Micro flow bio-molecular computation

In this paper we provide a model for micro-flow based bio-molecular computation (MF-BMC). It provides an abstraction for the design of algorithms which account for the constraints of the model. Our MF-BMC model uses abstractions of both the recombinant DNA (RDNA) technology as well as of the micro-flow technology and takes into account both of their limitations. For example, when considering the efficiency of the recombinant DNA operation of annealing, we take into account the limitation imposed by the concentration of the reactants. The fabrication technology used to construct MEMS is limited to constructing relatively thin 3D structures. We abstract this by limiting the model to a small constant number of layers (as is done with VLSI models). Besides our contribution of the MF-BMC model, the paper contains two other classes of results. The main result is the volume and time efficient algorithm for message routing in the MF-BMC model, specifically useful for PA-Match. We will show that routing of strands between chambers will occur in time O(N x D/ m x n), where N is the number of strands in the MF-BMC, n is the number of chambers where RDNA operations are occurring, D is the diameter of the topology of the layout of the chambers, and m is proportional to the channel width. Operations that need annealing, such as PA-Match, are shown feasible in O(N2logN/n/n) volume instead of the previous use of omega(N2) volume, with reasonable time constraints. Applications of the volume efficient algorithm include the use of the Join operation for databases, logarithmic depth solutions to SAT (Boolean formula satisfiability) problems and parallel algorithms that execute on a PRAM. Existent algorithms can be mapped to ones that work efficiently in the MF-BMC model, whereas previous methods for applications such as PRAM simulation in BMC were not both time and volume efficient. Our other class of results are theoretical lower bounds on the quantities of DNA and the time needed to solve a problem in the MF-BMC model, analogous to lower bounds in VLSI. We bound the product BT from below, and further show that BT2 has a stronger lower bound of I2. Here B is the maximum amount of information encoded in the MF-BMC system at a time. T is the time for an algorithm to complete, and I is the information content of a problem.     

Mortality Trends in Women and Men Presenting with Acute Coronary Syndrome: Insights from a 20-Year Registry

Background

Coronary artery disease (CAD) is the leading cause of mortality worldwide. The present study evaluated the impact of gender in patients hospitalized with acute coronary syndromes (ACS) over a 20-year period in Qatar.

Methods

Data were collected retrospectively from the registry of the department of cardiology for all patients admitted with ACS during the study period (1991–2010) and were analyzed according to gender.

Results

Among 16,736 patients who were admitted with ACS, 14262 (85%) were men and 2474 (15%) were women. Cardiovascular risk factors were more prevalent among women in comparison to men. On admission, women presented mainly with non-ST-elevation ACS and were more likely to be undertreated with β-blockers (BB), antiplatelet agents and reperfusion therapy in comparison to men. However, from 1999 through 2010, the use of aspirin, angiotensin-converting enzyme inhibitors and BB increased from 66% to 79%, 27% to 41% and 17% to 49%, respectively in women. In the same period, relative risk reduction for mortality was 64% in women and 51% in men. Across the 20-year period, the mortality rate decreased from 27% to 7% among the Middle Eastern Arab women. Multivariate logistic regression analysis showed that female gender was independent predictor of in-hospital mortality (odd ratio 1.51, 95% CI 1.27–1.79).

Conclusions

Women presenting with ACS are high-risk population and their in-hospital mortality remains higher for all age groups in comparison to men. Although, substantial improvement in the hospital outcome has been observed, guidelines adherence and improvement in the hospital care have not yet been optimized.