Free breathing lung T1 mapping using image registration in patients with idiopathic pulmonary fibrosis

Purpose To assess the use of image registration for correcting respiratory motion in free breathing lung T1 mapping acquisition in patients with idiopathic pulmonary fibrosis (IPF). Theory and Methods The method presented used image registration to synthetic images during postprocessing to remove respiratory motion. Synthetic images were generated from a model of the inversion recovery signal of the acquired images that incorporated a periodic lung motion model. Ten healthy volunteers and 19 patients with IPF underwent 2D Look‐Locker T1 mapping acquisition at 1.5T during inspiratory breath‐hold and free breathing. Eight healthy volunteers and seven patients with IPF underwent T1 mapping acquisition during expiratory breath‐hold. Fourteen patients had follow‐up scanning at 6 months. Dice similarity coefficient (DSC) was used to evaluate registration efficacy. Results Image registration increased image DSC (P < .001) in the free breathing inversion recovery images. Lung T1 measured during a free breathing acquisition was lower in patients with IPF when compared with healthy controls (inspiration: P = .238; expiration: P = .261; free breathing: P = .021). Measured lung T1 was higher in expiration breath‐hold than inspiration breath‐hold in healthy volunteers (P < .001) but not in patients with IPF (P = .645). There were no other significant differences between lung T1 values within subject groups. Conclusions The registration technique significantly reduced motion in the Look‐Locker images acquired during free breathing and may improve the robustness of lung T1 mapping in patients who struggle to hold their breath. Lung T1 measured during a free breathing acquisition was significantly lower in patients with IPF when compared with healthy controls

Management of paediatric tibial fractures using two types of circular external fixator: Taylor spatial frame and Ilizarov circular fixator.

Background The use of circular fixators for the treatment of tibial fractures is well established in the literature. The aim of this study was to compare the Ilizarov circular fixator (ICF) with the Taylor spatial frame (TSF) in terms of treatment results in consecutive patients with tibial fractures that required operative management. Method A retrospective analysis of patient records and radiographs was performed to obtain patient data, information on injury sustained, the operative technique used, time duration in frame, healing time and complications of treatment. The minimum follow-up was 24 months. Results Ten patients were treated with ICF between 2000 and 2005, while 15 patients have been treated with TSF since 2005. Two of the 10 treated with ICF and 5 of the 15 treated with TSF were open fractures. All patients went on to achieve complete union. Mean duration in the frame was 12.7 weeks for ICF and 14.8 weeks for the TSF group. Two patients in the TSF group had delayed union and required additional procedures including adjustment of fixator and bone grafting. There was one malunion in the TSF group that required osteotomy and reapplication of frame. There were seven and nine pin-site infections in the ICF and TSF groups, respectively, all of which responded to antibiotics. There were no refractures in either group. Conclusion In an appropriate patient, both types of circular fixator are equally effective but have different characteristics, with TSF allowing for postoperative deformity correction. Of concern are the two cases of delayed union in the TSF group, all in patients with high-energy injuries. We feel another larger study is required to provide further clarity in this matter. Level of evidence Level II—comparative study

Survival-Time Distribution for Inelastic Collapse

In a recent publication [PRL {\bf 81}, 1142 (1998)] it was argued that a randomly forced particle which collides inelastically with a boundary can undergo inelastic collapse and come to rest in a finite time. Here we discuss the survival probability for the inelastic collapse transition. It is found that the collapse-time distribution behaves asymptotically as a power-law in time, and that the exponent governing this decay is non-universal. An approximate calculation of the collapse-time exponent confirms this behaviour and shows how inelastic collapse can be viewed as a generalised persistence phenomenon.Comment: 4 pages, RevTe

Nonequilibrium phase transitions in models of adsorption and desorption

The nonequilibrium phase transition in a system of diffusing, coagulating particles in the presence of a steady input and evaporation of particles is studied. The system undergoes a transition from a phase in which the average number of particles is finite to one in which it grows linearly in time. The exponents characterizing the mass distribution near the critical point are calculated in all dimensions.Comment: 10 pages, 2 figures (To appear in Phys. Rev. E

Whole school mapping to investigate the school environment's potential to promote a healthy diet and physical activity in Malaysia

Introduction: The school is a vital part in the development of children's dietary practices as children consume a substantial proportion of their daily intake at school. The school environment offers an ideal location for health education and intervention against physical inactivity and poor nutritional intake. Methods: A mapping tool was developed to map the school environment on four levels: physical, economic, political, and socio-cultural that can potentially affect healthy eating and physical activity. The mapping was piloted and completed by interviewing twelve teachers (responsible for student affairs and the school curriculum), followed by observation at twelve randomly selected schools (six urban, six rural) in Terengganu, Eastern Peninsular Malaysia. Results: For physical environment, 55.0% of the criteria were met and while all schools taught nutrition and physical activity, this was not backed up with actual facilities for practising physical activity or food preparation. For economic environment, 17.7% of the criteria were met and eleven out of twelve schools had mobile caterers outside their front gates selling energy-dense food/drink. For political environment, 52.1% of the criteria were met and all teachers were aware of the existence of the national catering and nutrition guidelines, but they reported a lack of resources for implementation and monitoring. For socio-cultural environment, 59.2% of the criteria were met and all schools used sweet foods and drinks as rewards at large events. Conclusion: The findings suggest potential avenues exist for intervention in schools to provide a supportive environment that promotes healthier eating and physical activity to prevent obesity

Birthweight, HIV exposure and infant feeding as predictors of malnutrition in Botswanan infants

Background: A better understanding of the nutritional status of infants who are HIV-Exposed-Uninfected (HEU) and HIV-Unexposed-Uninfected (HUU) during their first 1000 days is a key to improving population health, particularly in sub-Saharan Africa. Methods: A cross-sectional study compared nutritional status, feeding practices and determinants of nutritional status of HEU and HUU infants residing in representative selected districts in Botswana during their first 1000 days of life. Four hundred and thirteen infants (37.3% HIV16 exposed), aged 6-24 months attending routine child health clinics were recruited. Anthropometric, 24-hour dietary intake and socio-demographic data was collected. Anthropometric z-scores were calculated using 2006 WHO growth standards. Modelling of the determinants of malnutrition was undertaken using logistic regression. Results: Overall, prevalence of stunting, wasting and underweight were 10.4%, 11.9% and 10.2% respectively. HEU infants were more likely to be underweight (15.6% vs. 6.9%), (p<0.01) and stunted (15.6% vs. 7.3%), (p<0.05) but not wasted (p= 0.14) than HUU infants. HEU infants tended to be formula fed (89.4%) whereas HUU infants tended to breastfeed (89.6%) for the first six months (p<0.001). Significant predictors of nutritional status were HIV exposure, birthweight, birth length, Apgar score and mother/caregiver’s education with little influence of socioeconomic status. Conclusions: HEU infants aged 6-24 months had worse nutritional status compared to HUU infants. Low birthweight was the main predictor of undernutrition in this population. Optimisation of infants’ nutritional status should focus on improving birthweight. In addition, specific interventions should target HEU infants in order to eliminate growth disparity between HEU and HUU infants

Factors associated with universal infant free school meal take up and refusal in a multicultural urban community

BackgroundUniversal infant free school meals (UIFSM) were introduced in September 2014 and are available to all key stage 1 (4–7 years) children attending state-maintained infant and primary schools in England. The present study aimed to investigate the school-based factors, child and family socio-demographic characteristics, and parental beliefs associated with UIFSM take up in an urban community.MethodsA cross-sectional questionnaire survey was completed in October to November 2015, amongst parents whose children attended eligible schools in Leicester, England. A questionnaire about school meals was also completed by each school.ResultsParents reported their child did not take (non-UIFSM, n = 159) or took (UIFSM, n = 517) a UIFSM on most days. The non-UIFSM group were more likely to be White-British, have a higher socio-economic status, have English as a first language, and involve their child in the decision over whether or not to take UIFSM, compared to the UIFSM group. Cluster analysis revealed that non-UIFSM parents were either concerned over quality of meals and what/how much their child ate, concerned only by what/how much their child ate or whether their child did not like the food provided. Two subsets of parents in the UIFSM group were either very positive about UIFSM or appeared to take meals because they were free. Schools used a variety of measures to increase and maintain UIFSM take up.ConclusionsParents like to have control over what their child eats at school and children need to enjoy their school meals. Using a range of interventions to target subsets of parents may help local authorities, schools and caterers to increase UIFSM take up

Experimental and quantitative imaging techniques in interstitial lung disease.

Interstitial lung diseases (ILDs) are a heterogeneous group of conditions, with a wide and complex variety of imaging features. Difficulty in monitoring, treating and exploring novel therapies for these conditions is in part due to the lack of robust, readily available biomarkers. Radiological studies are vital in the assessment and follow-up of ILD, but currently CT analysis in clinical practice is qualitative and therefore somewhat subjective. In this article, we report on the role of novel and quantitative imaging techniques across a range of imaging modalities in ILD and consider how they may be applied in the assessment and understanding of ILD. We critically appraised evidence found from searches of Ovid online, PubMed and the TRIP database for novel and quantitative imaging studies in ILD. Recent studies have explored the capability of texture-based lung parenchymal analysis in accurately quantifying several ILD features. Newer techniques are helping to overcome the challenges inherent to such approaches, in particular distinguishing peripheral reticulation of lung parenchyma from pleura and accurately identifying the complex density patterns that accompany honeycombing. Robust and validated texture-based analysis may remove the subjectivity that is inherent to qualitative reporting and allow greater objective measurements of change over time. In addition to lung parenchymal feature quantification, pulmonary vessel volume analysis on CT has demonstrated prognostic value in two retrospective analyses and may be a sign of vascular changes in ILD which, to date, have been difficult to quantify in the absence of overt pulmonary hypertension. Novel applications of existing imaging techniques, such as hyperpolarised gas MRI and positron emission tomography (PET), show promise in combining structural and functional information. Although structural imaging of lung tissue is inherently challenging in terms of conventional proton MRI techniques, inroads are being made with ultrashort echo time, and dynamic contrast-enhanced MRI may be used for lung perfusion assessment. In addition, inhaled hyperpolarised 129Xenon gas MRI may provide multifunctional imaging metrics, including assessment of ventilation, intra-acinar gas diffusion and alveolar-capillary diffusion. PET has demonstrated high standard uptake values (SUVs) of 18F-fluorodeoxyglucose in fibrosed lung tissue, challenging the assumption that these are 'burned out' and metabolically inactive regions. Regions that appear structurally normal also appear to have higher SUV, warranting further exploration with future longitudinal studies to assess if this precedes future regions of macroscopic structural change. Given the subtleties involved in diagnosing, assessing and predicting future deterioration in many forms of ILD, multimodal quantitative lung structure-function imaging may provide the means of identifying novel, sensitive and clinically applicable imaging markers of disease. Such imaging metrics may provide mechanistic and phenotypic information that can help direct appropriate personalised therapy, can be used to predict outcomes and could potentially be more sensitive and specific than global pulmonary function testing. Quantitative assessment may objectively assess subtle change in character or extent of disease that can assist in efficacy of antifibrotic therapy or detecting early changes of potentially pneumotoxic drugs involved in early intervention studies

Public health strategies to reduce sugar intake in the UK: an exploration of public perceptions using digital spaces

Background: To explore UK public perceptions of children’s sugar consumption, Public Health England’s Change4Life Sugar Smart App and the Soft Drinks Industry Levy, using solicited and unsolicited digital data. Methods: Data from three digital spaces were used: (1) an online questionnaire advertised on parenting forums; (2) posts to UK online parenting forums; (3) English-language Tweets from Twitter. Quantitative data were analysed using descriptive statistics and qualitative data using content and inductive thematic analysis. Results: Data were (study 1) 184 questionnaire participants; (study 2) 412 forum posts; (study 3) 618 Tweets. In study 1, 94.0% (n=173) agreed that children in the UK consumed too much sugar and this had a negative health effect (98.4%, n=181). Environments (n=135, 73.4%), media/advertising (n=112, 60.9%), and parents (n=107, 58.2%) were all reported as barriers to changing children’s sugar intake. In study 2, more posts were negative towards the Soft Drinks Industry Levy (n=189, 45.9%) than positive (n=145, 35.2%), and themes about the inability of the Levy to affect sugar consumption in children and childhood obesity emerged. Other themes related to distrust of the government, food industry and retailers. In study 3, the Sugar Smart App was viewed positively (n=474, 76.7%) with its function associated solely with identification of sugar content. Conclusions: Participants accepted the necessity of sugar reduction in children, but recognised the complexity of behaviour change. Public health activities were not always perceived as effective strategies for health promotion. There was some distrust in government, public health officials, and the food industry. A less simplistic approach to sugar reduction and more credible sources of information may, therefore, be welcomed by the public

Exact steady state solution of the Boltzmann equation: A driven 1-D inelastic Maxwell gas

The exact nonequilibrium steady state solution of the nonlinear Boltzmann equation for a driven inelastic Maxwell model was obtained by Ben-Naim and Krapivsky [Phys. Rev. E 61, R5 (2000)] in the form of an infinite product for the Fourier transform of the distribution function $f(c)$. In this paper we have inverted the Fourier transform to express $f(c)$ in the form of an infinite series of exponentially decaying terms. The dominant high energy tail is exponential, $f(c)\simeq A_0\exp(-a|c|)$, where $a\equiv 2/\sqrt{1-\alpha^2}$ and the amplitude $A_0$ is given in terms of a converging sum. This is explicitly shown in the totally inelastic limit ($\alpha\to 0$) and in the quasi-elastic limit ($\alpha\to 1$). In the latter case, the distribution is dominated by a Maxwellian for a very wide range of velocities, but a crossover from a Maxwellian to an exponential high energy tail exists for velocities $|c-c_0|\sim 1/\sqrt{q}$ around a crossover velocity $c_0\simeq \ln q^{-1}/\sqrt{q}$, where $q\equiv (1-\alpha)/2\ll 1$. In this crossover region the distribution function is extremely small, $\ln f(c_0)\simeq q^{-1}\ln q$.Comment: 11 pages, 4 figures; a table and a few references added; to be published in PR