1,109 research outputs found
Pulmonary toxicity screening studies in male rats with TiO(2 )particulates substantially encapsulated with pyrogenically deposited, amorphous silica
The aim of this study was to evaluate the acute lung toxicity in rats of intratracheally instilled TiO(2 )particles that have been substantially encapsulated with pyrogenically deposited, amorphous silica. Groups of rats were intratracheally instilled either with doses of 1 or 5 mg/kg of hydrophilic Pigment A TiO(2 )particles or doses of 1 or 5 mg/kg of the following control or particle-types: 1) R-100 TiO(2 )particles (hydrophilic in nature); 2) quartz particles, 3) carbonyl iron particles. Phosphate-buffered saline (PBS) instilled rats served as additional controls. Following exposures, the lungs of PBS and particle-exposed rats were evaluated for bronchoalveolar lavage (BAL) fluid inflammatory markers, cell proliferation, and by histopathology at post-instillation time points of 24 hrs, 1 week, 1 month and 3 months. The bronchoalveolar lavage results demonstrated that lung exposures to quartz particles, at both concentrations but particularly at the higher dose, produced significant increases vs. controls in pulmonary inflammation and cytotoxicity indices. Exposures to Pigment A or R-100 TiO(2 )particles produced transient inflammatory and cell injury effects at 24 hours postexposure (pe), but these effects were not sustained when compared to quartz-related effects. Exposures to carbonyl iron particles or PBS resulted only in minor, short-term and reversible lung inflammation, likely related to the effects of the instillation procedure. Histopathological analyses of lung tissues revealed that pulmonary exposures to Pigment A TiO(2 )particles produced minor inflammation at 24 hours postexposure and these effects were not significantly different from exposures to R-100 or carbonyl iron particles. Pigment A-exposed lung tissue sections appeared normal at 1 and 3 months postexposure. In contrast, pulmonary exposures to quartz particles in rats produced a dose-dependent lung inflammatory response characterized by neutrophils and foamy (lipid-containing) alveolar macrophage accumulation as well as evidence of early lung tissue thickening consistent with the development of pulmonary fibrosis. Based on our results, we conclude the following: 1) Pulmonary instillation exposures to Pigment A TiO(2 )particles at 5 mg/kg produced a transient lung inflammatory response which was not different from the lung response to R-100 TiO(2 )particles or carbonyl iron particles; 2) the response to Pigment A was substantially less active in terms of inflammation, cytotoxicity, and fibrogenic effects than the positive control particle-type, quartz particles. Thus, based on the findings of this study, we would expect that inhaled Pigment A TiO(2 )particles would have a low risk potential for producing adverse pulmonary health effects
Compressibility of titanosilicate melts
The effect of composition on the relaxed adiabatic bulk modulus (K0) of a range of alkali- and alkaline earth-titanosilicate [X 2 n/n+ TiSiO5 (X=Li, Na, K, Rb, Cs, Ca, Sr, Ba)] melts has been investigated. The relaxed bulk moduli of these melts have been measured using ultrasonic interferometric methods at frequencies of 3, 5 and 7 MHz in the temperature range of 950 to 1600°C (0.02 Pa s < s < 5 Pa s). The bulk moduli of these melts decrease with increasing cation size from Li to Cs and Ca to Ba, and with increasing temperature. The bulk moduli of the Li-, Na-, Ca- and Ba-bearing metasilicate melts decrease with the addition of both TiO2 and SiO2 whereas those of the K-, Rb- and Cs-bearing melts increase. Linear fits to the bulk modulus versus volume fraction of TiO2 do not converge to a common compressibility of the TiO2 component, indicating that the structural role of TiO2 in these melts is dependent on the identity of the cation. This proposition is supported by a number of other property data for these and related melt compositions including heat capacity and density, as well as structural inferences from X-ray absorption spectroscopy (XANES). The compositional dependence of the compressibility of the TiO2 component in these melts explains the difficulty incurred in previous attempts to incorporate TiO2 in calculation schemes for melt compressibility. The empirical relationship KV-4/3 for isostructural materials has been used to evaluate the compressibility-related structural changes occurring in these melts. The alkali metasilicate and disilicate melts are isostructural, independent of the cation. The addition of Ti to the metasilicate composition (i.e. X2TiSiO5), however, results in a series of melts which are not isostructural. The alkaline-earth metasilicate and disilicate compositions are not isostructural, but the addition of Ti to the metasilicate compositions (i.e. XTiSiO5) would appear, on the basis of modulus-volume systematics, to result in the melts becoming isostructural with respect to compressibility
Research priorities for improving infant and young child feeding in humanitarian emergencies
Background
There are many challenges during emergencies to ensure that optimal infant and young child feeding is protected, promoted and supported, but there is a dearth of evidence on strategies and programmes to improve Infant and Young Child Feeding in Emergencies (IYCF-E) and a need to determine research priorities.
Methods
Based on interviews with key informants who are experts in the subject, we developed a list of 48 research questions on IYCF-E. A framework, following the Child Health and Nutrition Research Initiative method to set priorities in child health research, was developed to rank the research questions. Four criteria were applied to create a ranking based on answerability, operational relevance, disease burden reduction and prevention, and originality. Using an on-line survey, prioritisation of research questions was done by 27 people from 14 NGOs, universities and research institutions, and UN organisations.
Results
The top-ten research questions identified focused on the following:
âą Use of cash-transfer to buy breast-milk substitutes;
âą Effectiveness of complementary feeding strategies;
âą Long-term effect of IYCF-E interventions;
âą Design of IYCF-E programmes in a context where breastfeeding rates are low and breast milk substitutes use is high;
âą Design of effective re-lactation interventions;
âą Provision of psychological support to young childrenâs care-takers;
âą Determination of number of beneficiaries and coverage of IYCF-E programmes;
âą Pros and cons of distributing ready-to-use infant formula compared with distributing powdered infant formula plus kit for safer use of BMS, when use of infant formula is necessary;
âą Assessment of the impact of specific IYCF-E programmes on nutritional status, morbidity and mortality;
âą Linking and mainstreaming IYCF-E interventions with other sectors such as health, WASH, food security and child protection.
Conclusion
The questions found by this study could form the basis of future research on IYCF-E and could be integrated into the agenda of relevant stakeholders. Results of studies based on these questions will be fundamental to fill the evidence gap in IYCF-E, improve IYCF-E programming and ultimately contribute to the reduction in morbidity and mortality among infants and young children in humanitarian emergencies
Does clinical management improve outcomes following self-Harm? Results from the multicentre study of self-harm in England
Background
Evidence to guide clinical management of self-harm is sparse, trials have recruited selected samples, and psychological treatments that are suggested in guidelines may not be available in routine practice.
Aims
To examine how the management that patients receive in hospital relates to subsequent outcome.
Methods
We identified episodes of self-harm presenting to three UK centres (Derby, Manchester, Oxford) over a 10 year period (2000 to 2009). We used established data collection systems to investigate the relationship between four aspects of management (psychosocial assessment, medical admission, psychiatric admission, referral for specialist mental health follow up) and repetition of self-harm within 12 months, adjusted for differences in baseline demographic and clinical characteristics.
Results
35,938 individuals presented with self-harm during the study period. In two of the three centres, receiving a psychosocial assessment was associated with a 40% lower risk of repetition, Hazard Ratios (95% CIs): Centre A 0.99 (0.90â1.09); Centre B 0.59 (0.48â0.74); Centre C 0.59 (0.52â0.68). There was little indication that the apparent protective effects were mediated through referral and follow up arrangements. The association between psychosocial assessment and a reduced risk of repetition appeared to be least evident in those from the most deprived areas.
Conclusion
These findings add to the growing body of evidence that thorough assessment is central to the management of self-harm, but further work is needed to elucidate the possible mechanisms and explore the effects in different clinical subgroups
"The Mystery of the Raddlesham Mumps": A case study for combined storytelling in a theatre play and Virtual Reality
âThe Mystery of the Raddlesham Mumpsâ is a poem by Murray Lachlan Young, aimed at both children and adults. This poem has been adapted as a theatre play with a short prequel as a Virtual Reality (VR)/tablet app. We used this unique combination to explore the potential interaction between these different media elements for the level of âpresenceâ and âimmersionâ in the story (i.e. the level to which one can imagine oneself within the story at the expense of the sense of physical time and space).
The theatre audience had the opportunity to play the VR/tablet app in the foyer before the performance started. After the performance, a questionnaire measured participantsâ level of immersion and presence in the theatre play and their enjoyment of both play and app. The results showed that people of all ages interacted with and liked the app. Ratings for the play were also high and did not depend on prior engagement with the app. However, the play was liked more by adults than children, and the reverse was true for the app, suggesting a potential generation shift in multimedia story telling
Imaging Coulomb Islands in a Quantum Hall Interferometer
In the Quantum Hall regime, near integer filling factors, electrons should
only be transmitted through spatially-separated edge states. However, in
mesoscopic systems, electronic transmission turns out to be more complex,
giving rise to a large spectrum of magnetoresistance oscillations. To explain
these observations, recent models put forward that, as edge states come close
to each other, electrons can hop between counterpropagating edge channels, or
tunnel through Coulomb islands. Here, we use scanning gate microscopy to
demonstrate the presence of quantum Hall Coulomb islands, and reveal the
spatial structure of transport inside a quantum Hall interferometer. Electron
islands locations are found by modulating the tunneling between edge states and
confined electron orbits. Tuning the magnetic field, we unveil a continuous
evolution of active electron islands. This allows to decrypt the complexity of
high magnetic field magnetoresistance oscillations, and opens the way to
further local scale manipulations of quantum Hall localized states
The characteristic blue spectra of accretion disks in quasars as uncovered in the infrared
Quasars are thought to be powered by supermassive black holes accreting
surrounding gas. Central to this picture is a putative accretion disk which is
believed to be the source of the majority of the radiative output. It is well
known, however, that the most extensively studied disk model -- an optically
thick disk which is heated locally by the dissipation of gravitational binding
energy -- is apparently contradicted by observations in a few major respects.
In particular, the model predicts a specific blue spectral shape asymptotically
from the visible to the near-infrared, but this is not generally seen in the
visible wavelength region where the disk spectrum is observable. A crucial
difficulty was that, toward the infrared, the disk spectrum starts to be hidden
under strong hot dust emission from much larger but hitherto unresolved scales,
and thus has essentially been impossible to observe. Here we report
observations of polarized light interior to the dust-emiting region that enable
us to uncover this near-infrared disk spectrum in several quasars. The revealed
spectra show that the near-infrared disk spectrum is indeed as blue as
predicted. This indicates that, at least for the outer near-infrared-emitting
radii, the standard picture of the locally heated disk is approximately
correct. The model problems at shorter wavelengths should then be directed
toward a better understanding of the inner parts of the revealed disk. The
newly uncovered disk emission at large radii, with more future measurements,
will also shed totally new light on the unanswered critical question of how and
where the disk ends.Comment: published in Nature, 24 July 2008 issue. Supplementary Information
can be found at
http://www.mpifr-bonn.mpg.de/div/ir-interferometry/suppl_info.pdf Published
version can be accessed from
http://www.nature.com/nature/journal/v454/n7203/pdf/nature07114.pd
The radiographic union scale in tibial (RUST) fractures:Reliability of the outcome measure at an independent centre
OBJECTIVES: The radiographic union score for tibial (RUST) fractures was developed by Whelan et al to assess the healing of tibial fractures following intramedullary nailing. In the current study, the repeatability and reliability of the RUST score was evaluated in an independent centre (a) using the original description, (b) after further interpretation of the description of the score, and (c) with the immediate post-operative radiograph available for comparison. METHODS: A total of 15 radiographs of tibial shaft fractures treated by intramedullary nailing (IM) were scored by three observers using the RUST system. Following discussion on how the criteria of the RUST system should be implemented, 45 sets (i.e. AP and lateral) of radiographs of IM nailed tibial fractures were scored by five observers. Finally, these 45 sets of radiographs were rescored with the baseline post-operative radiograph available for comparison. RESULTS: The initial intraclass correlation (ICC) on the first 15 sets of radiographs was 0.67 (95% CI 0.63 to 0.71). However, the original description was being interpreted in different ways. After agreeing on the interpretation, the ICC on the second cohort improved to 0.75. The ICC improved even further to 0.79, when the baseline post-operative radiographs were available for comparison. CONCLUSION: This study demonstrates that the RUST scoring system is a reliable and repeatable outcome measure for assessing tibial fracture healing. Further improvement in the reliability of the scoring system can be obtained if the radiographs are compared with the baseline post-operative radiographs. Cite this article: Mr J.M. Leow. The radiographic union scale in tibial (RUST) fractures: Reliability of the outcome measure at an independent centre. Bone Joint Res 2016;5:116â121. DOI: 10.1302/2046-3758.54.2000628
Responses of grape berry anthocyanin and tritratable acidity to the projected climate change across the Western Australian wine regions
More than a century of observations has established that climate influences grape berry composition. Accordingly, the projected global climate change is expected to impact on grape berry composition although the magnitude and direction of impact at regional and subregional scales are not fully known. The aim of this study was to assess potential impacts of climate change on levels of berry anthocyanin and titratable acidity (TA) of the major grapevine varieties grown across all of the Western Australian (WA) wine regions. Grape berry anthocyanin and TA responses across all WA wine regions were projected for 2030, 2050 and 2070 by utilising empirical models that link these berry attributes and climate data downscaled (to âŒ5 km resolution) from the csiro_mk3_5 and miroc3_2_medres global climate model outputs under IPCC SRES A2 emissions scenario. Due to the dependence of berry composition on maturity, climate impacts on anthocyanin and TA levels were assessed at a common maturity of 22 °Brix total soluble solids (TSS), which necessitated the determination of when this maturity will be reached for each variety, region and warming scenario, and future period.The results indicate that both anthocyanin and TA levels will be affected negatively by a warming climate, but the magnitude of the impacts will differ between varieties and wine regions. Compared to 1990 levels, median anthocyanins concentrations are projected to decrease, depending on global climate model, by up to 3â12 % and 9â33 % for the northern wine regions by 2030 and 2070, respectively while 2â18 % reductions are projected in the southern wine regions for the same time periods. Patterns of reductions in the median Shiraz berry anthocyanin concentrations are similar to that of Cabernet Sauvignon; however, the magnitude is lower (up to 9â18 % in southern and northern wine regions respectively by 2070). Similarly, uneven declines in TA levels are projected across the study regions. The largest reductions in median TA are likely to occur in the present day warmer wine regions, up to 40 % for Chardonnay followed by 15 % and 12 % for Shiraz and Cabernet Sauvignon, respectively, by 2070 under the high warming projection (csiro_mk3_5). It is concluded that, under existing management practices, some of the key grape attributes that are integral to premium wine production will be affected negatively by a warming climate, but the magnitudes of the impacts vary across the established wine regions, varieties, the magnitude of warming and future periods considered
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