Moiré Pattern Controlled Phonon Polarizer Based on Twisted Graphene.

Twisted van der Waals materials featuring Moiré patterns present new design possibilities and demonstrate unconventional behaviors in electrical, optical, spintronic, and superconducting properties. However, experimental exploration of thermal transport across Moiré patterns has not been as extensive, despite its critical role in nanoelectronics, thermal management, and energy technologies. Here, the first experimental study is conducted on thermal transport across twisted graphene, demonstrating a phonon polarizer concept from the rotational misalignment between stacked layers. The direct thermal and acoustic measurements, structural characterizations, and atomistic modeling, reveal a modulation up to 631% in thermal conductance with various Moiré angles, while maintaining a high acoustic transmission. By comparing experiments with density functional theory and molecular dynamics simulations, mode-dependent phonon transmissions are quantified based on the angle alignment of graphene band structures and attributed to the coupling among flexural phonon modes. The agreement confirms the dominant tuning mechanisms in adjusting phonon transmission from high-frequency thermal modes while having negligible effects on low-frequency acoustic modes near Brillouin zone center. This study offers crucial insights into the fundamental thermal transport in Moiré structures, opening avenues for the invention of quantum thermal devices and new design methodologies based on manipulations of vibrational band structures and phonon spectra.

Non-Pharmacological and Non-Surgical Feeding Interventions for Hospitalized Infants with Pediatric Feeding Disorder: A Scoping Review.

Infants born prematurely or with complex medical conditions often require treatment to facilitate safe and efficient feeding. Practice is based on evidence, so frontline clinicians look to the literature to make informed clinical decisions. The aim of this scoping review was to map and describe the literature base for infant feeding and swallowing interventions and to identify areas for further research. Four electronic databases were searched from the sources' inceptions through April 2020 using a search strategy designed by a health sciences research librarian. Thirteen grey literature sources were searched and forward and backward citation chasing was performed. Inclusion criteria were English-language studies reporting non-pharmacological and non-surgical interventions for hospitalized infants. Exclusion criteria included interventions exclusively for infants with cleft lip or palate or for infants being fed exclusively though enteral feeding. Data were extracted using a form created a priori and data were reported descriptively. We reviewed 6654 abstracts: 725 were chosen for full-text review and 136 met inclusion. Most studies explored interventions for infants born prematurely (n = 128). Studies were stratified by intervention domain: bridging (n = 91) and feeding/swallowing (n = 45); intervention approach: direct (n = 72), indirect (n = 31), or combination (n = 33); and outcome: feeding performance (n = 125), physiologic stability (n = 40), and swallowing physiology (n = 12). The body of research in infant feeding has grown; however, a need remains for research focused on populations of infants with various medical complexities and for frequently used interventions that lack supporting evidence.

Infant aspiration and associated signs on clinical feeding evaluation.

OBJECTIVES: Few studies have examined clinical signs of aspiration in infants <51 weeks post-menstrual age (PMA) for whom the laryngeal cough reflex is not fully developed. This retrospective study explored 1) the association between signs of aspiration on a clinical feeding evaluation (CFE) and/or comorbid conditions with aspiration (silent or overt) on a modified barium swallow study (MBS) for infants in this age range, 2) the association between lower respiratory infection (LRI) and aspiration on MBS, and 3) the sensitivity and specificity of detecting aspiration according to signs on CFE and the evaluating speech-language pathologist's (SLP) years of experience. METHODS: A retrospective review of charts of patients with MBS completed January 1, 2012-December 31, 2014 was performed. Patients were included if they were <51-weeks PMA at the time of MBS and had a CFE conducted no more than seven days prior to the MBS. Patient age, comorbidities, and MBS and CFE details were collected. The impact of CFE findings, patient age, comorbid syndromes/associations, and aerodigestive diagnoses on the odds of demonstrating silent aspiration (SA) or overt aspiration during MBS with thin liquids was determined using logistic regression, and the sensitivity and specificity of CFE for identifying SA was calculated. RESULTS: Results from 114 patients indicated that 46 (40 %) of the infants had SA and nine (8 %) had overt aspiration on MBS. Notable signs on CFEs were cough (36 %), oxygen desaturations (33 %), and chest congestion (32 %). On multiple regression analysis there was increased odds of SA on MBS with at least one clinical sign on CFE (OR: 24.3, p = 0.02), chronic lung disease, (OR: 18.2, p = 0.01), and airway abnormalities (OR: 2.94, p = 0.01). Cough on CFE was associated with increased odds of overt aspiration on MBS (OR: 5.69, p = 0.04). Neither SA nor overt aspiration were significantly associated with LRI. Sensitivity and specificity of CFE for correctly identifying the presence of SA were 98 % and 15 %, respectively; experience of the SLP was not a contributing factor. CONCLUSION: Further study is required to determine if specific signs on CFE are predictive of aspiration.

Consideration of Cough Reflex Development When Ordering Modified Barium Swallow Studies in Infants.

Infants < 51 weeks post-menstrual age (< 51 PMA) are often referred for modified barium swallow (MBS) studies for suspected silent aspiration (SA) given a possible association between SA and aspiration pneumonia. Infants this young are unlikely to have developed a mature laryngeal cough reflex, most likely rendering SA an expected finding in those who aspirate. The aims of this retrospective review were to (1) determine if SA resolves in a significant proportion of infants around the expected emergence of the laryngeal cough reflex, (2) determine which factors or characteristics are associated with and without SA resolution in these infants, and (3) determine if SA, or any aspiration, is associated with increased rates of lower respiratory infection (including aspiration pneumonia) in these infants. Results from the chart review revealed that 79/148 (53.4%) infants had SA on MBS < 51 PMA. 16/48 (33.3%) infants assessed for SA by the time of the expected emergence of the cough reflex had resolution. SA resolution was less common in infants with obstructive sleep apnea (p = 0.037). A total of 50/70 (71.4%) infants with a follow-up MBS had eventual SA resolution. Aspiration was not significantly associated with LRI, including aspiration pneumonia. The results suggested that the laryngeal cough reflex might develop later than reported in the literature and there is no association between aspiration and LRI. These findings may indicate that age should be considered before ordering an MBS solely to assess for SA in this population. The study provides preliminary evidence for future prospective research regarding SA resolution.

Pediatric dysphonia: It's not about the nodules.

OBJECTIVE: Despite the fact that vocal nodules are the most common cause of chronic dysphonia in children, uncertainty and lack of consensus complicates practically every diagnostic and management decision. Selecting an optimal staging system is fundamental to understanding a disease process, mandatory for uniform reporting, and crucial to predicting natural history and treatment outcomes. The ideal prognostic model for vocal nodules is under intense debate. The purpose of this study was to analyze the predictive power of vocal nodule grade to severity of voice metrics in children. METHODS: Seventy-nine patients diagnosed with vocal cord nodules between 2006 and 2012 were drawn from UPMC Children's Hospital of Pittsburgh Voice, Resonance and Swallowing Center Research Registry. Subject age at time of diagnosis, nodule grade, relevant co-morbidities, scores on The Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V), parent-reported Pediatric Voice Handicap Index (pVHI), the phonotraumatic behaviors profile, habitual speaking pitch fundamental frequencies, pitch range, volume intensity, and s/z ratio were recorded and compiled into a de-identified database for analysis. RESULTS: Based on the Kruskal-Wallis H Test, there was no statistically significant correlation between nodule grade and total pitch range (p = .21), s/z ratio (p = .50), volume intensity (p = .33), overall CAPE-V Scores (p = .15), or pVHI Scores (p = .29). Chi-squared tests also revealed no significant associations between nodule grade and abnormality in habitual speaking pitch (p = .14 for fundamental frequency while sustaining a vowel sound, p = .37 for fundamental frequency while speaking structured tasks i.e. counting, or p = .76 while speaking in conversation). CONCLUSION: The current "gold-standard" for grading vocal nodule size suggests that the nodules themselves are not driving the standard dysphonic metrics that are most commonly collected and monitored in such children. This outcome is consistent with other studies reporting similar findings and was expected based on the inconsistencies in the reported literature to date. By extension, the conventional wisdom of avoiding surgical treatment of vocal nodules in children seems prudent as there is little evidence to suggest that the nodules themselves are "driving" the severity of the dysphonia. Ultimately identifying the true "drivers" of dysphonia in children will suggest alternative therapies that are more specific and directed to the pathophysiology. Most pediatric voice care professionals will welcome such discoveries as those in the front line of patient care are often rendered helpless and frustrated.

Controlling, Understanding, and Redirecting the Thermal Rearrangement of 3,3-Dicyano-1,5-enynes.

The thermal [3,3] rearrangement of 3,3-dicyano-1,5-enynes to γ-allenyl alkylidenemalononitriles (the "enyne Cope rearrangement") has largely eluded synthetic value as the desired products, too, are thermally reactive and ultimately yield 6π electrocyclization products. Herein, we describe experimental and computational studies related to the thermal rearrangement of 1,5-enynes, structural features to halt the thermal rearrangement at the allene stage, and a reductive variant for preparing bifunctional allenyl malononitriles. We also describe various ways that the bifunctional building blocks can be manipulated and converted to cyclic and acyclic architectures.

Vocal characteristics of congenital anterior glottic webs in children: A case report.

This case report describes a 5-year-old girl with chronic dysphonia and high-pitched voice since birth. Vocal quality was noted to be harsh. Videostroboscopy revealed significant hyperfunction and a Type II congenital anterior glottic web. Endoscopic division of the anterior glottic web was performed with significant improvement in vocal quality and quality of life. This paper describes methods of analyzing, diagnosing, and treating anterior glottic web with a focus on quality of life. Also, unique acoustic and aerodynamic voice features are identified. No other descriptions of a voice characteristic for anterior glottic web currently exist in the literature.

The dopaminergic system in the aging brain of Drosophila.

Drosophila models of Parkinson's disease are characterized by two principal phenotypes: the specific loss of dopaminergic (DA) neurons in the aging brain and defects in motor behavior. However, an age-related analysis of these baseline parameters in wildtype Drosophila is lacking. Here we analyzed the DA system and motor behavior in aging Drosophila. DA neurons in the adult brain can be grouped into bilateral symmetric clusters, each comprising a stereotypical number of cells. Analysis of TH > mCD8::GFP and cell type-specific MARCM clones revealed that DA neurons show cluster-specific, stereotypical projection patterns with terminal arborization in target regions that represent distinct functional areas of the adult brain. Target areas include the mushroom bodies, involved in memory formation and motivation, and the central complex, involved in the control of motor behavior, indicating that similar to the mammalian brain, DA neurons in the fly brain are involved in the regulation of specific behaviors. Behavioral analysis revealed that Drosophila show an age-related decline in startle-induced locomotion and negative geotaxis. Motion tracking however, revealed that walking activity, and exploration behavior, but not centrophobism increase at late stages of life. Analysis of TH > Dcr2, mCD8::GFP revealed a specific effect of Dcr2 expression on walking activity but not on exploratory or centrophobic behavior, indicating that the siRNA pathway may modulate distinct DA behaviors in Drosophila. Moreover, DA neurons were maintained between early- and late life, as quantified by TH > mCD8::GFP and anti-TH labeling, indicating that adult onset, age-related degeneration of DA neurons does not occur in the aging brain of Drosophila. Taken together, our data establish baseline parameters in Drosophila for the study of Parkinson's disease as well as other disorders affecting DA neurons and movement control.