Carbon Dioxide Pressure and Catalyst Quantity Dependencies in Artificial Photosynthesis of Hydrocarbon Chains on Nanostructured Co/CoO Surfaces.

In this study, we investigated the influence of pressure and the quantity of Co/CoO catalyst on an artificial photosynthesis process that converts CO2 and H2O into hydrocarbons (CnH2n+2, where n ≤ 18). The adsorption of CO2 and H2O on Co/CoO surfaces proved to be pivotal in this photo-catalytic reaction. Photoexcited carbon dioxide and water molecules ((CO2)* and (H2O)*) generated by illuminating the catalyst surface led to the formation of alkene hydrocarbon molecules with carbon numbers following an approximate Poisson distribution. The optimal pressure was found to be 0.40 MPa. Pressure less than 0.40 MPa resulted in low CO2 adsorption, impeding excitation for photosynthesis. At greater pressure, oil/wax accumulation on Co/CoO surfaces hindered CO2 adsorption, limiting further photosynthesis reactions. The average number of carbon atoms in the hydrocarbons and hydrocarbon yield were correlated. The amount of Co/CoO was also found to affect the hydrocarbon yield. Our study contributes to the understanding of Co/CoO-catalyzed photosynthesis and suggests that an open-flow system could potentially enhance the productivity of long-chain hydrocarbons.

Temperature Dependence of the Artificial Photosynthesis Reactions Catalyzed by Nanostructured Co/CoO.

Carbon dioxide (CO2) and water (H2O) have been converted into hydrocarbons at temperature ranging from 58 to 242 °C through an artificial photosynthesis reaction catalyzed by nanostructured Co/CoO. The experimental results show that chain hydrocarbons (alkane hydrocarbons) (C n H2n+2, where 3 ≤ n ≤ 16) mainly form at a temperature higher than about 60 °C, the production rate reaches a maximum at 130 °C, and abruptly decreases above 130 °C, and then gradually increases until 220 °C. While the temperature is higher than 220 °C, benzene (C6H6) and its derivatives such as toluene (C7H8), p-xylene (C8H10), and C9H12 form. The modeling of temperature dependence of the reaction rate reveals that the vaporization of the adsorbed water contributes to the sharp peak; the activation energy is estimated as about 1 eV, which is in agreement with the reaction of CO and H2 to synthesize chain hydrocarbons. The experimental results support the mechanism that the chemisorbed CO2 and physisorbed H2O on the CoO surface are disassociated or excited with light, and the disassociated or excited molecules then synthesize hydrocarbons. When most of the water molecules leave from the CoO at temperature higher than 220 °C, the hydrogen source is of very low concentration while the carbon source remain the same because of the chemisorption, and thus benzene and its derivatives with low hydrogen atom number form.

Femtosecond Laser-Induced Thermal Transport in Silicon with Liquid Cooling Bath.

Nanostructured regular patterns on silicon surface are made by using femtosecond laser irradiations. This is a novel method that can modify the surface morphology of any large material in an easy, fast, and low-cost way. We irradiate a solid surface with a 400-nm double frequency beam from an 800-nm femtosecond laser, while the solid surface is submerged in a liquid or exposed in air. From the study of multiple-pulses and single-pulse irradiations on silicon, we find the morphologies of nanospikes and capillary waves to follow the same distribution and periodicity. Thermal transport near the solid surface plays an important role in the formation of patterns; a simulation was done to fully understand the mechanism of the pattern formation in single pulse irradiation. The theoretical models include a femtosecond laser pulse function, a two-temperature model (2-T model), and an estimation of interface thermal coupling. The evolution of lattice temperature over time will be calculated first without liquid cooling and then with liquid cooling, which has not been well considered in previous theoretical papers. The lifetime of the capillary wave is found to be longer than the solidification time of the molten silicon only when water cooling is introduced. This allows the capillary wave to be frozen and leaves interesting concentric rings on the silicon surface. The regular nanospikes generated on the silicon surface result from the overlapping capillary waves.

Incorporation of Keplerate-type Mo-O based macroanions into Zn2Al-LDH results in the formation of all-inorganic composite films with remarkable third-order optical nonlinearity.

Herein, new all-inorganic transparent composite films with the formula (Zn2Al-LDH/{Mo132-Ac})n have been fabricated by a layer-by-layer method using the exfoliated Zn2Al-LDH monolayer nanosheets and Keplerate-type macroanion {Mo132-Ac}. They were characterized by UV-vis absorption spectroscopy, SEM, AFM, and XPS techniques. The Z-scan measurements, which were conducted under laser irradiation at a wavelength of 532 nm, a pulse width of 6 ns, a repetition rate of 10 Hz, and the light intensity at a focus E0 of 10 µJ, revealed that all the films had notable saturated absorption and self-defocusing effect with a large third-order optical nonlinear susceptibility χ(3). With an increase in the number of layers (i.e., n) corresponding to the increase in the thickness of the films, the third-order nonlinear absorption ß and refractive effects of the films were improved (i.e., the χ(3) value was up to 1.99 × 10-11 esu when n = 24); this implied that the NLO responses could be modified by fine-tuning the thickness of the composite films to meet the demands of different devices.

Manual assembly of a rare-earth polyoxometalate microcrystal film showing highly polarized luminescence.

Currently, the realization of rationally designed architectures based on polyoxometalates (POMs) with designed functions has mostly been achieved through the preparation of functional films. However, the traditional approaches suffer from the drawbacks such as time-consuming processes, ill-defined structure and quality, random orientation of the POM molecules, and unsatisfactory performance. In this study, microcrystals of Ag9[EuW10O36]·36H2O (denoted as Ag9[EuW10O36]) were synthesized via a titration method by treating Na9[EuW10O36]·32H2O (denoted as Na9[EuW10O36]), selected as a prototype, with Ag+, leading to the formation of a water-insoluble crystalline powder with a uniform hexagonal platelet morphology. After this, a simple yet efficient manual assembly method was used to rapidly manufacture Ag9EuW10O36 microcrystal thin films on a glass substrate with high coverage, high crystallinity, and highly preferential orientation. Note that the as-prepared films emit orange polarized fluorescence with an anisotropy value of about 0.21, which places them among the materials of largest anisotropy. It is expected that the manual assembly approach can be generally adopted for the fabrication of many other kinds of polyoxometalate-based materials on various substrates for practical applications.

Fabrication and optical nonlinearities of composite films derived from the water-soluble Keplerate-type polyoxometalate and chloroform-soluble porphyrin.

Composite films derived from the water-soluble Keplerate-type polyoxometalate (NH4)42[Mo132O372(CH3COO)30(H2O)72]·ca. 300H2O·ca. 10CH3COONH4 (denoted (NH4)42{Mo132}) and chloroform-soluble tetraphenylporphyrin perchlorate [H2TPP](ClO4)2 are successfully fabricated by a layer-by-layer self-assembly method and characterized by UV-vis spectroscopy and X-ray photoelectron spectroscopy (XPS). The structure of the {Mo132} and [H2TPP](2+) in the films remain intact in light of the results of UV-vis spectroscopy and XPS. UV-vis spectra measurements reveal that the amounts of deposition of {Mo132} and [H2TPP](2+) remain constant in every adsorption cycle in the composite films assembly process. Nonlinear optical properties of the composite films have been investigated by using the Z-scan technique at a wavelength of 532 nm and pulse width of 7 ns. The results show that the composite films have notable nonlinear saturated absorption and self-defocusing effects. The combination of {Mo132} with [H2TPP](2+) can result in composite films with remarkably enhanced optical nonlinearities. The interfacial charge transfer induced by laser from porphyrin to POM in the films is thought to play a key role in the enhancement of NLO response. The third-order NLO susceptibility χ((3)) of the composite films increases with the increase of film thickness.

Effect of coronary revascularization on serum collagen biomarkers and left ventricular remodeling in patients with acute myocardial infarction.

OBJECTIVE: After an acute myocardial infarction (AMI), early coronary revascularization alleviates the synthesis of cardiac collagen and ventricular remodeling. However, the impact of late coronary revascularization on the synthesis of myocardial collagen or on serum collagen biomarkers is unknown. This study aimed to investigate the effects of late coronary revascularization on serum collagen biomarkers after AMI. METHODS: Forty-five patients were divided into early (n = 20) and late (n = 25) coronary revascularization groups. The early coronary revascularization group received either successful percutaneous coronary intervention (PCI) or thrombolytic therapy within 6 hours of their myocardial infarction (MI), whereas the late PCI group received PCI between 12 and 14 days after their MI. Serum type I procollagen (PICP) and type III procollagen (PIIINP) were measured by radioimmunoassay. RESULTS: In the early coronary revascularization group, the amount of serum PICP on days 60 and 180 was similar to that of week 1 (P > .05). The PICP on days 90 and 180 in the late coronary revascularization group was higher than in the early coronary revascularization group at the same time point (P < .05). No significant difference was evident in mean serum PIIINP between the two groups on day 60 or 180 after the MI (P < .05). CONCLUSION: Late coronary revascularization in patients with acute ST-elevation MI was associated with an elevation in serum PICP. Early coronary revascularization should be performed in patients with ST-elevation, to alleviate myocardial remodeling.

Effect of simvastatin on plasma interleukin-6 in patients with unstable angina.

PURPOSE: The primary aim of the study was to investigate the effect of sinvastatin on plasma interleukin-6 (IL-6) in patients with unstable angina pectoris (UAP). METHODS: Eighty-six patients with UAP were randomized into simvastatin (40 mg/d for 4 weeks) and the placebo group. Plasma IL-6 was measured by ELISA. RESULTS: There was a reduction in the plasma total cholesterol and LDL in the simvastatin group (P < 0.01). The simvastatin group also had better angina control than the placebo group (post-treatment angina score, 0.72+/-0.59 vs 1.07+/-0.76, P < 0.05). Following treatment, the average left ventricular ejection fraction in the simvastatin group was higher than in the placebo group (0.54+/-0.06 vs 0.51+/-0.05, P < 0.05), whereas the plasma BNP levels were lower (16.8+/-6.6 vs 26.4+/-1.4, P < 0.01). Before treatment, there was no difference in the plasma levels of IL-6 between the simvastatin and the placebo groups (P > 0.05). Following treatment, the IL-6 levels in the simvastatin group were lower than in the placebo group (0.7+/-0.4 vs 1.2+/-0.4 pg/ml, P < 0.05). CONCLUSIONS: Short-term treatment with simvastatin reduces plasma IL-6. The anti-inflammatory effect of simvastatin may contribute to its beneficial effects on the ventricular function and angina control.

L-carnitine as an adjunct therapy to percutaneous coronary intervention for non-ST elevation myocardial infarction.

OBJECTIVES: To evaluate the effects of L: -carnitine as an adjunct therapy to percutanenous coronary intervention (PCI) for non-ST elevation acute coronary syndrome (NSTEMI). MATERIALS AND METHODS: Ninety-six consecutive patients with NSTEMI were randomized into treatment group (L: -carnitine 5 g IV bolus followed by 10 g/day IV infusion for 3 days), and control group. All patients also underwent PCI within 24 h from the onset of chest pain. The peak values of creatine kinase-MB and troponin-I before and after PCI were observed. RESULTS: In the treatment group, the peak values of creatine kinase-MB were significantly lower than the control group at 12 h and 24 h after PCI (P < 0.01). The peak values of troponin-I in the treatment group were also lower than the control group at 8 h after PCI (P < 0.01). Multivariate regression analysis showed that L: -carnitine therapy was an independent predictor for the reduction of creatine kinase-MB (r = 0.596, P < 0.001) or troponin-I (r = 0.633, P < 0.001). CONCLUSION: L: -carnitine adjunct therapy appears to be associated with a reduced level of cardiac markers in patients with NSTEMI. These results support a larger clinical trial to investigate the effect of L: -carnitine on cardiac events following PCI.