Enhancing Catalytic Activity and Selectivity by Plasmon-Induced Hot Carriers.

Plasmon-assisted chemical transformation holds great potential for solar energy conversion. However, simultaneous enhancement of reactivity and selectivity is still challenging and the mechanism remains mysterious. Herein, we elucidate the localized surface plasmon resonance (LSPR)-induced principles underlying the enhanced activity (∼70%) and selectivity of photoelectrocatalytic redox of nitrobenzene (NB) on Au nanoparticles. Hot carriers selectively accelerate the conversion rate from NB to phenylhydroxylamine (PHA) by ∼14% but suppress the transformation rate from PHA to nitrosobenzene (NSB) by ∼13%. By adding an electron accepter, the as-observed suppression ratio is substantially enlarged up to 43%. Our experiments, supported by in situ surface-enhanced Raman spectroscopy and density functional theory simulations, reveal such particular hot-carrier-induced selectivity is conjointly contributed by the accelerated hot electron transfer and the corresponding residual hot holes. This work will help expand the applications of renewable sunlight in the directional production of value-added chemicals under mild conditions.

Enhanced catalytic activity of Au core Pd shell Pt cluster trimetallic nanorods for CO2 reduction.

Herein, Au core Pd shell Pt cluster nanorods (Au@Pd@Pt NRs) with enhanced catalytic activity were rationally designed for carbon dioxide (CO2) reduction. The surface composition and Pd-Pt ratios significantly influenced the catalytic activity, and the optimized structure had only a half-monolayer equivalent of Pt (θ Pt = 0.5) with 2 monolayers of Pd, which could enhance the catalytic activity for CO2 reduction by 6 fold as compared to the Pt surface at -1.5 V vs. SCE. A further increase in the loading of Pt actually reduced the catalytic activity; this inferred that a synergistic effect existed among the three different nanostructure components. Furthermore, these Au NRs could be employed to improve the photoelectrocatalytic activity by 30% at -1.5 V due to the surface plasmon resonance. An in situ SERS investigation inferred that the Au@Pd@Pt NRs (θ Pt = 0.5) were less likely to be poisoned by CO because of the Pd-Pt bimetal edge sites; due to this reason, the proposed structure exhibited highest catalytic activity. These results play an important role in the mechanistic studies of CO2 reduction and offer a new way to design new materials for the conversion of CO2 to liquid fuels.

[Breeding of new Artemisia annua variety "Kehao No.1"].

As a natural plant source of artemisinin,a first-line drug against malaria,Artemisia annua directly affects the extraction process of artemisinin and the source of artemisinin. At present,traditional breeding methods combined with tissue culture are often used to breed high-yield artemisinin-containing new varieties of A. annua. However,the breeding method has the disadvantages of low efficiency and continuous selection. In this study,heavy ion beam irradiation technology was used to observe the specific germplasm resources of A. annua,and the morphological characteristics,agronomic traits and artemisinin content were used as indicators to observe the selection materials and materials. The cultivated new varieties were compared with trials and regional trials. In addition,the new variety of A. annua was identified by SRAP molecular marker technology. The results showed that the new variety of A. annua, " Kehao No.1",had an average yield of 235. 0 kg of dry leaf per mu,which was more than 20% higher than that of the control. Especially,the average artemisinin content was 2. 0%,which was 45% higher than that of the control,and the " Kehao No.1" has high anti-white powder disease,high-yield and high-quality new varieties. Therefore,mutagenic breeding of heavy ion beam irradiation can significantly improve the yield and artemisinin content of the " Kehao No. 1" and it has a good promotion value.

The acquisition of Clostridium tyrobutyricum mutants with improved bioproduction under acidic conditions after two rounds of heavy-ion beam irradiation.

End-product inhibition is a key factor limiting the production of organic acid during fermentation. Two rounds of heavy-ion beam irradiation may be an inexpensive, indispensable and reliable approach to increase the production of butyric acid during industrial fermentation processes. However, studies of the application of heavy ion radiation for butyric acid fermentation engineering are lacking. In this study, a second (12)C(6+) heavy-ion irradiation-response curve is used to describe the effect of exposure to a given dose of heavy ions on mutant strains of Clostridium tyrobutyricum. Versatile statistical elements are introduced to characterize the mechanism and factors contributing to improved butyric acid production and enhanced acid tolerance in adapted mutant strains harvested from the fermentations. We characterized the physiological properties of the strains over a large pH value gradient, which revealed that the mutant strains obtained after a second round of radiation exposure were most resistant to harsh external pH values and were better able to tolerate external pH values between 4.5 and 5.0. A customized second round of heavy-ion beam irradiation may be invaluable in process engineering.

Comparison of the effects of high energy carbon heavy ion irradiation and Eucommia ulmoides Oliv. on biosynthesis butyric acid efficiency in Clostridium tyrobutyricum.

Clostridium tyrobutyricum is well documented as a fermentation strain for the production of butyric acid. In this work, using high-energy carbon heavy ion irradiated C. tyrobutyricum, then butyric acid fermentation using glucose or alkali and acid pretreatments of Eucommia ulmoides Oliv. as a carbon source was carried out. Initially, the modes at pH 5.7-6.5 and 37°C were compared using a model medium containing glucose as a carbon source. When the 72gL(-1) glucose concentration was found to be the highest yield, the maximum butyric acid production from glucose increased significantly, from 24gL(-1) for the wild type strains to 37gL(-1) for the strain irradiated at 126AMeV and a dose of 35Gy and a 10(7)ions/pulse. By feeding 100gL(-1) acid pretreatments of E. ulmoides Oliv. into the fermentations, butyrate yields (5.8gL(-1)) and butyrate/acetate (B/A) ratio (4.32) were achieved.

Radiation induces acid tolerance of Clostridium tyrobutyricum and enhances bioproduction of butyric acid through a metabolic switch.

BACKGROUND: Butyric acid as a renewable resource has become an increasingly attractive alternative to petroleum-based fuels. Clostridium tyrobutyricum ATCC 25755T is well documented as a fermentation strain for the production of acids. However, it has been reported that butyrate inhibits its growth, and the accumulation of acetate also inhibits biomass synthesis, making production of butyric acid from conventional fermentation processes economically challenging. The present study aimed to identify whether irradiation of C. tyrobutyricum cells makes them more tolerant to butyric acid inhibition and increases the production of butyrate compared with wild type. RESULTS: In this work, the fermentation kinetics of C. tyrobutyricum cultures after being classically adapted for growth at 3.6, 7.2 and 10.8 g·L-1 equivalents were studied. The results showed that, regardless of the irradiation used, there was a gradual inhibition of cell growth at butyric acid concentrations above 10.8 g·L-1, with no growth observed at butyric acid concentrations above 3.6 g·L-1 for the wild-type strain during the first 54 h of fermentation. The sodium dodecyl sulfate polyacrylamide gel electrophoresis also showed significantly different expression levels of proteins with molecular mass around the wild-type and irradiated strains. The results showed that the proportion of proteins with molecular weights of 85 and 106 kDa was much higher for the irradiated strains. The specific growth rate decreased by 50% (from 0.42 to 0.21 h-1) and the final concentration of butyrate increased by 68% (from 22.7 to 33.4 g·L-1) for the strain irradiated at 114 AMeV and 40 Gy compared with the wild-type strains. CONCLUSIONS: This study demonstrates that butyric acid production from glucose can be significantly improved and enhanced by using 12C6+ heavy ion-irradiated C. tyrobutyricum. The approach is economical, making it competitive compared with similar fermentation processes. It may prove useful as a first step in a combined method employing long-term continuous fermentation of acid-production processes.

The effect of microdosimetric 12C6+ heavy ion irradiation and Mg2+ on canthaxanthin production in a novel strain of Dietzia natronolimnaea.

BACKGROUND: Dietzia natronolimnaea is one of the most important bacterial bioresources for high efficiency canthaxanthin production. It produces the robust and stable pigment canthaxanthin, which is of special interest for the development of integrated biorefineries. Mutagenesis employing 12C6+ irradiation is a novel technique commonly used to improve microorganism productivity. This study presents a promising route to obtaining the highest feasible levels of biomass dry weight (BDW), and total canthaxanthin by using a microdosimetric model of 12C6+ irradiation mutation in combination with the optimization of nutrient medium components. RESULTS: This work characterized the rate of both lethal and non-lethal dose mutations for 12C6+ irradiation and the microdosimetric kinetic model using the model organism, D. natronolimnaea svgcc1.2736. Irradiation with 12C6+ ions resulted in enhanced production of canthaxanthin, and is therefore an effective method for strain improvement of D. natronolimnaea svgcc1.2736. Based on these results an optimal dose of 0.5-4.5 Gy, Linear energy transfer (LET) of 80 keV µm-1and energy of 60 MeV u-1 for 12C6+ irradiation are ideal for optimum and specific production of canthaxanthin in the bacterium. Second-order empirical calculations displaying high R-squared (0.996) values between the responses and independent variables were derived from validation experiments using response surface methodology. The highest canthaxanthin yield (8.14 mg) was obtained with an optimized growth medium containing 21.5 g L-1 D-glucose, 23.5 g L-1 mannose and 25 ppm Mg2+ in 1 L with an irradiation dose of 4.5 Gy. CONCLUSIONS: The microdosimetric 12C6+ irradiation model was an effective mutagenic technique for the strain improvement of D. natronolimnaea svgcc1.2736 specifically for enhanced canthaxanthin production. At the very least, random mutagenesis methods using 12C6+ions can be used as a first step in a combined approach with long-term continuous fermentation processes. Central composite design-response surface methodologies (CCD-RSM) were carried out to optimize the conditions for canthaxanthin yield. It was discovered D-glucose, Mg2+ and mannose have significant influence on canthaxanthin biosynthesis and growth of the mutant strain.

miR-26a suppresses tumor growth and metastasis by targeting FGF9 in gastric cancer.

The role of miR-26a in cancer cells seemed controversial in previous studies. Until now, the role of miR-26a in gastric cancer remains undefined. In this study, we found that miR-26a was strongly downregulated in gastric cancer (GC) tissues and cell lines, and its expression levels were associated with lymph node metastasis and clinical stage, as well as overall survival and replase-free survival of GC. We also found that ectopic expression of miR-26a inhibited GC cell proliferation and GC metastasis in vitro and in vivo. We further identified a novel mechanism of miR-26a to suppress GC growth and metastasis. FGF9 was proved to be a direct target of miR-26a, using luciferase assay and western blot. FGF9 overexpression in miR-26a-expressing cells could rescue invasion and growth defects of miR-26a. In addition, miR-26a expression inversely correlated with FGF9 protein levels in GC. Taken together, our data suggest that miR-26a functions as a tumor suppressor in GC development and progression, and holds promise as a prognostic biomarker and potential therapeutic target for GC.

High efficiency degradation crude oil by a novel mutant irradiated from Dietzia strain by 12C6+ heavy ion using response surface methodology.

Crude oil is an extremely complex mixture of hydrocarbons; also contaminate environmental, leading to carcinogenic, teratogenic and mutagenic. Petroleum hydrocarbons degradation Dietzia strain DMYR9 was isolated from oilfield. Response surface methodology was applied for statistical designing of process parameters for dry weight of biomass production in the process of degradation. The optimization process parameters were successfully employed for degradation crude oil and confirmed through confirmatory experiments. On 28th day, analysis was done by GC-MS, These data show that the crude oil samples of n-Hexadecane, Octadecane, n-Nonadecanec, n-Pentacosane, n-Hexacosane, n-Heneicosane, n-Docosane, n-Tetracosane, n-Octacosane and Tetraethyl removal efficiency could reach up to 0%. RSM optimization and use of effective (12)C(6+)-ion irradiation methods can considerably enhance ability to degradation of microbial. Hence, bioresource Dietzia strain DMYR9, high ability to degradation, can be further used for subsequent repair hydrocarbons polluted of environment.

Flexible solid-state supercapacitors based on carbon nanoparticles/MnO2 nanorods hybrid structure.

A highly flexible solid-state supercapacitor was fabricated through a simple flame synthesis method and electrochemical deposition process based on a carbon nanoparticles/MnO(2) nanorods hybrid structure using polyvinyl alcohol/H(3)PO(4) electrolyte. Carbon fabric is used as a current collector and electrode (mechanical support), leading to a simplified, highly flexible, and lightweight architecture. The device exhibited good electrochemical performance with an energy density of 4.8 Wh/kg at a power density of 14 kW/kg, and a demonstration of a practical device is also presented, highlighting the path for its enormous potential in energy management.

Facile electrochemical synthesis of single crystalline CeO2 octahedrons and their optical properties.

We developed a simple electrochemical process for the large-scale fabrication of single crystalline CeO(2) octahedrons and nanospheres from DMSO aqueous solution. The octahedrons with some structural defects have a size ranging from 200 to 300 nm. Moreover, highly crystalline CeO(2) nanospheres were also obtained via this electrochemical process based on the oriented attachment mechanism. The absorption edge of octahedrons and spheres shows a red-shift, and that of the octahedrons was near the visible region.

Use of additives in the electrodeposition of nanostructured Eu3+/ZnO films for photoluminescent devices.

Rare-earth ion-doped ZnO has been the focus of numerous investigations because of its unique optical properties and promising applications in optoelectronic devices. Here we presented a facile electrochemical deposition route for the controllable preparation of Eu3+/ZnO nanostructures on a large scale. The prepared Eu3+/ZnO deposits were characterized by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, selected area electron diffraction, and X-ray photoelectron spectroscopy. Herein, the growth mechanisms of Eu3+/ZnO nanosheets and nanorods were discussed. The formation process of Eu3+/ZnO foam-like nanostructures is illuminated in this paper. The room temperature photoluminescence properties of the Eu3+/ZnO foam-like nanostructures were investigated. The sharp 4f-4f transition emissions of Eu3+ can be directly observed at 593, 617, and 698 nm. An energy transfer between ZnO and Eu3+ is shown to occur under UV excitation.

Cadmium(II) and copper(II) complexes with imidazole-containing tripodal polyamine ligands: pH and anion effects on carbon dioxide fixation and assembling.

A new Cd(II) complex [Cd3(L)3(mu3-CO3)](ClO4)4.2CH3CN (1) with two-dimensional (2D) network structure was obtained by reaction of an imidazole-containing tripodal polyamine ligand N1-(2-aminoethyl)-N1-(2-imidazolethyl)-ethane-1,2-diamine (L) with Cd(ClO4)2.6H2O at pH 9.0 in air. The carbonate anions (CO3(2-)) are from the hydration of the atmospheric carbon dioxide, which is the same as in the previously reported Cu(II) complex [Cu3(L)3(mu3-CO3)](ClO4)4.3CH3CN (2). However, the coordination mode of CO3(2-) in 1 is mu3-eta2:eta2:eta2 while the one in 2 is mu3-eta1:eta1:eta1. One-dimensional (1D) chain Cd(II) and Cu(II) complexes [Cd(L)Cl]ClO4.H2O (3) and [Cu(L)(H2O)](ClO4)2 (4) without CO3(2-) were prepared by a similar method as that for 1 and 2 except for the different reaction pH, namely, 3 and 4 were obtained at pH 7 while 1 and 2 were obtained at pH 9. In addition, when Cu(NO3)2 was used to react with L at pH 9, a unique 1D double-stranded helical chain complex [Cu(L)Cl]NO3.1.25H2O (5) was obtained. The results revealed that the reaction pH and the counteranion have great impact on the carbon dioxide absorption and hydration as well as on the assembling and structure of the complexes. The magnetic property of complex 2 was investigated in the temperature range of 1.8-300 K, and weak ferromagnetic coupling among the mu3-eta1:eta1:eta1-CO3(2-) bridged Cu(II) atoms was observed.