Effect of Preoperative Neck Radiotherapy on the Reconstruction of Head and Neck Defects With the Supraclavicular Artery Island Flap.

Purpose: The supraclavicular artery island (SAI) flap is commonly used in the reconstruction of head and neck defects. However, the safety of SAI flaps for neck irradiated patient needs to be verified. To investigate the safety of using the SAI flap for patients who have undergone neck radiotherapy, as well as the risk factors for flap complications. Materials and Methods: Sixty-one patients (16 irradiated and 45 nonirradiated) with SAI flap-reconstructed head and neck defects were included, and relevant data were collected retrospectively. The gender, age, body mass index, presence of diabetes mellitus, preoperative albumin level, and flap size between irradiated and nonirradiated patients had no significant difference. Results: No significant difference was observed in the incidence of complications (total, mild, or severe) between the radiotherapy and nonradiotherapy groups. In univariate analysis, preoperative radiotherapy was not associated with postoperative complications of the SAI flap procedure (P = 1.00), while a low preoperative albumin level was a significant risk factor for postoperative complications (P < .05). Conclusions: Our data suggest that preoperative radiotherapy does not increase the risk of SAI flap postoperative complications compared with surgical reconstruction alone.

Unveiling the Role of Water in Heterogeneous Photocatalysis of Methanol Conversion for Efficient Hydrogen Production.

Water molecules, which act as both solvent and reactant, play critical roles in photocatalytic reactions for methanol conversion. However, the influence of water on the adsorption of methanol and desorption of liquid products, which are two essential steps that control the performance in photocatalysis, has been well under-explored. Herein, we reveal the role of water in heterogeneous photocatalytic processes of methanol conversion on the platinized carbon nitride (Pt/C3N4) model photocatalyst. In situ spectroscopy techniques, isotope effects, and computational calculations demonstrate that water shows adverse effects on the adsorption of methanol molecules and desorption processes of methanol oxidation products on the surface of Pt/C3N4, significantly altering the reaction pathways in photocatalytic methanol conversion process. Guided by these discoveries, a photothermal-assisted photocatalytic system is designed to achieve a high solar-to-hydrogen (STH) conversion efficiency of 2.3 %, which is among the highest values reported. This work highlights the important roles of solvents in controlling the adsorption/desorption behaviours of liquid-phase heterogeneous catalysis.

Computational electrocatalysis beyond conventional hydrogen electrode model: CO2 reduction to C2 species on copper facilitated by dynamically formed solvent halide ions at the solid-liquid interface.

The reduction of CO2 into value-added chemicals and fuels has been actively studied as a promising strategy for mitigating carbon dioxide emissions. However, the dilemma for the experimentalist in choosing an appropriate reaction medium and neglecting the effect of solvent ions when using a simple thermochemical model, normally leads to the disagreement between experimental observations and theoretical calculations. In this work, by considering the effects of both the anion and cation, a more realistic CO2 reduction environment at the solid-liquid interface between copper and solvent ions has been systematically studied by using ab initio molecular dynamics and density functional theory. We revealed that the co-occurrence of alkali ions (K+) and halide ions (F-, Cl-, Br-, and I-) in the electric double layer (EDL) can enhance the adsorption of CO2 by more than 0.45 eV compared to that in pure water, and the calculated energy barrier for CO-CO coupling also decreases 0.32 eV in the presence of I ion on a negatively charged copper electrode. The hydrated ions can modulate the distribution of the charge near the solid-liquid interface, which significantly promotes CO2 reduction and meanwhile impedes the hydrogen evolution reaction. Therefore, our work unveils the significant role of halide ions at the electrode-electrolyte interface for promoting CO2 reduction on copper electrode.

Maximal exposure of the parapharyngeal internal carotid artery via transnasal and transoral corridors.

BACKGROUND: The parapharyngeal internal carotid artery (pICA) could be surgically exposed through the transnasal and transoral corridors. However, their potential degree of exposure has not been established sufficiently. This study aims to elucidate the maximal exposure of the pICA via the transnasal and transoral corridors. METHODS: An endonasal transpterygoid nasopharyngectomy for exposure of the pICA was performed on eight cadaveric specimens (16 sides), while a transoral approach for exposure of the pICA was performed on six additional specimens (12 sides). In addition, the CT angiography of 60 consecutive patients (120 sides) was analyzed to establish the potential maximal exposure of the pICA through each corridor. RESULTS: The hard palate becomes a restricting factor for the inferior exposure of the pICA via the transnasal approach, whereas the entire pICA segment could be adequately displayed through the transoral corridor. The maximal exposed length of the pICA for a transnasal and transoral approach was 3.08 ± 0.30 cm and 6.56 ± 0.57 cm, respectively. This difference was statistically significant (p < 0.001). CONCLUSION: An endonasal exposure of the pICA seems limited to its superior aspect, whereas the transoral corridor could provide adequate exposure of the entire length of pICA.

Endoscopic transoral approach to the lateral poststyloid space.

The lateral poststyloid space (LPSS) located at the posterolateral aspect of the styloid process. This study aims to explore the anatomical relationships in LPSS via a transoral corridor, providing reference for addressing lesions extending to this region. An endoscopic transoral approach for exposure of the LPSS was performed on 6 cadaveric specimens (12 sides). Related landmarks were explored, and transoral extirpation of tumors extended into LPSS was employed in 12 patients. The deep lobe of the parotid gland, extratemporal facial nerve, and the accompanying artery in the LPSS were sufficiently exposed via the transoral corridor in all 12 cadaveric sides. The transoral corridor provided adequate exposure for tumors extending to the LPSS, and en bloc resection was achieved in these 12 patients. No facial nerve or vascular injury occurred, and no recurrence observed in this cohort with an average follow-up of 26 months. An endoscopic transoral approach provides a direct access to the LPSS. Appreciation of the anatomical relationships within the LPSS is valuable for employing a transoral extirpation of tumors extending to this specific region.

Comparison between free posterior tibial flap and free radial forearm flap for head and neck reconstruction: an anatomical study and a retrospective comparative cohort study.

Background: Both free posterior tibial flap (FPTF) and free radial forearm flap (FRFF) are commonly used for head and neck defects. They have many similarities in embryology, histology, and anatomy, but their advantages and disadvantages in head and neck repair have not been fully recognized. This study aimed to compare the cadaveric anatomy and clinical application of FPTF and FRFF for the reconstruction of head and neck defects after tumor resection. Methods: Anatomical dissection was performed on 10 fresh adult cadavers. The general characteristics of both flaps and the sites of recipients and donors were collected. A total of 31 and 25 patients underwent FPTF and FRFF construction, respectively. The patient medical records were assessed to obtain the clinical characteristics. Characteristics of the flap such as size, pedicle length, and clinical process data were collected and compared. The appearance, sensory disturbance, and effect on quality of life and daily activity were evaluated. Results: The posterior tibial artery was present and observed in all patients. The posterior vascular pedicle was longer than the radial artery. There was no difference between the diameters of arteries of FPTF and FRFF; however, the diameters of their veins differed. In terms of flap characteristics, FPTF was significantly larger and had a longer vascular pedicle than FRFF (40.68±11.07 vs. 53.77±29.02 cm2, P=0.03; 8.48±1.66 vs. 11.10±2.39 cm, P=0.00). Patients in the FPTF group had a significantly shorter total hospital stay (FRFF: 26.48±8.33 d; FPTF: 18.58±6.68 d), postoperative hospital stay (FRFF: 17.60±5.53 d; FPTF: 10.94±3.62 d), and flap harvest time (FRFF: 87.00±20.92 min; FPTF: 65.00±17.56 min) than FRFF group. There were far more complications of the donor site in the FRFF group than in the FPTF group. Also, according to the patients' subjective evaluations of the donor site, FPTF was superior to FRFF (P=0.00). Conclusions: FPTF is a reliable alternative to FRFF for head and neck reconstruction. These techniques share similar certain embryogenesis and anatomical characteristics but FPTF possesses unique aesthetic and clinical application advantages.

Endoscopic trans-lateral oropharyngeal wall approach to the petrous apex and the petroclival region.

BACKGROUND: A trans-lateral oropharyngeal wall approach (TLOWA) to the petrous apex has not been previously defined. This study aims to assess the feasibility of a TLOWA for surgical access to the petrous apex and the petroclival region. METHODS: An endoscopic TLOWA for exposure of the petrous apex and petroclival region was performed on five cadaveric specimens (10 sides). Associated anatomical landmarks were defined, and the strategies for maximal exposure of the internal carotid artery (ICA) were explored. RESULTS: Via a TLOWA, the parapharyngeal ICA was widely exposed in all 10 sides. Following transection of the Eustachian tube, the inferior petrous apex and petroclival region could be sufficiently exposed. After drilling the anteroinferior bony canal, the horizontal petrous ICA, foramen lacerum, and the paraclival ICA could be adequately revealed. CONCLUSION: The TLOWA may provide an alternative corridor for access to the petrous apex and the petroclival region. The parapharyngeal, petrous, lower paraclival ICAs, and the foramen lacerum could be adequately exposed via the TLOWA.

Exploration of anatomical landmarks for performing an endoscopic transoral nasopharyngectomy.

BACKGROUND: Performing a nasopharyngectomy via a transoral approach has been reported; however, defining landmarks to facilitate this approach has not been addressed. This study aims to explore anatomical landmarks to aid in performing a nasopharyngectomy via the transoral corridor. METHODS: An endoscopic transoral nasopharyngectomy was performed on six cadaveric specimens (12 sides). Related anatomical landmarks were defined, and the strategy to preserve the parapharyngeal internal carotid artery (pICA) was explored. RESULTS: An endoscopic transoral nasopharyngectomy was successfully achieved in all 12 sides. Utilizing the pterygoid hamulus as a landmark, the cartilaginous ET and attachments could be adequately exposed. Identification of the pICA is a prerequisite prior to Eustachian tube (ET) transection. The sphenoidal spine and the petrotympanic fissure could be sufficiently revealed in all 12 sides, which aided in transection of the cartilaginous ET without pICA injury. The ET and the prevertebral contents could be adequately removed via the transoral corridor. CONCLUSION: The pterygoid hamulus, sphenoidal spine and petrotympanic fissure serve as reliable landmarks for performing a transoral nasopharyngectomy. Identification of the pICA is a prerequisite prior to transection of the ET to avoid pICA injury.

Transoral Approach to the Jugular Foramen Region with Preservation of the Eustachian Tube.

OBJECTIVES/HYPOTHESIS: Transnasal exposure of the jugular foramen region (JFR) often requires transection of the Eustachian tube (ET). This study aims to propose a transoral corridor for access to the JFR with preservation of the ET. STUDY DESIGN: Cadaveric dissection and case illustration. METHODS: An endoscopic transoral approach for exposure of the JFR was performed on 5 cadaveric specimens (10 sides). Six patients who underwent a transoral resection of schwannoma within the JFR were retrospectively analyzed. RESULTS: Direct exposure of the JFR with a 0° scope via a transoral approach was feasible, and the internal carotid artery and lower cranial nerves could be adequately exposed, and preservation of the ET was achieved in all 10 sides of the cadaveric specimens. For six patients with JFR tumors, the transoral approach provided adequate access to achieve a gross total resection with ET preservation. Intraoperative cerebral spinal fluid (CSF) leak was encountered in one patient, and a multilayer reconstruction was employed for reconstruction. No operative field or intracranial infection, persistent CSF leak, or emergent airway issues occurred. No recurrence occurred in this cohort with an average follow-up of 12 months. CONCLUSIONS: The transoral approach provided a reliable corridor for access into the JFR with preservation of the ET. For select lesions with expansion into the posterior cranial fossa, a transoral corridor may serve as an alternative for tumor extirpation. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:1374-1380, 2022.

Single-Boron Catalysts for Nitrogen Reduction Reaction.

Boron has been explored as p-block catalysts for nitrogen reduction reaction (NRR) by density functional theory. Unlike transition metals, on which the active centers need empty d orbitals to accept the lone-pair electrons of the nitrogen molecule, the sp3 hybrid orbital of the boron atom can form B-to-N π-back bonding. This results in the population of the N-N π* orbital and the concomitant decrease of the N-N bond order. We demonstrate that the catalytic activity of boron is highly correlated with the degree of charge transfer between the boron atom and the substrate. Among the 21 concept-catalysts, single boron atoms supported on graphene and substituted into h-MoS2 are identified as the most promising NRR catalysts, offering excellent energy efficiency and selectivity against hydrogen evolution reaction.

Improved catalytic combustion of methane using CuO nanobelts with predominantly (001) surfaces.

Through computational calculations, CuO(001) has been identified as an active surface for methane oxidation. Experimental validation with CuO nanobelts comprised of predominantly (001) surfaces has been performed and it is confirmed that the performance of such nanobelts is much higher than normal nanoparticles and nanowires. First principle calculations further clarified that two-coordinated oxygen plays a key role for methane adsorption and oxidation.

Biomass-derived carbon composites for enrichment of dilute methane from underground coal mines.

Ventilation air methane (VAM), which is the main source of greenhouse gas emissions from coal mines, has been a great challenge to deal with due to its huge flow rates and dilute methane levels (typically 0.3-1.0 vol%) with almost 100% humidity. As part of our continuous endeavor to further improve the methane adsorption capacity of carbon composites, this paper presents new carbon composites derived from macadamia nut shells (MNSs) and incorporated with carbon nanotubes (CNTs). These new carbon composites were fabricated in a honeycomb monolithic structure to tolerate dusty environment and to minimize pressure drop. This paper demonstrates the importance of biomass particle size distributions when formed in a composite and methane adsorption capacities at low pressures relevant to VAM levels. The selectivity of methane over nitrogen was about 10.4 at each relevant partial pressure, which was much greater than that (6.5) obtained conventionally (at very low pressures), suggesting that capturing methane in the presence of pre-adsorbed nitrogen would be a practical option. The equilibrium and dynamic performance of biomass-derived carbon composites were enhanced by 30 and 84%, respectively, compared to those of our previous carbon fiber composites. In addition, the presence of moisture in ventilation air resulted in a negligible effect on the dynamic VAM capture performance of the carbon composites, suggesting that our carbon composites have a great potential for site applications at coal mines because the cost and performance of solid adsorbents are critical factors to consider.

Enhanced Photoelectrocatalytic Activity of BiOI Nanoplate-Zinc Oxide Nanorod p-n Heterojunction.

The development of highly efficient and robust photocatalysts has attracted great attention for solving the global energy crisis and environmental problems. Herein, we describe the synthesis of a p-n heterostructured photocatalyst, consisting of ZnO nanorod arrays (NRAs) decorated with BiOI nanoplates (NPs), by a facile solvothermal method. The product thus obtained shows high photoelectrochemical water splitting performance and enhanced photoelectrocatalytic activity for pollutant degradation under visible light irradiation. The p-type BiOI NPs, with a narrow band gap, not only act as a sensitizer to absorb visible light and promote electron transfer to the n-type ZnO NRAs, but also increase the contact area with organic pollutants. Meanwhile, ZnO NRAs provide a fast electron-transfer channel, thus resulting in efficient separation of photoinduced electron-hole pairs. Such a p-n heterojunction nanocomposite could serve as a novel and promising catalyst in energy and environmental applications.

Experimental and theoretical study of the oxidation of ventilation air methane over Fe2O3 and CuO.

Coal mine ventilation air methane (VAM) is an important contributor to methane emissions from the energy sector. Although various technologies are under development, treatment of the VAM with an efficient and cost-effective approach has been an ongoing challenge due to massive flow rates of the ventilation air and low and variable methane concentrations. Recently a new concept based on the principle of chemical looping combustion (CLC) has been proposed for VAM abatement (Appl. Energy, 2014, 113, 1916), in which oxidation of low-concentration CH4 balanced by N2 with Fe2O3 or CuO as the oxygen carrier was studied. Here, we thoroughly examined the feasibility of CLC of VAM based on experimental study and theoretical calculations. Reduction of Fe2O3 and CuO and evolution of gas products during CH4 oxidation were investigated using TGA-MS under two reaction atmospheres: 1 vol% CH4 balanced by N2 and the simulated VAM containing 1 vol% CH4, 20 vol% O2, 0.4 vol% CO2 and balance N2. It was found that the CLC of VAM is fundamentally infeasible because the reduced phase of Fe2O3 and CuO cannot be formed for chemical looping when reacting with the simulated VAM containing abundant oxygen. Theoretical calculations revealed that Fe2O3 and CuO remain stable without the transition to the reduced phase as the generated oxygen vacancy on the surface of metal oxides during CH4 oxidation can recover quickly with O2 adsorption and dissociation. Calculations confirmed that both Fe2O3 and CuO play a role of surface catalyst in VAM oxidation. More importantly, it was found that the low-coordinated metal atoms and oxygen vacancies can stabilize CHx radicals to promote the dissociation of CH4, which is generally the rate-determining step for CH4 oxidation. Such findings are useful for new development and understanding of high-performance and low-cost metal oxide catalysts for CH4 oxidation.

Nanostructured metal-free electrochemical catalysts for highly efficient oxygen reduction.

Replacing precious and nondurable Pt catalysts with cheap and commercially available materials to facilitate sluggish cathodic oxygen reduction reaction (ORR) is a key issue in the development of fuel cell technology. The recently developed cost effective and highly stable metal-free catalysts reveal comparable catalytic activity and significantly better fuel tolerance than that of current Pt-based catalysts; therefore, they can serve as feasible Pt alternatives for the next generation of ORR electrocatalysts. Their promising electrocatalytic properties and acceptable costs greatly promote the R&D of fuel cell technology. This review provides an overview of recent advances in state-of-the-art nanostructured metal-free electrocatalysts including nitrogen-doped carbons, graphitic-carbon nitride (g-C(3) N(4) )-based hybrids, and 2D graphene-based materials. A special emphasis is placed on the molecular design of these electrocatalysts, origin of their electrochemical reactivity, and ORR pathways. Finally, some perspectives are highlighted on the development of more efficient ORR electrocatalysts featuring high stability, low cost, and enhanced performance, which are the key factors to accelerate the commercialization of fuel cell technology.

Titanate-silica mesostructured nanocables: synthesis, structural analysis and biomedical applications.

1D hierarchical composite mesostructures of titanate and silica were synthesized via an interfacial surfactant templating approach. Such mesostructures have complex core-shell architectures consisting of single-crystalline H(2)Ti(3)O(7) nanobelts inside the ordered mesoporous SiO(2) shell, which are nontoxic and highly biocompatible. The overall diameter of as-prepared 1D hierarchical composite mesostructures is only approx. 34.2 nm with a length over 500 nm on average. A model to explain the formation mechanism of these mesostructures has been proposed; the negatively charged surface of H(2)Ti(3)O(7) nanobelts controls the formation of the octadecyltrimethylammonium bromide (C(18)TAB) bilayer, which in turn regulates the cooperative self-assembly of silica and C(18)TAB complex micelles on the interface to produce a mesoporous silica shell. More importantly, the application of synthesized mesostructured nanocables as anticancer drug reservoirs has also been explored, which indicates that the membranes containing these mesoporous nanocables have a great potential to be used as transdermal drug delivery systems.

[Effect of different surgical methods on leprosy plantar ulcers].

OBJECTIVE: To explore the effects of different surgical methods on plantar ulcers in leprosy. METHODS: The clinical data of 71 patients with leprosy plantar ulcers and treated with different surgical methods between October 1950 and October 2006 were analyzed retrospectively. In group A, 34 cases underwent debridement, including 26 males and 8 females aged 53-88 years old (average 72.4 years old); the course of ulcer averaged 29.0 years; the size of ulcer ranged from 5 cm x 3 cm x 2 cm to 11 cm x 7 cm x 3 cm; the disability degrees of the affected foot was mild in 25 cases and severe in 9 cases according to the self-designed evaluation system. In group B, 22 cases received foot pressure rebuilding surgery, including 19 males and 3 females aged 48-83 years old (average 69.8 years old); the course of ulcer averaged 33.5 years; the size of ulcer ranged from 5 cm x 3 cm x 2 cm to 12 cm x 7 cm x 3 cm; the disability degrees of the affected foot was mild in 12 cases and severe in 10 cases. In group C, 15 cases were repaired with the transposition of toe flap, foot arch flap, acrotarsium flap, or medial tibia flap, including 11 males and 4 females aged 43-73 years old (average 64.6 years old); the course of ulcer averaged 29.3 years; the size of ulcer ranged from 6 cm x 3 cm x 2 cm to 11 cm x 5 cm x 3 cm; the disability degrees of the affected foot was mild in 9 cases and severe in 6 cases. No significant differences were evident among three groups in terms of the general information (P > 0.05), except for the difference between group A and group C on age (P < 0.05). RESULTS: Group A: 19 out of 34 cases healed and the average healing time was 46.8 days; all patients were followed up for 2-45 years (average 17.2 years); the rate of ulcer healing 1 year after operation was 55.9% (19/34); 12 healed ulcer patients relapsed at average 1.5 years after operation; the rate of ulcer healing at last follow-up was 20.6% (7/34). Group B: 18 out of 22 cases healed and the average healing time was 29.2 days; all patients were followed up for 2-50 years (average 13.3 years); the rate of ulcer healing 1 year after operation was 81.8% (18/22); 7 healed ulcer patients relapsed at average 3.3 years after operation; the rate of ulcer healing at last follow-up was 50.0% (11/22). Group C: 14 out of 15 cases healed and the average healing time was 27.1 days; all patients were followed up for 3-12 years (average 8.8 years). The rate of ulcer healing 1 year after operation was 93.3% (14/15); 7 healed ulcer patients relapsed at average 4 years after operation; the rate of ulcer healing at final follow-up was 46.7% (7/15). For the rate of ulcer healing 1 year after operation, there was a significant difference between group A and group B, and between group A and group C (P < 0.05), but no significant difference was evident between group B and group C (P > 0.05). For the rate of ulcer healing at the final follow-up visit, there was a significant difference between group A and group B (P < 0.05), but no significant difference was evident between group A and group C, and between group B and group C (P > 0.05). CONCLUSION: The surgical treatment of plantar ulcers in leprosy should include the alleviation of the plantar high-pressure zone and the transposition of the flaps, providing good short-term and long-term therapeutic effect.

Surface charging of layered double hydroxides during dynamic interactions of anions at the interfaces.

In this research, we investigated the effect of dynamic anion adsorption/exchange on the surface charging property of Mg(2)AlClLDH and Mg(2)AlCO(3)LDH particles that show the average zeta potential of 41 and 34 mV in the as-prepared suspension, respectively. The addition of NaCl up to 3x10(-3) M in the suspension does not obviously affect the zeta potential of both LDHs, which can be attributed to the less affinity of Cl(-) to LDH. The introduction of Na(2)CO(3) severely reduces the zeta potential at the CO(3)(2-) concentration higher than 1x10(-4) M, and to the negative value in both LDH systems at ca. 2x10(-3) M, which is presumably resulted from the exchange and the re-orientation of CO(3)(2-) in a tilt/vertical style on the surface. All four organic anions (dodecyl sulfate, folate, citrate and polyacrylate) also significantly affect the zeta potential of the LDH particles. At the lower concentrations of organic anionic groups (<1x10(-4) M), the zeta potential was slightly affected, i.e. limited exchange/adsorption. However, the concentration increasing to some point suddenly decreases and reverses the zeta potential of the LDH particles, which is presumably caused by the hydrophobic interactions that bind the hydrophobic hydrocarbon chains (especially in dodecyl sulfate) into the micelle-like bilayer bunches on the LDH surface. In addition, the effect of pH in 5.5-11.0 on the LDH particle surface charging is mainly reflected through the conversion of CO(3)(2-) to HCO(3)(-)/H(2)CO(3) when pH decreases from ca. 11 to 6, with limited contribution from protonation/deprotonation and exchange/adsorption.