Utility of an Instantaneous Salt Dilution Method for Measuring Streamflow in Headwater Streams.

Streamflow records are biased toward large streams and rivers, yet small headwater streams are often the focus of ecological research in response to climate change. Conventional flow measurement instruments such as acoustic Doppler velocimeters (ADVs) do not perform well during low-flow conditions in small streams, truncating the development of rating curves during critical baseflow conditions dominated by groundwater inflow. We revisited an instantaneous solute tracer injection method as an alternative to ADVs based on paired measurements to compare their precision, efficiency, and feasibility within headwater streams across a range of flow conditions. We show that the precision of discharge measurements using salt dilution by slug injection and ADV methods were comparable overall, but salt dilution was more precise during the lowest flows and required less time to implement. Often, headwater streams were at or below the depth threshold where ADV measurements could even be attempted and transects were complicated by coarse bed material and cobbles. We discuss the methodological benefits and limitations of salt dilution by slug injection and conclude that the method could facilitate a proliferation of streamflow observation across headwater stream networks that are highly undersampled compared to larger streams.

Harnessing In Situ Simulation to Identify Human Errors and Latent Safety Threats in Adult Tracheostomy Care.

BACKGROUND: Tracheostomies are associated with high rates of complications and preventable harm. Safe tracheostomy management requires highly functioning teams and systems, but health care providers are poorly equipped with tracheostomy knowledge and resources. In situ simulation has been used as a quality improvement tool to audit multidisciplinary team emergency response in the actual clinical environment where care is delivered but has been underexplored for tracheostomy care. METHODS: From July 2021 to May 2022, the study team conducted in situ simulations of a tracheostomy emergency scenario at Montefiore Medical Center to identify human errors and latent safety threats (LSTs). Simulations included structured debriefs as well as audiovisual recording that allowed for blind rating of these human errors and LSTs. Provider knowledge deficits were further characterized using pre-simulation quizzes. RESULTS: Twelve human errors and 15 LSTs were identified over 20 simulations with 88 participants overall. LSTs were divided into the following categories: communication, equipment, and infection control. Only 50.0% of teams successfully replaced the tracheostomy tube within the scenario's five-minute time limit. In addition, knowledge gaps were highly prevalent, with a median pre-simulation quiz score of 46% (interquartile range 36-64) among participants. CONCLUSION: An in situ simulation-based quality improvement approach shed light on human errors and LSTs associated with tracheostomy care across multiple settings in one health system. This method of engaging frontline health care provider key stakeholders will inform the development, adaptation, and implementation of interventions.

Update on injection augmentation pharyngoplasty in the treatment of velopharyngeal insufficiency.

PURPOSE OF REVIEW: Velopharyngeal insufficiency (VPI) refers to a structural defect resulting in incomplete closure between the soft palate and posterior pharyngeal wall, leading to inadequate speech and deglutition. Traditional surgical options for VPI include sphincter pharyngoplasty, pharyngeal flaps and palatoplasty. Although these procedures have been successfully used over the past several decades, they are associated with complications such as pain, bleeding, infection and obstructive sleep apnoea. They also require postoperative admission. Injection augmentation pharyngoplasty (IAP) is increasingly being viewed as a viable, less invasive surgical option for patients with mild to moderate VPI. RECENT FINDINGS: Both autologous fat and alloplastic synthetics have been used as injectable materials, with low morbidity and good speech outcomes. However, given the overall lack of standardization across studies, no single material has shown clear superiority. SUMMARY: IAP is a promising alternative to more invasive surgeries in the treatment of patients with mild to moderate VPI. The purpose of this review is to provide an overview of this approach, with an emphasis on its safety and efficacy.

Evaluating Safety of Awake, Bilateral Injection Laryngoplasty for Bilateral Vocal Fold Atrophy.

OBJECTIVE: Office-based injection laryngoplasty (IL) has emerged as a useful procedure for otolaryngologists to correct glottic insufficiency while avoiding the costs and risks of general anesthesia. This is the first study focused on addressing the safety of bilateral IL for bilateral vocal fold (VF) atrophy. METHODS: Patient records were reviewed from Emory University Hospital Midtown during the period of 2005 to 2017. Patients who underwent awake, bilateral transthyrohyoid, transoral, transcricothyroid, or transthyroid cartilage IL for bilateral VF atrophy were analyzed. All procedures, including repeat injections, were bilateral. Complication rate was used to evaluate safety. Patients with vocal cord paralysis, paresis, scar, and sulcus were excluded from the study. RESULTS: Total 174 procedures met inclusion criteria. There were four complications, yielding a complication rate of 2.3%. Complications included aborted cases for difficult anatomy or poor patient tolerance, injection material not resorbing, and a VF hematoma. No patients had any airway emergencies or required admission to the hospital or evaluation in the emergency room. CONCLUSIONS: This study illustrates a low complication rate for awake, bilateral IL in treating bilateral VF atrophy. This supports other studies that promote the safety of this procedure in the awake setting. Complications were associated with patient tolerance, unique anatomy, and in one case, anticoagulant medication. The low complication rate supports the conclusion that bilateral medialization IL is safe to perform in the office-based, awake setting.

Nonpolar-to-Polar Trimerization Transitions in the S = 1 Kagomé Magnet Na2Ti3Cl8.

Kagomé lattice magnets have emerged as a versatile platform on which to discover and explore the underlying physics of quantum-spin liquids and related states of matter, although experimental examples of ideal kagomé lattices remain rare. Here we report that Na2Ti3Cl8 is an ideal realization of an insulating S = 1 kagomé magnet. This material undergoes a discrete two-step trimerization upon cooling, transforming from a centrosymmetric, paramagnetic high-temperature (HT) R3m phase to noncentrosymmetric, polar, and trimerized intermediate- (IT) and low-temperature (LT) R3m phases via two successive first-order phase transitions. Symmetry mode decomposition analysis shows that trimerization requires activation of the proper polar order parameter Γ2- and that this mode becomes active at the HT → IT phase transition. The magnitude of this order parameter approximately doubles at the IT → LT transition, with possible activation of a second polar mode, corresponding to Na2 and Ti3Cl8 displacing layers toward each other, at the IT → LT transition. Specific heat measurements reveal comparable changes in entropy between the LT → IT transition, 18.6(1.0) J (mol of f.u.)-1 K-1, and the IT → LT transition, 16.8(1.0) J (mol of f.u.)-1 K-1, demonstrating loss of the magnetic degrees of freedom and constraining possible models for the magnetic and electronic structures of the IT and LT phases. Thus, Na2Ti3Cl8 demonstrates a novel mechanism to obtain polar structures driven by geometrically frustrated lattices and metal-metal bonding and highlights the rich physics arising from kagomé lattice materials.

Barriers to thyroid cancer screening with ultrasound in patients with familial adenomatous polyposis.

OBJECTIVES/HYPOTHESIS: To identify barriers to care in patients with familial adenomatous polyposis (FAP) that have not undergone ultrasound for thyroid cancer (TC) screening. STUDY DESIGN: Case series and survey. METHODS: A study was conducted examining referral patterns for thyroid ultrasound (TUS) in FAP patients for TC screening. Patients with FAP seen at our institution were identified using International Classification of Diseases, Ninth Revision and Tenth Revision codes. Chart review was performed for TUS and the results were recorded. Patients and healthcare providers were surveyed to determine barriers to TUS and opportunities for improvement. RESULTS: Thirteen out of 35 patients surveyed (37%) were told by a healthcare provider that TUS was recommended for TC screening. The incidence for TC in FAP patients ranges from 15 to 12%, whereas the general population risk is 0.02% to 1%. In our series, one patient of 12 (8%) had TC. Barriers to care included poor patient education about the risk of TC in FAP and miscommunication among specialties for referral for TUS. Also, patients enrolled in a FAP registry have improved care, as they are more likely to undergo TUS than those not enrolled. CONCLUSIONS: FAP patients are at a higher risk of developing TC. Therefore, it is important for these patients to be informed and follow the recommended guideline to get a baseline TUS for screening as well as receive better patient education about the risk of TC and improved communication among specialties. Additionally, patients enrolled in a FAP registry are more likely to undergo ultrasound for TC screening, so there needs to be more centralized coordination for the multidisciplinary care of this disease. LEVEL OF EVIDENCE: NA Laryngoscope, 129:2436-2441, 2019.

Control of the iridium oxidation state in the hollandite iridate solid solution K(1-x)Ir4O8.

The synthesis and physical properties of the K(1-x)Ir4O8 (0 ≤ x ≤ 0.7) solid solution are reported. The structure of KIr4O8, solved with single-crystal X-ray diffraction at T = 110 K, is found to be tetragonal, space group I4/m, with a = 10.0492(3) Å and c = 3.14959(13) Å. A highly anisotropic displacement parameter is found for the potassium cation. Density functional theory calculations suggest that this anisotropy is due to a competition between atomic size and bond valence. KIr4O8 has a significant electronic contribution to the specific heat, γ = 13.9 mJ mol-Ir(-1) K(-2), indicating an effective carrier mass of m*/me ≈ 10. Further, there is a magnetic-field-dependent upturn in the specific heat at T < 3 K, suggestive of a magnetically sensitive phase transition below T < 1.8 K. Resistivity and magnetization measurements show that both end-members of the solid solution, KIr4O8 and K(1-x)Ir4O8 (x ≈ 0.7), are metallic, with no significant trends in the temperature-independent contributions to the magnetization. These results are interpreted and discussed in the context of the importance of the variability of the oxidation state of iridium. The differences in physical properties between members of the K(1-x)Ir4O8 (0 ≤ x ≤ 0.7) series are small and appear to be insensitive to the iridium oxidation state.

Neurogenic factor-induced Langerhans cell activation in diabetic mice with mechanical allodynia.

BACKGROUND: Langerhans cells (LCs) are antigen-presenting dendritic cells located in the skin. It has been reported that LC activation is associated with painful diabetic neuropathy (PDN); however, the mechanism of LC activation is still unclear. METHODS: The db/db mouse, a rodent model of PDN, was used to study the roles of LCs in the development of PDN in type 2 diabetes. Hind foot pads from db/db and control db/+ mice from 5 to 24 weeks of age (encompassing the period of mechanical allodynia development and its abatement) were collected and processed for immunohistochemistry studies. LCs were identified with immunohistochemistry using an antibody against CD207 (Langerin). The intraepidermal nerve fibers and subepidermal nerve plexus were identified by immunohistochemistry of protein gene product 9.5 (PGP 9.5) and tropomyosin-receptor kinase (Trk) A, the high affinity nerve growth factor receptor. RESULTS: CD207-positive LCs increased in the db/db mouse during the period of mechanical allodynia, from 8 to 10 weeks of age, in both the epidermis and subepidermal plexus. At 16 weeks of age, when mechanical allodynia diminishes, LC populations were reduced in the epidermis and subepidermal plexus. Epidermal LCs (ELCs) were positive for Trk A. Subepidermal LCs (SLCs) were positive for CD68, suggesting that they are immature LCs. Additionally, these SLCs were positive for the receptor of advanced glycation end products (RAGE) and were in direct contact with TNF-α-positive nerve fibers in the subepidermal nerve plexus during the period of mechanical allodynia. Intrathecal administration of SB203580, a p38 kinase inhibitor, significantly reduced mechanical allodynia, TNF-α expression in the subepidermal plexus, and increased both ELC and SLC populations during the period of mechanical allodynia. CONCLUSIONS: Our data support the hypothesis that increased LC populations in PDN are activated by p38-dependent neurogenic factors and may be involved in the pathogenesis of PDN.