A massive multicystic parapharyngeal tumor: A case report.

Cervical sympathetic chain schwannomas are uncommon benign tumors that usually develop in the retrostyloid compartment of the parapharyngeal space. Differentiating cervical sympathetic chain schwannomas from other lesions of the retrostyloid parapharyngeal space can be very difficult. We present a case of a major ingrowth of a cervical lesion, covering the larynx and obstructing the airway beyond the midline. The imaging revealed an extensive parapharyngeal lesion with significant cystic degeneration, which complicated the radiological diagnosis. Severe cystic degeneration of a cervical schwannoma is associated with fast expansion, and near-fully cystic schwannomas have been described in the literature.

Visualizing nanoscale heterogeneity in perylene thin films via tip-enhanced photoluminescence with unsupervised machine learning.

We investigate the properties of ultrathin 3,4,9,10-perylenetetracarboxylic diimide (PTCDI) films using a combination of tip-enhanced photoluminescence and unsupervised machine learning. We expose nanoscale spectral heterogeneities that can be understood on the basis of the interplay between vibronic effects, intermolecular excitons, and intramolecular excitons in PTDCI films.

Tunable Localized Charge Transfer Excitons in Nanoplatelet-2D Chalcogenide van der Waals Heterostructures.

Observation of interlayer, charge transfer (CT) excitons in van der Waals heterostructures (vdWHs) based on 2D-2D systems has been well investigated. While conceptually interesting, these charge transfer excitons are highly delocalized and spatially localizing them requires twisting layers at very specific angles. This issue of localizing the CT excitons can be overcome via making nanoplate-2D material heterostructures (N2DHs) where one of the components is a spatially quantum confined medium. Here, we demonstrate the formation of CT excitons in a mixed dimensional system comprising MoSe2 and WSe2 monolayers and CdSe/CdS-based core/shell nanoplates (NPLs). Spectral signatures of CT excitons in our N2DHs were resolved locally at the 2D/single-NPL heterointerface using tip-enhanced photoluminescence (TEPL) at room temperature. By varying both the 2D material and the shell thickness of the NPLs and applying an out-of-plane electric field, the exciton resonance energy was tuned by up to 100 meV. Our finding is a significant step toward the realization of highly tunable N2DH-based next-generation photonic devices.

Recurrence of sleep apnea in children after intracapsular coblation tonsillectomy: A comprehensive exploration of tonsil regrowth.

OBJECTIVES: Sleep apnea is a prevalent issue in children, associated with significant morbidities such as cardiovascular and neurocognitive disorders. There is increasing interest in intra-capsular tonsillectomy by coblation (ICTC) as a method to address obstructive sleep apnea (OSA) in children. However, the literature remains controversial regarding the most effective intra-capsular tonsillectomy (ICT) technique with the least morbidity. Our current research extends a previous study that established the effectiveness and safety of ICTC, demonstrating rapid post-surgical recovery with minimal analgesic needs. This new investigation specifically focuses on long-term follow-up. Our aim is to assess tonsil regrowth and the risk of recurrence of OSA symptoms at a mean follow-up of 6.1 years post-surgery. By presenting the results of this extended study, our goal is to gain a better understanding of the long-term effectiveness of this surgical intervention in treating OSA in children. Thus, considering the initial benefits, we will also explore potential long-term implications. MATERIALS AND METHODS: This research follows up on children from our previous study who underwent ICTC, with or without adenoidectomy, for OSA resulting from tonsillar hypertrophy at a tertiary-level university hospital between March 2016 and March 2018. They were followed up for an average of 6.1 years postoperatively. Symptom recurrence is assessed by comparing preoperative OSA-18 questionnaire results with those obtained at the 6.1-year mark. Tonsil regrowth is evaluated by comparing preoperative Brodsky scores with those obtained at 6.1 years. RESULTS: The mean total score of OSA-18 significantly decreased from 79.41 (SD = 14.95) before ICTC to 25.47 (SD = 8.92) at 6.1 years postoperatively (p < 0.001, mean difference = 53.94, 95 % CI [50.32, 57.56]). Similarly, the mean Brodsky score dropped from 2.95 (SD = 0.51) before ICTC to 1.04 (SD = 0.24) 6.1 years postoperatively (p < 0.001, mean difference = 1.92, 95 % CI [1.80, 2.04]). The overall regrowth rate was 2.35 % (n = 2), with a revision surgery rate of 1.18 % (n = 1). CONCLUSION: ICTC exhibits minimal risk of tonsil regrowth and maintains long-term efficacy in preventing the recurrence of OSA symptoms. Therefore, it justifies broader utilization in addressing OSA symptoms arising from tonsillar hypertrophy in children.

Core/Shell-Like Localized Emission at Atomically Thin Semiconductor-Au Interface.

Localized emission in atomically thin semiconductors has sparked significant interest as single-photon sources. Despite comprehensive studies into the correlation between localized strain and exciton emission, the impacts of charge transfer on nanobubble emission remains elusive. Here, we report the observation of core/shell-like localized emission from monolayer WSe2 nanobubbles at room temperature through near-field studies. By altering the electronic junction between monolayer WSe2 and the Au substrate, one can effectively adjust the semiconductor to metal junction from a Schottky to an Ohmic junction. Through concurrent analysis of topography, potential, tip-enhanced photoluminescence, and a piezo response force microscope, we attribute the core/shell-like emissions to strong piezoelectric potential aided by induced polarity at the WSe2-Au Schottky interface which results in spatial confinement of the excitons. Our findings present a new approach for manipulating charge confinement and engineering localized emission within atomically thin semiconductor nanobubbles. These insights hold implications for advancing the nano and quantum photonics with low-dimensional semiconductors.

Classical vs. quantum plasmon-induced molecular transformations at metallic nanojunctions.

Chemical transformations near plasmonic metals have attracted increasing attention in the past few years. Specifically, reactions occurring within plasmonic nanojunctions that can be detected via surface and tip-enhanced Raman (SER and TER) scattering were the focus of numerous reports. In this context, even though the transition between localized and nonlocal (quantum) plasmons at nanojunctions is documented, its implications on plasmonic chemistry remain poorly understood. We explore the latter through AFM-TER-current measurements. We use two molecules: i) 4-mercaptobenzonitrile (MBN) that reports on the (non)local fields and ii) 4-nitrothiophenol (NTP) that features defined signatures of its neutral/anionic forms and dimer product, 4,4'-dimercaptoazobenzene (DMAB). The transition from classical to quantum plasmons is established through our optical measurements: It is marked by molecular charging and optical rectification. Simultaneously recorded force and current measurements support our assignments. In the case of NTP, we observe the parent and DMAB product beneath the probe in the classical regime. Further reducing the gap leads to the collapse of DMAB to form NTP anions. The process is reversible: Anions subsequently recombine into DMAB. Our results have significant implications for AFM-based TER measurements and their analysis, beyond the scope of this work. In effect, when precise control over the junction is not possible (e.g., in SER and ambient TER), both classical and quantum plasmons need to be considered in the analysis of plasmonic reactions.

Controlling the Fluctuating Tip-Enhanced Raman Spectra of Chloramben on Silver Nanocubes.

Tip-enhanced Raman (TER) scattering from molecules residing at plasmonic junctions can be used to detect, identify, and image single molecules. This is most evident for flat molecules interrogated under conditions of extreme temperatures and pressure. It is also the case for (bio)molecular systems that feature preferred orientations/conformations under ambient laboratory conditions. More complex molecules that can adopt multiple conformations and/or feature different protonation or charge states give rise to complex TER spectra. We illustrate how the latter can be controlled in the case of chloramben molecules coated onto plasmonic silver nanocubes. We show that characteristic molecular Raman spectra cannot be obtained when tunneling plasmons are operative, i.e., when the tip is in direct contact with the chemically functionalized plasmonic nanoparticles. We rationalize these observations and propose an approach to less invasive and hence more analytical TER spectral imaging.

CT Scan in Children Suspected of Foreign Body Aspiration: A Systematic Review and Meta-analysis.

OBJECTIVE: The goal of this study is to evaluate the sensitivity and specificity of computed tomography (CT) scans in the diagnosis of foreign body aspiration (FBA) in children, and to determine whether chest CT scans would reduce the need for diagnostic rigid bronchoscopies. DATA SOURCES: MEDLINE, EMBASE, Scopus, and the Cochrane Central Register of Controlled Trials (CENTRAL) databases were searched for relevant articles and conference proceedings that were published in English through November 1, 2022. REVIEW METHODS: We included prospective and retrospective studies comparing chest CT scans and rigid bronchoscopy for the diagnosis of FBA in pediatric patients (<16 years old). The pooled estimates of the sensitivity and specificity of the chest CT scan in the diagnosis of FBA were calculated using a fixed- or common-effects analysis and a random-effects analysis that accounts for heterogeneity if present. Forest plots were constructed to combine the evidence identified during the systematic review. RESULTS: Eighteen articles (4178 patients) were included. The average age of the children was 2.26 (±0.75) years, and 65% (±5.64%) of them were boys. Cough was the most prevalent symptom upon presentation. The pooled analysis showed that the sensitivity of chest CT scan in detecting a foreign body in children was 99% (95% confidence interval, CI [97, 100]; I2 = 72%, τ2 = 0.0065, p < .01). The false negative rate was 1.8% (95% CI [0.3, 2.7]; I2 = 72%, p < .01). The specificity of chest CT scan was 92% (95% CI [83, 98]; I2 = 83%, τ2 = 0.0437, p < .01). CONCLUSIONS: Chest CT scan is a sensitive and specific test for the diagnosis of FBA in the pediatric population. Its use can help to reduce unnecessary rigid bronchoscopies, especially in patients with a low clinical suspicion of aspiration. It should not be a replacement for the gold standard bronchoscopy, particularly in cases where there is a clear history and symptoms suggestive of aspiration.

Chemical characterization of microplastic particles formed in airborne waste discharged from sewer pipe repairs.

Microplastic particles are of increasing environmental concern due to the widespread uncontrolled degradation of various commercial products made of plastic and their associated waste disposal. Recently, common technology used to repair sewer pipes was reported as one of the emission sources of airborne microplastics in urban areas. This research presents results of the multi-modal comprehensive chemical characterization of the microplastic particles related to waste discharged in the pipe repair process and compares particle composition with the components of uncured resin and cured plastic composite used in the process. Analysis of these materials employs complementary use of surface-enhanced Raman spectroscopy, scanning transmission X-ray spectro-microscopy, single particle mass spectrometry, and direct analysis in real-time high-resolution mass spectrometry. It is shown that the composition of the relatively large (100 µm) microplastic particles resembles components of plastic material used in the process. In contrast, the composition of the smaller (micrometer and sub-micrometer) particles is significantly different, suggesting their formation from unintended polymerization of water-soluble components occurring in drying droplets of the air-discharged waste. In addition, resin material type influences the composition of released microplastic particles. Results are further discussed to guide the detection and advanced characterization of airborne microplastics in future field and laboratory studies pertaining to sewer pipe repair technology.

Probing Local Optical Fields via Ultralow Frequency Raman Scattering from a Corrugated Probe.

We revisit nanoscale local optical field imaging via tip-enhanced Raman scattering (TERS). Rather than taking advantage of molecular reporters to probe different aspects of the local fields, we show how ultralow frequency Raman (ULF) scattering from the (nanocorrugated) metallic probe itself can be used for the same purpose. The bright ULF-TERS response we record allows non-invasive (tapping mode feedback) local field imaging, enables visualization of the local fields of small (≥20 nm) isolated plasmonic particles, and can also be exploited to distinguish between Si and SiO2 domains with 5 nm spatial resolution. We describe our approach and its limitations, particularly when it comes to using all-metallic versus molecular reporters.

Subnanometer Visualization of Spatially Varying Local Field Resonances that Drive Tip-Enhanced Optical Spectroscopy.

Our knowledge of the electromagnetic fields that power modern nanoscale optical measurements, including (non)linear tip-enhanced Raman and photoluminescence, chiefly stems from numerical simulations. Aside from idealized in silico vs heterogeneous (nano)structures in the laboratory, challenges in quantitative descriptions of nanoscale light-matter interactions more generally stem from the very nature of the problem, which lies at the interface of classical and quantum theories. This is particularly the case in ultrahigh spatial resolution measurements that are sensitive to local optical field variations that take place on subnanometer length scales. This work approaches this challenge through extinction-based spectral nanoimaging experiments. We demonstrate <1 nm spatial resolution in hyperspectral extinction measurements that track spatially varying plasmon resonances. We describe the principles behind our experiments and highlight more general implications of our observations.

Ipratropium Bromide Nasal Spray in Non-Allergic Rhinitis: A Systematic Review and Meta-Analysis.

OBJECTIVE: This study aims to compare the effectiveness of intranasal ipratropium bromide (INIB) to a placebo in reducing nasal symptoms, particularly rhinorrhea, and enhancing quality of life in non-allergic rhinitis (NAR) patients. STUDY DESIGN: Systematic review and meta-analysis. METHODS: A comprehensive review of the literature was conducted on Medline, Embase, and Cochrane libraries. Randomized controlled trials (RCTs) and non-randomized comparative parallel group trials comparing IB nasal spray to placebo were included. RESULTS: Five RCTs assessed a total of 472 participants with a diagnosis of NAR. IB nasal spray 0.03% were used across all studies. IB has a better impact on decreasing rhinorrhea than the placebo, with a standardized mean difference (SMD) of 0.93 (95% CI 0.06-1.8). The mean change in rhinorrhea severity was 85% (95% CI 77-92%) and I^2 26% (p = 0.24). IB outperformed the placebo in terms of shortening the symptom's duration/day, as shown by an SMD of 0.35 (95% CI 0.15-0.55). The difference between treatments was noticeable within the first week and remained consistent throughout the treatment. Patients who were administered IB experienced a substantially greater improvement in physical and mental outcomes. Nasal adverse events with IB were generally intermittent and brief. CONCLUSION: Compared with a placebo, IB nasal spray is both safe and effective in treating the rhinorrhea associated with NAR. IB significantly reduces the severity and duration of rhinorrhea. The treatment was determined to be beneficial by both patients and physicians and resulted in a better quality of life. LEVEL OF EVIDENCE: 1 Laryngoscope, 133:3247-3255, 2023.

Influence of surface and intermolecular interactions on the properties of supported polyoxometalates.

Polyoxometalates (POMs) with localized radical or open-shell metal sites have the potential to be used as transformative electronic spin based molecular qubits (MQs) for quantum computing (QC). For practical applications, MQs have to be immobilized in electronically or optically addressable arrays which introduces interactions with supports as well as neighboring POMs. Herein, we synthesized Keggin POMs with both tungsten (W) and vanadium (V) addenda atoms. Ion soft landing, a highly-controlled surface modification technique, was used to deliver mass-selected V-doped POMs to different self-assembled monolayer surfaces on gold (SAMs) without the solvent, counterions, and contaminants that normally accompany deposition from solution. Alkylthiol, perfluorinated, and carboxylic-acid terminated monolayers were employed as representative model supports on which different POM-surface and POM-POM interactions were characterized. We obtained insights into the vibrational properties of supported V-doped POMs and how they are perturbed by interactions with specific surface functional groups using infrared reflection absorption and scattering-type scanning near-field optical microscopy, as well as tip enhanced Raman spectroscopy. Different functional groups on SAMs and nanoscale heterogeneity are both shown to modulate the observed spectroscopic signatures. Spectral shifts are also found to be dependent on POM-POM interactions. The electronic structure of the V-doped POMs was determined in the gas phase using negative ion photoelectron spectroscopy and on surfaces with scanning Kelvin probe microscopy. The chemical functionality and charge transfer properties of the SAMs are demonstrated to exert an influence on the charge state and electronic configuration of supported V-doped POMs. The geometric and electronic structure of the POMs were also calculated using density functional theory. Our joint experimental and theoretical findings provide insight into how V substitution as well as POM-surface and POM-POM interactions influence the vibrational properties of POMs.

Tip-Enhanced Raman Chemical and Chemical Reaction Imaging in H2O with Sub-3-nm Spatial Resolution.

Reproducible chemical and chemical reaction nanoimaging at solid-liquid interfaces remains challenging, particularly when resolutions on the order of a few nanometers are sought. In this work, we demonstrate the latter through liquid-tip-enhanced Raman (TER) measurements that target gold nanoplates functionalized with 4-mercaptobenzonitrile (MBN). In addition to chemical imaging and local optical field nanovisualization with high spatial resolution, we observe the signatures of 4-mercaptobenzoic acid, which forms as a result of plasmon-induced hydrolysis of MBN. Evidently, the solvent leads to distinct plasmon-induced/enhanced chemical reaction pathways that have not been documented. This work shows that such reactions that take place at solid-liquid interfaces can be tracked with a record sub-3-nm spatial resolution via TER spectral nanoimaging in liquids.

High spatial resolution ambient tip-enhanced (multipolar) Raman scattering.

This article summarizes lessons learnt from ambient tip-enhanced Raman (TER) mapping of molecules interacting with plasmonic nanostructures. It is shown that numerous physical and chemical phenomena contribute to high-resolution TER spectral images. As a result, selectively tracking interfacial chemical transformations via TERS is more challenging than currently appreciated.

Ambient Tip-Enhanced Two Photon Photoluminescence from CdSe/ZnS Quantum Dots.

Nonlinear nano-optical measurements that combine ultrafast spectroscopy with tools of scanning probe microscopy are scarce. This is particularly the case when high spatial resolution on the order of a few nanometers is sought after in experiments performed under ambient laboratory conditions. In this work, we demonstrate the latter through measurements that track two-photon photoluminescence from aggregates of CdSe/ZnS quantum dots with sub-5 nm spatial resolution. Our proof-of-principle measurements that only take advantage of a plasmonic probe (as opposed to a gap mode) pave the way for nonlinear photoluminescence-based spectral nanoimaging of realistic/heterogeneous (bio) molecular and (bio) material systems.

Multipolar Raman Scattering vs Interfacial Nanochemistry: Case of 4-Mercaptopyridine on Gold.

Caution needs to be exercised in associating changes in plasmon-enhanced Raman spectra with chemical transformations. This is demonstrated through a detailed analysis of tip-enhanced Raman (TER) scattering from 4-mercaptopyridine (MPY) on gold. The substrate used consists of gold nanoplates atop a gold surface featuring heterogeneous grooves, all coated with a monolayer of MPY. The brightest spectra across the substrate exhibit features that can only be recovered by considering the generalized polarizability of oriented MPY molecules. The complex TER spectra we observe do not mark interfacial chemistry but rather multipolar TER scattering driven by local field gradients.

Excited-State-Selective Ultrafast Relaxation Dynamics and Photoisomerization of trans-4,4'-Azopyridine.

Excited-state dynamics of trans-4,4'-azopyridine in ethanol is studied using femtosecond transient absorption with 30 fs temporal resolution. Exciting the system at three different wavelengths, 460 and 290 (275) nm, to access the S1 nπ* and S2 ππ* electronic states, respectively, reveals a 195 cm-1 vibrational coherence, which suggests that the same mode is active in both nπ* and ππ* relaxation channels. Following S1-excitation, relaxation proceeds via a nonrotational pathway, where a fraction of the nπ* population is trapped in a planar minimum (lifetime, 2.1 ps), while the remaining population travels further to a second shallow minimum (lifetime, 300 fs) prior to decay into the ground state. Population of the S2 state leads to 30 fs nonrotational relaxation with a concurrent buildup of nπ* population and nearly simultaneous formation of hot ground-state species. An increase in the cis-isomer quantum yield upon ππ* versus nπ* excitation is observed, which is opposite to trans-azobenzene.

Atmospheric emission of nanoplastics from sewer pipe repairs.

Nanoplastic particles are inadequately characterized environmental pollutants that have adverse effects on aquatic and atmospheric systems, causing detrimental effects to human health through inhalation, ingestion and skin penetration1-3. At present, it is explicitly assumed that environmental nanoplastics (EnvNPs) are weathering fragments of microplastic or larger plastic debris that have been discharged into terrestrial and aquatic environments, while atmospheric EnvNPs are attributed solely to aerosolization by wind and other mechanical forces. However, the sources and emissions of unintended EnvNPs are poorly understood and are therefore largely unaccounted for in various risk assessments4. Here we show that large quantities of EnvNPs may be directly emitted into the atmosphere as steam-laden waste components discharged from a technology commonly used to repair sewer pipes in urban areas. A comprehensive chemical analysis of the discharged waste condensate has revealed the abundant presence of insoluble colloids, which after drying form solid organic particles with a composition and viscosity consistent with EnvNPs. We suggest that airborne emissions of EnvNPs from these globally used sewer repair practices may be prevalent in highly populated urban areas5, and may have important implications for air quality and toxicological levels that need to be mitigated.

Multimodal (Non)Linear Optical Nanoimaging and Nanospectroscopy.

This Perspective highlights recent advances in linear and nonlinear spectral nanoimaging. The described developments are motivated by the need to characterize molecular and material systems noninvasively with nanometer spatial and femtosecond temporal resolution. Indeed, the ability to image and chemically characterize heterogeneous interfaces with joint nano-femto resolution is a prerequisite to advancing our fundamental understanding of processes as diverse as heterogeneous catalysis, microbial communication, and energy flow in pristine/defect-containing low-dimensional quantum materials, to name a few. We describe pioneering work and recent demonstrations of (non)linear optical nanoimaging and nanospectroscopy, with an emphasis on high spatial resolution measurements conducted under ambient laboratory conditions.