Bidirectional ventricular tachycardia in cardiac sarcoidosis.

A 73-year-old man with history of pulmonary sarcoidosis was found to have runs of non-sustained bidirectional ventricular tachycardia (BVT) with two different QRS morphologies on a Holter monitor. Cardiac magnetic resonance delayed gadolinium imaging revealed a region of patchy mid-myocardial enhancement within the left ventricular basal inferolateral myocardium. An 18-fluorodeoxyglucose positron emission tomography (FDG-PET) showed increased uptake in the same area, consistent with active sarcoid, with no septal involvement. Follow-up FDG-PET one year later showed disease progression with new septal involvement. Cardiac sarcoidosis, characterized by myocardial inflammation and interstitial fibrosis that can lead to conduction system disturbance and macro re-entrant arrhythmias, should be considered in differential diagnosis of BVT. BVT may indicate septal involvement with sarcoidosis before the lesions are large enough to be detected radiologically

Building Social Capital Through Microfinance

A number of development assistance programs promote community interaction as a means of building social capital. Yet, despite strong theoretical underpinnings, the role of repeat interactions in sustaining cooperation has proven difficult to identify empirically. We provide the first experimental evidence on the economic returns to social interaction in the context of microfinance. Random variation in the frequency of mandatory meetings across first-time borrower groups generates exogenous and persistent changes in clients' social ties. We show that the resulting increases in social interaction among clients more than a year later are associated with improvements in informal risk-sharing and reductions in default. A second field experiment among a subset of clients provides direct evidence that more frequent interaction increases economic cooperation among clients. Our results indicate that group lending is successful in achieving low rates of default without collateral not only because it harnesses existing social capital, as has been emphasized in the literature, but also because it builds new social capital among participants

Numerical simulation of colloidal dispersion filtration: description of critical flux and comparison with experimental results

During filtration via membrane processes, colloids accumulate at the porous surface leading to fouling phenomena. In this study, a rigorous simulation of momentum and mass transfer using CFD modelling has been developed to describe such an accumulation during cross flow filtration. These simulations integrate detailed modeling of physicochemical properties specific to colloidal dispersions (because of the surface interactions (repulsive and attractive) occurring between the colloids particles). These interactions are accounted for via the experimental variation of the colloidal osmotic pressure with volume fraction (associated with a variation in the diffusion coefficient) which are fitted by a relationship integrated into the CFD code. It contains a description of the colloidal phase transition leading to the formation of a condensed phase (deposit or gel layer) from the accumulated dispersed phase (concentration polarization). It is then possible to determine the critical flux which separates filtration conditions below which mass accumulation is reversible (in the dispersed phase) and above which it is irreversible (in the condensed phase). The computed value of critical flux is compared with that determined experimentally for a dispersion of latex particles

Comparison of ecosystem processes in a woodland and prairie pond with different hydroperiods

Shallow lakes and ponds constitute a significant number of water bodies worldwide. Many are heterotrophic, indicating that they are likely net contributors to global carbon cycling. Climate change is likely to have important impacts on these waterbodies. In this study, we examined two small Minnesota ponds; a permanent woodland pond and a temporary prairie pond. The woodland pond had lower levels of phosphorus and phytoplankton than the prairie pond. Using the open water oxygen method, we found the prairie pond typically had a higher level of gross primary production (GPP) and respiration (R) than the woodland pond, although the differences between the ponds varied with season. Despite the differences in GPP and R between the ponds the net ecosystem production was similar with both being heterotrophic. Since abundant small ponds may play an important role in carbon cycling and are likely to undergo changes in temperature and hydroperiod associated with climate change, understanding pond metabolism is critical in predicting impacts and designing management schemes to mitigate changes

Analysis of Possible Solutions to Support the Timely Delivery of the Columbia-Class Submarine

Symposium Student Poster ShowStrategic deterrence is the number one priority of the Department of Defense. In order to prevent a gap in nuclear deterrent capability, the successor to the Ohio class, the Columbia class, must be built according to schedule. However, the Columbia-class submarine has experienced numerous schedule delays which threaten its timely delivery. This thesis conducts a root cause analysis of the issues which have contributed to schedule delays and proposes a way moving forward which minimizes the likelihood of future setbacks. These issues are framed in a fictitious case study and the recommendations to solve the problems are discussed in a follow-on analysis.Approved for public release; distribution is unlimited

Simulations of Mixed Morphology Supernova Remnants With Anisotropic Thermal Conduction

We explore the role of anisotropic thermal conduction on the evolution of supernova remnants through interstellar media with a range of densities via numerical simulations. We find that a remnant expanding in a dense environment can produce centre-bright hard x-ray emission within 20 kyr, and centre-bright soft x-ray emission within 60 kyr of the supernova event. In a more tenuous environment, the appearance of a centre-bright structure in hard x-rays is delayed until about 60 kyr. The soft x-ray emission from such a remnant may not become centre bright during its observable lifetime. This can explain the observations that show that mixed-morphology supernova remnants preferentially occur close to denser, molecular environments. Remnants expanding into denser environments tend to be smaller, making it easier for thermal conduction to make larger changes in the temperatures of their hot gas bubbles. We show that the lower temperatures make it very favorable to use high-stage ions as diagnostics of the hot gas bubbles in SNRs. In particular, the distribution of O VIII transitions from shell-bright at early epochs to centre-bright at later epochs in the evolution of an SNR expanding in a dense ISM when the physics of thermal conduction is included.Comment: 8 pages, 5 figures, submitted to Monthly Notice

Evidence for a regulatory role of Cullin-RING E3 ubiquitin ligase 7 in insulin signalling

Dysfunctional regulation of signalling pathways downstream of the insulin receptor plays a pivotal role in the pathogenesis of insulin resistance and type 2 diabetes. In this study we report both in vitro and in vivo experimental evidence for a role of Cullin-RING E3 ubiquitin ligase 7 (CRL7) in the regulation of insulin signalling and glucose homeostasis. We show that Cul7−/− mouse embryonic fibroblasts displayed enhanced AKT and Erk MAP kinase phosphorylation upon insulin stimulation. Depletion of CUL7 by RNA interference in C2C12 myotubes led to increased activation of insulin signalling pathways and cellular glucose uptake, as well as a reduced capacity of these cells to execute insulin-induced degradation of insulin receptor substrate 1 (IRS1). In vivo, heterozygosity of either Cul7 or Fbxw8, both key components of CRL7, resulted in elevated PI3 kinase / AKT activation in skeletal muscle tissue upon insulin stimulation when compared to wild-type controls. Finally, Cul7+/− or Fbxw8+/− mice exhibited enhanced insulin sensitivity and plasma glucose clearance. Collectively, our findings point to a yet unrecognized role of CRL7 in insulin-mediated control of glucose homeostasis by restraining PI3 kinase / AKT activities in skeletal muscle cells

ANALYSIS OF POSSIBLE SOLUTIONS TO SUPPORT THE TIMELY DELIVERY OF THE COLUMBIA CLASS SUBMARINE

Ballistic missile submarines (SSBNs) are a stealthy, survivable launch platform that contributes to strategic deterrence, the number one mission of the Department of Defense. Ohio-class SSBNs, which have filled the role of sea-based deterrence for the last 40 years, are reaching their retirement criteria. In order to prevent a gap in nuclear deterrent capability, the successor to the Ohio-class, the Columbia-class, must be built according to schedule. However, the Columbia-class submarine is experiencing setbacks due to multiple issues with the software used to generate key design documents, an industrial base that is struggling to support the construction of three submarines per year (two Virginia-class fast attack submarines and one Columbia-class SSBN), and quality assurance issues with key manufacturers. With a mission as important as strategic deterrence on the line, developing a useful solution quickly is of the highest importance. This research analyzed the Columbia-class submarine acquisition program, generated a case study, and concluded with a case study analysis that utilizing the Defense Production Act Title III, which could re-bolster the submarine industrial base, and fully restoring and improving existing quality assurance programs, could increase the likelihood of delivering the first Columbia-class submarine on schedule while also optimizing for cost, performance, and technological risk.Lieutenant, United States NavyApproved for public release. Distribution is unlimited