Epidemiological evidence indicates that regular physical activity and/or frequent structured exercise reduces the incidence of many chronic diseases in older age, including communicable diseases such ...as viral and bacterial infections, as well as non-communicable diseases such as cancer and chronic inflammatory disorders. Despite the apparent health benefits achieved by leading an active lifestyle, which imply that regular physical activity and frequent exercise enhance immune competency and regulation, the effect of a single bout of exercise on immune function remains a controversial topic. Indeed, to this day, it is perceived by many that a vigorous bout of exercise can temporarily suppress immune function. In the first part of this review, we deconstruct the key pillars which lay the foundation to this theory-referred to as the "open window" hypothesis-and highlight that: (i) limited reliable evidence exists to support the claim that vigorous exercise heightens risk of opportunistic infections; (ii) purported changes to mucosal immunity, namely salivary IgA levels, after exercise do not signpost a period of immune suppression; and (iii) the dramatic reductions to lymphocyte numbers and function 1-2 h after exercise reflects a transient and time-dependent redistribution of immune cells to peripheral tissues, resulting in a heightened state of immune surveillance and immune regulation, as opposed to immune suppression. In the second part of this review, we provide evidence that frequent exercise enhances-rather than suppresses-immune competency, and highlight key findings from human vaccination studies which show heightened responses to bacterial and viral antigens following bouts of exercise. Finally, in the third part of this review, we highlight that regular physical activity and frequent exercise might limit or delay aging of the immune system, providing further evidence that exercise is beneficial for immunological health. In summary, the over-arching aim of this review is to rebalance opinion over the perceived relationships between exercise and immune function. We emphasize that it is a misconception to label any form of acute exercise as immunosuppressive, and, instead, exercise most likely improves immune competency across the lifespan.
In this article, we review the current state of artificial intelligence applications in retinopathy of prematurity (ROP) and provide insight on challenges as well as strategies for bringing these ...algorithms to the bedside.
In the past few years, there has been a dramatic shift from machine learning approaches based on feature extraction to 'deep' convolutional neural networks for artificial intelligence applications. Several artificial intelligence for ROP approaches have demonstrated adequate proof-of-concept performance in research studies. The next steps are to determine whether these algorithms are robust to variable clinical and technical parameters in practice. Integration of artificial intelligence into ROP screening and treatment is limited by generalizability of the algorithms to maintain performance on unseen data and integration of artificial intelligence technology into new or existing clinical workflows.
Real-world implementation of artificial intelligence for ROP diagnosis will require massive efforts targeted at developing standards for data acquisition, true external validation, and demonstration of feasibility. We must now focus on ethical, technical, clinical, regulatory, and financial considerations to bring this technology to the infant bedside to realize the promise offered by this technology to reduce preventable blindness from ROP.
Purpose
To develop 2D turbo spin‐echo (TSE) imaging using annular spiral rings (abbreviated “SPRING‐RIO TSE”) with compensation of concomitant gradient fields and B0 inhomogeneity at both 0.55T and ...1.5T for fast T2‐weighted imaging.
Methods
Strategies of gradient waveform modifications were implemented in SPRING‐RIO TSE for compensation of self‐squared concomitant gradient terms at the TE and across echo spacings, along with reconstruction‐based corrections to simultaneously compensate for the residual concomitant gradient and B0 field induced phase accruals along the readout. The signal pathway disturbance caused by time‐varying and spatially dependent concomitant fields was simulated, and echo‐to‐echo phase variations before and after sequence‐based compensation were compared. Images from SPRING‐RIO TSE with no compensation, with compensation, and Cartesian TSE were also compared via phantom and in vivo acquisitions.
Results
Simulation showed how concomitant fields affected the signal evolution with no compensation, and both simulation and phantom studies demonstrated the performance of the proposed sequence modifications, as well as the readout off‐resonance corrections. Volunteer data showed that after full correction, the SPRING‐RIO TSE sequence achieved high image quality with improved SNR efficiency (15%–20% increase), and reduced RF SAR (˜50% reduction), compared to the standard Cartesian TSE, presenting potential benefits, especially in regaining SNR at low‐field (0.55T).
Conclusion
Implementation of SPRING‐RIO TSE with concomitant field compensation was tested at 0.55T and 1.5T. The compensation principles can be extended to correct for other trajectory types that are time‐varying along the echo train and temporally asymmetric in TSE‐based imaging.
Fullerenes in Space Maier, John P.; Campbell, Ewen K.
Angewandte Chemie,
April 24, 2017, Letnik:
56, Številka:
18
Journal Article
Recenzirano
Odprti dostop
In 1985 the football structure of C60, buckminsterfullerene was proposed and subsequently confirmed following its macroscopic synthesis in 1990. From the very beginning the role of C60 and C60+ in ...space was considered, particularly in the context of the enigmatic diffuse interstellar bands. These are absorption features found in the spectra of reddened star light. The first astronomical observations were made around one hundred years ago and despite significant efforts none of the interstellar molecules responsible have been identified. The absorption spectrum of C60+ was measured in a 5 K neon matrix in 1993 and two prominent bands near 9583 Å and 9645 Å were observed. On the basis of this data the likely wavelength range in which the gas phase C60+ absorptions should lie was predicted. In 1994 two diffuse interstellar bands were found in this spectral region and proposed to be due to C60+. It took over 20 years to measure the absorption spectrum of C60+ under conditions similar to those prevailing in diffuse clouds. In 2015, sophisticated laboratory experiments led to the confirmation that these two interstellar bands are indeed caused by C60+, providing the first answer to this century old puzzle. Here, we describe the experiments, concepts and astronomical observations that led to the detection of C60+ in interstellar space.
Looking to the stars: In 1985 the fullerenes were discovered through experiments aimed at understanding the formation of carbon chains found in interstellar space. Thirty years later spectroscopic experiments have confirmed the presence of C60+ in diffuse clouds of molecules and dust and given the first answer to a long standing astronomical puzzle.
Individual performance criterion measurement is central to effective personnel management in the military services, and to all other organizations as well. The articles in this special issue ...summarize the state of the art in all major phases of performance criterion development and assessment. The overall record, while it varies in terms of current progress across the major parts, is admirable. What's next is an equally thorough examination of the utility of validity.
Abstract Background The objective of this study was to investigate whether the preoperative platelet-lymphocyte (P/L) ratio represents a significant prognostic index in resected pancreatic ductal ...adenocarcinoma. Methods A total of 110 patients undergoing pancreatoduodenectomy for pancreatic ductal adenocarcinoma over a 10-year period were identified from a prospectively maintained database. Results The preoperative P/L ratio was found to be a more significant prognostic marker ( P < .001) than either the lymphocyte count ( P = .007) or platelet count ( P = .068) on univariate Cox survival analysis. The median overall survival in patients with a P/L ratio of 150 or less (n = 48) was 19.7 months, 13.7 months in those with a P/L ratio of 151 to 300 (n = 43), and 5.8 months in patients with a value of greater than 300 (n = 19) (log-rank, P = .006). The preoperative P/L ratio retained significance on multivariate analysis ( P < .001), along with tumor size ( P = .010) and lymph node ratio ( P = .013). Conclusions The preoperative P/L ratio represents a significant independent prognostic index in patients of resected pancreatic adenocarcinoma.
The ISO 9001:2015 standard released in September 2015 contains, for the first time, a specification for 'organizational knowledge' as a resource and during the following three years more than 1.1 ...million organisations seeking recertification will need to take this into account. There are few clear guidelines about the practical implications of addressing this knowledge requirement, and therefore this paper attempts to identify some theoretical and practical frameworks. Firstly, it considers the complementary nature of quality management and knowledge management. Secondly, it conducts the first content analysis of how knowledge has emerged in the evolving ISO 9001 standards and how three of the main elements in the data, information, knowledge and wisdom pyramid are represented. Thirdly, it identifies that the knowledge cycle provides a coherent structure for assisting organisations to understand the new standard and applying knowledge requirements in practice. Next, it examines the issues faced with explicit and tacit knowledge. Finally, it summarises a number of conclusions.
In March 2022, the first ISMRM Workshop on Low-Field MRI was held virtually. The goals of this workshop were to discuss recent low field MRI technology including hardware and software developments, ...novel methodology, new contrast mechanisms, as well as the clinical translation and dissemination of these systems. The virtual Workshop was attended by 368 registrants from 24 countries, and included 34 invited talks, 100 abstract presentations, 2 panel discussions, and 2 live scanner demonstrations. Here, we report on the scientific content of the Workshop and identify the key themes that emerged. The subject matter of the Workshop reflected the ongoing developments of low-field MRI as an accessible imaging modality that may expand the usage of MRI through cost reduction, portability, and ease of installation. Many talks in this Workshop addressed the use of computational power, efficient acquisitions, and contemporary hardware to overcome the SNR limitations associated with low field strength. Participants discussed the selection of appropriate clinical applications that leverage the unique capabilities of low-field MRI within traditional radiology practices, other point-of-care settings, and the broader community. The notion of "image quality" versus "information content" was also discussed, as images from low-field portable systems that are purpose-built for clinical decision-making may not replicate the current standard of clinical imaging. Speakers also described technical challenges and infrastructure challenges related to portability and widespread dissemination, and speculated about future directions for the field to improve the technology and establish clinical value.
When a free-living bacterium transitions to a host-beneficial endosymbiotic lifestyle, it almost invariably loses a large fraction of its genome 1, 2. The resulting small genomes often become stable ...in size, structure, and coding capacity 3–5, as exemplified by Sulcia muelleri, a nutritional endosymbiont of cicadas. Sulcia’s partner endosymbiont, Hodgkinia cicadicola, similarly remains co-linear in some cicadas diverged by millions of years 6, 7. But in the long-lived periodical cicada Magicicada tredecim, the Hodgkinia genome has split into dozens of tiny, gene-sparse circles that sometimes reside in distinct Hodgkinia cells 8. Previous data suggested that all other Magicicada species harbor complex Hodgkinia populations, but the timing, number of origins, and outcomes of the splitting process were unknown. Here, by sequencing Hodgkinia metagenomes from the remaining six Magicicada and two sister species, we show that each Magicicada species harbors Hodgkinia populations of at least 20 genomic circles. We find little synteny among the 256 Hodgkinia circles analyzed except between the most closely related cicada species. Gene phylogenies show multiple Hodgkinia lineages in the common ancestor of Magicicada and its closest known relatives but that most splitting has occurred within Magicicada and has given rise to highly variable Hodgkinia gene dosages among species. These data show that Hodgkinia genome degradation has proceeded down different paths in different Magicicada species and support a model of genomic degradation that is stochastic in outcome and nonadaptive for the host. These patterns mirror the genomic instability seen in some mitochondria.
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•The Hodgkinia genome in all Magicicada exist as complexes of ≥20 circular molecules•Together, these circles contain most of the ancestral Hodgkinia gene set•The gene dosage of Hodgkinia genes is wildly different in different cicada species•The genomic complexity of Hodgkinia is most likely nonadaptive for the host cicada
The stability of nutritional endosymbiont genomes reflects their importance to their hosts. Campbell et al. show that this stability has dramatically eroded in an endosymbiont of the 13- and 17-year periodical cicadas and that the outcome of this instability is wildly different in different cicadas.
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