Size distribution of polycyclic aromatic hydrocarbons in space: an old new light on the 11.2/3.3 µm intensity ratio.

The intensity ratio of the 11.2/3.3 µm emission bands is considered to be a reliable tracer of the size distribution of polycyclic aromatic hydrocarbons (PAHs) in the interstellar medium (ISM). This paper describes the validation of the calculated intrinsic infrared (IR) spectra of PAHs that underlie the interpretation of the observed ratio. The comparison of harmonic calculations from the NASA Ames PAH IR spectroscopic database to gas-phase experimental absorption IR spectra reveals a consistent underestimation of the 11.2/3.3 µm intensity ratio by 34%. IR spectra based on higher level anharmonic calculations, on the other hand, are in very good agreement with the experiments. While there are indications that the 11.2/3.3 µm ratio increases systematically for PAHs in the relevant size range when using a larger basis set, it is unfortunately not yet possible to reliably calculate anharmonic spectra for large PAHs. Based on these considerations, we have adjusted the intrinsic ratio of these modes and incorporated this in an interstellar PAH emission model. This corrected model implies that typical PAH sizes in reflection nebulae such as NGC 7023 - previously inferred to be in the range of 50 to 70 carbon atoms per PAH are actually in the range of 40 to 55 carbon atoms. The higher limit of this range is close to the size of the C60 fullerene (also detected in reflection nebulae), which would be in line with the hypothesis that, under appropriate conditions, large PAHs are converted into the more stable fullerenes in the ISM.

Use of electromagnetic navigational bronchoscopy in robotic pulmonary resection.

Robotic resection of pulmonary lesions has become a more common approach in the field of thoracic surgery. The greatest drawback of robotic resection is the lack of tactile feedback as compared to open approaches, making identification of intrapulmonary lesion difficult. Electromagnetic navigational bronchoscopy (navibronch) enables pre-incisional marking of pulmonary lesions for intraoperative identification. We sought to determine how effective navibronch was in our institution's robotic cases. Thirty-one patients underwent robotically assisted resection of 35 lesions with the assistance of navibronch from 7/2014 to 9/2015. Retrospective demographic and operative data were collected on these patients, and statistical analysis was conducted using ANOVA means testing, Chi-square, and non-parametric tests. The average age in this patient population was 63.7 ± 13.5 years. Eight patients (25.8%) were male. Twenty-five (80.6%) of the patients had pathology involving one lobe, with six (19.4%) in two lobes. 34 of the resections (97.1%) resulted in dye being localized to the first specimen; 34 (97.1%) were found to have the target pathology in the initial specimen. Further resection was carried out in 22 (62.9%) cases, with the final resection resulting in a segment in 2 (5.7%) and a lobe in 14 (40.0%). The mean number of lung specimens collected was 1.94 ± 0.13. The mean number of tumors in each target resection was 1.46 ± 0.66 in final pathology. Malignancy was found in 19 (54.3%) of final specimens. There were no complications related to navibronch. Navibronch is an effective technique in the identification and localization of pulmonary lesions in robotically assisted lung resections.

Procalcitonin as a biomarker of bacterial infection in pediatric patients after congenital heart surgery.

BACKGROUND: Bacterial infection (BI) after congenital heart surgery (CHS) is associated with increased morbidity and is difficult to differentiate from systemic inflammatory response syndrome caused by cardiopulmonary bypass (CPB). Procalcitonin (PCT) has emerged as a reliable biomarker of BI in various populations. AIM: To determine the optimal PCT threshold to identify BI among children suspected of having infection following CPB. SETTING AND DESIGN: Single-center retrospective observational study. MATERIALS AND METHODS: Medical records of all the patients admitted between January 2013 and April 2015 were reviewed. Patients in the age range of 0-21 years of age who underwent CHS requiring CPB in whom PCT was drawn between postoperative days 0-8 due to suspicion of infection were included. STATISTICAL ANALYSIS: The Wilcoxon rank-sum test was used for nonparametric variables. The diagnostic performance of PCT was evaluated using a receiver operating characteristic (ROC) curve. RESULTS: Ninety-eight patients were included. The median age was 2 months (25th and 75th interquartile of 0.1-7.5 months). Eleven patients were included in the BI group. The median PCT for the BI group (3.42 ng/mL, 25th and 75th interquartile of 2.34-5.67) was significantly higher than the median PCT for the noninfected group (0.8 ng/mL, 25th and 75th interquartile 0.38-3.39), P = 0.028. The PCT level that yielded the best compromise between the sensitivity (81.8%) and specificity (66.7%) was 2 ng/mL with an area under the ROC curve of 0.742. CONCLUSION: A PCT less than 2 ng/mL makes BI unlikely in children suspected of infection after CHS.

Risk factor analysis for second-stage palliation of single ventricle anatomy.

BACKGROUND: Single ventricle hearts can be surgically palliated by a series of operations culminating in the Fontan procedure, which establishes a total cavopulmonary connection. The second-stage procedure creates a physiologic connection between the superior vena cava and the pulmonary artery. METHODS: From 1998 to 2010, 557 patients with single ventricle heart disease underwent second-stage surgical palliation. This cohort was retrospectively analyzed to assess patient outcome by a number of anatomic, physiologic, and procedural factors. The analysis excluded patients undergoing hybrid first-stage procedures. RESULTS: The median age at operation was 165 days (range, 59 days to 49 years). The most common anatomic subtypes were hypoplastic left heart syndrome (52%), tricuspid atresia (12%), unbalanced atrioventricular septal defect (10%), double inlet left ventricle (9%), or other (17%). Left ventricular hypoplasia was present in 70%. A hemi-Fontan procedure was done in 89%, and 11% received a bidirectional Glenn. Concomitant atrioventricular valve repair was necessary in 9%. Early mortality was 4.7%, and 5.9% died after discharge but before Fontan. No early or late deaths occurred in patients with tricuspid atresia and double inlet left ventricle. Multivariate analysis demonstrated ventricular dysfunction, atrioventricular valve regurgitation, and unbalanced atrioventricular septal defect were significant adverse risk factors for survival to Fontan. CONCLUSIONS: Second-stage palliation can be performed at low risk for patients with left ventricular dominance, but significant risk remains for patients with left ventricular hypoplasia and unbalanced atrioventricular septal defect. Atrioventricular valve insufficiency is a persistent problem that has not been neutralized by repair strategies.

Paraneoplastic pemphigus in a burn intensive care unit: case report and review of the literature.

Paraneoplastic pemphigus is a rare cause of acute diffuse blistering in the adult patient. It commonly presents with subepidermal blistering, epidermal necrosis, and symptoms of mucosal irritation, such as conjunctivitis and vaginal ulceration. Because of its rarity, it is frequently misdiagnosed as Stevens-Johnson syndrome or toxic epidermal necrolysis. In this study, the authors will describe clinical and histologic manifestations of paraneoplastic pemphigus. This case report describes a 45-year-old woman with paraneoplastic pemphigus who was admitted and treated in a burn intensive care unit. Although initially diagnosed with Stevens-Johnson syndrome, the patient had progression of desquamation when potentially offending medications were discontinued. Diffuse adenopathy was noted on examination, and biopsy confirmed a low-grade lymphoma. Paraneoplastic pemphigus is a rare but important cause of acute diffuse blistering in adults. This disorder should be considered in the differential diagnosis of patients with diffuse blistering.

Short-term adaptation and temporal processing in the cryophilic response of Caenorhabditis elegans.

When navigating spatial thermal gradients, the nematode C. elegans migrates toward colder temperatures until it reaches its previous cultivation temperature, exhibiting cryophilic movement. The strategy for effecting cryophilic movement is the biased random walk: C. elegans extends (shortens) periods of forward movement that are directed down (up) spatial thermal gradients by modulating the probability of reorientation. Here, we analyze the temporal sensory processor that enables cryophilic movement by quantifying the movements of individual worms subjected to defined temperature waveforms. We show that step increases in temperature as small as 0.05 degrees C lead to transient increases in the probability of reorientation followed by gradual adaptation to the baseline level; temperature downsteps leads to similar but inverted responses. Short-term adaptation is a general property of sensory systems, allowing organisms to maintain sensitivity to sensory variations over broad operating ranges. During cryophilic movement C. elegans also uses the temporal dynamics of its adaptive response to compute the time derivative of gradual temperature variations with exquisite sensitivity. On the basis of the time derivative, the worm determines how it is oriented in spatial thermal gradients during each period of forward movement. We show that the operating range of the cryophilic response extends to lower temperatures in ttx-3 mutants, which affects the development of the AIY interneurons. We show that the temporal sensory processor for the cryophilic response is affected by mutation in the EAT-4 glutamate vesicular transporter. Regulating the operating range of the cryophilic response and executing the cryophilic response may have separate neural mechanisms.