Hydrogen Bond Blueshifts in Nitrile Vibrational Spectra Are Dictated by Hydrogen Bond Geometry and Dynamics.

Vibrational Stark effect (VSE) spectroscopy has become one of the most important experimental approaches to determine the strength of noncovalent, electrostatic interactions in chemistry and biology and to quantify their influence on structure and reactivity. Nitriles (C≡N) have been widely used as VSE probes, but their application has been complicated by an anomalous hydrogen bond (HB) blueshift which is not encompassed within the VSE framework. We present an empirical model describing the anomalous HB blueshift in terms of H-bonding geometry, i.

Critical Evaluation of Polarizable and Nonpolarizable Force Fields for Proteins Using Experimentally Derived Nitrile Electric Fields.

Molecular dynamics (MD) simulations are frequently carried out for proteins to investigate the role of electrostatics in their biological function. The choice of force field (FF) can significantly alter the MD results, as the simulated local electrostatic interactions lack benchmarking in the absence of appropriate experimental methods. We recently reported that the transition dipole moment (TDM) of the popular nitrile vibrational probe varies linearly with the environmental electric field, overcoming well-known hydrogen bonding (H-bonding) issues for the nitrile frequency and, thus, enabling the unambiguous measurement of electric fields in proteins ( , (17), 7562-7567).

Structural Characterization of Fluorescent Proteins Using Tunable Femtosecond Stimulated Raman Spectroscopy.

The versatile functions of fluorescent proteins (FPs) as fluorescence biomarkers depend on their intrinsic chromophores interacting with the protein environment. Besides X-ray crystallography, vibrational spectroscopy represents a highly valuable tool for characterizing the chromophore structure and revealing the roles of chromophore-environment interactions. In this work, we aim to benchmark the ground-state vibrational signatures of a series of FPs with emission colors spanning from green, yellow, orange, to red, as well as the solvated model chromophores for some of these FPs, using wavelength-tunable femtosecond stimulated Raman spectroscopy (FSRS) in conjunction with quantum calculations.

Exposure to lead-free frangible firing emissions containing copper and ultrafine particulates leads to increased oxidative stress in firing range instructors.

Background: Since the introduction of copper based, lead-free frangible (LFF) ammunition to Air Force small arms firing ranges, instructors have reported symptoms including chest tightness, respiratory irritation, and metallic taste. These symptoms have been reported despite measurements determining that instructor exposure does not exceed established occupational exposure limits (OELs). The disconnect between reported symptoms and exposure limits may be due to a limited understanding of LFF firing byproducts and subsequent health effects.

Nitrile Infrared Intensities Characterize Electric Fields and Hydrogen Bonding in Protic, Aprotic, and Protein Environments.

Nitriles are widely used vibrational probes; however, the interpretation of their IR frequencies is complicated by hydrogen bonding (H-bonding) in protic environments. We report a new vibrational Stark effect (VSE) that correlates the electric field projected on the -C≡N bond to the transition dipole moment and, by extension, the nitrile peak area or integrated intensity. This linear VSE applies to H-bonding and non-H-bonding interactions.

Comprehensive characterization of firing byproducts generated from small arms firing of lead-free frangible ammunition.

Following the introduction of lead-free frangible ammunition in United States Air Force small arms firing ranges, Combat Arms instructors have routinely reported experiencing adverse health symptoms during live fire training exercises, including sore throat, cough, and headache. Previous studies have found that these symptoms occur despite occupational exposure limits not being exceeded. To better characterize the potential source and mechanisms for health symptoms, a comprehensive characterization of the physicochemical properties of gases and aerosols emitted during the firing of the M9 pistol and M4 rifle using lead-free frangible ammunition was completed.

Cardiovascular Collapse with Intravenous Amiodarone in Children: A Multi-Center Retrospective Cohort Study.

Objective: To determine the incidence of cardiovascular collapse in children receiving intravenous (IV) amiodarone and to identify the population at risk.

Design: A multicenter study of patients ≤ 18 years of age who received intravenous amiodarone between January 2005 and December 2015. A retrospective analysis was performed to identify patients who developed cardiovascular collapse (bradycardia and/or hypotension).

Development and impact of arrhythmias after the Norwood procedure: A report from the Pediatric Heart Network.

Objectives: The study objective was to determine the predictors of new-onset arrhythmia among infants with single-ventricle anomalies during the post-Norwood hospitalization and the association of those arrhythmias with postoperative outcomes (ventilator time and length of stay) and interstage mortality.

Methods: After excluding patients with preoperative arrhythmias, we used data from the Pediatric Heart Network Single Ventricle Reconstruction Trial to identify risk factors for tachyarrhythmias (atrial fibrillation, atrial flutter, supraventricular tachycardia, junctional ectopic tachycardia, and ventricular tachycardia) and atrioventricular block (second or third degree) among 544 eligible patients. We then determined the association of arrhythmia with outcomes during the post-Norwood hospitalization and interstage period, adjusting for identified risk factors and previously published factors.

Hemodynamic effects of sustained postoperative cardiac resynchronization therapy in infants after repair of congenital heart disease: Results of a randomized clinical trial.

Background: It is unknown whether continuous cardiac resynchronization therapy (CRT) can lead to sustained improvement in hemodynamics after surgery for congenital heart disease (CHD).

Objective: We investigated whether CRT improves cardiac index (CI) and blood pressure in infants after biventricular repair of CHD.

Methods: We randomized infants younger than 4 months after biventricular CHD surgery to standard care or standard care plus CRT for 48 hours or until extubation if sooner.

Cox-Maze IV in Total Anomalous Pulmonary Venous Drainage After Sutureless Repair.

Modifications of conventional ablation strategies can make arrhythmia surgery more efficient after primary sutureless repair of total anomalous pulmonary venous drainage. We present a surgical technique performed in a 3-year-old patient who experienced ongoing atrial arrhythmia after sutureless repair. A new modified Cox-Maze IV procedure was performed, which respects the special characteristics of patients after sutureless repairs, showing good short-term results.

Associations Between Day of Admission and Day of Surgery on Outcome and Resource Utilization in Infants With Hypoplastic Left Heart Syndrome Who Underwent Stage I Palliation (from the Single Ventricle Reconstruction Trial).

Newborns with hypoplastic left heart syndrome and other single right ventricular variants require substantial health care resources. Weekend acute care has been associated with worse outcomes and increased resource use in other populations but has not been studied in patients with single ventricle. Subjects of the Single Ventricle Reconstruction trial were classified by whether they had a weekend admission and by day of the week of Norwood procedure.

Optimizing outcomes of catheter ablation in infants and toddlers.

Since the introduction of transcatheter ablation in the late 1980s, there has been significant technical development. With a very high success rate and low complication rate, ablation has now become the standard of care in children and adults. However, long-term data remain insufficient and the application of ablation therapy in small children is debatable.

Cryotherapy ablation of parahisian accessory pathways in children.

Background: Because of its safety profile, cryoablation has become an alternative therapy for septal arrhythmias, including parahisian accessory pathways (APs). Data regarding its efficacy, safety, and late outcome for parahisian APs in children are limited.

Objective: The purpose of this study was to evaluate the safety and efficacy of cryoablation of parahisian APs in children.

The psychological and social impact of camp for children with chronic illnesses: a systematic review update.

Advances in medicine have reduced mortality among children with complex medical conditions, resulting in a growing number of young patients living with chronic illnesses. Despite an improved prognosis, these children experience significant psychosocial morbidity, such as depression and anxiety. Therapeutic summer recreation camps have been proposed as an intervention to enhance quality of life among these children.

Kruppel-like factor 15 is a critical regulator of cardiac lipid metabolism.

The mammalian heart, the body's largest energy consumer, has evolved robust mechanisms to tightly couple fuel supply with energy demand across a wide range of physiologic and pathophysiologic states, yet, when compared with other organs, relatively little is known about the molecular machinery that directly governs metabolic plasticity in the heart. Although previous studies have defined Kruppel-like factor 15 (KLF15) as a transcriptional repressor of pathologic cardiac hypertrophy, a direct role for the KLF family in cardiac metabolism has not been previously established. We show in human heart samples that KLF15 is induced after birth and reduced in heart failure, a myocardial expression pattern that parallels reliance on lipid oxidation.

Sudden cardiac death in children and adolescents between 1 and 19 years of age.

Background: Understanding pediatric sudden cardiac death (SCD) may inform age-specific prevention strategies.

Objective: To characterize potential underlying causes of SCD in children and adolescents

Methods: We performed a retrospective population-based study in Ontario, Canada, of all SCD cases in a 5-year period (2005-2009) involving persons aged 1-19 years identified from the comprehensive database of the Office of the Chief Coroner. Of 1204 coroner's cases, 351 potential SCD cases were reviewed.

Scope and nature of sudden cardiac death before age 40 in Ontario: a report from the cardiac death advisory committee of the office of the chief coroner.

Background: Understanding sudden cardiac death in the young may inform prevention strategies.

Objective: To determine the scope and nature of sudden death in a geographically defined population.

Methods: We performed a retrospective population-based cohort study in Ontario, Canada, of all sudden cardiac death cases involving persons aged 2-40 years identified from the 2008 comprehensive Coroner database.

Arrhythmia associated with tetracaine in an extremely low birth weight premature infant.

Infants in NICUs undergo a variety of painful procedures. The management of pain has become an integral part of newborn infant care with the use of both systemic and topical agents to provide analgesia and anesthesia for procedural pain. Tetracaine and prilocaine-lidocaine are the 2 topical anesthetics most frequently used.

Triphasic mitral and tricuspid flows: a sign of diastolic dysfunction in a young patient with severely dilated atria and giant pulmonary veins.

This report presents a case with severe dilation of both atria and giant pulmonary veins manifested with atrial fibrillation. The following cardiac magnetic resonance findings are highly suggestive of restrictive physiology: E/A ratio greater than two, prominent A wave across the pulmonary veins and inferior vena cava, and more interestingly, a triphasic flow across the mitral and tricuspid valves.

Cause, timing, and location of death in the Single Ventricle Reconstruction trial.

Objectives: The Single Ventricle Reconstruction trial randomized 555 subjects with a single right ventricle undergoing the Norwood procedure at 15 North American centers to receive either a modified Blalock-Taussig shunt or right ventricle-to-pulmonary artery shunt. Results demonstrated a rate of death or cardiac transplantation by 12 months postrandomization of 36% for the modified Blalock-Taussig shunt and 26% for the right ventricle-to-pulmonary artery shunt, consistent with other publications. Despite this high mortality rate, little is known about the circumstances surrounding these deaths.

Risk factors for hospital morbidity and mortality after the Norwood procedure: A report from the Pediatric Heart Network Single Ventricle Reconstruction trial.

Objectives: We sought to identify risk factors for mortality and morbidity during the Norwood hospitalization in newborn infants with hypoplastic left heart syndrome and other single right ventricle anomalies enrolled in the Single Ventricle Reconstruction trial.

Methods: Potential predictors for outcome included patient- and procedure-related variables and center volume and surgeon volume. Outcome variables occurring during the Norwood procedure and before hospital discharge or stage II procedure included mortality, end-organ complications, length of ventilation, and hospital length of stay.