Torsades de pointes and the classic short-long-short activation sequence in the setting of atrial fibrillation

Torsades de pointes (TdP) is an ominous form of rapid polymorphic ventricular tachycardia occurring in the setting of QT prolongation that must be addressed immediately as it often leads to ventricular fibrillation. TdP is associated with many factors that prolong the QT interval, including hypokalemia, hypomagnesemia, hypocalcemia, drugs (antiemetics, antipsychotics, SSRI's, TCA's, macrolide and fluoroquinolone antibiotics) and congenital long QT syndrome. We present a case of TdP in the setting of electrolyte abnormalities and atrial fibrillation with a classic short-long-short (SLS) activation sequence on EKG prior to deteriorating into TdP.An 88-year-old female with a history of atrial fibrillation and dementia presented to the emergency room with progressive weakness. Patient requires total care from her son at baseline. Her vitals were stable on arrival. Chemistry revealed hypokalemia, hypocalcemia, and hypomagnesemia which were contributed to poor appetite. Her troponin was elevated. Urinalysis revealed pyuria suggestive of urinary tract infection. Patient's EKG revealed atrial fibrillation and old left bundle brand block on arrival. She was given magnesium oxide and potassium chloride for electrolyte replacement.Shortly thereafter, the patient was noted to have several episodes of non-sustained ventricular tachycardia. Multiple EKGs were performed and exhibited prolonged QTc greater than 500 ms. While in the emergency room, patient was noted to have seizure-like activity and found to be pulseless. The EKG during this period showed a run of atrial fibrillation that progressed to TdP after a SLS activation sequence. The patient required chest compressions, one round of epinephrine and defibrillation before achieving ROSC with spontaneous movement and breathing. She was admitted to ICU and received aggressive electrolyte replacement and non-QT prolonging antibiotic treatment for her urinary tract infection. Her home medication list was reviewed and trazadone was discontinued due to potential QTc prolongation. Her troponin was concluded to be type 2 myocardial infract in the setting of active infection and defibrillation. She did not have any additional arrhythmia throughout her hospital stay.TdP is an uncommon but well recognized polymorphic ventricular tachycardia pattern that involves a twisting of the QRS complexes around the isoelectric line. In the setting of QTc prolongation, a SLS activation sequence has been observed to precede TdP. The sequence was theorized to promote heterogeneity of myocardial repolarization that creates potential reentry that results in TdP. Our case demonstrated another layer of arrhythmia as patient has underlying atrial fibrillation. The R-R variation in atrial fibrillation makes the widely used Bazett formula difficult to access QTc. Additionally, atrial fibrillation has been described in literature to be associated with TdP when treated with Class III antiarrhythmic for rhythm control. TdP occurring in atrial fibrillation in the absence of antiarrhythmic drugs is poorly understood. Prompt recognition of this life-threatening arrhythmia and prompt defibrillation to restore perfusion rhythm continues to be the cornerstone of treatment for an unstable patient with TdP. A careful history and medication reconciliation often guide prompt action to prevent future occurrence

Understanding the twist-bend nematic phase: the characterisation of 1-(4-cyanobiphenyl-4'-yloxy)-6-(4-cyanobiphenyl-4'--yl)hexane (CB6OCB) and comparison with CB7CB

The synthesis and characterisation of the nonsymmetric liquid crystal dimer, 1-(4-cyanobiphenyl-40-yloxy)-6- (4-cyanobiphenyl-40-yl)hexane (CB6OCB) is reported. An enantiotropic nematic (N)–twist-bend nematic (NTB) phase transition is observed at 109 1C and a nematic–isotropic phase transition at 153 1C. The NTB phase assignment has been confirmed using polarised light microscopy, freeze fracture transmission electron microscopy (FFTEM), 2H-NMR spectroscopy, and X-ray diffraction. The effective molecular length in both the NTB and N phases indicates a locally intercalated arrangement of the molecules, and the helicoidal pitch length in the NTB phase is estimated to be 8.9 nm. The surface anchoring properties of CB6OCB on a number of aligning layers is reported. A Landau model is applied to describe high-resolution heat capacity measurements in the vicinity of the NTB–N phase transition. Both the theory and heat capacity measurements agree with a very weak first-order phase transition. A complementary extended molecular field theory was found to be in suggestive accord with the 2H-NMR studies of CB6OCB-d2, and those already known for CB7CB-d4. These include the reduced transition temperature, TNTBN/TNI, the order parameter of the mesogenic arms in the N phase close to the NTB–N transition, and the order parameter with respect to the helix axis which is related to the conical angle for the NTB phase.Postprint (published version

Interacting universes and the cosmological constant

We study some collective phenomena that may happen in a multiverse scenario. First, it is posed an interaction scheme between universes whose evolution is dominated by a cosmological constant. As a result of the interaction, the value of the cosmological constant of one of the universes becomes very close to zero at the expense of an increasing value of the cosmological constant of the partner universe. Second, we found normal modes for a 'chain' of interacting universes. The energy spectrum of the multiverse, being this taken as a collective system, splits into a large number of levels, some of which correspond to a value of the cosmological constant very close to zero. We finally point out that the multiverse may be much more than the mere sum of its parts.Comment: 7 page

Design acceleration in chemical engineering

Nowadays, Chemical Engineering has to face a new industrial context with for example: the gradually falling of hydrocarbon reserves after 2020-2030, relocation, emerging of new domains of application (nano-micro technologies) which necessitate new solutions and knowledges… All this tendencies and demands accelerate the need of tool for design and innovation (technically, technologically). In this context, this paper presents a tool to accelerate innovative preliminary design. This model is based on the synergy between: TRIZ (Russian acronym for Theory of Inventive Problem Solving) and Case Based Reasoning (CBR). The proposed model offers a structure to solve problem, and also to store and make available past experiences in problems solving. A tool dedicated to chemical engineering problems, is created on this model and a simple example is treated to explain the possibilities of this tool

Tumor suppressor p53 binds with high affinity to CTG-CAG trinucleotide repeats and induces topological alterations in mismatched duplexes

DNA binding is central to the ability of p53 to function as a tumor suppressor. In line with the remarkable functional versatility of p53, which can act on DNA as a transcription, repair, recombination, replication, and chromatin accessibility factor, the modes of p53 interaction with DNA are also versatile. One feature common to all modes of p53-DNA interaction is the extraordinary sensitivity of p53 to the topology of its target DNA. Whereas the strong impact of DNA topology has been demonstrated for p53 binding to sequence-specific sites or to DNA lesions, the possibility that DNA structure-dependent recognition may underlie p53 interaction with other types of DNA has not been addressed until now. We demonstrate for the first time that conformationally flexible CTG·CAG trinucleotide repeats comprise a novel class of p53-binding sites targeted by p53 in a DNA structure-dependent mode in vitro and in vivo. Our major finding is that p53 binds to CTG·CAG tracts by different modes depending on the conformation of DNA. Although p53 binds preferentially to hairpins formed by either CTG or CAG strands, it can also bind to linear forms of CTG·CAG tracts such as canonic B DNA or mismatched duplex. Intriguingly, by binding to a mismatched duplex p53 can induce further topological alterations in DNA, indicating that p53 may act as a DNA topology-modulating factor

Overview of experimental results in PbPb collisions at sqrt{s_NN} = 2.76 TeV by the CMS Collaboration

The CMS experiment at the LHC is a general-purpose apparatus with a set of large acceptance and high granularity detectors for hadrons, electrons, photons and muons, providing unique capabilities for both proton-proton and ion-ion collisions. The data collected during the November 2010 PbPb run at sqrt{s_NN} = 2.76 TeV was analyzed and multiple measurements of the properties of the hot and dense matter were obtained. Global event properties, detailed study of jet production and jet properties, isolated photons, quarkonia and weak bosons were measured and compared to pp data and Monte Carlo simulations.Comment: 8 pages, 10 figures, proceedings for Quark Matter 2011, Annecy, France, May 23-28, 201

Statement and Action Agenda from the Girls in Emergencies Collaborative

Many adolescent girls—the poorest girls in the poorest communities—already live in an “emergency.” Humanitarian crises only amplify the call on their coping and caring capacities, while exacerbating their vulnerabilities. The frequency and intensity of emergencies, including natural disasters, conflicts, and infectious disease outbreaks such as Ebola, appear to be growing. These emergencies threaten entire communities and whole countries, often with global implications. Many become virtually permanent

A Comprehensive Three-Dimensional Model of the Cochlea

The human cochlea is a remarkable device, able to discern extremely small amplitude sound pressure waves, and discriminate between very close frequencies. Simulation of the cochlea is computationally challenging due to its complex geometry, intricate construction and small physical size. We have developed, and are continuing to refine, a detailed three-dimensional computational model based on an accurate cochlear geometry obtained from physical measurements. In the model, the immersed boundary method is used to calculate the fluid-structure interactions produced in response to incoming sound waves. The model includes a detailed and realistic description of the various elastic structures present. In this paper, we describe the computational model and its performance on the latest generation of shared memory servers from Hewlett Packard. Using compiler generated threads and OpenMP directives, we have achieved a high degree of parallelism in the executable, which has made possible several large scale numerical simulation experiments that study the interesting features of the cochlear system. We show several results from these simulations, reproducing some of the basic known characteristics of cochlear mechanics.Comment: 22 pages, 5 figure

The Grizzly, March 5, 2020

Musical 9 to 5 Sells Out Lenfest Theater • UC Mourns the Loss of Carol Williams • Calling for Nominations for Faculty Awards • Talk on the Role of Women in Campaign Funding • Weekly Lunches Encourage Conversation • Everything to Know About UC UNICEF • Opinion: On Bloomberg and the Boys in Blue • Men\u27s Lax Can Count on Bobby McClure Scoring Goals • Ursinus Baseball is Ready for the New Seasonhttps://digitalcommons.ursinus.edu/grizzlynews/1601/thumbnail.jp