Toward decentralized wastewater treatment: A flow-through module using microtubular gas diffusion electrodes for micropollutants removal.

Electro-Fenton (EF) represents an eco-friendly and cost-effective advanced oxidation process that can remove highly persistent and hazardous pharmaceuticals, e.g., contrast media agents, from water bodies. However, up to date, EF modules incorporate a planar carbonaceous gas diffusion electrode (GDE) cathode containing fluorinated compounds as polymeric binders. Here, we introduce a novel flow-through module that deploys freestanding carbon microtubes (CMT) as microtubular GDEs, omitting any risks of secondary pollution by highly-persistent fluorinated compounds (e.g., Nafion). The flow-through module was characterized for electrochemical hydrogen peroxide (H2O2) generation and micropollutant removal via EF. H2O2 electro-generation experiments illustrated high production rates (1.1 ± 0.1-2.7 ± 0.1 mg cm-2 h-1) at an applied cathodic potential of - 0.6 V vs. SHE, depending on the porosity of CMTs. Diatrizoate (DTZ), as the model pollutant, with a high initial concentration of 100 mg L-1 was successfully oxidized (95-100 %), reaching mineralization (TOC-total organic carbon removal) efficiencies up to 69 %. Additionally, Electro-adsorption experiments demonstrated the capability of positively charged CMTs to remove negatively charged DTZ with a capacity of 11 mg g-1 from a 10 mg L-1 DTZ solution. These results reveal the potential of the as-designed module to serve as an oxidation unit coupled with other separation techniques, e.g., electro-adsorption or membrane processes.

Micromodel of a Gas Diffusion Electrode Tracks In-Operando Pore-Scale Wetting Phenomena.

Utilizing carbon dioxide (CO2 ) as a resource for carbon monoxide (CO) production using renewable energy requires electrochemical reactors with gas diffusion electrodes that maintain a stable and highly reactive gas/liquid/solid interface. Very little is known about the reasons why gas diffusion electrodes suffer from unstable long-term operation. Often, this is associated with flooding of the gas diffusion electrode (GDE) within a few hours of operation. A better understanding of parameters influencing the phase behavior at the electrolyte/electrode/gas interface is necessary to increase the durability of GDEs. In this work, a microfluidic structure with multi-scale porosity featuring heterogeneous surface wettability to realistically represent the behavior of conventional GDEs is presented. A gas/liquid/solid phase boundary was established within a conductive, highly porous structure comprising a silver catalyst and Nafion binder. Inoperando visualization of wetting phenomena was performed using confocal laser scanning microscopy (CLSM). Non-reversible wetting, wetting of hierarchically porous structures and electrowetting were observed and analyzed. Fluorescence lifetime imaging microscopy (FLIM) enabled the observation of reactions on the model electrode surface. The presented methodology enables the systematic evaluation of spatio-temporally evolving wetting phenomena as well as species characterization for novel catalyst materials under realistic GDE configurations and process parameters.

Freestanding Nitrogen-Doped Carbons with Hierarchical Porosity for Environmental Applications: A Green Templating Route with Bio-Based Precursors.

Powdery hierarchical porous carbons serve as cost-effective, functional materials in various fields, namely energy storage, heterogeneous catalysis, electrochemistry, and water/wastewater treatment. Such powdered activated carbons (PAC) limit new module designs and require further preparation steps, for example, adding polymeric binders, to be shaped into a standalone geometry. Polymeric binders, however, can block PACs' catalytic and active sites and, more importantly, pose the risk of secondary pollution for environmental purposes, especially in the context of clean water supply. This study introduces a novel synthesis method for fabricating freestanding nitrogen-doped carbons with hierarchical porosity using chitosan and sucrose as green precursors. Chitosan supplies nitrogen and acts as a backbone, giving a freestanding geometry to the final product, and sucrose is a carbon-rich precursor. The proposed method employs ice- and hard-templating for macropores and mesopores and combines carbonization and activation steps with no required activating agent. Final freestanding carbons function as adsorbents for removing persistent pollutants, as binder-free electrodes with high specific surface area and capacitive current, and as tubular gas diffusion electrodes for oxygen reduction reactions. These freestanding carbons enable new module designs and can be scaled-up by numbering-up, serving as bio-based functional materials for a wide range of applications involving porous heteroatom-doped carbons.

Evaluation of Outcome Variability Associated With Lateral Wall, Mid-scalar, and Perimodiolar Electrode Arrays When Controlling for Preoperative Patient Characteristics.

OBJECTIVE: Determine the impact of electrode array selection on audiometric performance when controlling for baseline patient characteristics. STUDY DESIGN: Retrospective evaluation of a prospective cochlear implant (CI) database (January 1, 2012-May 31, 2017). SETTING: Tertiary Care University Hospital. PATIENTS: Three hundred twenty-eight adult CI recipients. INTERVENTIONS/MAIN OUTCOMES MEASURED: Hearing outcomes were measured through unaided/aided pure tone thresholds and speech recognition testing before and after cochlear implantation. All reported postoperative results were performed at least 6 months after CI activation. All device manufacturers were represented. RESULTS: Of the 328 patients, 234 received lateral wall (LW) arrays, 46 received perimodiolar (PM) arrays, and 48 received mid-scalar (MS) arrays. Patients receiving PM arrays had significantly poorer preoperative earphone and aided PTAs and SRTs, and aided Consonant-Nucleus-Consonant(CNC) word and AzBio +10 SNR scores compared with patients receiving LW arrays (all p ≤ 0.04), and poorer PTAs and AzBio +10 SNR scores compared with MS recipients (all p ≤ 0.02). No preoperative audiological variables were found to significantly differ between MS and LW patients. After controlling for preoperative residual hearing and speech recognition ability in a hierarchical multiple regression analysis, no statistically significant difference in audiological outcomes was detected (CNC words, AzBio quiet, or AzBio +10 SNR) among the three electrode array types (all p > 0.05). CONCLUSION: While previous studies have demonstrated superior postoperative speech recognition scores in LW electrode array recipients, these differences lose significance when controlling for baseline hearing and speech recognition ability. These data demonstrate the proclivity for implanting individuals with greater residual hearing with LW electrodes and its impact on postoperative results.

Modern Management of Nasal Hemangiomas.

IMPORTANCE: Current treatment approaches for infantile hemangiomas of the nose include observation, pharmacologic agents, surgery, and/or laser therapy. Because of the known functional, social, and cosmetic effect of nasal deformities, obtaining the best possible result is critical. Optimal timing, type, duration, and extent of therapy remain unclear. OBSERVATIONS: Results of a review of 86 patients (64 females and 22 males; mean age, 4.8 months [range, 2 days-23 years]) with infantile hemangiomas of the nose treated from January 1, 1999, to December 31, 2015, and a review of the literature are presented to gain insight into the preferred approach to the treatment of these lesions. Patients underwent single-modality and multimodality treatment with pulsed-dye laser (n = 73), oral corticosteroids (n = 11), intralesional corticosteroids (n = 2), propranolol hydrochloride (n = 30), and surgery (n = 50). The treatment decision algorithms and outcomes based on tumor phase and infantile hemangioma subtype are reviewed in detail. Nine articles met the criteria to be included in the literature review. Literature from the era before the approval of propranolol advocates for early use of oral or intralesional corticosteroids followed by surgery or pulsed-dye laser in cases of unacceptable outcomes. Literature from the era after the approval of propranolol supports early initiation of oral ß-blockers until proliferation ceases or until additional intervention is necessary. CONCLUSIONS AND RELEVANCE: Despite a lack of higher levels of evidence, there exists a general consensus between the literature and clinical experience advocating for early multimodality treatment to achieve the best result possible by the time the children reach certain sociodevelopmental milestones.

Titanium Ossicular Chain Reconstruction Revision Success and Preoperative Factors Predicting Success.

Objective Determine rates of success after revision titanium ossicular chain reconstruction with either partial or total ossicular replacement prosthesis and assess preoperative factors predicting positive outcomes. Study Design Case series with planned data collection. Setting Tertiary hospital. Subjects and Methods The charts of 76 surgical patients who underwent revision titanium ossicular chain reconstruction from 2003 to 2014 were abstracted from a prospectively maintained database at the Medical University of South Carolina. Postoperative air-bone gap (ABG) after revision surgery at short-term (<6 months) and intermediate to long-term (>1 year) follow-up and preoperative factors associated with postoperative ABG ≤20 dB were recorded. A paired t test or Wilcoxon signed-rank sum test was utilized to compare preoperative, short-term, or intermediate to long-term results. Results Seventy-six patients underwent revision ossiculoplasty and met inclusion criteria. Mean postoperative ABG was 22.5 at short-term follow-up ( P < .0001) and 24.4 at intermediate to long-term follow-up ( P = .003). Postoperative ABG ≤20 dB was achieved in 51.5% of patients. The only preoperative factor associated with postoperative ABG ≤20 dB was location of original primary ossiculoplasty ( P = .01). Conclusions This is one of the larger studies involving revision titanium ossiculoplasty. Revision surgery showed a significant improvement in postoperative ABG. The location of the original ossiculoplasty correlated with success of revision surgery (defined as postoperative ABG ≤20 dB). Patients who had the primary ossiculoplasty at an outside hospital may have better audiometric outcomes than patients who had it at a tertiary hospital.

Postinflammatory medial canal fibrosis: An institutional review and meta-analysis of short- and long-term outcomes.

OBJECTIVE: Few studies report outcomes of surgical management of postinflammatory medial canal fibrosis (PIMCF). The objectives were to compare short- and long-term outcomes after surgical repair of PIMCF at our institution and systematically aggregate published data for meta-analysis. DATA SOURCES: Medical records for the case series; PubMed, Scopus, and OVID/Medline for the systematic review/meta-analysis. METHODS: Patients undergoing surgical treatment of PIMCF were identified. Short-term (<2 years) and long-term (>2 years) postoperative outcomes were evaluated for the case series and aggregated for the meta-analysis. RESULTS: At our institution, 16 patients (21 ears) were identified. Compared to the preoperative air-bone gap (ABG) (27.7 ± 7.5 dB), mean postoperative short-term ABG (8.2 ± 7.5 dB) and long-term ABG (15.3 ± 11.3 dB) were significantly improved (P < 0.001 for both). Although short-term restenosis rate was low (0%) among long-term follow-up patients, 64% (9 of 14) experienced some degree of recurrent canal narrowing, including one case of complete restenosis (7%). Similarly, meta-analysis pooled preoperative ABG (29.3 ± 9.7 dB, 95% confidence interval [CI] 27.0-31.6) improved significantly during short-term (11.4 ± 8.0 dB, 95% CI 8.3-4.5, P < 0.0001) and long-term (14.3 ± 9.6 dB, 95% CI 11.6-16.9, P = 0.0004) follow-ups, with partial deterioration in hearing over time. Long-term complete restenosis rate (13.8%) was worse than short-term (8.0%), with no significant difference over time (P = 0.85). CONCLUSION: Postinflammatory medial canal fibrosis is a rare condition that can successfully be treated with surgery to restore patency of the external auditory canal. Patients who experience improved hearing early on, however, are at significant risk of restenosis and recurrence of their conductive hearing loss with time. LEVEL OF EVIDENCE: N/A. Laryngoscope, 2016 127:488-495, 2017.

Evidence-Based Medicine in the Treatment of Infantile Hemangiomas.

Over the past decade, the treatment of infantile hemangiomas has undergone dramatic breakthroughs. This review critically evaluates the latest literature that supports the myriad treatment options for infantile hemangiomas. It chronicles the fading role of steroid therapy and evolution of propranolol use as the major treatment modality. Although propranolol is helping this disease become more of a medical disease and less of a surgical dilemma, the report also reveals a continued search to find nonsystemic treatment options. In summary, this is an evidence-based medicine review for the treatment of infantile hemangiomas.

The effects of residual hearing in traditional cochlear implant candidates after implantation with a conventional electrode.

OBJECTIVE: To analyze the effects of residual hearing on postoperative speech performance in traditional cochlear implant (CI) patients implanted with a conventional electrode. STUDY DESIGN: Retrospective review. SETTING: Academic tertiary referral center. PATIENTS: A total of 129 adults implanted by a single surgeon at a tertiary care facility between June 2005 and November 2010 with measurable preoperative pure tone thresholds at any frequency were included. INTERVENTION: Cochlear implantation with a conventional electrode via an anterior inferior cochleostomy. MAIN OUTCOME MEASURE: Speech perception using monosyllabic word scores in quiet and sentences in quiet and noise in the electric (CI-only) condition of the implanted ear. Preservation of hearing was defined as complete for postoperative thresholds within 10 dB of preimplant values and partial if greater than 11 dB. Pure tone audiometry and speech perception testing were performed preoperatively and at regular intervals postoperatively, with the 1-year evaluation being the final outcome period. RESULTS: Preservation at any frequency or level was not a factor in speech perception outcome, although preservation was more common in low frequencies. Hearing preservation was correlated with younger age at implantation, but was not related to length of hearing loss, cause of deafness, device type, sex, preoperative speech performance, or low-frequency pure-tone average. CONCLUSION: Hearing can be preserved in traditional CI patients implanted with a conventional electrode. Although preservation of hearing may have implications for future technology, it is not currently correlated with speech performance in the CI-only condition.