Operando X-ray Absorption Spectroscopy Study of SnO2 Nanoparticles for Electrochemical Reduction of CO2 to Formate.

Tin-based electrocatalysts exhibit a remarkable ability to catalyze CO2 to formate selectively. Understanding the size-property relationships and exploring the evolution of the active size still lack complete understanding. Herein, we prepared SnO2 nanoparticles (NPs) with a controllable size supported on commercial carbon spheres (SnO2/C-n, n = 1, 2, and 3) by a simple low-temperature annealing method. The transmission electron microscopy/scanning transmission electron microscopy images and fitting results of the small-angle X-ray scattering profile confirm the increased size of SnO2 NPs due to the increase of SnO2 loading. The catalytic performance of SnO2 has proved the size-dependent effect during the CO2 reduction reaction process. The as-prepared SnO2/C-1 displayed the maximum Faradic efficiency of formate (FEHCOO-) of 82.7% at -1.0 V versus reversible hydrogen electrode (RHE). In contrast, SnO2/C-2 and SnO2/C-3 with larger particle sizes achieved lower maximum FEHCOO- and larger overpotential. Moreover, we employed operando X-ray absorption spectroscopy to study the evolution of the oxidation state and local coordination environment of SnO2 under working conditions. In addition to the observed shifts of the rising edge of Sn K-edge X-ray absorption near-edge structure spectra to a lower energy side as the applied voltage decreases, the decreased coordination number of Sn in the Sn-O scattering path and the presence of Sn metal contribution in the extended X-ray absorption fine structure spectra verify the reduction of SnO2 to SnOx and metallic Sn.

Patterns of regional recurrence in papillary thyroid cancer patients with lateral neck metastases undergoing neck dissection.

BACKGROUND: Practice variability exists for the extent of neck dissection undertaken for papillary thyroid carcinoma (PTC) metastatic to the lateral neck nodes, with disagreement over routine level V dissection. METHODS: We performed a retrospective medical record review of PTC patients with lateral neck nodal metastases treated at University Health Network from 2000 to 2012. Predictive factors for regional neck recurrence, including extent of initial neck dissection, were analyzed using Cox regression. RESULTS: Out of 204 neck dissections in 178 patients, 110 (54%) underwent selective and 94 (46%) had comprehensive dissection including level Vb. Mean follow-up was 6.3 years (SD). Significant predictors of regional failure were the total number of suspicious nodes on preoperative imaging (p = 0.029), largest positive node on initial neck dissection (p < 0.01), and whether patients received adjuvant radiotherapy (p = 0.028). The 5-year ipsilateral regional recurrence rate was 8 and 9% with selective and comprehensive dissection, respectively (p = 0.89). CONCLUSION: The extent of neck dissection did not predict the probability of regional recurrence in PTC patients presenting with lateral neck metastases.

Determining Patient Preferences for Indeterminate Thyroid Nodules: Observation, Surgery or Molecular Tests.

BACKGROUND: Gene-expression classifiers (GEC) and genetic mutation panels (GMP) have been shown to improve preoperative diagnostic evaluations of indeterminate thyroid nodules. Despite the improvement, uncertainty regarding the proper management exists. Patient preferences may better inform the management of these indeterminate thyroid nodules. METHODS: Hypothetical scenarios were administered to two groups of patients: those with previous FNA-confirmed indeterminate thyroid nodules (Group A, n = 50) and those presenting to a general otolaryngology clinic for other reasons (Group B, n = 50). We evaluated patient preferences for surgery, observation and the use of molecular tests while varying the risk of malignancy, cost and diagnostic properties of the tests. RESULTS: The mean threshold for choosing surgery over observation was a 38.6% risk of malignancy on FNA. When offered either GEC, GMP or both (with their inherent imperfect diagnostic properties) in addition to the indeterminate FNA, 85.0% of respondents picked at least one of the molecular tests over either observation or surgery if the test(s) were free of charge. However, only 51.7% of respondents chose at least one of the tests when asked to pay the current cost of the test(s) (p < 0.001). On multivariable analysis, sex, the presence of an indeterminate FNA diagnosis and income level significantly predicted the desire to proceed with a molecular test above standard management. CONCLUSION: Patient preferences for thyroid nodule management are dependent on the risk of malignancy, prognosis of cancer and costs. Patients prefer molecular tests over standard management with indeterminate thyroid nodules, but the costs of the test(s) reduce the desire.

Tuberculous lymphadenitis of the head and neck in Canadian children: Experience from a low-burden region.

BACKGROUND: Children are more likely than adults to develop extra-pulmonary tuberculosis (EPTB), which often presents as cervical lymphadenopathy. The role of surgery in management is uncertain. We reviewed all head and neck EPTB cases presenting to our tertiary care pediatric institution over a twelve-year period. METHODS: All children 18 years of age and younger with EPTB involving the head and neck were included. We recorded clinical data and age at diagnosis, birth country, BCG vaccination status, as well as radiographic, surgical, histological, and microbiological results. RESULTS: All 16 patients presented with cervical lymphadenopathy. Fourteen were born outside of Canada in TB endemic areas and all had foreign-born parents. Diagnosis was confirmed microbiologically from lymph node biopsies in 14 cases. Multi-drug resistant TB was identified in two cases: both had previous excisional node biopsies that had not been cultured. Two patients had culture negative suppuration despite adequate anti-tuberculous treatment that required surgery for cure. CONCLUSION: Ongoing suppuration despite appropriate drug therapy is seen in a minority of patients. We found that excisional lymph node biopsy of diseased cervical lymph nodes is diagnostic, and also therapeutic in some cases with ongoing suppuration despite appropriate drug therapy. Mycobacterial culture of lymph nodes is important for diagnosis and determination of drug resistance patterns.

Absorbable Steroid-Impregnated Spacer After Endoscopic Sinus Surgery to Reduce Synechiae Formation.

OBJECTIVE: Middle meatal synechiae formation after endoscopic sinus surgery (ESS) for chronic rhinosinusitis (CRS) leads to higher rates of revision surgery. We aimed to determine if there are different rates of postoperative synechiae following ESS for CRS between patients who received a nonabsorbable spacer (NAS) placed in the ethmoid cavity versus patients who had a steroid-impregnated absorbable spacer (AS) placed at the middle meatal entry. METHODS: We conducted a retrospective cohort study of patients who underwent ESS for CRS at a single tertiary referral center from October 2009 to October 2013. We collected data on synechiae formation between the middle turbinate and lateral nasal wall within 1 month of surgery and postoperative epistaxis. RESULTS: One hundred forty-six patients with 252 nasal cavities (52.0%) received steroid-impregnated AS, and 128 patients with 233 nasal cavities (48.0%) received NAS. Synechiae formation occurred in 2.0% of cavities with AS and 5.6% of cavities with NAS, but this difference was not statistically significant (OR = 0.34, P = .052). One patient in each cohort had significant postoperative epistaxis requiring additional nasal packing (P > .99). CONCLUSION: Steroid-impregnated absorbable spacers had statistically insignificant reduction in postoperative synechiae formation when compared to nonabsorbable spacers. Low rates of postoperative epistaxis were observed regardless of the type of spacer used.

Long-term treatment with tenofovir in Asian-American chronic hepatitis B patients is associated with abnormal renal phosphate handling.

BACKGROUND: Increased risk of defective urinary phosphate reabsorption and osteoporosis has been reported in HIV and chronic hepatitis B (CHB) patients treated with tenofovir disoproxil fumarate (TDF). AIMS: Goals of this study were to evaluate the prevalence of renal phosphate wasting and abnormal bone mineral density in CHB patients taking TDF compared to CHB patients treated with entecavir (ETV) and untreated CHB patients. METHODS: This is a cross-sectional study of 146 consecutive Asian-American CHB patients who were treatment naïve (n = 60) or treated with either TDF (n = 42) or ETV (n = 44). Proximal tubular handling of phosphate was assessed by the maximal rate of tubular reabsorption of phosphate (TmPO4) divided by glomerular filtration rate (GFR) (TmPO4/GFR). Bone mineral density (BMD) was measured using dual X-ray absorptiometry. RESULTS: TmPO4/GFR was similar among CHB patients treated with TDF compared to untreated patients and patients taking ETV. However, among patients treated with ≥18 months of TDF or ETV, prevalence of abnormal TmPO4/GFR was higher among patients treated with TDF compared to ETV (48.5 % (16/33) vs. 12.5 % (3/24), p = 0.005). Overall prevalence of osteoporosis in this cohort of CHB patients was 14 %, with no significant difference between the three groups. Renal phosphate handling did not correlate with osteoporosis. CONCLUSIONS: Chronic hepatitis B patients treated with ≥18 months of TDF experienced an increased risk of proximal tubular dysfunction. TDF did not increase the risk of osteoporosis. Longitudinal studies are needed to confirm these findings.

Lymphadenopathy: defining a palpable lymph node.

BACKGROUND: The threshold size required to detect lymphadenopathy via palpation has never been formally determined. The purpose of this study was to determine the threshold, sensitivity, and error of node palpation and how this changes with experience. METHODS: Lymphadenopathy models were created using polyvinyl alcohol cryogel (PVA-C) to mimic tissue tactility. Node diameter ranged from 0.5 to 4 cm. Study subjects were medical students, otolaryngology residents, and otolaryngology consultants. Each subject provided 22 estimates of size. Primary outcomes were the sensitivity, error (true vs estimated size), and threshold of palpation. RESULTS: Thirty subjects completed the study. Sensitivity was 60%, 74%, and 86% for students, residents, and consultants, respectively (p < .01). Error was 0.88 cm, 0.61 cm, and 0.57 cm, respectively (p < .05). Palpation threshold was 1.32 cm, 0.83 cm, and 0.75 cm, respectively (p < .05). All participants detected nodes ≥2 cm, whereas consultants detected nodes ≥1 cm. CONCLUSION: Experience is associated with decreased palpation threshold and error, and increased sensitivity. Educational interventions should target nodes <2 cm.

Aspirin desensitization for aspirin-exacerbated respiratory disease (Samter's Triad): a systematic review of the literature.

OBJECTIVES: To critically review the current literature regarding aspirin desensitization treatment for nasal polyposis in patients with Aspirin-Exacerbated Respiratory Disease (AERD). STUDY DESIGN: Systematic review of the literature. METHODS: All English literature published between January 1995 and February 2013 reporting specifically nasal outcomes following aspirin desensitization in AERD patients were eligible for inclusion. Exclusion criteria were non-investigative, non-human, and ex-vivo studies. Studies were categorized by level of evidence and evaluated for quality using the Downs and Black scale. RESULTS: A total of 614 citations were retrieved and eleven studies met the criteria for analysis. Outcome measurements included self-reported symptom scores, amount of corticosteroid use, rate of revision surgery, and quantitative measurements such as rhinomanometry. Overall, most studies reported a significant improvement in symptom scores, decrease in corticosteroid use, and decrease in revision surgery. A few studies showed promising results with quantitative outcomes. However, most studies were of Level 2 evidence with small samples sizes. Rates of adverse events ranged from 12.5% to 23%. CONCLUSIONS: Unlike traditional treatments for nasal polyposis, aspirin desensitization targets AERD etiology rather than phenotype and can be an effective therapeutic option. While the current literature shows encouraging results, additional studies are needed to better define clinical benefits.

Development of a tissue-mimicking neck model for medical education.

BACKGROUND: The ability to palpate neck masses and lymph nodes and appreciate qualities such as size, location, and consistency is critical for patient care and an important clinical skill for all physicians. Medical students currently learn neck palpation by practicing on healthy, standardized patients; however, studies of similar procedures have shown that educational models with simulated pathology help improve technique and confidence. OBJECTIVE: Our goal was to create a tissue-mimicking neck model with palpable masses. METHODS: Iterative design and development of a high-fidelity neck model using polyvinyl alcohol-cryogel (PVA-C), a nontoxic and biocompatible polymer that exhibits favourable tissue-mimicking elastic properties. Model geometries were digitally reconstructed from high-resolution cadaveric magnetic resonance imaging sections to create physical moulds through stereolithography. PVA-C was formulated to mimic the characteristics of human tissue. RESULTS: A life-like neck model was built and consists of these components: muscle, larynx, spine, soft tissue, pathologic nodes, and skin. DISCUSSION: A final neck model prototype has been completed and will be evaluated by otolaryngology consultants and residents for face and construct validity and assessed in a randomized, controlled trial to evaluate how it impacts students' ability to detect neck masses.