ABSTRACT
An Au-Fe2O3@mesoporous SiO2 nanoreactor with a multiyolks/shell structure was synthesized through a multistep method. In this nanoreactor, the spindle Fe2O3 and Au nanoparticles were inside the same mesoporous SiO2 shell as the yolks but in a noncontact manner. The noncontact synergistic effect between Au nanoparticles and the Fe2O3 spindle was studied with a Fenton-like reaction. The catalytic activity of the Au-Fe2O3@mesoporous SiO2 nanoreactor to the Fenton-like reaction for the degradation of organic dyes was dramatically enhanced by the noncontact synergistic effect.
ABSTRACT
AIMS: Fragmented QRS (f-QRS) complexes are associated with adverse cardiovascular events in patients with coronary heart disease; however, the effects on patients with dilated cardiomyopathy (DCM) remain elusive. This study is to investigate the changes of left ventricular (LV) synchrony and systolic function in DCM patients with f-QRS complexes. METHODS AND RESULTS: Twenty DCM patients with f-QRS complexes and 29 DCM patients without f-QRS (n-QRS) complexes were enrolled. The LV segmental longitudinal, radial and circumferential time to peak strain and general longitudinal systolic strain, radial strain, circumferential strain were measured, respectively, by speckle tracking imaging. The LV segmental standard deviations and maximal differences were also calculated. The LV dyssynchrony was defined as the time in peak anteroseptal wall to posterior wall strain >130 ms or longitudinal strain delay index >25%. The mean QRS durations in f-QRS and n-QRS groups were not different (P = ns). The incidence of LV dyssynchrony was 15/20 (75%) vs. 5/29 (17%) in two groups (P < 0.01). Two patients died of sudden death in f-QRS group during 2 years follow-up; however, no death in n-QRS group (P < 0.05). Patients in f-QRS group showed worsening LV dyssynchrony in f-QRS group after 2 years follow-up (P < 0.05). Overall, LV function was comparable at baseline (P = ns), but had significantly worsened only in the f-QRS group (P < 0.05). CONCLUSION: The f-QRS complex is significantly associated with LV dyssynchrony in DCM patients and can be used as a reliable index to evaluate ventricular synchrony and predict the prognosis in DCM patients with narrow QRS complexes.
Subject(s)
Arrhythmias, Cardiac/etiology , Cardiomyopathy, Dilated/complications , Heart Conduction System/physiopathology , Ventricular Dysfunction, Left/etiology , Ventricular Function, Left , Action Potentials , Arrhythmias, Cardiac/diagnosis , Arrhythmias, Cardiac/mortality , Arrhythmias, Cardiac/physiopathology , Cardiomyopathy, Dilated/diagnosis , Cardiomyopathy, Dilated/mortality , Cardiomyopathy, Dilated/physiopathology , Case-Control Studies , Death, Sudden, Cardiac/etiology , Echocardiography, Doppler, Color , Electrocardiography , Female , Humans , Male , Middle Aged , Predictive Value of Tests , Prognosis , Prospective Studies , Risk Factors , Systole , Time Factors , Ventricular Dysfunction, Left/diagnosis , Ventricular Dysfunction, Left/mortality , Ventricular Dysfunction, Left/physiopathologyABSTRACT
Flower-like MgO is a highly effective catalyst for the synthesis of dimethyl carbonate through the transesterification method, and coating the catalyst with mesoporous silica significantly enhances the stability of the MgO catalyst.
Subject(s)
Formates/chemical synthesis , Magnesium Oxide/chemistry , Silicon Dioxide/chemistry , Catalysis , Esterification , Formates/chemistry , PorosityABSTRACT
Through a simple polymeric carbon assisted method, a yolk-shell structured Fe(2)O(3)@mesoporous SiO(2) nanoreactor was synthesized and showed excellent activity in Fenton-like reactions toward methylene blue total degradation.
Subject(s)
Coloring Agents/chemistry , Ferric Compounds/chemistry , Hydrogen Peroxide/chemistry , Iron/chemistry , Metal Nanoparticles/chemistry , Silicon Dioxide/chemistry , Catalysis , Metal Nanoparticles/ultrastructure , Methylene Blue/chemistry , Oxidation-Reduction , PorosityABSTRACT
A nanoreactor with temperature-responsive poly(N-isopopylacrylamide) (PNIPAM) coated on the external pore mouth of mesoporous silica hollow spheres and Au nanoparticles at the internal pore mouth were fabricated. Such spatial separation allows both Au nanoparticles and PNIPAM to function without interfering with each other. Transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectra, and temperature-dependent optical transmittance curves demonstrate successful grafting of PNIPAM. This nanoreactor shows repeated on/off catalytic activity switched by temperature control. It shows excellent catalytic activity toward 4-nitrophenol (4-NP) reduction at 30 °C [below lower critical solution temperature (LCST) of PNIPAM] with a turnover frequency (TOF) of 14.8 h(-1). However, when the temperature was 50 °C (above LCST), the TOF dropped to 2.4 h(-1). Kinetic studies indicated that diffusion into the mesopores of the catalyst was the key factor, and the temperature-responsive behavior of PNIPAM was able to control this diffusion.
Subject(s)
Acrylamides/chemistry , Gold/chemistry , Metal Nanoparticles/chemistry , Nanospheres/chemistry , Polymers/chemistry , Silicon Dioxide/chemistry , Temperature , Acrylic Resins , Models, Molecular , Particle Size , Porosity , Surface PropertiesSubject(s)
Arterio-Arterial Fistula/diagnostic imaging , Coronary Vessel Anomalies/diagnostic imaging , Pulmonary Artery/abnormalities , Arterio-Arterial Fistula/surgery , Coronary Angiography/methods , Coronary Vessel Anomalies/surgery , Female , Humans , Middle Aged , Pulmonary Artery/diagnostic imaging , Pulmonary Artery/surgery , Tomography, X-Ray Computed/methodsABSTRACT
A true nanoreactor composed of mesoporous silica hollow spheres and Pd nanoparticles residing inside the spheres shows superior activity in Suzuki coupling reactions with 99.5% yield in 3 min.
ABSTRACT
Surface hydroxyl group rich nano-structured solids dramatically increase the rate of several organic reactions; such effect is attributed to the formation of interfacial hydrogen bonds between the surface hydroxyl groups and the reactants; this catalytic effect is versatile and applicable for a broad range of reaction conditions.
