722 research outputs found
Tuning of Human Modulation Filters Is Carrier-Frequency Dependent
Licensed under the Creative Commons Attribution License
Preterm birth and exercise capacity: what do we currently know?
ObjectivesThe long-term cardiopulmonary outcomes following preterm birth during the surfactant era remain unclear. Respiratory symptoms, particularly exertional symptoms, are common in preterm children. Therefore, cardiopulmonary exercise testing may provide insights into the pathophysiology driving exertional respiratory symptoms in those born preterm. This review aims to outline the current knowledge of cardiopulmonary exercise testing in the assessment of children born preterm in the surfactant era.DesignThis study is a narrative literature review.MethodsPublished manuscripts concerning the assessment of pulmonary outcomes using cardiopulmonary exercise testing in preterm children (aged <18 years) were reviewed. Search terms related to preterm birth, bronchopulmonary dysplasia, and exercise were entered into electronic databases, including Medline, PubMed, and Google Scholar. Reference lists from included studies were scanned for additional manuscripts.ResultsPreterm children have disrupted lung development with significant structural and functional lung disease and increased respiratory symptoms. The association between these (resting) assessments of respiratory health and exercise capacity is unclear; however, expiratory flow limitation and an altered ventilatory response (rapid, shallow breathing) are seen during exercise. Due to the heterogeneity of participants, treatments, and exercise protocols, the effect of the aforementioned limitations on exercise capacity in children born preterm is conflicting and poorly understood.ConclusionRisk factors for reduced exercise capacity in those born preterm remain poorly understood; however, utilizing cardiopulmonary exercise testing to its full potential, the pathophysiology of exercise limitation in survivors of preterm birth will enhance our understanding of the role exercise may play. The role of exercise interventions in mitigating the risk of chronic disease and premature death following preterm birth has yet to be fully realized and should be a focus of future robust randomized controlled trials
Geographical differences and temporal improvements in forced expiratory volume in 1 second of preterm-born children
Importance Although preterm birth is associated with later deficits in lung function, there is a paucity of information on geographical differences and whether improvements occur over time, especially after surfactant was introduced.
Objective To determine deficits in percentage predicted forced expiratory volume in 1 second (%FEV1) in preterm-born study participants, including those with bronchopulmonary dysplasia (BPD) in infancy, when compared with term-born control groups.
Data Sources Eight databases searched up to December 2021.
Study Selection Studies reporting spirometry for preterm-born participants with or without a term-born control group were identified.
Data Extraction and Synthesis Data were extracted and quality assessed by 1 reviewer and checked by another. Data were pooled using random-effects models and analyzed using Review Manager and the R metafor package.
Main Outcomes and Measures Deficits in %FEV1 between preterm-born and term groups. Associations between deficits in %FEV1 and year of birth, age, introduction of surfactant therapy, and geographical region of birth and residence were also assessed.
Results From 16âŻ856 titles, 685 full articles were screened: 86 with and without term-born control groups were included. Fifty studies with term controls were combined with the 36 studies from our previous systematic review, including 7094 preterm-born and 17âŻ700 term-born participants. Of these studies, 45 included preterm-born children without BPD, 29 reported on BPD28 (supplemental oxygen dependency at 28 days), 26 reported on BPD36 (supplemental oxygen dependency at 36 weeksâ postmenstrual age), and 86 included preterm-born participants. Compared with the term-born group, the group of all preterm-born participants (all preterm) had deficits of %FEV1 of â9.2%; those without BPD had deficits of â5.8%, and those with BPD had deficits of approximately â16% regardless of whether they had BPD28 or BPD36. As year of birth increased, there was a statistically significant narrowing of the difference in mean %FEV1 between the preterm- and term-born groups for the all preterm group and the 3 BPD groups but not for the preterm-born group without BPD. For the all BPD group, when compared with Scandinavia, North America and western Europe had deficits of â5.5% (95% CI, â10.7 to â0.3; Pâ=â.04) and â4.1% (95% CI, â8.8 to 0.5; Pâ=â.08), respectively.
Conclusions and Relevance Values for the measure %FEV1 were reduced in preterm-born survivors. There were improvements in %FEV1 over recent years, but geographical region had an association with later %FEV1 for the BPD groups
Robust estimation of microbial diversity in theory and in practice
Quantifying diversity is of central importance for the study of structure,
function and evolution of microbial communities. The estimation of microbial
diversity has received renewed attention with the advent of large-scale
metagenomic studies. Here, we consider what the diversity observed in a sample
tells us about the diversity of the community being sampled. First, we argue
that one cannot reliably estimate the absolute and relative number of microbial
species present in a community without making unsupported assumptions about
species abundance distributions. The reason for this is that sample data do not
contain information about the number of rare species in the tail of species
abundance distributions. We illustrate the difficulty in comparing species
richness estimates by applying Chao's estimator of species richness to a set of
in silico communities: they are ranked incorrectly in the presence of large
numbers of rare species. Next, we extend our analysis to a general family of
diversity metrics ("Hill diversities"), and construct lower and upper estimates
of diversity values consistent with the sample data. The theory generalizes
Chao's estimator, which we retrieve as the lower estimate of species richness.
We show that Shannon and Simpson diversity can be robustly estimated for the in
silico communities. We analyze nine metagenomic data sets from a wide range of
environments, and show that our findings are relevant for empirically-sampled
communities. Hence, we recommend the use of Shannon and Simpson diversity
rather than species richness in efforts to quantify and compare microbial
diversity.Comment: To be published in The ISME Journal. Main text: 16 pages, 5 figures.
Supplement: 16 pages, 4 figure
The PELICAN (Prematurity's Effect on the Lungs In Children and Adults Network) ERS clinical research collaboration: understanding the impact of preterm birth on lung health throughout life
An estimated 15 million babies (âŒ11%) are born preterm each year (before 37â
weeks of gestation), the rates of which are increasing worldwide [1]. Enhanced perinatal care, including antenatal corticosteroids, postnatal surfactant and improved respiratory management, have markedly improved survival outcomes since the 1990s, particularly for babies born very preterm (<32â
weeks gestation) [1]. However, long-term pulmonary sequelae are frequent in preterm survivors and ongoing clinical management is often required. Development and severity of bronchopulmonary dysplasia (BPD), a chronic lung condition diagnosed during the neonatal period [2], is a key determinant of long-term adverse outcomes of prematurity
High cable forces deteriorate pinch force control in voluntary-closing body-powered prostheses
It is generally asserted that reliable and intuitive control of upper-limb prostheses requires adequate feedback of prosthetic finger positions and pinch forces applied to objects. Body-powered prostheses (BPPs) provide the user with direct proprioceptive feedback. Currently available BPPs often require high cable operation forces, which complicates control of the forces at the terminal device.
The aim of this study is to quantify the influence of high cable forces on object manipulation with voluntary-closing prostheses. Able-bodied male subjects were fitted with a bypass-prosthesis with low and high cable force settings for the prehensor. Subjects were requested to grasp and transfer a collapsible object as fast as they could without dropping or breaking it. The object had a low and a high breaking force setting. Subjects conducted significantly more successful manipulations with the low cable force setting, both for the low (33 % more) and high (50 %) objectâs breaking force. The time to complete the task was not different between settings during successful manipulation trials. In conclusion: high cable forces lead to reduced pinch force control during object manipulation. This implies that low cable operation forces should be a key design requirement for voluntary-closing BPPs
A Note on Data-Driven Contaminant Simulation
Abstract. In this paper we introduce a numerical procedure for per-forming dynamic data driven simulations (DDDAS). The main ingredi-ent of our simulation is the multiscale interpolation technique that maps the sensor data into the solution space. We test our method on various synthetic examples. In particular we show that frequent updating of the sensor data in the simulations can significantly improve the prediction results and thus important for applications. The frequency of sensor data updating in the simulations is related to streaming capabilities and ad-dressed within DDDAS framework. A further extension of our approach using local inversion is also discussed.
A novel asynchronous access method with binary interfaces
© 2008 Silva et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
Luzp4 defines a new mRNA export pathway in cancer cells
Cancer testis antigens (CTAs) represented a poorly characterized group of proteins whose expression is normally restricted to testis but are frequently up-regulated in cancer cells. Here we show that one CTA, Luzp4, is an mRNA export adaptor. It associates with the TREX mRNA export complex subunit Uap56 and harbours a Uap56 binding motif, conserved in other mRNA export adaptors. Luzp4 binds the principal mRNA export receptor Nxf1, enhances its RNA binding activity and complements Alyref knockdown in vivo. Whilst Luzp4 is up-regulated in a range of tumours, it appears preferentially expressed in melanoma cells where it is required for growth
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