentists were quick to change behaviour following the introduction of a revised contractual structure in 2006. The coalition government in the UK has stated its intention to introduce a new NHS dental contract. Our data suggest that part of the process of changing behaviours, norms and attitudes will require the rebuilding of trust in the NHS amongst NHS dentists, as opposed to merely redesigning incentive structures, though the two are related.
Grazing networks provide useful functional connectivity for plants in fragmented systems
Authors: Auffret Alistair G. , Schmucki Reto , Reimark Josefin , Cousins Sara A.O.
Published: April 2012

Question

To what extent does the movement of animals between fragmented habitat patches provide functional connectivity via endozoochorous seed dispersal?

Location

The Stockholm archipelago, Sweden.

Methods

We followed all movements of livestock between islands during one grazing season. After each movement, manure was collected and its seed content assessed through seedling emergence. Seedling data were then compared to vegetation surveys from the grazed islands with regard to functional traits.

Results

Light‐ and nitrogen‐demanding locally abundant species, and those with relatively small and persistent seeds were more likely to be moved between islands. For quantitative traits, only a subset of the available trait ranges were dispersed, with extreme values left behind. Species apparently specialized to other means of dispersal emerged from the manure samples. Neither dispersed traits nor seed density changed with timing of movement, but seed richness and diversity both increased throughout the season. The subsets of endozoochorously‐dispersed species in the established vegetation were more similar than non‐dispersed subsets between islands linked by livestock.

Conclusions

Grazing networks contribute to the connectivity of the core species in the system, and could provide useful tools for grassland management in fragmented landscapes.
T‐RFLP‐based differences in oral microbial communities as risk factor for development of oral diseases under stress
Authors: Horz H.‐P. , Ten Haaf A. , Kessler O. , Said Yekta S. , Seyfarth I. , Hettlich M. , Lampert F. , Küpper T. , Conrads G.
Published: April 2012

The human oral microbiome is comprised of approximately 800 different bacterial species many of which are as yet uncultivated. Their dynamics and variability in relation to health and disease are still poorly understood. Here we tested the hypothesis that the emergence of stress‐induced periodontal diseases is predictable based on the composition of the initial microbiota. As a model, we analysed 58 individuals performing a challenging expedition (exposure to various stress‐factors due to changes in diet, hygiene, temperature, physical and mental stress) in remote regions of the Himalayans (Annapurna Himal). Plaque samples were taken at start (Bhulbule) and destination (3000 meter difference in altitude) seven days later (Manang). Twenty‐eight individuals remained symptom‐free (Group I) while 30 participants developed periodontal problems, mostly gingivitis (Group II). The microbiota was monitored via T‐RFLP‐analysis of amplified 16S rRNA genes directly from the plaque samples. Based on the Additive‐Main‐Effects‐Multiplicative‐Interactions‐model (AMMI) using the T‐Rex software variation from T‐RF main effects was at least 95%, indicating that most variation was due to inherent differences in microbial communities among individuals. However, an interaction signal up to 3% was consistently observed between groups I and II but not between the two time points of sampling regardless of selected analytical parameters. The data, supported by heterogeneity, diversity and similarity indices indicated marked differences between groups I and II already prior the onset of clinical symptoms. These differences may provide the basis for using ecological parameters of oral microbial communities as early diagnostic marker for the onset of oral disorders and infections.
Safety and efficacy of paclitaxel liposome for elderly patients with advanced non‐small cell lung cancer: A multi‐center prospective study
Authors: Ding Zhen‐Yu , Zhou Lin , Liu Yong‐Mei , Lu You
Published: April 2012

Background:  Lung cancer in elderly patients poses an increasingly challenge for oncologists. The optimal treatment needs to be explored. The purpose of this study was to evaluate the safety and efficacy of the novel form of paclitaxel liposome for elderly patients with non‐small cell lung cancer (NSCLC).

Methods:  This multi‐center prospective trial recruited patients aged at least 70 years with advanced or recurrent NSCLC. Eligibility criteria included presence of measurable lesions, an Eastern Cooperative Oncology Group performance status of 0–2, as well as adequate organ function. Patients received paclitaxel liposome at the escalating dose of 135 mg/m2, 150 mg/m2 and 175 mg/m2 every three weeks.

Results:  Forty‐two patients were enrolled with a median age of 73 years (range 70–81). No complete response was observed. Partial response was obtained in 6.7%, 14.2% and 7.7% of patients, and 13.3%, 42.9% and 38.5% had stable disease from the three dose groups. In these groups, 26.7%, 21.4% and 25% of patients experienced grade 3–4 neutropenia. Time to progression was 1.2 months (95% confidence interval [CI], 1.1–1.3 months), 1.2 months (95% CI, 0.9–1.3 months) and 1.9 months (95% CI, 1.4–2.3 months), respectively. Overall survival in the dose group of 135 mg/m2 was 4.9 months (95%CI, 1.0–11.5 months) and was not reached in the other two groups.

Conclusions:  Paclitaxel liposome administered at the dose of 150 mg/m2 every three weeks was the safest and most effective of the three dose levels. However, the treatment achieved only mild effects. It was unnecessary to conduct further phase III randomized trials on this topic.
Bio-Morphing of Progressive Pathologies in Haversian Cortical Bone
Authors: Budyn É. , Jonvaux J. , Hoc T.
Published: April 2012

We present an evolutionary microstructural model to study the mechanical behavior of pathological Haversian cortical bone in the framework of linear elasticity. The Haversian cortical bone includes Haversian canals, osteons, cement lines, and interstitial bone. The composite microstructure is built using a Monte Carlo (MC) algorithm and initially displays a healthy morphology, which then evolves to mimic bone progressive aging, due to osteoporosis or low remodeling. The MC algorithm incorporates bone macroscopic morphological components such as porosity and osteonal volume fraction, microscopic parameters such as osteonal and Haversian canal diameter distributions, and also pathological growth laws characteristic of aging diseases. The local mechanical properties are measured by nanoindentation and microextensometry. The microstructures are discretised by a finite element 3D model to calculate the evolving representative volume element of aging bone, the macroscopic elastic bulk properties and microscopic strain and stress fields. The macroscopic anisotropy and local strain of aging bone are compared to those of healthy tissue in order to understand how morphological changes affect bone failure.
Influence of Melting Heat Transfer in the Stagnation-Point Flow of a Jeffrey Fluid in the Presence of Viscous Dissipation
Authors: Mustafa M. , Hayat T. , Hendi Awatif A.
Published: April 2012

This communication studies the effect of melting heat transfer on the stagnation-point flow of a Jeffrey fluid over a stretching sheet. Heat transfer analysis is carried out in the presence of viscous dissipation. The arising differential system has been solved by the homotopy analysis method (HAM). The results indicate an increase in the velocity and the boundary layer thickness with an increase in the values of the elastic parameter (Deborah number) for a Jeffrey fluid which are opposite to those accounted for in the literature for the other subclasses of rate type fluids. Furthermore, an increase in the melting process corresponds to an increase in the velocity and a decrease in the temperature. A comparative study between the current computations and the previous studies is also presented in a limiting sense.
Effect of Contact Conditions on Void Coalescence at Low Stress Triaxiality Shearing
Authors: Dahl Jonas , Nielsen Kim L. , Tvergaard Viggo
Published: April 2012

Recent numerical cell-model studies have revealed the ductile failure mechanism in shear to be governed by the interaction between neighboring voids, which collapse to micro-cracks and continuously rotate and elongate until coalescence occurs. Modeling this failure mechanism is by no means trivial as contact comes into play during the void collapse. In the early studies of this shear failure mechanism, Tvergaard (2009, “Behaviour of Voids in a Shear Field,” Int. J. Fract., 158, pp. 41-49) suggested a pseudo-contact algorithm, using an internal pressure inside the void to resemble frictionless contact and to avoid unphysical material overlap of the void surface. This simplification is clearly an approximation, which is improved in the present study. The objective of this paper is threefold: (i) to analyze the effect of fully accounting for contact as voids collapse to micro-cracks during intense shear deformation, (ii) to quantify the accuracy of the pseudo-contact approach used in previous studies, and (iii) to analyze the effect of including friction at the void surface with the main focus on its effect on the critical strain at coalescence. When accounting for full contact at the void surface, the deformed voids develop into shapes that closely resemble micro-cracks. It is found that the predictions using the frictionless pseudo-contact approach are in rather good agreement with corresponding simulations that fully account for frictionless contact. In particular, good agreement is found at close to zero stress triaxiality. Furthermore, it is shown that accounting for friction at the void surface strongly postpones the onset of coalescence, hence, increasing the overall material ductility. The changes in overall material behavior are here presented for a wide range of initial material and loading conditions, such as various stress triaxialities, void sizes, and friction coefficients.
Experimental and Finite Element Modal Analysis of a Pliant Elastic Membrane for Micro Air Vehicles Applications
Authors: Chakravarty Uttam Kumar , Albertani Roberto
Published: April 2012

This paper investigates the modal characteristics of a latex membrane for micro air vehicles applications. Finite element (FE) models are developed for characterizing the latex membrane at dynamic loading and validated by experimental results. The membrane at different pre-tension levels is attached to a circular steel ring, mounted on a shaker, and placed inside the vacuum chamber for modal characterization using a scanning laser Doppler vibrometer (LDV). The experimental modal analysis is conducted by imposing a structural excitation to the ring for investigating the membrane vibration characteristics at both atmospheric and reduced pressures in a vacuum chamber. FE models are developed for the natural frequencies of the membrane at different uniform and non-uniform pre-tension levels with the effect of the added mass of air. The Mooney-Rivlin hyperelastic material model is selected for the membrane. The natural frequencies of the membrane computed by experimental and FE models are correlated well, although discrepancy is expected among experimental and FE results within reasonable limits due to the variation of the thickness of the membrane. The natural frequencies increase with the mode and pre-tension level of the membrane but decrease due to an increase in ambient pressure. The damping ratios have very minimal effect on the frequencies due to low values but help to reduce the amplitude of vibration. Natural frequencies of the membrane do not change with the uniform and non-uniform nature of the pre-tension, although they increase with the pre-tension level. It is also found that the effect of added mass on the natural frequencies increases with an increase of the size of the membrane specimen.
On Singularity of Rigid-Body Dynamics Using Quaternion-Based Models
Authors: Choi Homin , Yang Bingen
Published: April 2012

It is well known that use of quaternions in dynamic modeling of rigid bodies can avoid the singularity due to Euler rotations. This paper shows that the dynamic response of a rigid body modeled by quaternions may become unbounded when a torque is applied to the body. A theorem is derived, relating the singularity to the axes of the rotation and applied torque, and to the degrees of freedom of the body in rotation. To avoid such singularity, a method of equivalent couples is proposed.
Magnetron-sputter deposition of Fe3S4 thin films and their conversion into pyrite (FeS2) by thermal sulfurization for photovoltaic applications
Authors: Liu Hongfei , Chi Dongzhi
Published: April 2012

The authors report on the fabrication of FeS2 (pyrite) thin films by sulfurizing Fe3S4 that were deposited by direct current magnetron sputtering at room temperature. Under the selected sputtering conditions, Fe3S4 nanocrystal films are obtained and the nanocrystals tend to locally cluster and closely pack into ricelike nanoparticles with an increase in film thickness. Meanwhile, the film tends to crack when the film thickness is increased over ∼1.3 μm. The film cracking can be effectively suppressed by an introduction of a 3-nm Cu intermediate layer prior to Fe3S4 deposition. However, an introduction of a 3-nm Al intermediate layer tends to enhance the film cracking. By post-growth thermal sulfurization of the Fe3S4 thin films in a tube-furnace, FeS2 with high phase purity, as determined by using x ray diffraction, is obtained. Optical absorption spectroscopy was employed to characterize the resultant FeS2 thin films, which revealed two absorption edges at 0.9 and 1.2 eV, respectively. These two absorption edges are assigned to the direct bandgap (0.9 eV) and the indirect allowed transitions (1.2 eV) of FeS2, respectively.
Phylogenetics and evolution ofTrx SETgenes in fully sequenced land plants
Authors: Zhu Xinyu , Chen Caoyi , Wang Baohua
Published: April 2012

Plant Trx SET proteins are involved in H3K4 methylation and play a key role in plant floral development. Genes encoding Trx SET proteins constitute a multigene family in which the copy number varies among plant species and functional divergence appears to have occurred repeatedly. To investigate the evolutionary history of the Trx SET gene family, we made a comprehensive evolutionary analysis on this gene family from 13 major representatives of green plants. A novel clustering (here named as cpTrx clade), which included the III-1, III-2, and III-4 orthologous groups, previously resolved was identified. Our analysis showed that plant Trx proteins possessed a variety of domain organizations and gene structures among paralogs. Additional domains such as PHD, PWWP, and FYR were early integrated into primordial SET–PostSET domain organization of cpTrx clade. We suggested that the PostSET domain was lost in some members of III-4 orthologous group during the evolution of land plants. At least four classes of gene structures had been formed at the early evolutionary stage of land plants. Three intronless orphan Trx SET genes from the Physcomitrella patens (moss) were identified, and supposedly, their parental genes have been eliminated from the genome. The structural differences among evolutionary groups of plant Trx SET genes with different functions were described, contributing to the design of further experimental studies.
An updated doubled haploid oat linkage map and QTL mapping of agronomic and grain quality traits from Canadian field trials
Authors: Tanhuanpää Pirjo , Manninen Outi , Beattie Aaron , Eckstein Peter , Scoles Graham , Rossnagel Brian , Kiviharju Elina
Published: April 2012

The first doubled haploid oat linkage map constructed at MTT Agrifood Research Finland was supplemented with additional microsatellites and Diversity Array Technology (DArT) markers to produce a map containing 1058 DNA markers and 34 linkage groups. The map was used to locate quantitative trait loci (QTLs) for 11 important breeding traits analyzed from Finnish and Canadian field trials. The new markers enabled most of the linkage groups to be anchored to the ‘Kanota’ × ‘Ogle’ oat ( Avena sativa L.) reference map and allowed comparison of the QTLs located in this study with those found previously. Two to 12 QTLs for each trait were discovered, of which several were expressed consistently across several environments.
Concurrent Use of Cigarettes and Smokeless Tobacco in Minnesota
Authors: Boyle Raymond G. , Claire Ann W. St. , Kinney Ann M. , D'Silva Joanne , Carusi Charles
Published: April 2012

Cigarette smokers are being encouraged to use smokeless tobacco (SLT) in locations where smoking is banned. We examined state-wide data from Minnesota to measure changes over time in the use of SLT and concurrent use of cigarettes and SLT. The Minnesota Adult Tobacco Survey was conducted four times between 1999 and 2010 and has provided state-wide estimates of cigarette smoking, SLT use and concurrent use of SLT by smokers. The prevalence of SLT was essentially unchanged through 2007, then increased significantly between 2007 and 2010 (3.1% versus 4.3%,P<0.05). Similarly, the prevalence of cigarette smokers who reported using SLT was stable then increased between 2007 and 2010 (4.4% versus 9.6%,P<0.05). The finding of higher SLT use by smokers could indicate that smokers in Minnesota are in an experimental phase of testing alternative products as they adjust to recent public policies restricting smoking in public places. The findings are suggestive that some Minnesota smokers are switching to concurrent use of cigarettes and SLT. Future surveillance reports will be necessary to confirm the results.
Arboreal Burials inNicrophorusspp. (Coleoptera: Silphidae)
Authors: Lowe Amanda J. , Lauff Randolph F.
Published: April 2012

Nicrophorusbeetles are well known for interring small vertebrates below ground for the purpose of rearing their young. However, thearborealuse of carrion has not been previously investigated. Nest boxes were suspended in the canopy of two forest habitats in Nova Scotia, Canada, to determine if this microhabitat fostered the same behaviour. Although four species ofNicrophorusas well asOiceoptoma noveboracense(Forster) were recorded in association with carrion,arborealreproduction was recorded exclusively and for the first time inN. tomentosusWeber andN. defodiensMannerheim. BothN. sayiLaporte andN. pustulatusHerschel were associated with the arboreal carrion but did not reproduce on it during these experiments.