From gastric aspiration to airway inflammation

The airways are poorly protected from potentially damaging agents contained within gastric contents. While digestive factors are obvious damaging agents, gastric aspiration may also deliver microbial agents, cytokines or food antigens to airway tissues. Direct damage or the triggering of the inflammatory cascade by gastric aspiration is believed to drive airways disease onset and/or progression. Evidence exists from experimental models demonstrating direct instillation of damaging factors to a range of airways epithelia causes damage and/or an inflammatory response. Clinical longitudinal studies have also noted an association between the presence of biomarkers of reflux in airways samples and disease progression. A shared pathophysiology of many chronic airways diseases is a more negative intrathoracic pressure. Such changes would drive an increased abdominothoracic pressure gradient. These changes in respiratory mechanics mean that chronic lung disease patients may be predisposed to reflux and subsequent aspiration. Therefore, it appears that gastric aspiration and airways disease progression may be linked not solely as cause and effect, but seemingly within a vicious cycle. A range of physiological factors govern both occurrence of gastric reflux into the pharynx/larynx and could also increase the susceptibility of certain individuals to disease progression. A range of long-term surgical and pharmacological intervention studies are necessary to test the benefit of such therapies in reducing disease progression or driving symptom improvement. Such studies may be hampered by the reliability of available therapies in halting gastric aspiration and the difficulty in the clinical or biochemical assessment of gastric aspiration

Solving the Klein-Gordon equation using Fourier spectral methods: A benchmark test for computer performance

The cubic Klein-Gordon equation is a simple but non-trivial partial differential equation whose numerical solution has the main building blocks required for the solution of many other partial differential equations. In this study, the library 2DECOMP&FFT is used in a Fourier spectral scheme to solve the Klein-Gordon equation and strong scaling of the code is examined on thirteen different machines for a problem size of 512^3. The results are useful in assessing likely performance of other parallel fast Fourier transform based programs for solving partial differential equations. The problem is chosen to be large enough to solve on a workstation, yet also of interest to solve quickly on a supercomputer, in particular for parametric studies. Unlike other high performance computing benchmarks, for this problem size, the time to solution will not be improved by simply building a bigger supercomputer.Comment: 10 page

The association between histamine 2 receptor antagonist use and Clostridium difficile infection: a systematic review and meta-analysis.

Background Clostridium difficile infection (CDI) is a major health problem. Epidemiological evidence suggests that there is an association between acid suppression therapy and development of CDI. Purpose We sought to systematically review the literature that examined the association between histamine 2 receptor antagonists (H2RAs) and CDI. Data source We searched Medline, Current Contents, Embase, ISI Web of Science and Elsevier Scopus from 1990 to 2012 for all analytical studies that examined the association between H2RAs and CDI. Study selection Two authors independently reviewed the studies for eligibility. Data extraction Data about studies characteristics, adjusted effect estimates and quality were extracted. Data synthesis Thirty-five observations from 33 eligible studies that included 201834 participants were analyzed. Studies were performed in 6 countries and nine of them were multicenter. Most studies did not specify the type or duration of H2RAs therapy. The pooled effect estimate was 1.44, 95% CI (1.22–1.7), I2 = 70.5%. This association was consistent across different subgroups (by study design and country) and there was no evidence of publication bias. The pooled effect estimate for high quality studies was 1.39 (1.15–1.68), I2 = 72.3%. Meta-regression analysis of 10 study-level variables did not identify sources of heterogeneity. In a speculative analysis, the number needed to harm (NNH) with H2RAs at 14 days after hospital admission in patients receiving antibiotics or not was 58, 95% CI (37, 115) and 425, 95% CI (267, 848), respectively. For the general population, the NNH at 1 year was 4549, 95% CI (2860, 9097). Conclusion In this rigorous systematic review and meta-analysis, we observed an association between H2RAs and CDI. The absolute risk of CDI associated with H2RAs is highest in hospitalized patients receiving antibiotics

Cost of hospital management of Clostridium difficile infection in United States - a meta-analysis and modelling study

Background: Clostridium difficile infection (CDI) is the leading cause of infectious nosocomial diarrhoea but the economic costs of CDI on healthcare systems in the US remain uncertain. Methods: We conducted a systematic search for published studies investigating the direct medical cost associated with CDI hospital management in the past 10 years (2005-2015) and included 42 studies to the final data analysis to estimate the financial impact of CDI in the US. We also conducted a meta-analysis of all costs using Monte Carlo simulation. Results: The average cost for CDI case management and average CDI-attributable costs per case were $42,316 (90$ 39,886, $44,765) and$ 21,448 (90 % CI: $21,152,$ 21,744) in 2015 US dollars. Hospital-onset CDIattributable cost per case was $34,157 (90$ 33,134, $35,180), which was 1.5 times the cost of communityonset CDI ($ 20,095 [ 90 % CI: $4991,$ 35,204]). The average and incremental length of stay (LOS) for CDI inpatient treatment were 11.1 (90 % CI: 8.7-13.6) and 9.7 (90 % CI: 9.6-9.8) days respectively. Total annual CDI-attributable cost in the US is estimated US$6.3 (Range:$ 1.9-$ 7.0) billion. Total annual CDI hospital management required nearly 2.4 million days of inpatient stay. Conclusions: This review indicates that CDI places a significant financial burden on the US healthcare system. This review adds strong evidence to aid policy-making on adequate resource allocation to CDI prevention and treatment in the US. Future studies should focus on recurrent CDI, CDI in long-term care facilities and persons with comorbidities and indirect cost from a societal perspective. Health-economic studies for CDI preventive intervention are needed.Sanofi PasteurSCI(E)[email protected]

Enablers and limiters of measuring performance: a grounded theory study of Saudi universities

In recent years, the development of management control systems and performance measurement in particular within higher education institutions has been a major focus of policy makers and academics. Recent studies have, for example, attempted to provide an objective framework for performance of academic administration (Dorweiler, and Yakhou, 2005), they have examined how private sector performance management techniques could be applied to higher education (Chen et al., 2006, Umashankar and Dutta, 2007), they have tested the usefulness of performance management for universities in developing countries (Waal, 2007) and investigated the relationship between strategy, accounting and performance management in UK Higher Education (Broad et al., 2007). This paper reflects on the use of performance measurement systems within two Saudi government universities. It has become apparent that government universities within Saudi Arabia follow similar rules and regulations, yet the manner in which they have operationalised their internal performance measurement systems is very different. This paper is concerned with developing an understanding of the thinking, perciption and use of performance measures in a Saudi university context. This research uses an interpretive grounded theory approach (Strauss and Corbin, 1998) to generate a theory which is grounded in data obtained during the study. It particularly focuses on the actions, interactions and processes of those involved and suggests that there are enablers and limiters of performance management, which operate at organisational and individual levels. Data was collected through face to face semi-structured interviews with over fifty administrators and academics within the two universities. The data was analysed using the coding structures advocated by Strauss and Corbin (1998) to develop a contextualised theory which helps understand the complexities of performance management within the universities studied

Electrical Power Savings in Pump and Compressor Networks via Load Management

Large industrial plants commonly use multiple parallel units in pump and compressor networks for improved reliability. Sometimes, installed equipment capacity can far exceed actual requirements. This excess capacity can be translated into energy cost savings through “optimum load management”. A key decision parameter in determining the operating policy is the Trigger Point at which to switch from N units to N+1, and vice versa. The Trigger Point is defined as the actual flow rate at which the switching is made to the “ideal” (generally maximum) flow rate at which the switching should be made. At the plant under study, the implicit Trigger Point was generally found to be around 85%, probably because this made it easy to have a smooth transition during the switching operation. A number of pumping and compression networks were analyzed to determine what the potential savings would be if this trigger point were increased to 90 or 95%. The savings potential was found to range from 0 to 23%, with an average of 4.4%. Our study demonstrated that by tightening up operating policies to make sure that the minimum number of machines is being run, significant cost savings are possible with zero capital investment, and negligible sacrifice in operating flexibility or reliability. This paper describes the methodology used, as well as representative results from our study