Safety and efficacy of remote ischemic conditioning in adult moyamoya disease patients undergoing revascularization surgery: a pilot study.

Background and purpose: Revascularization surgery for patients with moyamoya disease (MMD) is very complicated and has a high rate of postoperative complications. This pilot study aimed to prove the safety and efficacy of remote ischemic conditioning (RIC) in adult MMD patients undergoing revascularization surgery. Methods: A total of 44 patients with MMD were enrolled in this single-center, open-label, prospective, parallel randomized study, including 22 patients assigned to the sham group and 22 patients assigned to the RIC group. The primary outcome was the incidence of major neurologic complications during the perioperative period. Secondary outcomes were the modified Rankin Scale (mRS) score at discharge, at 90 days post-operation, and at 1 year after the operation. The outcome of safety was the incidence of adverse events associated with RIC. Blood samples were obtained to monitor the serum concentrations of cytokines (VEGF, IL-6). Results: No subjects experienced adverse events during RIC intervention, and all patients could tolerate the RIC intervention in the perioperative period. The incidence of major neurologic complications was significantly lower in the RIC group compared with the control group (18.2% vs. 54.5%, P = 0.027). The mRS score at discharge in the RIC group was also lower than the control group (0.86 ± 0.99 vs. 1.18 ± 1.22, P = 0.035). In addition, the serum IL-6 level increased significantly at 7 days after bypass surgery in the control group and the serum level of VEGF at 7 days post-operation in the RIC group. Conclusion: In conclusion, our study demonstrated the neuroprotective effect of RIC by reducing perioperative complications and improving cerebral blood flow in adult MMD patients undergoing revascularization surgery. Thus, RIC seems to be a potential treatment method for MMD. Clinical trial registration: ClinicalTrials.gov, identifier: NCT05860946.

Quenching as a Route to Defect-Rich Ru-Pyrochlore Electrocatalysts toward the Oxygen Evolution Reaction.

Defects have a significant impact on the electrocatalysts performance. Introducing defect structures in metal oxides such as pyrochlores and perovskites has proved to be an effective strategy to enhance electrocatalytic activity. However, it is hard to build numerous defect sites in such high-temperature oxides due to the strong metal-oxygen bonds and the so-called self-purification effect, which becomes increasingly important as the particle size reduced to the nanoscale. Here, a facile strategy is demonstrated to fabricate defect-rich yttrium ruthenate oxides Y2 Ru2 O7- δ with the pyrochlore structure (denoted Drich -YRO) by the liquid nitrogen (<-196 °C) quenching. Owing to the almost instantaneous cooling in oxygen-deficient condition, a large number of defects-including oxygen vacancies, grain boundaries, pores and surficial disorder-are preserved in the room temperature material and act as electrocatalytic active sites for oxygen evolution. As a result, Drich -YRO shows excellent catalytic activity and high electrochemical stability, along with a high performance in the operation of proton exchange membrane electrolyzer. The quenching strategy employed in this work provides a facile approach for constructing defect-rich structures in high-temperature oxides and should lead to new applications in energy conversion and storage devices for such materials.

Application of intraoperative electrocorticography in bypass surgery for adult moyamoya disease: a preliminary study.

OBJECTIVE: Postoperative complications of surgical revascularization in moyamoya disease (MMD) are difficult to predict because of poor knowledge of the underlying pathophysiological process. Since the aim of surgery is to improve brain dynamics by increasing regional blood flow, we hypothesize that postoperative complications are closely related to aberrant electrophysiological changes. Thus, we evaluated the clinical significance of intraoperative electrocorticography (iECoG) in bypass surgery for adult MMD. METHODS: Ninety-one adult patients operated on by the same neurosurgeon in our institute were involved (26 in the iECoG group, 65 in the traditional group). Two 1 × 6 subdural electrode grids were placed parallel to the middle frontal gyrus and superior temporal gyrus to record ECoG data continuously during the procedure in the iECoG group. Selected from several M4 candidate arteries, the recipient artery was determined to be closer to the cortex with lower power spectral density (PSD) in the beta band. The PSD parameter we used was the (delta+theta)/(alpha+beta) (DTAB) ratio (DTABR). Next, the pre- and post-bypass PSD values were evaluated, and correlations between post-/pre-bypass PSD parameter ratios and neurological/neuropsychological performance (in terms of changes in National Institutes of Health Stroke Scale [NIHSS] and Mini-Mental State Examination [MMSE] scores) were analyzed. RESULTS: Postoperative complications (transient neurological events) in the iECoG group were significantly lower than those in the traditional group (p = 0.046). In the iECoG group, the post-/pre-bypass DTABR ratio in the bypass area was significantly correlated with postoperative NIHSS (p = 0.002, r2 = 0.338) and MMSE changes (p = 0.007, r2 = 0.266). In the nonbypass area, neither postoperative NIHSS nor MMSE changes showed a significant correlation with the post-/pre-bypass DTABR ratio (p > 0.05). Additionally, patients with postoperative complications exhibited significantly higher DTABR (1.67 ± 0.33 vs. 0.95 ± 0.08, p = 0.003) and PSD of the theta band (1.54 ± 0.21 vs. 1.13 ± 0.08, p = 0.036). CONCLUSIONS: This study is the first to explain and guide surgical revascularization from the perspective of electrophysiology. Intraoperative ECoG is not only sensitive in reflecting and predicting postoperative neurological and cognitive performance but also usable as a reference for recipient artery selection.

Recent advances in electrocatalysis with phthalocyanines.

Applications of phthalocyanines (Pcs) in electrocatalysis-including the oxygen reduction reaction (ORR), the carbon dioxide reduction reaction (CO2RR), the oxygen evolution reaction (OER), and the hydrogen evolution reaction (HER)-have attracted considerable attention recently. Pcs and their derivatives are more attractive than many other macrocycles as electrocatalysts since, although they are structurally related to natural porphyrin complexes, they offer the advantages of low cost, facile synthesis and good chemical stability. Moreover, their high tailorability and structural diversity mean Pcs have great potential for application in electrochemical devices. Here we review the structure and composition of Pcs, methods of synthesis of Pcs and their analogues, as well as applications of Pc-based heterogeneous electrocatalysts. Optimization strategies for Pc-based materials for electrocatalysis of ORR, CO2RR, OER and HER are proposed, based on the mechanisms of the different electrochemical reactions. We also discuss the structure/composition-catalytic activity relationships for different Pc materials and Pc-based electrocatalysts in order to identify future practical applications. Finally, future opportunities and challenges in the use of molecular Pcs and Pc derivatives as electrocatalysts are discussed.

Intermetallic FePt@PtBi Core-Shell Nanoparticles for Oxygen Reduction Electrocatalysis.

The development of active and stable platinum (Pt)-based oxygen reduction reaction (ORR) electrocatalysts with good resistance to poisoning is a prerequisite for widespread practical application of fuel cells. An effective strategy for enhancing the electrocatalytic performance is to tune or control the physicochemical state of the Pt surface. Herein, we show a general surface-engineering approach to prepare a range of nanostructured Pt alloys by coating with alloy PtBi shells. FePt@PtBi core-shell nanoparticles showed the best ORR performance with a mass activity of 0.96 A mgPt -1 and a specific activity of 2.06 mA cm-2 , respectively 7 times and 11 times those of the corresponding values for benchmark Pt/C. Moreover, FePt@PtBi shows much better tolerance to methanol and carbon monoxide than conventional Pt-based electrocatalysts. The observed comprehensive enhancement in ORR performance of FePt@PtBi can be attributed to the increased compressive strain of the Pt surface due to in-plane shearing resulting from the presence of the large Bi atoms in the surface-structured PtBi overlayers, as well as charge displacement via Pt-Bi bonding which mitigates crossover issues.

Edge-Functionalized Polyphthalocyanine Networks with High Oxygen Reduction Reaction Activity.

Two-dimensional (2D) conjugated aromatic networks (CAN) have been fabricated by ball milling of polymeric cobalt phthalocyanine precursors edge-functionalized with different aromatic acid anhydride substituents. The optimal CAN, obtained by using tetraphenylphthalic anhydride, consists of uniform and thin (2.9 nm) layers with a high BET surface (92 m2 g-1), resulting in well-defined Co-N4 active sites with a high degree of exposure. Thence, this material exhibits excellent electrocatalytic oxygen reduction reaction (44 mA mgcat.-1). Compared to a benchmark Pt/C catalyst, this value denotes 1.2- and 6.0-fold enhancements, respectively, in terms of the mass of Pt and total Pt/C. When utilized as air electrode catalysts in Zn-air batteries, this material provides a maximum areal power density (137 mW cm-2) and mass power density (0.68 W mgcat.-1), values which also clearly surpass those of benchmark Pt/C catalyst. This support-free and pyrolysis-free strategy developed in this work delivers a novel route for the applications of 2D materials in clean energy conversion and storage.

Evaluation of Hemodynamic Change by Indocyanine Green-FLOW 800 Videoangiography Mapping: Prediction of Hyperperfusion Syndrome in Patients with Moyamoya Disease.

OBJECTIVE: Hyperperfusion syndrome (HPS) after bypass surgery for moyamoya disease (MMD) mainly results from redistribution of blood flow, which leads to poor outcomes, while effective methods to predict HPS are still lacking. Indocyanine green (ICG) videoangiography can assess regional cerebral blood flow changes semiquantitatively with the application of FLOW 800 software. The purpose of this study was to investigate whether the intraoperative evaluation of local hemodynamic changes around anastomotic sites using FLOW 800 videoangiography mapping can predict the incidence of HPS and clinical outcomes. METHODS: Of the patients who were diagnosed with MMD in our hospital between August 2018 and December 2019, who underwent superficial temporal artery-middle cerebral artery bypass surgeries, we investigated 65 hemispheres (in 62 patients) in which intraoperative ICG analysis was performed using FLOW 800 (Zeiss Meditec, Oberkochen, Germany) to evaluate the local cerebral hemodynamics before and after anastomosis. Regions of interest were set at more than 2 points on the brain surface according to the location and situation of recipient arteries in the surgical area. Peak cerebral blood volume (CBV), regional cerebral blood flow (CBF), and time to peak (TTP) were calculated from the selected points. As the data were available intraoperatively, anastomoses were performed in a suitable area. According to the occurrence of HPS, patients were divided into the asymptomatic and symptomatic groups, from which hemodynamic parameters were compared. Furthermore, ROC analysis was performed to determine the diagnostic accuracy of change rates in CBV, CBF, and TTP (i.e., ΔCBV, ΔCBF, and ΔTTP) for predicting HPS. RESULTS: Data from the 62 patients were analyzed, and all patients were closely assessed during hospitalization after the procedures. The values of ΔCBV and ΔCBF were significantly higher in the symptomatic group (p < 0.01), while ΔTTP is slightly lower in the symptomatic group with no statistical differences (p = 0.72). Hemodynamic parameters including ΔCBV and ΔCBF, calculated by FLOW 800, had high sensitivity and specificity according to the ROC curve (ΔCBV: AUC = 0.743, 95% CI, 0.605-0.881, p = 0.002; ΔCBF: AUC = 0.852, 95% CI, 0.750-0.954, p < 0.01), which could be used as predictors for HPS. CONCLUSIONS: Intraoperative ICG-FLOW 800 videoangiography mapping is a safe method which can reflect hemodynamic characteristics in the surgical area for MMD, the findings of which correlate with the occurrence of HPS. Parameters including ΔCBV and ΔCBF are proven to be efficient in the prediction of HPS.

Metal-Organic-Framework-Derived Co2 P Nanoparticle/Multi-Doped Porous Carbon as a Trifunctional Electrocatalyst.

Developing efficient and low-cost replacements for precious metals as electrocatalysts active in electrochemical reactions-the oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR)-is a top priority in renewable energy technology. In this work a highly active and very stable trifunctional electrocatalyst composed of Co2 P embedded in Co, N, and P multi-doped carbon has been synthesized using zeolitic imidazolate frameworks as precursors. The synergistic effects between Co2 P and the multi-heteroatom-doped carbon substrates afford materials having electrocatalytic activities for HER, OER, and ORR, which are comparable-or even superior to-those of commercial RuO2 or Pt/C catalysts. Density functional theory calculations show that Co2 P has a higher density of states at the Fermi level than Con P (0 < n < 2), which promotes electron transfer and intermediates adsorption in the catalytic process. Zinc-air batteries and water splitting devices assembled using the materials as electrode electrocatalysts show good performance and outstanding stability. This work represents a breakthrough in improving the catalytic performance of non-precious metal electrocatalysts for OER, HER, and ORR, and opens new avenues for clean energy generation.

Two-Dimensional Conjugated Aromatic Networks as High-Site-Density and Single-Atom Electrocatalysts for the Oxygen Reduction Reaction.

Two-dimensional conjugated aromatic networks (CAN) with ultra-thin conjugated layers (ca. 3.5 nm) and high single-metal-atom-site density (mass content of 10.7 wt %, and 0.73 metal atoms per nm2 ) are prepared via a facile pyrolysis-free route involving a one-step ball milling of the solid-phase-synthesized polyphthalocyanine. These materials display outstanding oxygen reduction reaction (ORR) mass activity of 47 mA mgcat. -1 represents 1.3- and 6.4-fold enhancements compared to Pt and Pt/C in benchmark Pt/C, respectively. Moreover, the primary Zn-air batteries constructed with CAN as an air electrode demonstrate a mass/volume power density of 880 W gcat. -1 /615 W cmcat. -3 and stable long-term operation for 100 h. This strategy offers a new way to design high-performance electrocatalysts with atomic precision for use in other energy-storage and conversion applications.

Sustainable Carbonaceous Materials Derived from Biomass as Metal-Free Electrocatalysts.

Although carbon is the second most abundant element in the biosphere, a large proportion of the available carbon resources in biomass from agriculture, stock farming, ocean fisheries, and other human activities is currently wasted. The use of sustainable carbonaceous materials as an alternative to precious metals in electrocatalysis is a promising pathway for transforming sustainable biomass resources into sustainable energy-conversion systems. The development of rational syntheses of metal-free carbonaceous catalysts derived from sustainable biomass has therefore become a topic of significant interest in materials chemistry. However, great efforts are still required to develop methods that are low cost, scalable, and environmentally friendly and which afford carbonaceous materials having an electrocatalytic performance comparable to, or even better than, existing precious metal catalysts. Herein, recent achievements in developing metal-free carbonaceous catalysts based on biomass are reviewed and discussed and the critical issues which still need to be addressed are highlighted. The focus is on representative synthesis and optimization strategies applicable to different kinds of biomass, as well as studies of the physicochemical structure and electrochemical performance of the resulting metal-free carbonaceous catalysts. Finally, some guidelines for the future development of this important area are provided.

Tunable non-equilibrium gating of flexible DNA nanochannels in response to transport flux.

Biological nanochannels made from proteins play a central role in cellular signalling. The rapid emergence of DNA nanotechnology in recent years has opened up the possibility of making similar nanochannels from DNA. Building on previous work on switchable DNA nanocompartment, we have constructed complex DNA nanosystems to investigate the gating behaviour of these nanochannels. Here we show that DNA nanochannels can be gated by stress exerted by permeating solute particles at non-equilibrium states due to the high flexibility of the nanochannels. This novel gating mechanism results in tunable ratchet-like transport of solute particles through the nanochannels. A simple model that couples non-equilibrium channel gating with transport flux can quantitatively explain a number of the phenomena we observe. With only one set of model parameters, we can reproduce diverse gating behaviours, modulated by an inherent gating threshold. This work could lead to the development of new devices based on DNA nanochannels.