Aromatic Ethers Induced Electronic Structure Reconstruction on Encapsulated Nickel Catalysts for High-Performance Catalytic Hydrogenation.

Carbon-encapsulated metal (CEM) catalysts effectively address supported metal catalyst instability by protecting the active metal with a shell. However, mass transfer limitations lead to reduced activity for catalytic hydrogenation reaction over most CEM catalysts. Herein, we introduce a dopant strategy aimed at incorporating nickel metal within graphene-like shells (GLS) featuring oxygen-containing functional groups (OFGs). The core of this strategy involves precise control of GLS modification and the demonstrated pivotal influence of aromatic ether linkages (═C-O-C) in GLS for significant enhancement of catalytic performance. The introduction of ═C-O-C into GLS with stability was beneficial to improve the work function of the catalyst and promoted electron transmission from Ni metal core to GLS, further elevating the catalytic activity, based on the Mott-Schottky effect. In addition, the experimental characterization and density functional theory (DFT) calculations showcased that the ═C-O-C reconstructed the electronic state of GLS, imparting it highly specific for the adsorption of hydrogen and para-chloronitrobenzene (p-CNB) to obtain para-chloroaniline (p-CAN) with high selectivity. This work manifested a feasible direction for the precise modulation and design of the OFGs in CEM catalysts to achieve highly efficient catalytic hydrogenation.

Iron-Based Catalysts with Oxygen Vacancies Obtained by Facile Pyrolysis for Selective Hydrogenation of Nitrobenzene.

The development of preparation strategies for iron-based catalysts with prominent catalytic activity, stability, and cost effectiveness is greatly significant for the field of catalytic hydrogenation but still remains challenging. Herein, a method for the preparation of iron-based catalysts by the simple pyrolysis of organometallic coordination polymers is described. The catalyst Fe@C-2 with sufficient oxygen vacancies obtained in specific coordination environment exhibited superior nitro hydrogenation performance, acid resistance, and reaction stability. Through solvent effect experiments, toxicity experiments, TPSR, and DFT calculations, it was determined that the superior activity of the catalyst was derived from the contribution of sufficient oxygen vacancies to hydrogen activation and the good adsorption ability of FeO on substrate molecules.

Occurrence of ventricular septal perforation in patients with permanent left bundle branch pacing followed up using echocardiographic and computed tomography images.

OBJECTIVE: To explore short-term changes after left bundle branch pacing (LBBP) using echocardiography and computed tomography (CT), especially for postoperative ventricular septal perforation. METHODS: Between January and September 2019, 33 patients with atrioventricular block underwent LBBP at Beijing Anzhen Hospital. All the patients were evaluated using electrocardiography, pacing, parameters and echocardiographic measurements, including for major complications, during the 1, 3, 6, 12 and 24-month follow-up. Interval perforations were examined during a 1-month follow-up echocardiogram and CT. RESULTS: Left bundle branch pacing was successfully performed in 100% (33/33) of patients. The mean seizure threshold was stable and unchanged postoperatively at the 1, 3, 6, 12 and 24-month follow-up. The paced QRS duration of the LBBP was 119.72 ± 2.53 ms and <130 ms in all patients. Unipolar impedance during the procedure was higher than 500 Ω (662.00 ± 181.50 Ω). No ventricular septal perforation occurred at the end of the procedure. At the 1-month follow-up, two patients reported transthoracic echocardiography, with CT revealing septal lead perforation. Through CT, two other patients were found to have septal lead perforation, and echocardiography indicated that the pacing lead had penetrated the interventricular septum and entered the left subendocardium. At the 1, 3, 6, 12 and 24-month follow-up, these four patients exhibited no significant increase in pacing threshold or impedance (p > .05). No ventricular thrombus or stroke was detected. CONCLUSION: Permanent LBBP is safe and feasible in patients with bradycardia. Echocardiography and/or CT can more accurately evaluate changes in cardiac structure and function after LBBP.

Photocatalytic oxidation of NO on reduction type semiconductor photocatalysts: effect of metallic Bi on CdS nanorods.

We report the first visible light photocatalytic oxidation of NO on CdS nanorods (CdS-NRs), one of the typical reduction type semiconductor photocatalysts. The NO removal rate in a continuous reactor sharply increases from 44% to 58% after in situ deposition of Bi nanoplates on CdS-NRs. The LSPR effect of metallic Bi causes the dramatic production of superoxide radicals (˙O2-) and singlet oxygen (1O2) that are responsible for the oxidation of NO.

Initial experience with ablation of the innervation surrounding sinus and atrioventricular nodes to treat paroxysmal bradyarrhythmia.

BACKGROUND: The symptomatic bradyarrhythmia is Class I indication for pacing therapy which is not a radical cure. The present study aimed to assess the feasibility and to present the initial results of the restricted ablation of the parasympathetic innervation surrounding sinus and atrioventricular (AV) nodes for treating patients with bradyarrhythmia. METHODS: A total of 13 patients with cardiogenic syncope were included from May 2008 to June 2015. Under the guidance of fluoroscopy and /or three-dimensional geometry by 64-slice spiral computed tomography, atrial activation sequence in sinus rhythm was mapped. Chamber geometry was reconstructed manually or automatically using the Niobe II magnetic navigation system integrated with the CARTO-remote magnetic technology (RMT) system. Cardioneuroablation was targeted at the high-amplitude fractionated electrograms surrounding the regions of His bundle and the site with the earliest activation in sinus rhythm. Areas surrounding the sinus node, AV node, and the phrenic nerve were avoided. RESULTS: Thirteen patients completed the studies. Ablation was successfully performed in 12 patients and failed in one. The high-frequency potential was recorded in atrial electrograms surrounding the sinus or AV nodes in all the patients and disappeared in 15 s after radiofrequency applications. The vagal reaction was observed before the improvement of the sinus and AV node function. No complications occurred during the procedures. Patients were followed up for a mean of 13.0 ±â€Š5.9 months. During the follow up ten patients remained free of symptoms, and two patients had a permanent cardiac pacemaker implanted due to spontaneous recurrence of syncope. The heart rate of post-ablation was higher than pre-ablation (69.0 ±â€Š11.0 vs. 49.0 ±â€Š10.0 beats/min, t = 4.56, P = 0.008). The sinus node recovery time, Wenckebach block point, and atrium-His bundle interval were significantly shorter after ablation (1386.0 ±â€Š165.0 vs. 921.0 ±â€Š64.0 ms, t = 7.45, P = 0.002; 590.0 ±â€Š96.0 vs. 464.0 ±â€Š39.0 ms, t = 2.38, P = 0.023; 106.0 ±â€Š5.0 vs. 90.0 ±â€Š12.0 ms, t = 9.80, P = 0.013 before and after ablation procedure, respectively). CONCLUSIONS: Ablation of sinoatrial and AV nodal peripheral fibrillar myocardium electrical activity might provide a new treatment to ameliorate paroxysmal sinus node dysfunction, high degree AV block, and vagal-mediated syncope.

Microwave assisted combustion of phytic acid for the preparation of Ni2P@C as a robust catalyst for hydrodechlorination.

Ni2P@C facilely prepared by microwave assisted combustion with phytic acid and nickel nitrate followed by reduction at 650 °C exhibits even higher activity for the hydrodechlorination of HCFC-22 than Pd/C. This method is also applicable for the synthesis of other metal phosphides, providing a versatile method for the fabrication of carbon encapsulated metal phosphide particles.

In Situ Incorporation of Diamino Silane Group into Waterborne Polyurethane for Enhancing Surface Hydrophobicity of Coating.

A series of waterborne polyurethanes (WPU) with crosslinked siloxane were obtained through introducing 3-(2-aminoethylamino)propyldimethoxymethylsilane (APTS) into WPU by in situ polymerization. The properties of WPU modified by APTS were studied through a variety of experimental methods. The water contact angle of the WPU coating surface increased from 64° to 86°, and the water resistance reduced to 3.90% when 3 wt% APTS was added, which improved the coating surface hydrophobicity. Firstly, Fourier transform infrared (FT-IR) and 1H-NMR spectra demonstrated the successful incorporation of APTS to polyurethanes and completed the hydrolytic condensation reaction-generated Si-O-Si crosslinking structure. Furthermore, the surface energy of the membrane was reduced when the crosslinking structure migrated and enriched on the surface of film. Besides, the crosslinking structure was abundant, and the distribution of siloxane in WPU was more uniform.

Surface-Group-Oriented, Condensation Cyclization-Driven, Nitrogen-Doping Strategy for the Preparation of a Nitrogen-Species-Tunable, Carbon-Material-Supported Pd Catalyst.

A nitrogen-carbon framework with the thickness of several molecules was fabricated through a straightforward nitrogen-doping strategy, in which specially designed surface-oxygen-containing groups (SOGs) first introduced onto the porous carbon support were used to guide the generation of a surface-nitrogen-containing structure through condensation reactions between SOGs and the amidogen group of organic amines under hydrothermal conditions. The results indicate that different kinds of SOGs generate different types and abundances of N species. The CO-releasing groups are apt to form a high proportion of amino groups, whereas the CO2-releasing groups, especially carboxyl and lactones, are mainly transformed into pyrrolic-type nitrogen. In the framework with dominant pyrrolic-type nitrogen, an electron-rich Pd activated site composed of Pd, pyrrolic-type N and C is built, in which electron transfer occurs from N to C and Pd atoms. This activated site contributes to the formation of electron-rich activated hydrogen and desorption of p-chloroaniline, which work together to achieve the superior selectivity about 99.90 % of p-chloroaniline and the excellent reusable performance. This strategy not only provides low-cost, nitrogen-doped carbon materials, but also develops a new method for the fabrication of different kinds of nitrogen species structures.

Highly efficient hydrogen peroxide direct synthesis over a hierarchical TS-1 encapsulated subnano Pd/PdO hybrid.

We report a hierarchical TS-1 encapsulated subnano Pd/PdO hybrid catalyst that shows unprecedented activity in H2O2 direct synthesis from H2 and O2. The macro reaction rate in 30 min is up to 35 010 mmol gPd -1 h-1 at ambient temperature. Such high catalytic activity is achieved due to the hierarchical porous structure of TS-1 and the formation of the encapsulated subnano Pd/PdO hybrid after oxidation/reduction/oxidation treatment.

High volume practice proved the safety of off-pump coronary artery bypass surgery in left main coronary artery lesions: a two-year single center experience.

BACKGROUND: Left main coronary artery (LMCA) stenosis has been recognized as a risk factor for early death among patients undergoing coronary artery bypass grafting (CABG). This study aimed to assess if LMCA lesions pose an additional risk of early or mid-term mortality and/or a major adverse cardiac and cerebrovascular event (MACCE) after off-pump coronary artery bypass grafting (OPCABG), compared with non-left main coronary artery stenosis (non-mainstem disease). METHODS: From January 1, 2009 to December 31, 2010, 4869 patients had a primary isolated OPCABG procedure at Beijing Anzhen Hospital. According to the pathology of LMCA lesions, they were retrospectively classified as a non-mainstem disease group (n = 3933) or a LMCA group (n = 936). Propensity scores were used to match the two groups, patients from the non-mainstem disease group (n = 831) were also randomly selected to match patients from the LMCA group (n = 831). Freedom from MACCE in the two groups was calculated using the Kaplan-Meier method. RESULTS: The difference in the mortality and the rate of MACCE during the first 30 days between the non-mainstem disease group and the LMCA group did not reach statistical significance (P = 0.429, P = 0.127 respectively). With a mean follow-up of (12.8 ± 7.5) months and a cumulative follow-up of 1769.6 patient-years, the difference in the freedom from MACCEs between the two groups, calculated through Kaplan-Meier method, did not reach statistical significance (P = 0.831). CONCLUSION: Analysis of a high volume of OPCABG procedures proved that LMCA lesions do not pose additional early and mid-term risk to OPCABG. Therefore, a LMCA lesion is as safe as non-mainstem disease lesion during the OPCABG procedure.

N-heterocyclic carbene catalyzed direct carbonylation of dimethylamine.

N-Heterocyclic carbene (NHC) catalyzed direct carbonylation of dimethylamine leading to the formation of DMF was successfully accomplished under metal-free conditions. The catalytic efficiency was investigated and the turnover numbers can reach as high as >300. The possible mechanism was also proposed.

Ablation of ligament of Marshall attenuates atrial vulnerability to fibrillation induced by inferior left atrial fat pad stimulation in dogs.

BACKGROUND: The role of ligament of Marshall (LOM) in the mechanism of "vagal" atrial fibrillation (AF) is still unknown. OBJECTIVE: To investigate the impact of LOM ablation on atrial vulnerability to AF induced by inferior left atrial fat pad (ILAFP) stimulation in dogs. METHODS: AF inducibility and atrial effective refractory period (ERP) were elevated before and after LOM ablation in 8 of 14 dogs (the ablation group). Same protocol but without LOM ablation was conducted in the remaining 6 dogs (the control group). The activation patterns of LOM and left pulmonary veins (LPVs) during sustained AF were analyzed. The distribution of epicardial cholinergic nerve fibers between LOM and ILAFP was investigated in the control group. RESULTS: Ablation of LOM significantly attenuated AF inducibility (87.5% vs 33.3%, P < 0.001) and prolonged ERPs of the structures in contiguity with LOM (P < 0.05) in the ablation group. In contrast, there was no significant change in ERPs and AF inducibility in the control group. During sustained AF, fractionated atrial electrograms were more common in the LOM area than the LPVs (84% vs 18% of the analyzed episodes, P < 0.001). In 46.7% of the episodes with identifiable LOM spikes, atrial potentials, and LOM spikes were related in 2:1 or 3:2 pattern during the intermittent organized activity. Acetylcholinesterase staining revealed a close cholinergic nerved relationship between LOM and ILAFP. CONCLUSIONS: LOM plays a critical role in maintaining AF induced by stimulation of ILAFP. Ablation of LOM can markedly attenuate AF inducibility in this model.

CuCl/CCl(4)-promoted convenient synthesis of sulfonyl amidines from tertiary amines and sulfonyl azides.

Promoted by CuCl/CCl(4), a variety of sulfonyl azides and tertiary amines were successfully coupled to give sulfonyl amidine derivatives in good to excellent yields. A possible mechanism for this reaction is discussed.

[Determination of 49 pesticide residues in tobacco by gas chromatography-tandem mass spectrometry].

A method was developed for rapid determination of 49 pesticide residues in tobacco based on gas chromatography-tandem mass spectrometry (GC-MS/MS). Tobacco was extracted with 0.1% acetic acid-acetonitrile solution. The supernatant was quantitatively transferred and dried with nitrogen. The concentrated extract was dissolved with acetonitrile-ethyl acetate (1 : 1, v/v) solution and cleaned up by primary secondary amine (PSA) sorbents, MgSO4 and C18 sorbents, then determined by GC-MS/MS with mirex as internal standard. The ranges of spiked recoveries of 49 pesticides at 0.05 microg/L and 5 microg/L were 60.4%-104.8% and 70%-115% , respectively. The relative standard deviations were below 15%. The detection limits of 16 pesticides were 0.01-0.03 microg/kg and those of the other 33 pesticides were less than 0.01 microg/kg; the correlation coefficients were larger than 0.991. This method is simple, rapid and characterized with acceptable sensitivity and accuracy to meet the requirements for the analysis of multiple pesticide residues in tobacco.

[Asymptomatic recurrence of atrial tachy-arrhythmia after circumferential pulmonary vein isolation in patients with atrial fibrillation].

OBJECTIVE: To investigate the incidence, type, and predictors of asymptomatic relapse of atrial tachy-arrhythmia (ATa) after circumferential pulmonary vein isolation (CPVI) in patients with atrial fibrillation (AF). METHODS: Forty-eight consecutive patients with AF underwent CPVI and were followed up. Forty-eight hours Holter recording was performed 1, 3, and 6 months respectively after the initial CPVI procedure. Predictors of asymptomatic ATa relapse were determined by Logistic regression analysis for eight variables as follows: age, gender, AF type, existence of organic heart disease, diameter of left atria, left ventricular ejection fraction, procedure time, and heart rate variability after the procedure. RESULTS: Complete Holter data were acquired in 42 patients, 26 males and 16 females, aged: 58 +/- 14, including 25 patients with paroxysmal AF and 17 with non-paroxysmal AF. The standard deviations of R-R interval (SDNN) of the non-paroxysmal AF group was 92 ms +/- 19 ms, significantly longer than that of the paroxysmal AF group (78 ms +/- 15 ms, P = 0.011). The incidence of asymptomatic ATa recurrence rates 1, 3 and 6 months after CPVI were 8%, 12%, and 8% respectively in paroxysmal AF group and 23.5%, 29.4%, and 35.3% respectively in the non-paroxysmal AF group. The incidence of asymptomatic ATa recurrence 6 months after CPVI in the non-paroxysmal AF group was significant higher than that in the paroxysmal AF group (P < 0.05). AF was the dominant arrhythmia among the asymptomatic recurrence ATa, while atrial tachycardia constituted the major arrhythmia of the symptomatic recurrent ATa. CONCLUSION: (1) Asymptomatic ATa relapse is common among the patients undergoing CPVI. (2) The dominant type of asymptomatic recurrent arrhythmia is AF. (3) The independent predictors for asymptomatic ATa recurrence include non-paroxysmal AF, left atrial enlargement, and increase of SDNN.

Can pulmonary vein antrum be defined by electrophysiological mapping?

Atrial fibrillation (AF) is the most common sustained arrhythmia, and treatments with anti-arrhythmia drugs (AADs) have been frustrating. Limitations of AADs prompted the development of percutaneous catheter ablation. In contrast to AADs, percutaneous catheter ablation offers the possibility of a lasting cure. The successful cure of AF by percutaneous catheter ablation comes from a widespread recognize that pulmonary vein antrum (PVA) plays an important role in the genesis and maintenance of AF, and circular ablation along the PVA can eliminate majority of AF. PVA is comprised of pulmonary vein-left atrium junctions. However, during ablation procedure, definition of PVA solely depends on angiography, and it is largely experience-dependent and there is a great deal of variation involved. Our study in patients with AF found that a unique potential with double deflections could be documented along PVA, but it cannot be recorded at PV side or LA side. Thus, we propose that documentation of PVA potentials can be used as a landmark to define PVA. Unlike angiography, documentation of PVA potentials can be objectively carried out by different operators, and the variations due to experience can be avoided.

Is circumferential pulmonary vein isolation preferable to stepwise segmental pulmonary vein isolation for patients with paroxysmal atrial fibrillation?

BACKGROUND: Stepwise segmental pulmonary vein isolation (SPVI) and circumferential pulmonary vein isolation (CPVI) have been developed to treat patients with atrial fibrillation (AF), but the preferable approach for paroxysmal AF (PAF) has not been established. METHODS AND RESULTS: One hundred and ten patients with symptomatic PAF were randomized into a stepwise SPVI group (n=55) or CPVI group (n=55). Systemic SPVI combined with left atrial linear ablation tailored by inducibility of AF was performed in the stepwise SPVI group. Circumferential linear ablation around the left and right-sided pulmonary veins (PVs) guided by 3-dimensional electroanatomic mapping was performed in the CPVI group. The endpoints of ablation are non-induciblity of AF in the stepwise SPVI group and continuity of circular lesions combined with PV isolation in the CPVI group. After the initial procedures, atrial tachyarrhythmis (ATa) recurred within the first 3 months in 23 of the 55 patients (41.8%) who underwent stepwise SPVI and in 20 of the 55 patients (36.4%) who had CPVI (p=0.69). Repeat procedures were performed in 7 patients from the stepwise SPVI group and 5 from the CPVI group (p=0.76). During the 3-9 months after the last procedure, 46 patients (83.6%) from the CPVI group and 43 (78.2%) from the stepwise SPVI group did not have symptomatic ATa while not taking anti-arrhythmic drugs (p=0.63). Severe subcutaneous hematoma or PV stenosis occurred in 3 patients. CONCLUSIONS: The efficacy of stepwise SPVI is comparable to that of CPVI for patients with PAF.

Pulmonary vein tachycardia after pulmonary vein isolation in patients with atrial fibrillation.

BACKGROUND: Pulmonary vein (PV) isolation has been developed to treat patients with atrial fibrillation (AF), and the electrophysiological endpoint of PV isolation is the disappearance or dissociation of pulmonary vein potentials (PVPs). Pulmonary vein tachycardia (PVT) is the dissociated PV rhythm with a rapid rate. However, the characteristics and significance of PVT after pulmonary vein isolation in patients with AF remains unclear. METHODS: From June 2003 to June 2005, a total of 285 consecutive patients with drug refractory AF were included in this study, and they underwent segmental pulmonary vein ablation (SPVA) or circumferential pulmonary vein ablation (CPVA). PV isolation was the initial endpoint for both approaches with documenting disappearance or dissociation of PVPs. PVT was characterized as dissociated activities within PVs with a circle length (CL) of < 300 ms, and was classified into organized PVT or disorganized PVT according to the variance of CL. Systematic follow-up was conducted after initial procedures. Continuous variables were analyzed by Student's t test and categorical variables were analyzed by chi-square test. RESULTS: Three hundred and fifteen PVs were ablated in 85 patients underwent SPVA approach, 400 circular lesions surrounding ipsilateral PVs (including 790 PVs) were produced in the rest of 200 patients received CPVA approach. Electrical isolation was achieved in all of these PVs. Of these, PVPs were abolished in 89.8% (992/1105) of the ablated PVs, dissociated PV rhythms were documented in the rest 10.2 % (113/1105) of the treated PVs. Among the 113 dissociated PV rhythms, 28 met the criteria of PVT with mean CL of (155 +/- 43) ms (2 PVTs in 2 patients received SPVA, 26 PVTs in 18 patients underwent CPVA). PVT was more frequently documented in patients underwent CPVA approach [9.0% (18/200) vs 2.3% (2/85), P = 0.04]. During the 6-month follow-up, it was indicated that no significant difference existed in AF free rate between patients with PVT and those without PVT (P = 0.75). CONCLUSIONS: PVT dissociated from LA activations can be documented after PV isolation, especially in patients underwent CPVA approach. However, PVT does not affect the follow-up results.

Achievement of pulmonary vein isolation in patients undergoing circumferential pulmonary vein ablation: a randomized comparison between two different isolation approaches.

INTRODUCTION: Circumferential pulmonary vein ablation (CPVA) with the endpoint of pulmonary vein (PV) isolation has been developed as an effective therapy for atrial fibrillation (AF). This endpoint can be achieved either by closing gaps along circular lines or by segmental PV isolation inside the circular lines after creation of initial CPVA lesions. We investigated whether the clinical outcome depends on the PV isolation approach used during the first-time CPVA procedure. METHODS AND RESULTS: One hundred consecutive patients (69 male; age, 56.7 +/- 11.6 years) who underwent first-time CPVA for treatment of symptomatic AF were enrolled. PV isolation was randomly achieved either by CPVA alone (aggressive CPVA [A-CPVA] group, n = 50) or by a combination of CPVA with segmental PV ostia ablation (modified CPVA [M-CPVA] group, n = 50). Recurrence of atrial tachyarrhythmias (ATa) within 3 months after the initial procedure occurred in 30 patients (60%) in the M-CPVA group and in only 15 patients (30%) in the A-CPVA group (P < 0.01). ATa relapse after the first 3 months was detected in 21 patients (42%) in the M-CPVA group, compared with 9 patients (18%) in the A-CPVA group (P = 0.01). At 13 +/- 4 months, patients treated by the A-CPVA approach had greater freedom from ATa recurrence than patients who underwent M-CPVA (P = 0.01). The M-CPVA approach was the only independent predictor associated with procedural failure (RR 0.318; 95% CI 0.123-0.821; P = 0.02). CONCLUSIONS: When PV isolation is the endpoint of CPVA, the efficacy of the A-CPVA approach is better than that of M-CPVA.