2,005 research outputs found
Definition study of the Shuttle Imaging Radar-A (SIR-A) antenna on the second space shuttle mission (OFT-2)
A definition is derived for an antenna configuration fixed-mounted high in the payload bay on the hybrid OFT-2 pallet which is compatible with Orbiter interface requirements. Tests showed that the combination of the selected panels and the designed corporate feed meets SIR-A performance requirement of 33 db gain. The effects of Orbiter structure proximity on performance were determined by scale model tests to be negligible. The potential for improved performance during subsequent reflights includes a multiple-beam capability and dual polarization
Oral health of seafarers - a review
The research base needs to be expanded to cover all seafarers. Dental professional expertise should be sought in policy and guideline development relevant to oral health. A strategy comprising preventive, screening, and treatment service components should be developed and a certificate of dental health introduced. Funding strategies in a complex environment of transnational stakeholders for the improvement of oral-health services for seafarers are needed. Aspects of military oral health care systems could be an example for civilian operators
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Post-assembly Modification of Phosphine Cages Controls Host-Guest Behavior.
We report the design, synthesis, and post-assembly modification of a new phosphine-paneled supramolecular cage framework, the anion binding ability of which can be modified rationally through selective post-assembly functionalization. The parent phosphine-paneled cage can be modified in situ through oxidation, methylation, or auration. These covalent and coordinative modifications to the exterior of the cage strongly influence the guest-binding properties of the host.European Research Council (695009), UK Engineering and Physical Sciences
Research Council (EPSRC, EP/P027067/1
Dental practice during a world cruise: Characterization of oral health at sea
Aims: To describe oral health of passengers and crew attending the dental service
aboard during a two months world cruise.
Methods: In a retrospective, descriptive epidemiologic study design the routine
documentation of all dental treatment provided at sea was analysed after the voyage. Subjects were n = 57 passengers (3.5 % of 1619) with a mean age of 71 (± 9.8) years
and n =56 crew (5.6 % of 999) with a mean age of 37 (± 12.0) years. Age, gender,
nationality, number of natural teeth and implants were extracted. The prosthetic status
was described by recording the number of teeth replaced by fixed prosthesis and
number of teeth replaced by removable prosthesis. Oral health-related quality of life
(OHRQoL) was measured using the 14-item Oral Health Impact Profile (OHIP-14) and
characterised by the OHIP sum score.
Results: Women attended for treatment more often than men. Passengers had a
mean number of 20 natural teeth plus substantial fixed and removable prosthodontics.
Crew had a mean of 26 teeth. British crew and Australian passengers attended the dental
service above average. Crew tended to have a higher average OHIP-14 sum score than
passengers indicating an increased rate of perceived problems. Emergency patients from
both crew and passengers have a higher sum score than patients attending for routine
treatment.
Conclusion: In passengers the average number of teeth appears to be higher than
that of an age matched population of industrialized countries. However, the passengers’
socioeconomic status was higher which has an effect on this finding. Socioeconomic
factors also serve to explain the high standard of prosthetic care in passengers. Crew in
general present with less sophisticated prosthetic devices. This is in line with their
different socioeconomic status and origin from developing countries. The level of dental
fees aboard in comparison to treatment costs in home countries may explain some of the
differences in attendance. Passengers have enjoyed high standards of prosthetic care in
the past and will expect a similarly high standard from ship based facilities. The ease of
access to quality dental care may explain the relatively low level of perceived problems
as characterised by oral health-related quality of life scores. The dental officer aboard
has to be prepared to care for very varied diagnostic and treatment needs
Disease Outbreaks: Tuning Predictive Machine Learning
Climate change is expected to exacerbate diarrhoea outbreaks in
developing nations, a leading cause of morbidity and mortality in
such regions. The development of predictive models with the
ability to capture complex relationships between climate factors and
diarrhoea may be effective for diarrhoea outbreak control. Various
supervised Machine Learning (ML) algorithms and Deep Learning
(DL) methods have been used in developing predictive models for
various disease. Despite their advances in a range of healthcare applications, overall method task performance still largely
depends on available training data and parameter settings which is
a significant challenge for most predictive machine learning methods. This study investigates the impact of Relevance Estimation
and Value Calibration (REVAC), an evolutionary parameter optimization method applied to predictive task performance of various
ML and DL methods applied to ranges of real-world and synthetic
data-sets (diarrhoea and climate based) for daily diarrhoea outbreak
prediction in a regional case-study (South African provinces). Preliminary results indicate that REVAC is better suited for the DL
models regardless of the data-set used for making predictions
Predicting Disease Outbreaks with Climate Data
The incidence of most diseases varies greatly with
seasons, and global climate change is expected to increase
its risk. Predictive models that automatically capture trends
between climate and diseases are likely to be beneficial in
minimizing disease outbreaks. Machine learning (ML) predictive
analytic tools have been popularized across many health-care
applications, however the optimal task performance of such
ML tools largely depends on manual parameter tuning and
calibration. Such manual tuning significantly limits the full
potential of ML methods, especially for high-dimensional and
complex task domains, as typified by real-world health-care
application data-sets. Additionally, the inaccessibility of many
health-care data-sets compounds innate problems of method
comparison, predictive accuracy and the overall advancement of
ML based health-care applications. In this study we investigate
the impact of Relevance Estimation and Value Calibration, an
evolutionary parameter optimization method applied to automate
parameter tuning for comparative ML methods (Deep learning
and Support Vector Machines) applied to predict daily diarrhoea
cases across various geographic regions. Data-augmentation is
also used to complement real-world noisy, sparse and incomplete
data-sets with synthetic data-sets for training, validation and
testing. Results support the efficacy of evolutionary parameter
optimization and data synthesis to boost predictive accuracy in
the given task, indicating a significant prediction accuracy boost
for the deep-learning models across all data-sets
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Anion Pairs Template a Trigonal Prism with Disilver Vertices.
Here we describe the formation of a trigonal prismatic cage, utilizing 2-formyl-1,8-naphthyridine subcomponents to bind pairs of silver(I) ions in close proximity. This cage is the first example of a new class of subcomponent self-assembled polyhedral structures having bimetallic vertices, as opposed to the single metal centers that typically serve as structural elements within such cages. Our new cage self-assembles around a pair of anionic templates, which are shown by crystallographic and solution-phase data to bind within the central cavity of the structure. Many different anions serve as competent templates and guests. Elongated dianions, such as the strong oxidizing agent peroxysulfate, also serve to template and bind within the cavity of the prism. The principle of using subcomponents that have more than one spatially close, but nonchelating, binding site may thus allow access to other higher-order structures with multimetallic vertices.European Research Council (695009) and the UK Engineering and Physical Sciences Re‐ search Council (EPSRC, EP/P027067/1).
European Union's Horizon 2020 research and innovation program, Marie Sklodowska‐Curie Grant (642192)
CD22 regulates early B cell development in BOB.1/OBF.1-deficient mice
BOB.1/OBF1 (also called OCA-B), a B lymphocyte-specific transcriptional coactivator, is recruited to octamer-containing promoters by interacting with the Oct-1 or Oct-2 proteins. BOB.1/OBF.1-deficient mice show impaired secondary immunoglobulin isotype secretion and complete absence of germinal centers. Furthermore, numbers of splenic B cells are reduced due to a developmental block at the transitional B cell stage in the bone marrow. We found that surface expression of CD22 is selectively increased on B lineage cells in the bone marrow of BOB.1/OBF.1-deficient mice. CD22 is known as a negative regulator of B cell receptor signaling. We therefore investigated whether defects in B cell development in the BOB.1/OBF1-deficient mice might be due to CD22 up-regulation. Mice were generated lacking both genes. In BOB.1/OBF.1 xCD22 double-deficient mice, numbers of transitional B cells in the bone marrow were normal. Consequently, double-deficient mice also had normal B to T cell ratios in the spleen. We show that BOB.1/OBF.1(-/-) B cells were incapable to induce BCR-triggered Ca2+ mobilization. This Ca2+-signalling defect was restored in BOBA/ OBF1 xCD22 double-deficient B cells. Nevertheless, double-deficient animals were unable to mount humoral immune responses and to form germinal centers. Finally, we demonstrate that CD22(-/-) splenic B cells proliferate independently of BOB.1/OBF1 upon stimulation with LPS. These studies suggest that the B cell differentiation defect observed in BOB.1/OBF.1(-/-) mice is BCR-signal dependent. However, the impairment in germinal center formation is caused by a different mechanism
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Kinetics of Toehold-Mediated DNA Strand Displacement Depend on FeII4L4 Tetrahedron Concentration.
The toehold-mediated strand displacement reaction (SDR) is a powerful enzyme-free tool for molecular manipulation, DNA computing, signal amplification, etc. However, precise modulation of SDR kinetics without changing the original design remains a significant challenge. We introduce a new means of modulating SDR kinetics using an external stimulus: a water-soluble FeII4L4 tetrahedral cage. Our results show that the presence of a flexible phosphate group and a minimum toehold segment length are essential for FeII4L4 binding to DNA. SDRs mediated by toehold ends in different lengths (3-5) were investigated as a function of cage concentration. Their reaction rates all first increased and then decreased as cage concentration increased. We infer that cage binding on the toehold end slows SDR, whereas the stabilization of intermediates that contain two overhangs accelerates SDR. The tetrahedral cage thus serves as a versatile tool for modulation of SDR kinetics.George and Lilian Schiff Foundation Studentship;
Winton Programme for the Physics of Sustainability;
St. John’s Benefactors’ Scholarshi
Mass coral bleaching of P. versipora in Sydney Harbour driven by the 2015–2016 heatwave
© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. High-latitude coral communities are distinct from their tropical counterparts, and how they respond to recent heat wave events that have decimated tropical reefs remains unknown. In Australia, the 2016 El Niño resulted in the largest global mass coral bleaching event to date, reaching as far south as Sydney Harbour (~ 34°S). Coral bleaching was observed for the first time (affecting ca., 60% of all corals) as sea surface temperatures in Sydney Harbour remained > 2 °C above the long-term mean summer maxima, enabling us to examine whether high-latitude corals bleached in a manner described for tropical corals. Responses of the geographically cosmopolitan Plesiastrea versipora and southerly restricted Coscinaraea mcneilli were contrasted across two harbour sites, both in situ and among samples-maintained ex situ in aquaria continually supplied with Sydney Harbour seawater. While both coral taxa hosted the same species of microalgal endosymbiont (Breviolum spp; formerly clade B), only P. versipora bleached both in situ and ex situ via pronounced losses of endosymbiont cells. Both species displayed very different metabolic responses (growth, photosynthesis, respiration and calcification) and bleaching susceptibilities under elevated temperatures. Bacterial microbiome profiling, however, revealed a convergence of bacterial community composition across coral species throughout the bleaching. Corals species found in temperate regions, including the generalist P. versipora, will therefore likely be highly susceptible to future change as heat waves grow in frequency and severity unless their thermal thresholds increase. Our observations provide further evidence that high-latitude systems are susceptible to community reorganisation under climate change
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