Akirin is critical for early tinman induction and subsequent formation of the heart in Drosophila melanogaster.

The regulation of formation of the Drosophila heart by the Nkx 2.5 homologue Tinman is a key event during embryonic development. In this study, we identify the highly conserved transcription cofactor Akirin as a key factor in the earliest induction of tinman by the Twist transcription cofactor. akirin mutant embryos display a variety of morphological defects in the heart, including abnormal spacing between rows of aortic cells and abnormal patterning of the aortic outflow tract. akirin mutant embryos have a greatly reduced level of tinman transcripts, together with a reduction of Tinman protein in the earliest stages of cardiac patterning. Further, akirin mutants have reduced numbers of Tinman-positive cardiomyoblasts, concomitant with disrupted patterning and organization of the heart. Finally, despite the apparent formation of the heart in akirin mutants, these mutant hearts exhibit fewer coordinated contractions in akirin mutants compared with wild-type hearts. These results indicate that Akirin is crucial for the first induction of tinman by the Twist transcription factor, and that the success of the cardiac patterning program is highly dependent upon establishing the proper level of tinman at the earliest steps of the cardiac developmental pathway.

Smartphone ECG aids real time diagnosis of palpitations in the competitive college athlete.

IMPORTANCE: Rapidly detecting dangerous arrhythmias in a symptomatic athlete continues to be an elusive goal. The use of handheld smartphone electrocardiogram (ECG) monitors could represent a helpful tool connecting the athletic trainer to the cardiologist. OBSERVATIONS: Six college athletes presented to their athletic trainers complaining of palpitations during exercise. A single lead ECG was performed using the AliveCor Heart Monitor and sent wirelessly to the Team Cardiologist who confirmed an absence of dangerous arrhythmia. CONCLUSIONS AND RELEVANCE: AliveCor monitoring has the potential to enhance evaluation of symptomatic athletes by allowing trainers and team physicians to make diagnosis in real-time and facilitate faster return to play.

Charge transfer and blue shifting of vibrational frequencies in a hydrogen bond acceptor.

A comprehensive Raman spectroscopic/electronic structure study of hydrogen bonding by pyrimidine with eight different polar solvents is presented. Raman spectra of binary mixtures of pyrimidine with methanol and ethylene glycol are reported, and shifts in ν1, ν3, ν6a, ν6b, ν8a, ν8b, ν9a, ν15, ν16a, and ν16b are compared to earlier results obtained for water. Large shifts to higher vibrational energy, often referred to as blue shifts, are observed for ν1, ν6b, and ν8b (by as much as 14 cm(-1)). While gradual blue shifts with increasing hydrogen bond donor concentration are observed for ν6b and ν8b, ν1 exhibits three distinct spectral components whose relative intensities vary with concentration. The blue shift of ν1 is further examined in binary mixtures of pyrimidine with acetic acid, thioglycol, phenylmethanol, hexylamine, and acetonitrile. Electronic structure computations for more than 100 microsolvated structures reveal a significant dependence of the magnitude of the ν1 blue shift on the local microsolvation geometry. Results from natural bond orbital (NBO) calculations also reveal a strong correlation between charge transfer and blue shifting of pyrimidine's normal modes. Although charge transfer has previously been linked to blue shifting of the X-H stretching frequency in hydrogen bond donors, here, a similar trend in a hydrogen bond acceptor is demonstrated.

Interpreting mismatches between linguistic and genetic patterns among speakers of Tanimuka (Eastern Tukanoan) and Yukuna (Arawakan).

Northwestern Amazonia is home to a great degree of linguistic diversity, and the human societies in that region are part of complex networks of interaction that predate the arrival of Europeans. This study investigates the population and language contact dynamics between two languages found within this region, Yukuna and Tanimuka, which belong to the Arawakan and Tukanoan language families, respectively. We use evidence from linguistics, ethnohistory, ethnography and population genetics to provide new insights into the contact dynamics between these and other human groups in NWA. Our results show that the interaction between these groups intensified in the last 500 years, to the point that it is difficult to differentiate between them genetically. However, this close interaction has led to more substantial contact-induced language changes in Tanimuka than in Yukuna, consistent with a scenario of language shift and asymmetrical power relations.

The social lives of isolates (and small language families): the case of the Northwest Amazon.

The Americas are home to patches of extraordinary linguistic (genealogical) diversity. These high-diversity areas are particularly unexpected given the recent population of the Americas. In this paper, we zoom in on one such area, the Northwest Amazon, and address the question of how the diversity in this area has persisted to the present. We contrast two hypotheses that claim opposite mechanisms for the maintenance of diversity: the isolation hypothesis suggests that isolation facilitates the preservation of diversity, while the integration hypothesis proposes that conscious identity preservation in combination with contact drives diversity maintenance. We test predictions for both hypotheses across four disciplines: biogeography, cultural anthropology, population genetics and linguistics. Our results show signs of both isolation and integration, but they mainly suggest considerable diversity in how groups of speakers have interacted with their surroundings.

Effects of hydrogen bonding on vibrational normal modes of pyrimidine.

The effects of weak intermolecular interactions on 10 vibrational normal modes of pyrimidine are investigated by Raman spectroscopy and electronic structure computations. Hydrogen-bonded networks of water induce a shift to higher energy in certain normal modes of pyrimidine with increasing water concentration, while other modes are relatively unaffected. Pyrimidine molecules also exhibit weak C-H...N interactions and shifted normal modes upon crystallization. The selective nature of the shifting of normal modes to higher energy allows for definitive assignments of the nearly degenerate nu(8a) and nu(8b) modes with polarized Raman spectroscopy. Natural bond orbital (NBO) analyses indicate that when water molecules donate hydrogen bonds to the nitrogen atoms of pyrimidine, there is significant charge transfer from pyrimidine to water, much of which can be accounted for by substantial decreases in the populations of the nitrogen lone pair orbitals. Despite the overall decrease of electron density in pyrimidine upon complexation with water, there are concomitant changes in NBO populations that polarize the pi-electron system toward the proton acceptor N atoms, as well as contractions of the bonds associated with the N-C-N and C-C-C regions of the pyrimidine ring.

Techniques for Percutaneous Access.

Percutaneous epicardial access continues to have a growing role within cardiac electrophysiology. The classic approach has typically been with a Tuohy needle via a subxiphoid approach guided by fluoroscopic landmarks and tactile feedback. Recent developments have highlighted the role of the micropuncture needle, electroanatomic mapping, and real-time pressure sensors to reduce complications. Further, different access sites, such as the right atrial appendage, have been described and may offer a novel approach to percutaneous epicardial access. In addition, future directions of percutaneous access may involve direct visualization, near-field impedance monitoring, and real-time virtual imaging.

Ablation of Refractory Papillary Muscle Ventricular Tachycardia Warranting Multiple Adjunctive Ablation Techniques: A Combined Approach for Success.

A 27-year-old male presented to our institution with recurrent unifocal premature ventricular contraction/nonsustained ventricular tachycardia (VT) with associated cardiomyopathy. The patient had undergone three prior ablation procedures with continued arrhythmia. Mapping led to identification of the VT arising from the basal aspect of the left ventricular anterolateral papillary muscle. Conventional ablation techniques were unsuccessful. We incorporated adjunctive ablation techniques in this case that ultimately led to a successful outcome. The present discussion covers the roles of intracardiac echocardiography, induced apnea, and low-ionic irrigation.

Complete AV Block Induced by Right Coronary Artery Spasm Following Radiofrequency Ablation for Atrial Fibrillation.

Coronary artery spasm during catheter ablation for arrhythmias is a rare but previously reported complication. Timing of presentation, manifestations of vasospasm, and purported mechanisms vary somewhat in the prior literature. We present a case of chest pain, inferior lead ST elevation, and complete AV block with angiographically confirmed right coronary artery (RCA) vasospasm that occurred immediately after catheter ablation for atrial fibrillation.

The Caenorhabditis elegans Ephrin EFN-4 Functions Non-cell Autonomously with Heparan Sulfate Proteoglycans to Promote Axon Outgrowth and Branching.

The Eph receptors and their cognate ephrin ligands play key roles in many aspects of nervous system development. These interactions typically occur within an individual tissue type, serving either to guide axons to their terminal targets or to define boundaries between the rhombomeres of the hindbrain. We have identified a novel role for the Caenorhabditis elegans ephrin EFN-4 in promoting primary neurite outgrowth in AIY interneurons and D-class motor neurons. Rescue experiments reveal that EFN-4 functions non-cell autonomously in the epidermis to promote primary neurite outgrowth. We also find that EFN-4 plays a role in promoting ectopic axon branching in a C. elegans model of X-linked Kallmann syndrome. In this context, EFN-4 functions non-cell autonomously in the body-wall muscle and in parallel with HS modification genes and HSPG core proteins. This is the first report of an epidermal ephrin providing a developmental cue to the nervous system.