A general low frequency acoustic radiation capability for NASTRAN

A new capability called NASHUA is described for calculating the radiated acoustic sound pressure field exterior to a harmonically-excited arbitrary submerged 3-D elastic structure. The surface fluid pressures and velocities are first calculated by coupling a NASTRAN finite element model of the structure with a discretized form of the Helmholtz surface integral equation for the exterior fluid. After the fluid impedance is calculated, most of the required matrix operations are performed using the general matrix manipulation package (DMAP) available in NASTRAN. Far field radiated pressures are then calculated from the surface solution using the Helmholtz exterior integral equation. Other output quantities include the maximum sound pressure levels in each of the three coordinate planes, the rms and average surface pressures and normal velocities, the total radiated power and the radiation efficiency. The overall approach is illustrated and validated using known analytic solutions for submerged spherical shells subjected to both uniform and nonuniform applied loads

Monitoring the premalignant potential of Barrett's oesophagus'.

The landscape for patients with Barrett's oesophagus (BE) has changed significantly in the last decade. Research and new guidelines have helped gastroenterologists to better identify those patients with BE who are particularly at risk of developing oesophageal adenocarcinoma. In parallel, developments in endoscopic image enhancement technology and optical biopsy techniques have improved our ability to detect high-risk lesions. Once these lesions have been identified, the improvements in minimally invasive endoscopic therapies has meant that these patients can potentially be cured of early cancer and high-risk dysplastic lesions without the need for surgery, which still has a significant morbidity and mortality. The importance of reaching an accurate diagnosis of BE remains of paramount importance. More work is needed, however. The vast majority of those undergoing surveillance for their BE do not progress towards cancer and thus undergo a regular invasive procedure, which may impact on their psychological and physical well-being while incurring significant cost to the health service. New work that explores cheaper endoscopic or non-invasive ways to identify the at-risk individual provides exciting avenues for research. In future, the diagnosis and monitoring of patients with BE could move away from hospitals and into primary care

Whole genome sequencing and prediction of antimicrobial susceptibilities in non-tuberculous mycobacteria

Non-tuberculous mycobacteria (NTM) are opportunistic pathogens commonly causing chronic, pulmonary disease which is notoriously hard to treat. Current treatment for NTM infections involves at least three active drugs (including one macrolide: clarithromycin or azithromycin) over 12 months or longer. At present there are limited phenotypic in vitro drug susceptibility testing options for NTM which are standardised globally. As seen with tuberculosis, whole genome sequencing has the potential to transform drug susceptibility testing in NTM, by utilising a genotypic approach. The Comprehensive Resistance Prediction for Tuberculosis is a database used to predict Mycobacterium tuberculosis resistance: at present there are no similar databases available to accurately predict NTM resistance. Recent studies have shown concordance between phenotypic and genotypic NTM resistance results. To benefit from the advantages of whole genome sequencing, further advances in resistance prediction need to take place, as well as there being better information on novel drug mutations and an understanding of the impact of whole genome sequencing on NTM treatment outcomes

Experimental evidence of a {\phi} Josephson junction

We demonstrate experimentally the existence of Josephson junctions having a doubly degenerate ground state with an average Josephson phase \psi=\pm{\phi}. The value of {\phi} can be chosen by design in the interval 0<{\phi}<\pi. The junctions used in our experiments are fabricated as 0-{\pi} Josephson junctions of moderate normalized length with asymmetric 0 and {\pi} regions. We show that (a) these {\phi} Josephson junctions have two critical currents, corresponding to the escape of the phase {\psi} from -{\phi} and +{\phi} states; (b) the phase {\psi} can be set to a particular state by tuning an external magnetic field or (c) by using a proper bias current sweep sequence. The experimental observations are in agreement with previous theoretical predictions

Cost-effectiveness analysis of endoscopic eradication therapy for treatment of high-grade dysplasia in Barrett's esophagus

AIM: The aim was to evaluate the cost-effectiveness of endoscopic eradication therapy (EET) with combined endoscopic mucosal resection and radiofrequency ablation for the treatment of high-grade dysplasia (HGD) arising in patients with Barrett's esophagus compared with endoscopic surveillance alone in the UK. MATERIALS & METHODS: The cost-effectiveness model consisted of a decision tree and modified Markov model. A lifetime time horizon was adopted with the perspective of the UK healthcare system. RESULTS: The base case analysis estimates that EET for the treatment of HGD is cost-effective at a GB£20,000 cost-effectiveness threshold compared with providing surveillance alone for HGD patients (incremental cost-effectiveness ratio: GB£1272). CONCLUSION: EET is likely to be a cost-effective treatment strategy compared with surveillance alone in patients with HGD arising in Barrett's esophagus in the UK

Learning curves and the influence of procedural volume for the treatment of dysplastic Barrett's esophagus

BACKGROUND AND AIMS: Endoscopic resections (ER) and radiofrequency ablation (RFA) are the established treatments for Barrett's-associated dysplasia and early esophageal neoplasia. The UK RFA Registry collects patient outcomes from 24 centers in the United Kingdom and Ireland treating patients. Learning curves for treatment of Barrett's dysplasia and the impact of center caseload on patient outcomes is still unknown. METHODS: We examined outcomes of 678 patients treated with RFA in the UK Registry using risk-adjusted CUSUM plots to identify change points in complete resolution of intestinal metaplasia (CR-IM) and complete resolution of dysplasia (CR-D) outcomes. We compared outcomes between those treated at high- (>100 enrolled patients), medium- (51-100) and low- (<50) volume centers. RESULTS: There was no association between center volume and CR-IM and CR-D rates, but there were lower recurrence rates in high-volume versus low-volume centers (Log Rank p=0.001).There was a significant change-point for outcomes at 12 cases for CR-D (reduction from 24.5% to 10.4%; P<0.001) and at 18 cases for CR-IM (30.7% to 18.6%; P<0.001) from RA-CUSUM curve analysis. CONCLUSION: Our data suggest that 18 supervised cases of endoscopic ablation may be required before competency in endoscopic treatment of Barrett's dysplasia can be achieved. The difference in outcomes between a high-volume and low-volume center does not support further centralization of services to only high-volume centers

Providing web-based mental health services to at-risk women

<p>Abstract</p> <p>Background</p> <p>We examined the feasibility of providing web-based mental health services, including synchronous internet video conferencing of an evidence-based support/education group, to at-risk women, specifically poor lone mothers. The objectives of this study were to: (i) adapt a face-to-face support/education group intervention to a web-based format for lone mothers, and (ii) evaluate lone mothers' response to web-based services, including an online video conferencing group intervention program.</p> <p>Methods</p> <p>Participating mothers were recruited through advertisements. To adapt the face-to-face intervention to a web-based format, we evaluated participant motivation through focus group/key informant interviews (n = 7), adapted the intervention training manual for a web-based environment and provided a computer training manual. To evaluate response to web-based services, we provided the intervention to two groups of lone mothers (n = 15). Pre-post quantitative evaluation of mood, self-esteem, social support and parenting was done. Post intervention follow up interviews explored responses to the group and to using technology to access a health service. Participants received $20 per occasion of data collection. Interviews were taped, transcribed and content analysis was used to code and interpret the data. Adherence to the intervention protocol was evaluated.</p> <p>Results</p> <p>Mothers participating in this project experienced multiple difficulties, including financial and mood problems. We adapted the intervention training manual for use in a web-based group environment and ensured adherence to the intervention protocol based on viewing videoconferencing group sessions and discussion with the leaders. Participant responses to the group intervention included decreased isolation, and increased knowledge and confidence in themselves and their parenting; the responses closely matched those of mothers who obtained same service in face-to-face groups. Pre-and post-group quantitative evaluations did not show significant improvements on measures, although the study was not powered to detect these.</p> <p>Conclusions</p> <p>We demonstrated that an evidence-based group intervention program for lone mothers developed and evaluated in face-to-face context transferred well to an online video conferencing format both in terms of group process and outcomes.</p

Genetic variation in Mycobacterium tuberculosis isolates from a London outbreak associated with isoniazid resistance.

BACKGROUND: The largest outbreak of isoniazid-resistant (INH-R) Mycobacterium tuberculosis in Western Europe is centred in North London, with over 400 cases diagnosed since 1995. In the current study, we evaluated the genetic variation in a subset of clinical samples from the outbreak with the hypothesis that these isolates have unique biological characteristics that have served to prolong the outbreak. METHODS: Fitness assays, mutation rate estimation, and whole-genome sequencing were performed to test for selective advantage and compensatory mutations. RESULTS: This detailed analysis of the genetic variation of these INH-R samples suggests that this outbreak consists of successful, closely related, circulating strains with heterogeneous resistance profiles and little or no associated fitness cost or impact on their mutation rate. CONCLUSIONS: Specific deletions and SNPs could be a peculiar feature of these INH-R M. tuberculosis isolates, and could potentially explain their persistence over the years