375 research outputs found
Direct digital control of an efficient silicon+lequid crystal phase shifter
We demonstrate a phase shifter based on a silicon slot waveguide infiltrated with liquid crystal. We achieve a phase shift of 73 pi for a 5V drive voltage, with a voltage-length product of 0.022V.mm around 1V. We can drive the phase shifter directly with a 1V, duobinary pulse-width-modulated signal, allowing direct digital CMOS control of an analog optical phase shifter
Psychometric properties of the Dutch version of the London Measure of Unplanned Pregnancy in women with pregnancies ending in birth
OBJECTIVE: To evaluate the psychometric properties of the Dutch version of the London Measure of Unplanned Pregnancy in women with pregnancies ending in birth. METHODS: A two-phase psychometric evaluation design was set-up. Phase I comprised the translation from English into Dutch and pretesting with 6 women using cognitive interviews. In phase II, the reliability and validity of the Dutch version of the LMUP was assessed in 517 women giving birth recently. Reliability (internal consistency) was assessed using Cronbach's alpha, inter-item correlations, and corrected item-total correlations. Construct validity was assessed using principal components analysis and hypothesis testing. Exploratory Mokken scale analysis was carried out. RESULTS: 517 women aged 15-45 completed the Dutch version of the LMUP. Reliability testing showed acceptable internal consistency (alpha = 0.74, positive inter-item correlations between all items, all corrected item-total correlations >0.20). Validity testing confirmed the unidimensional structure of the scale and all hypotheses were confirmed. The overall Loevinger's H coefficient was 0.57, representing a 'strong' scale. CONCLUSION: The Dutch version of the LMUP is a reliable and valid measure that can be used in the Dutch-speaking population in Belgium to assess pregnancy planning. Future research is necessary to assess the stability of the Dutch version of the LMUP, and to evaluate its psychometric properties in women with abortions
Effect of material properties on reverse flow in nematic liquid crystal devices with homeotropic alignment
Outcomes for Pressure Ulcer Trials (OUTPUTs) project: review and classification of outcomes reported in pressure ulcer prevention research
In order to overcome inconsistencies in the reporting of outcomes in clinical trials, core outcome sets (COSs) have been developed in many clinical areas and the awareness of this concept is growing steadily. The Outcomes for Pressure Ulcer Trials (OUTPUTs) project aims to improve the quality of evidence from pressure ulcer prevention trials by developing a COS. As an initial step in the COS process we aimed to identify and classify both outcomes and concepts that represent potential outcomes for future trials that have been reported in pressure ulcer prevention research. A review was conducted in 12 major databases covering the literature indexed until 2016. Outcomes and relevant concepts reported in primary studies and/or reviews on pressure ulcer prevention in adult patients were extracted as presented in the articles, and afterwards inductively grouped into outcome domains. The domains were then categorized according to the outcome domain taxonomy recently proposed by the COMET group. In total 332 studies were included and 68 outcome domains were identified, covering multiple aspects of pressure ulcer prevention. Pressure ulcer occurrence was reported in 71% of all included studies, representing the most frequent outcome, followed by costs (22% of all studies) and acceptability of intervention and comfort (18% of all studies). A plethora of different outcomes are applied in pressure ulcer prevention research and substantial variations in definitions and reporting of similar outcomes were observed. A COS for pressure ulcer prevention trials is needed to overcome the noncomparability of outcomes
Multi Locus Sequence Typing of Chlamydia Reveals an Association between Chlamydia psittaci Genotypes and Host Species
Chlamydia comprises a group of obligate intracellular bacterial parasites responsible for a variety of diseases in humans and animals, including several zoonoses. Chlamydia trachomatis causes diseases such as trachoma, urogenital infection and lymphogranuloma venereum with severe morbidity. Chlamydia pneumoniae is a common cause of community-acquired respiratory tract infections. Chlamydia psittaci, causing zoonotic pneumonia in humans, is usually hosted by birds, while Chlamydia abortus, causing abortion and fetal death in mammals, including humans, is mainly hosted by goats and sheep. We used multi-locus sequence typing to asses the population structure of Chlamydia. In total, 132 Chlamydia isolates were analyzed, including 60 C. trachomatis, 18 C. pneumoniae, 16 C. abortus, 34 C. psittaci and one of each of C. pecorum, C. caviae, C. muridarum and C. felis. Cluster analyses utilizing the Neighbour-Joining algorithm with the maximum composite likelihood model of concatenated sequences of 7 housekeeping fragments showed that C. psittaci 84/2334 isolated from a parrot grouped together with the C. abortus isolates from goats and sheep. Cluster analyses of the individual alleles showed that in all instances C. psittaci 84/2334 formed one group with C. abortus. Moving 84/2334 from the C. psittaci group to the C. abortus group resulted in a significant increase in the number of fixed differences and elimination of the number of shared mutations between C. psittaci and C. abortus. C. psittaci M56 from a muskrat branched separately from the main group of C. psittaci isolates. C. psittaci genotypes appeared to be associated with host species. The phylogentic tree of C. psittaci did not follow that of its host bird species, suggesting host species jumps. In conclusion, we report for the first time an association between C. psittaci genotypes with host species
Identification of novel inhibitors of auxin-induced Ca2+ signaling via a plant-based chemical screen
Many signal perception mechanisms are connected to Ca2+-based second messenger signaling to modulate specific cellular responses. The well-characterized plant hormone auxin elicits a very rapid Ca2+ signal. However, the cellular targets of auxin-induced Ca2+ are largely unknown. Here, we screened a biologically annotated chemical library for inhibitors of auxin-induced Ca2+ entry in plant cell suspensions to better understand the molecular mechanism of auxin-induced Ca2+ and to explore the physiological relevance of Ca2+ in auxin signal transduction. Using this approach, we defined a set of diverse, small molecules that interfere with auxin-induced Ca2+ entry. Based on annotated biological activities of the hit molecules, we found that auxin-induced Ca2+ signaling is, among others, highly sensitive to disruption of membrane proton gradients and the mammalian Ca2+ channel inhibitor bepridil. Whereas protonophores nonselectively inhibited auxin-induced and osmotic-stress-induced Ca2+ signals, bepridil specifically inhibited auxin-induced Ca2+. We found evidence that bepridil severely alters vacuolar morphology and antagonized auxin-induced vacuolar remodeling. Further exploration of this plant-tailored collection of inhibitors will lead to a better understanding of auxin-induced Ca2+ entry and its relevance for auxin responses
Factors influencing the implementation of advanced midwife practitioners in healthcare settings: a qualitative study
Objective: To explore factors influencing the implementation of advanced midwife practitioner roles.
Design: Semi-structured individual face-to-face and focus group interviews were conducted. Data analysis was performed using the Framework Method.
Setting and participants: A purposive sample (n = 32) included chief nursing officers, middle managers, head midwives/nurses, primary care team leaders, midwives with and without advanced midwife practitioner roles, heads of midwifery educations, and obstetricians.
Findings: Budgetary constraints on a governmental and healthcare organizational level were mentioned as main barriers for role implementation. The current fee-for-service financing model of healthcare professionals was also seen as an impediment. Obstetricians considered the implementation of advanced midwife practitioner roles as a possible financial and professional threat. Documenting the added value of advanced midwife practitioner roles was regarded a prerequisite for gaining support to implement such roles. Healthcare managers' and midwives' attitudes towards these roles were considered essential. Participants warned against automatically transferring the concept of advanced practice nursing to midwifery. Although participants seldom discussed population healthcare needs as a driver for implementation, healthcare organizations' heightened focus on quality improvement and client safety was seen as an opportunity for implementation. University hospitals were perceived as pioneers regarding advanced midwife practitioner roles.
Key conclusions and implications for practice: Multiple factors influencing role implementation on a governmental, healthcare organizational, and workforce level illustrate the complexity of the implementation process, and highlight the need for a well-thought-out implementation plan involving all relevant stakeholders. Pilot projects for the implementation of advanced midwife practitioners in university hospitals might be useful
Optimal outcomes and women's positive pregnancy experience: a comparison between the World Health Organization guideline and recommendations in European national antenatal care guidelines.
BACKGROUND: The publication of the World Health Organization (WHO) recommendations on antenatal care in 2016 introduced the perspective of women as a necessary component of clinical guidelines in maternity care. WHO highlights the crucial role played by evidence-based recommendations in promoting and supporting normal birth processes and a positive experience of pregnancy. This paper aims to explore and critically appraise recommendations of national antenatal care guidelines across European countries in comparison with the WHO guideline. METHODS: We collected guidelines from country partners of the EU COST Action IS1405. Components of the documents structure and main recommendations within and between them were compared and contrasted with the WHO guideline on antenatal care with a particular interest in exploring whether and how women's experience was included in the recommendations. RESULTS: Eight out of eleven countries had a single national guideline on antenatal care while three countries did not. National guidelines mostly focused on care of healthy women with a straightforward pregnancy. The level of concordance between the national and the WHO recommendations varied along a continuum from almost total concordance to almost total dissonance. Women's views and experiences were accounted for in some guidelines, but mostly not placed at the same level of importance as clinical items. CONCLUSIONS: Findings outline convergences and divergences with the WHO recommendations. They highlight the need for considering women's views more in the development of evidence-based recommendations and in practice for positive impacts on perinatal health at a global level, and on the experiences of each family
A whole-plant functional scheme predicting the early growth of tropical tree species: evidence from 15 tree species in Central Africa
Key message: This study highlighted the consistency of a functional scheme integrating leaf, stem and root traits, biomass allocation and stem anatomy for 15 tropical tree species at the seedling stage. This functional scheme was shaped by the trade-offs for resource use and the hydraulics of the plants and was found to determine seedling growth. Abstract: Functional traits determine plant functioning, performance and response to the environment and define species functional strategy. The functional strategy of 15 African tree species was assessed by (1) highlighting the structure of traits covariance and the underlying functional trade-offs, (2) inferring a whole-plant functional scheme and (3) testing the correlation of the functional scheme with plant performance for two early developmental stages (seedlings and saplings). We selected 10 seedlings for each of the 15 species studied from a nursery in south-eastern Cameroon and measured 18 functional traits, including leaf, stem and root traits, biomass allocation and stem anatomy. We assessed the height and diameter growth of the seedlings and the DBH growth and survival for the saplings of nearby plantations. Multivariate analyses highlighted the covariations among the functional traits of the leaf/stem/root, biomass allocation ratios and stem anatomy. The major trait covariation axes were driven by two trade-offs, first between resource acquisition and conservation and second between hydraulic safety and efficiency. The axes were integrated into a Bayesian network inferring a functional scheme at the whole-plant scale, which was found to predict the growth of the seedlings but not the performance of the saplings. The functional strategies of the seedlings were determined by an integrated whole-plant scheme reflecting the trade-offs for resource use and plant hydraulics. The scheme predicted the growth of the seedlings through mechanistic pathways from the wood stem to all the plant traits, but it appeared to shift at the stage of the saplings. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature
Auxin-regulated reversible inhibition of TMK1 signaling by MAKR2 modulates the dynamics of root gravitropism
Plants are able to orient their growth according to gravity, which ultimately controls both shoot and root architecture.1 Gravitropism is a dynamic process whereby gravistimulation induces the asymmetric distribution of the plant hormone auxin, leading to asymmetric growth, organ bending, and subsequent reset of auxin distribution back to the original pre-gravistimulation situation.1, 2, 3 Differential auxin accumulation during the gravitropic response depends on the activity of polarly localized PIN-FORMED (PIN) auxin-efflux carriers.1, 2, 3, 4 In particular, the timing of this dynamic response is regulated by PIN2,5,6 but the underlying molecular mechanisms are poorly understood. Here, we show that MEMBRANE ASSOCIATED KINASE REGULATOR2 (MAKR2) controls the pace of the root gravitropic response. We found that MAKR2 is required for the PIN2 asymmetry during gravitropism by acting as a negative regulator of the cell-surface signaling mediated by the receptor-like kinase TRANSMEMBRANE KINASE1 (TMK1).2,7, 8, 9, 10 Furthermore, we show that the MAKR2 inhibitory effect on TMK1 signaling is antagonized by auxin itself, which triggers rapid MAKR2 membrane dissociation in a TMK1-dependent manner. Our findings suggest that the timing of the root gravitropic response is orchestrated by the reversible inhibition of the TMK1 signaling pathway at the cell surface
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