A Regional Reduction in Ito and IKACh in the Murine Posterior Left Atrial Myocardium Is Associated with Action Potential Prolongation and Increased Ectopic Activity.

BACKGROUND: The left atrial posterior wall (LAPW) is potentially an important area for the development and maintenance of atrial fibrillation. We assessed whether there are regional electrical differences throughout the murine left atrial myocardium that could underlie regional differences in arrhythmia susceptibility. METHODS: We used high-resolution optical mapping and sharp microelectrode recordings to quantify regional differences in electrical activation and repolarisation within the intact, superfused murine left atrium and quantified regional ion channel mRNA expression by Taqman Low Density Array. We also performed selected cellular electrophysiology experiments to validate regional differences in ion channel function. RESULTS: Spontaneous ectopic activity was observed during sustained 1Hz pacing in 10/19 intact LA and this was abolished following resection of LAPW (0/19 resected LA, P<0.001). The source of the ectopic activity was the LAPW myocardium, distinct from the pulmonary vein sleeve and LAA, determined by optical mapping. Overall, LAPW action potentials (APs) were ca. 40% longer than the LAA and this region displayed more APD heterogeneity. mRNA expression of Kcna4, Kcnj3 and Kcnj5 was lower in the LAPW myocardium than in the LAA. Cardiomyocytes isolated from the LAPW had decreased Ito and a reduced IKACh current density at both positive and negative test potentials. CONCLUSIONS: The murine LAPW myocardium has a different electrical phenotype and ion channel mRNA expression profile compared with other regions of the LA, and this is associated with increased ectopic activity. If similar regional electrical differences are present in the human LA, then the LAPW may be a potential future target for treatment of atrial fibrillation

Automatic Lung Segmentation in CT Images with Accurate Handling of the Hilar Region

A fully automated and three-dimensional (3D) segmentation method for the identification of the pulmonary parenchyma in thorax X-ray computed tomography (CT) datasets is proposed. It is meant to be used as pre-processing step in the computer-assisted detection (CAD) system for malignant lung nodule detection that is being developed by the Medical Applications in a Grid Infrastructure Connection (MAGIC-5) Project. In this new approach the segmentation of the external airways (trachea and bronchi), is obtained by 3D region growing with wavefront simulation and suitable stop conditions, thus allowing an accurate handling of the hilar region, notoriously difficult to be segmented. Particular attention was also devoted to checking and solving the problem of the apparent ‘fusion’ between the lungs, caused by partial-volume effects, while 3D morphology operations ensure the accurate inclusion of all the nodules (internal, pleural, and vascular) in the segmented volume. The new algorithm was initially developed and tested on a dataset of 130 CT scans from the Italung-CT trial, and was then applied to the ANODE09-competition images (55 scans) and to the LIDC database (84 scans), giving very satisfactory results. In particular, the lung contour was adequately located in 96% of the CT scans, with incorrect segmentation of the external airways in the remaining cases. Segmentation metrics were calculated that quantitatively express the consistency between automatic and manual segmentations: the mean overlap degree of the segmentation masks is 0.96 ± 0.02, and the mean and the maximum distance between the mask borders (averaged on the whole dataset) are 0.74 ± 0.05 and 4.5 ± 1.5, respectively, which confirms that the automatic segmentations quite correctly reproduce the borders traced by the radiologist. Moreover, no tissue containing internal and pleural nodules was removed in the segmentation process, so that this method proved to be fit for the use in the framework of a CAD system. Finally, in the comparison with a two-dimensional segmentation procedure, inter-slice smoothness was calculated, showing that the masks created by the 3D algorithm are significantly smoother than those calculated by the 2D-only procedure

Age differences in the association of childhood obesity with area-level and school-level deprivation: cross-classified multilevel analysis of cross-sectional data.

OBJECTIVE: Evidence suggests that area-level deprivation is associated with obesity independently of individual socioeconomic status; however, although the school may also have an impact on child health, few studies have investigated the association between school-level deprivation and the body mass index (BMI) of students. The aim of this study was to assess the relationship between the BMI for children of different ages and area-level and school-level deprivation. SUBJECTS: BMI measurements were collected through the National Child Measurement Programme (NCMP) that samples from two school years: 396,171 reception year pupils (4-5-year olds) and 392,344 year 6 pupils (10-11-year olds) from 14,054 primary schools in England. DESIGN: Cross-classified multilevel models with four levels: individual (n=788,525), lower super output areas corresponding to area of residence (n=29,606), schools (n=14,054) and primary care trusts (PCTs, n=143), which coordinate the collection of data within a large area, were used to study the relationship between measures of deprivation at an area and school level, and childhood BMI within England. RESULTS: A positive association was found between the area and school measures of deprivation, and student BMI. Both the measures of deprivation explained a greater proportion of variance in BMI z-scores for year 6 students than for the reception year students, with a greater difference between the year groups found with the school-level measure of socioeconomic status than for the the area-level measure. CONCLUSIONS: Deprivation explains a greater proportion of the variance in BMI for older compared with younger children, perhaps reflecting the impact of deprivation as children age, highlighting the widening of health inequalities through childhood. The association with school-level deprivation illustrates the impact of the school on BMI status throughout the primary school years

The 2017 terahertz science and technology roadmap

Science and technologies based on terahertz frequency electromagnetic radiation (100 GHz-30 THz) have developed rapidly over the last 30 years. For most of the 20th Century, terahertz radiation, then referred to as sub-millimeter wave or far-infrared radiation, was mainly utilized by astronomers and some spectroscopists. Following the development of laser based terahertz time-domain spectroscopy in the 1980s and 1990s the field of THz science and technology expanded rapidly, to the extent that it now touches many areas from fundamental science to 'real world' applications. For example THz radiation is being used to optimize materials for new solar cells, and may also be a key technology for the next generation of airport security scanners. While the field was emerging it was possible to keep track of all new developments, however now the field has grown so much that it is increasingly difficult to follow the diverse range of new discoveries and applications that are appearing. At this point in time, when the field of THz science and technology is moving from an emerging to a more established and interdisciplinary field, it is apt to present a roadmap to help identify the breadth and future directions of the field. The aim of this roadmap is to present a snapshot of the present state of THz science and technology in 2017, and provide an opinion on the challenges and opportunities that the future holds. To be able to achieve this aim, we have invited a group of international experts to write 18 sections that cover most of the key areas of THz science and technology. We hope that The 2017 Roadmap on THz science and technology will prove to be a useful resource by providing a wide ranging introduction to the capabilities of THz radiation for those outside or just entering the field as well as providing perspective and breadth for those who are well established. We also feel that this review should serve as a useful guide for government and funding agencies

Measurements and data science, in ICT for Smart Water Systems: Concepts, Methods and Technology:Satellite Remote Sensing of Soil Moisture for Hydrological Applications: A Review of Issues to Be Solved

Accurate soil moisture indicator is critically important for hydrological applications such as water resource management and hydrological modelling. Modern satellite remote sensing has shown a huge potential for providing soil moisture measurements at a large scale. However its effective utilisation in the aforementioned areas still needs comprehensive research. This chapter focuses on exploring the advances and potential issues in the current application of satellite soil moisture observations in hydrological modelling. It has been proposed that hydrological application of soil moisture data requires the data relevant to hydrology. In order to meet the requirement, the following two research tasks are suggested: the first is to carry out comprehensive assessments of satellite soil moisture observations for hydrological modelling, not merely based on evaluations against point-based in situ measurements; the second is that a soil moisture product (e.g. soil moisture deficit) directly applicable to hydrological modelling should be developed. Only fully accomplishing these two steps will push forward the utilisation of satellite soil moisture in hydrological modelling to a greater extent