Ventricular tachycardia associated with lacosamide co-medication in drug-resistant epilepsy.

We report a case of sustained ventricular tachycardia following the initiation of lacosamide as adjunctive epilepsy treatment. A 49-year-old male with intractable frontal lobe seizures experienced severe ventricular tachycardia following the addition of 400 mg lacosamide to his existing regimen of carbamazepine, lamotrigine, clonazepam, and valproate. The tachycardia occurred during a cardiac stress test; stress tests prior to initiation of lacosamide were normal. Conduction defects, including QRS prolongation, persisted during hospitalization until lacosamide was discontinued. The patient had no prior history of cardiac arrhythmia but did possess cardiac risk factors, including hypertension, hypercholesterolemia, and low heart rate variability. This case represents one part of a growing body of literature suggesting a link between arrhythmia and use of lacosamide, which enhances slow inactivation of sodium channels in both the brain and the heart. We believe further study may be necessary to assess the safety of lacosamide in epilepsy patients with cardiac risk factors

Short-time rotational diffusion in monodisperse charge-stabilized colloidal suspensions

We investigate the combined effects of electrostatic interactions and hydrodynamic interactions on the short-time rotational self-diffusion coefficient in charge-stabilized suspensions. We calculate this coefficient as a function of volume fraction for various effective particle charges and amounts of added electrolyte. The influence of the hydrodynamic interactions on the rotational diffusion coefficient is less pronounced for charged particles than for uncharged ones. Salt-free suspensions are weakly influenced by hydrodynamic interactions. For these strongly correlated systems we obtain a quadratic volume fraction-dependence of the diffusion coefficient, which is well explained in terms of an effective hard sphere model.Comment: 21 pages, LaTeX, 7 Postscript figures included using epsf, to appear in Physica

Comparison between different approaches for the evaluation of the hot spot structural stress in welded pressure vessel components

Fatigue cracks in welds often occur at the toe of a weld where stresses are difficult to calculate at the design stage. To circumvent this problem the ASME Boiler and PV code Section VIII Division 2 Part 5 [1] uses the structural stress normal to the expected crack to predict fatigue life using elastic analysis and as welded fatigue curves. The European Unfired Pressure Vessel Code [2] uses a similar approach. The structural stress excludes the notch stress at the weld toe itself. The predicted fatigue life has a strong dependency on the calculated value of structural stress. This emphasizes the importance of having a unique and robust way of extracting the structural stress from elastic finite element results. Different methods are available for the computation of the structural hotspotstress at welded joints. These are based on the extrapolation of surface stresses close to the weld toe, on the linearisation of stresses in the through-thickness direction or on the equilibrium of nodal forces. This paper takes a critical view on the various methods and investigates the effects of the mesh quality on the value of the structural stress. T-shaped welded plates under bending are considered as a means for illustration

StocHy: automated verification and synthesis of stochastic processes

StocHy is a software tool for the quantitative analysis of discrete-time stochastic hybrid systems (SHS). StocHy accepts a high-level description of stochastic models and constructs an equivalent SHS model. The tool allows to (i) simulate the SHS evolution over a given time horizon; and to automatically construct formal abstractions of the SHS. Abstractions are then employed for (ii) formal verification or (iii) control (policy, strategy) synthesis. StocHy allows for modular modelling, and has separate simulation, verification and synthesis engines, which are implemented as independent libraries. This allows for libraries to be easily used and for extensions to be easily built. The tool is implemented in C++ and employs manipulations based on vector calculus, the use of sparse matrices, the symbolic construction of probabilistic kernels, and multi-threading. Experiments show StocHy's markedly improved performance when compared to existing abstraction-based approaches: in particular, StocHy beats state-of-the-art tools in terms of precision (abstraction error) and computational effort, and finally attains scalability to large-sized models (12 continuous dimensions). StocHy is available at www.gitlab.com/natchi92/StocHy

An empirical evaluation of two-stage species tree inference strategies using a multilocus dataset from North American pines

Background As it becomes increasingly possible to obtain DNA sequences of orthologous genes from diverse sets of taxa, species trees are frequently being inferred from multilocus data. However, the behavior of many methods for performing this inference has remained largely unexplored. Some methods have been proven to be consistent given certain evolutionary models, whereas others rely on criteria that, although appropriate for many parameter values, have peculiar zones of the parameter space in which they fail to converge on the correct estimate as data sets increase in size. Results Here, using North American pines, we empirically evaluate the behavior of 24 strategies for species tree inference using three alternative outgroups (72 strategies total). The data consist of 120 individuals sampled in eight ingroup species from subsection Strobus and three outgroup species from subsection Gerardianae, spanning ∼47 kilobases of sequence at 121 loci. Each “strategy” for inferring species trees consists of three features: a species tree construction method, a gene tree inference method, and a choice of outgroup. We use multivariate analysis techniques such as principal components analysis and hierarchical clustering to identify tree characteristics that are robustly observed across strategies, as well as to identify groups of strategies that produce trees with similar features. We find that strategies that construct species trees using only topological information cluster together and that strategies that use additional non-topological information (e.g., branch lengths) also cluster together. Strategies that utilize more than one individual within a species to infer gene trees tend to produce estimates of species trees that contain clades present in trees estimated by other strategies. Strategies that use the minimize-deep-coalescences criterion to construct species trees tend to produce species tree estimates that contain clades that are not present in trees estimated by the Concatenation, RTC, SMRT, STAR, and STEAC methods, and that in general are more balanced than those inferred by these other strategies. Conclusions When constructing a species tree from a multilocus set of sequences, our observations provide a basis for interpreting differences in species tree estimates obtained via different approaches that have a two-stage structure in common, one step for gene tree estimation and a second step for species tree estimation. The methods explored here employ a number of distinct features of the data, and our analysis suggests that recovery of the same results from multiple methods that tend to differ in their patterns of inference can be a valuable tool for obtaining reliable estimates

Kettle Cooling and Sustainability Project

A particular frozen food processing facility uses a once-through cooling process to bring their kettle-cooked product’s temperature down from nearly boiling temperatures to the eighty degree Fahrenheit range. This process is water intensive and facility managers are seeking to reduce their potable water consumption. Sales engineers from Air Treatment Corporation, an HVAC&R manufacturers’ rep, initiated a number of meetings to propose heat rejection solutions and illustrate their associated payback potentials. This report contains methods of analyzing a food production process, the technical sales process, thermodynamic principles, refrigeration technologies, and the application of technical knowledge to provide a long-term, system solution. To justify the purchase of a system solution, a detailed engineering economic analysis was conducted to account for the time-value of money and equipment specifications. The goal of this report is to show the potential for monetary savings by combining technical, system solutions with sustainability