Rapid and Energy-Efficient Frontal Curing of Multifunctional Composites Using Integrated Nanostructured Heaters.

Current technologies for the manufacture of fiber-reinforced polymer composites are energy-intensive, environmentally unfriendly, and time-consuming and require expensive equipment and resources. In addition, composites typically lack key nonstructural functionalities (e.g., electrical conductivity for deicing, lightning strike protection, and structural health monitoring), which are crucial to many applications such as aerospace and wind energy. Here, we present a new approach for rapid and energy-efficient manufacturing of multifunctional composites without using traditional expensive autoclaves, ovens, or heated molds used for curing of composites. Our approach is predicated on embedding a thin conductive nanostructured paper in the composite layup to act as a resistive heater for triggering frontal polymerization of the matrix thermosetting resin of the composite laminate. Upon passing electric current, the nanostructured paper quickly heats up and initiates frontal polymerization, which then rapidly propagates through the thickness of the laminate, resulting in rapid curing of composites (within seconds to few minutes) irrespective of the size of the composite laminate. The integrated nanostructured paper remains advantageous during the service of the composite part by imparting new functionalities (e.g., deicing) to the cured composite, owing to its excellent electrical conductivity and electrothermal properties. In this work, we first study the influence of several composite processing parameters on the electrothermal properties of the nanostructured paper and determine the power required for rapid initiation of frontal polymerization. We then successfully fabricate a 10 cm × 10 cm composite panel within 1 min using only 4.49 kJ of energy, which is 4 orders of magnitude less than the energy consumed by the traditional bulk, oven-curing technique. Detailed experiments are conducted to provide an in-depth understanding of the effect of heater position, tooling material, and input power on frontal curing of composite laminates. The multifunctional response of produced composites is demonstrated by performing a deicing experiment, where a 50 × 50 × 3 mm3 cube of ice is completely melted within 3 min using an input power of 77 W.

Electrothermal Performance of Heaters Based on Laser-Induced Graphene on Aramid Fabric.

Nanostructured heaters based on laser-induced graphene (LIG) are promising for heat generation and temperature control in a variety of applications due to their high efficiency as well as a fast, facile, and highly scalable fabrication process. While recent studies have shown that LIG can be written on a wide range of precursors, the reports on LIG-based heaters are mainly limited to polyimide film substrates. Here, we develop and characterize nanostructured heaters by direct writing of laser-induced graphene on nonuniform and structurally porous aramid woven fabric. The synthesis and writing of graphene on aramid fabric is conducted using a 10.6 µm CO2 laser. The quality of laser-induced graphene and electrical properties of the heater fabric is tuned by controlling the lasing process parameters. Produced heaters exhibit good electrothermal efficiency with steady-state temperatures up to 170 °C when subjected to an input power density of 1.5 W cm-2. In addition, the permeable texture of LIG-aramid fabric heaters allows for easy impregnation with thermosetting resins. We demonstrate the encapsulation of fabric heaters with two different types of thermosetting resins to develop both flexible and stiff composites. A flexible heater is produced by the impregnation of LIG-aramid fabric by silicone rubber. While the flexible composite heater exhibits inferior electrothermal performance compared to neat LIG-aramid fabric, it shows consistent electrothermal performance under various electrical and mechanical loading conditions. A multifunctional fiber-reinforced composite panel with integrated de-icing functionality is also manufactured using one ply of LIG-aramid fabric heater as part of the composite layup. The results of de-icing experiments show excellent de-icing capability, where a 5 mm thick piece of ice is completely melted away within 2 min using an input power of 12.8 W.

Pituitary Abscess: A Rare Clinical Entity in the Presence of Acute Rhinosinusitis: A Case Report.

A pituitary abscess is an often-overlooked diagnosis in the clinical presentation of a sellar mass. Due to its rare incidence and nonspecific presentation, diagnosis and treatment is often delayed. The authors describe a 56-year-old male patient presenting with acute onset of severe headache, visual field deficit, and radiologic findings of an expansile sellar lesion. The presenting symptoms were unremarkable for the diagnosis of meningitis, cavernous sinus thrombosis, and septicemia. Recent medical history included symptoms of rhinosinusitis on the days preceding his acute presentation. The initial clinical presentation was suggestive of a possible pituitary apoplexy. Intraoperative findings revealed purulent output upon surgical entry of the sella. Histopathology confirmed the diagnosis of a pituitary abscess. Review of the clinical and radiologic data revealed evidence of multiple opacifications within the paranasal sinuses, along with dehiscence overlying the sellar bone, supporting a diagnosis of secondary pituitary abscess. This case, along with a review of the available literature, will serve to expand our knowledge of this rare disease process that is often overlooked. Clinicians should be mindful of this condition, and include a primary versus secondary pituitary abscess in the differential workup on such cases.

Sinonasal Phosphaturic Mesenchymal Tumor: A Rare and Misinterpreted Entity.

Objectives Oncogenic osteomalacia is a paraneoplastic syndrome in which the tumor secretes a peptide-like hormone, fibroblast growth factor, resulting in urinary loss of phosphates. Methods We present the case of a 50-year-old woman with a benign phosphaturic mesenchymal tumor (PMT) involving the ethmoid sinus with obstruction of the ostiomeatal complex causing unilateral nasal airway obstruction. Results The tumor was initially thought to be an esthesioneuroblastoma based on primary pathology interpretation and on clinical and radiographic appearance. However, a benign PMT was later confirmed by further testing. Conclusion The tumor was removed entirely by the endoscopic transnasal approach, leading to a full resolution of symptoms.

The naso-axial line: a new method of accurately predicting the inferior limit of the endoscopic endonasal approach to the craniovertebral junction.

BACKGROUND: The endoscopic endonasal approach (EEA) has developed as an emerging surgical corridor to the craniovertebral junction (CVJ). In addition to understanding its indications and surgical anatomy, the ability to predict its inferior limit is vital for optimal surgical planning. OBJECTIVE: To develop a method that accurately predicts the inferior limit of the EEA on the CVJ radiologically and to compare this with other currently used methods. METHODS: Predissection computerized tomographic scans of 9 cadaver heads were used to delineate a novel line, the naso-axial line (NAxL), to predict the inferior EEA limit on the upper cervical spine. A previously described method with the use of the nasopalatine line (NPL or Kassam line) was also used. On computerized tomographic scans obtained following dissection of the EEA, the predicted inferior limits were compared with the actual extent of dissection. RESULTS: The postdissection inferior EEA limit ranged from the dens tip to the upper half of the C2 body, which matched the limit predicted by NAxL, with no statistically significant difference between them. In contrast to the NAxL, the NPL predicted a significantly lower EEA limit (P < .001), ranging from the lower half of the C2 body to the superior end plate of C3. CONCLUSION: The novel NAxL more accurately predicts the inferior limit of the EEA than the NPL. This method, which can be easily used on preoperative sagittal scans, accounts for variations in patients' anatomy and can aid surgeons in the assessment of the EEA to address caudal CVJ pathology.

The increased risk of community-acquired methicillin-resistant Staphylococcus aureus neck abscesses in young children.

OBJECTIVES/HYPOTHESIS: To analyze the microbiological origins of deep neck space infections requiring surgical intervention in a pediatric population. STUDY DESIGN: Retrospective cohort study. METHODS: The study population (N = 136) included all pediatric patients surgically treated for deep neck space abscesses in a metropolitan tertiary care children's hospital over the course of 5 years (September 2004-August 2009). Demographic and clinical information was compared with microbiological isolate data. RESULTS: Microbiological analysis of 118 bacterial isolates demonstrated 49 (42%) methicillin-resistant Staphylococcus aureus (MRSA), 35 (30%) methicillin-sensitive S. aureus, and 34 (28%) non-S. aureus (N-SA) isolates. The median age was 16 months (range, 1 month-13years). Patients <16 months of age were 10 times more likely to have an S. aureus (SA) infection versus N-SA (P <.0001). MRSA comprised the majority of all SA isolates (58%). Eighty percent of all SA abscesses were located in the lateral neck. African American pediatric patients accounted for 70% of all deep neck space infections, and 86% of all MRSA infections. Clindamycin resistance was noted in 8% (4/49) of all community-acquired MRSA isolates. CONCLUSIONS: Children younger than 16 months and/or with lateral neck abscesses are at a significantly increased risk of having an SA infection, the majority being MRSA.

Treatment of methicillin-resistant Staphylococcus aureus pediatric head and neck infections: results of a national survey of otolaryngologists in the United States.

OBJECTIVE: Little information is available concerning the treatment of pediatric head and neck infections caused by methicillin-resistant Staphylococcus aureus (MRSA), which is resistant to antimicrobial agents such as cephalosporins. The objective of this investigation is to describe clinical characteristics of pediatric MRSA head and neck infections in the United States and how they are treated. DESIGN: National survey. SETTING: United States. METHODS: Practicing members of the American Academy of Otolaryngology-Head and Neck Surgery were surveyed regarding patients aged < 18 years with MRSA head and neck infections during 2006. MAIN OUTCOME MEASURES: Clinical characteristics and treatment of pediatric MRSA infections. RESULTS: Of 701 surveys sent, 201 were completed (adjusted response rate 30%). Otolaryngologists responding to the survey reported treating a total of 1123 pediatric MRSA head and neck infections in 2006. Forty-seven percent reported treating pediatric patients with MRSA infections in the otologic region, 39% in the oropharyngeal/neck region, and 17% in the sinonasal region. The antimicrobials most frequently used to treat these infections were clindamycin, trimethoprim-sulfamethoxazole, and vancomycin. Cephalosporins and fluoroquinolones were also commonly prescribed. CONCLUSIONS: Otolaryngologists in the United States reported treating a broad range of MRSA head and neck infections in pediatric patients. Although most were treated with appropriate antimicrobials, some were treated with agents not active against MRSA.

Pediatric airway consultation survey in a tertiary care children's hospital: an interobserver analysis.

We conducted a prospective analysis to independently observe the initial opinion of: (1) consulting pediatric residents (postgraduate year 2 [PGY-2]), (2) corresponding consulting attending physicians (general pediatric or pediatric emergency medicine), and (3) consulting otolaryngology PGY-2 residents when assessing patients for "noisy breathing." Each was asked to define the type of noisy breathing present and to formulate a diagnosis based on a limited set of choices. The final diagnosis was determined by a single attending pediatric otolaryngologist (S.E.S.) at the completion of the diagnostic workup. The accuracy for characterization of breath sounds for the pediatric residents, attending pediatricians, and otolaryngology residents were 26.1%, 23.5%, and 98.6%, respectively. The positive predictive values for the determination of diagnosis were 71.6%, 69.4%, and 76.6%, respectively. These findings indicate that pediatric residents and attending pediatricians may be deficient in their ability to characterize the breath sounds commonly seen in patients with noisy breathing. Further education of pediatricians may lead to a more accurate diagnostic evaluation of a child with noisy breathing.

Nationwide trends in pediatric Staphylococcus aureus head and neck infections.

OBJECTIVES: To evaluate the epidemiologic manifestations of pediatric Staphylococcus aureus head and neck infections nationwide and to identify possible trends in the antibiotic drug susceptibility of S aureus during a 6-year period. DESIGN: Retrospective review of microbiologic data from a peer-reviewed national database. SETTING: More than 300 hospitals nationwide. PATIENTS: All pediatric patients with head and neck infections involving S aureus. MAIN OUTCOME MEASURES: Anatomic sites were divided into oropharynx/neck, sinonasal, and otologic infection categories. Demographic and antimicrobial drug susceptibility patterns were reviewed. RESULTS: A total of 21,009 pediatric head and neck S aureus infections that occurred between January 2001 and December 31, 2006 were gathered from the database. Predominance was observed in the oropharyngeal/neck category (60.3%). For all sites, the mean patient age was 6.7 years (range, 0-18 years), with a 51.7% male predominance. There was a high occurrence in the North East Central region of the United States. Overall, methicillin-resistant S aureus was seen in 21.6% of all patient isolates (n = 4534), with rates of 11.8%, 12.5%, 18.1%, 27.2%, 25.5%, and 28.1% for 2001 through 2006, respectively. This represents a 16.3% increase in methicillin-resistant S aureus during these 6 years for all pediatric head and neck S aureus infections. CONCLUSIONS: There is an alarming nationwide increase in the prevalence of pediatric methicillin-resistant S aureus head and neck infections. Disparities in the treatment of various head and neck infections nationwide may contribute to the regional differences in the prevalence of such infections. Judicious use of antibiotic agents and increased effectiveness in diagnosis and treatment are warranted to reduce further antimicrobial drug resistance in pediatric head and neck infections.

A rare cause of dysphonia.

Although dysphonia is a common complaint among patients seen in an otolaryngology clinic, an autoimmune cause of the problem is less common. Autoimmune disease can be the source of various laryngologic manifestations, but diagnosis depends on a high index of suspicion, careful patient evaluation and testing, and videolaryngoscopy (videostroboscopy if available) to uncover specific identifying findings. This report describes a patient presenting with upper-range vocal difficulties who was found to have early systemic lupus erythematosus.

The role of airway fluoroscopy in the evaluation of children with stridor.

OBJECTIVE: To determine the sensitivity and specificity of airway fluoroscopy in the diagnosis of pediatric laryngotracheal abnormalities. DESIGN: Retrospective chart review. SETTING: Tertiary care children's hospital. PATIENTS: Thirty-nine children, with a mean age of 18 months at the time of evaluation, were evaluated for stridor. MAIN OUTCOME MEASURES: Diagnoses made by airway fluoroscopy and endoscopy. The medical records of patients who had undergone both airway fluoroscopy and airway endoscopy for the evaluation of stridor over a 5-year period were reviewed. The sensitivity, specificity, and positive and negative predictive values of airway fluoroscopy in the diagnosis of laryngomalacia, tracheomalacia, airway stenosis at any level, and airway mass lesions were determined using endoscopic evaluation as the "gold standard." RESULTS: Twenty-three of 39 patients (59%) received a different diagnosis by airway endoscopy than by airway fluoroscopy. The sensitivity of airway fluoroscopy in the diagnosis of laryngomalacia, tracheomalacia, airway stenosis, and an airway mass was 27%, 20%, 69%, and 43%, respectively. The specificity for the same diagnoses was 100%, 94%, 100%, and 100%, respectively. CONCLUSIONS: Airway fluoroscopy appears to be reliable in the diagnosis of laryngomalacia, tracheomalacia, airway stenosis, and airway masses because of its high specificity. However, its sensitivity in detecting these common causes of stridor is poor. Negative fluoroscopic study results require further diagnostic evaluation if the clinical indication exists; therefore, the value of fluoroscopy as a screening tool remains uncertain.

Proximal pharyngeal reflux correlates with increasing severity of lingual tonsil hypertrophy.

OBJECTIVE: To determine if degree of lingual tonsil hypertrophy (LTH) correlates with pharyngeal reflux. DESIGN: Prospective. METHODS: Patients with flexible laryngoscopic evidence of LTH were included. Degree of LTH was graded mild, moderate, or severe by two otolaryngologists blinded to pH study results. Three-sensor pH study results were correlated to LTH grade. RESULTS: Nineteen patients were included (five with mild LTH, eight with moderate LTH, and six with severe LTH). Nasopharyngeal reflux (NPR) events