Global discovery of adaptive mutations.

Although modern DNA sequencing enables rapid identification of genetic variation, characterizing the phenotypic consequences of individual mutations remains a labor-intensive task. Here we describe array-based discovery of adaptive mutations (ADAM), a technology that searches an entire bacterial genome for mutations that contribute to selectable phenotypic variation between an evolved strain and its parent. We found that ADAM identified adaptive mutations in laboratory-evolved Escherichia coli strains with high sensitivity and specificity

Giant thermoelectric effect in graphene-based topological insulators with nanopores

Designing thermoelectric materials with high figure of merit $ZT=S^2 G T/\kappa$ requires fulfilling three often irreconcilable conditions, i.e., the high electrical conductance $G$, small thermal conductance $\kappa$ and high Seebeck coefficient $S$. Nanostructuring is one of the promising ways to achieve this goal as it can substantially suppress lattice contribution to $\kappa$. However, it may also unfavorably influence the electronic transport in an uncontrollable way. Here we theoretically demonstrate that this issue can be ideally solved by fabricating graphene nanoribbons with heavy adatoms and nanopores. These systems, acting as a two-dimensional topological insulator with robust helical edge states carrying electrical current, yield a highly optimized power factor $S^2G$ per helical conducting channel. Concurrently, their array of nanopores impedes the lattice thermal conduction through the bulk. Using quantum transport simulations coupled with first-principles electronic and phononic band structure calculations, the thermoelectric figure of merit is found to reach its maximum $ZT \simeq 3$ at $T \simeq 40$ K. This paves a way to design high-$ZT$ materials by exploiting the nontrivial topology of electronic states through nanostructuring.Comment: 7 pages, 4 figures; PDFLaTe

An approximate dynamic programming approach to food security of communities following hazards

Food security can be threatened by extreme natural hazard events for households of all social classes within a community. To address food security issues following a natural disaster, the recovery of several elements of the built environment within a community, including its building portfolio, must be considered. Building portfolio restoration is one of the most challenging elements of recovery owing to the complexity and dimensionality of the problem. This study introduces a stochastic scheduling algorithm for the identification of optimal building portfolio recovery strategies. The proposed approach provides a computationally tractable formulation to manage multi-state, large-scale infrastructure systems. A testbed community modeled after Gilroy, California, is used to illustrate how the proposed approach can be implemented efficiently and accurately to find the near-optimal decisions related to building recovery following a severe earthquake.Comment: As opposed to the preemptive scheduling problem, which was addressed in multiple works by us, we deal with a non-preemptive stochastic scheduling problem in this work. Submitted to 13th International Conference on Applications of Statistics and Probability in Civil Engineering, ICASP13 Seoul, South Korea, May 26-30, 201

Oscillatory Positive Expiratory Pressure (OPEP) therapy in COPD

People with chronic obstructive pulmonary disease (COPD) commonly have a productive cough due to mucus hypersecretion. Clearing mucus from the chest can be difficult, as lung hyperinflation, respiratory muscle dysfunction and premature airway collapse impede the ability to generate an effective cough. Airway Clearance Techniques (ACTs) with the use of oscillating positive expiratory pressure (OPEP) devices can be added to the usual care for sputum clearance. However, assessment of the effect of OPEP devices is so far based on short-term studies with low-grade evidence and there is a lack of information regarding their long-term impact and effectiveness. In this thesis, I have four results chapters to discuss this gap. First, using accepted systematic review methodology to rigorously examine the current evidence on the use of OPEP devices for the treatment of cough and sputum clearance in patients with COPD who frequently produce sputum. Second, conduct a randomised clinical trial (acronym: O-COPD) to evaluate the impact of an OPEP device (the Acapella) on the health-related quality of life in patients with COPD over three-months. Third, study cough characteristics and its relationship to overnight sleep disturbances. Fourth, evaluate the impact of an OPEP device (the Acapella) on cough frequency and sleep actigraphy in a subset of the O-COPD group. In summary, results from the O-COPD trial, coupled with the systematic review, can address the concerns raised regarding the long-term effectiveness of OPEP devices in treating sputum aspects in stable COPD patients. COPD patients with sputum production who received OPEP treatment for three months, compared to the usual care, demonstrated better disease management and improvement in general and cough-related quality of life (LCQ). The findings suggest that adding the OPEP device is effective in optimising the usual care and, perhaps, can be the new mode of usual care in managing cough and sputum production in COPD patients. Larger and longer clinical trials are required to guide the long-term use of OPEP and patient selection.Open Acces

Alterations in T1 of normal and reperfused infarcted myocardium after Gd-BOPTA versus GD-DTPA on inversion recovery EPI.

This study tested whether Gd-BOPTA/Dimeg or Gd-DTPA exerts greater relaxation enhancement for blood and reperfused infarcted myocardium. Relaxivity of Gd-BOPTA is increased by weak binding to serum albumin. Thirty-six rats were subjected to reperfused infarction before contrast (doses = 0.05, 0.1, and 0.2 mmol/kg). delta R1 was repeatedly measured over 30 min. Gd-BOPTA caused greater delta R1 for blood and myocardium than did Gd-DTPA; clearance of both agents from normal- and infarcted myocardium was similar to blood clearance; plots of delta R1 myocardium/delta R1 blood showed equilibrium phase contrast distribution. Fractional contrast agent distribution volumes were approximately 0.24 for both agents in normal myocardium, 0.98 and 1.6 for Gd-DTPA and Gd-BOPTA, respectively, in reperfused infarction. The high value for Gd-BOPTPA was ascribed to greater relaxivity in infarction versus blood. It was concluded that Gd-BOPTA/Dimeg causes a greater delta R1 than Gd-DTPA in regions which contain serum albumin