ApcD is required for state transition but not involved in blue-light induced quenching in the cyanobacterium Anabaena sp.PCC7120

Pbycobilisomes(PBS) are able to transfer absorbed energy to photosystem I and Ⅱ,and the distribution of light energy between two photosystems is regulated by state transitions.In this study we show that energy transfer from PBS to photosystem I(PSI) requires ApcD.Cells were unable to perform state transitions in the absence of ApcD.The apcD mutant grows more slowly in light mainly absorbed by PBS,indicating that ApcD-dependent energy transfer to PSI is required for optimal growth under this condition.The apcD mutant showed normal blue-light induced quenching,suggesting that ApcD is not required for this process and state transitions are independent of blue-light induced quenching.Under nitrogen fixing condition,the growth rates of the wild type and the mutant were the same,indicating that energy transfer from PBS to PSI in heterocysts was not required for nitrogen fixation.     

Microstructure investigation and multicolor upconversion in Yb~(3+)/Ln~(3+)(Ln=Er/Tm/Ho) ions doped α-Sialon

Yb~(3+)/Ln~(3+)(Ln=Er/Tm/Ho)-α-sialon ceramics were fabricated by hot press sintering technique.Their microstructure and luminescent properties were studied by XRD,EDS,HRTEM and photoluminescence measurements.The results showed that the sintered ceramics consisted ofα-Sialon with a trace amount ofβ-Sialon phase.The frequency upconversion and downconversion properties of Yb~(3+)/Ln~(3+)(Ln=Er/Tm/Ho)-α-Sialon ceramics were investigated under 980 nm low-power excitation.The different concentrations of Yb~(3+)/Ln~(3+)(Ln=Er/Tm/Ho)produced multicolor emissions characteristics of each Ln~(3+)ion as a result of the energy transfer from Yb~(3+)to Er~(3+),Tm~(3+)and Ho~(3+)ions.The EDS spectra measurements and mappings showed that the Ln~(3+)ions were well incorporated in theα-Sialon matrix.Temporal evolution of the emission decay behavior has been investigated to understand the energy transfer mechanism.     

Study of ionizable drugs transfer across the water／1,2-dichloroethane interface with phase volume ratio equal to unity using a three-electrode system

The electrochemical behavior of ionizable drugs (Amitripty/ine, Diphenhydramine and Trihexyphenedyl) at the water/1,2-dichloroethane interface with the phase volume ratio (r=Vo/Vw) equal to 1 are investigated by cyclic voltammetry. The system is composed of an aqueous droplet supported at an Ag/AgCI disk electrode and it was covered with an organic solution. In this manner, a conventional three-electrode potentiostat can be used to study the ionizable drugs transfer process at a liquid/liquid interface.Physicochemical parameters such as the formal transfer potential, the Gibbs energy of transfer and the standard partition coefficients of the ionized forms of these drugs can be evaluated from cyclic voltammograms obtained. The obtained results have been summarized in ionic partition diagrams, which are a useful tool for predicting and interpreting the transfer mechanisms of ionizable drugs at the liquid/liquid interfaces and biological membranes.     

Recent Advances in Protein Extraction and Chiral Separation of Blomolecules

Reverse micelles create unique environment in organic media. They are capable of solubilizing hydrophilic biomolecules （e.g., proteins, peptides, amino acids, and DNAs） in their aqueous interior. This feature brings about the practical use of biomaterials in organic media because reverse micelles solubilize them with the intrinsic activity. In this paper, we focus on recent two topics concerning protein extraction and chiral separation of biomolecules using liquid membranes. In the first topic, we present recent attempts to extract proteins from an aqueous solution into isooctane using reverse micelles, and some important operational parameters to achieve an efficient protein transfer are discussed. Furthermore, novel function of reverse micelles as a protein activation medium is introduced. In the reverse micellar phase, denatured proteins were completely reactivated in the reverse micellar solution. The reverse micellar technique is found to be a useful tool not only for protein separation but also for protein refolding. Furthermore, we found that a cyclic ligand carixarene has an extraction ability to set up optimum conditions for protein transfer. In the second topic, we have found that a supported liquid membrane （SLM） encapsulating enzymes shows high enantioselectivity （enantioselective excess value is over 96%） in the transport of racemic pharmaceutical compound ibuprofen. A different experiment also suggests that the α-chymotrypsin-catalyzed reactions droved the enantioselective transport of L-phenylalanine based on the enantioselectivity of the enzyme. The SLM encapsulating the surfactant-enzyme complex enabled the highly enantioselective separation of racemic mixtures. It can be envisioned that arrangement of appropriate enzymes in the SLM system will allow enantioselective separation of various useful organic compounds.     

Fine Control of Metal Assembly in Dendrimers

1 Results Dendrimers are highly branched organic macromolecules with successive layers or "generations" of branch units surrounding a central core.Organic inorganic hybrid versions have also been produced,by trapping metal ions or metal clusters within the voids of the dendrimers.Their unusual,tree-like topology endows these nanometre-sized macromolecules with a gradient in branch density from the interior to the exterior,which can be exploited to direct the transfer of charge and energy from the dendrimer periphery to its core.     

Fine Control of Metal Assembly in Dendrimers

1 Results Dendrimers are highly branched organic macromolecules with successive layers or “generations“ of branch units surrounding a central core.Organic inorganic hybrid versions have also been produced,by trapping metal ions or metal clusters within the voids of the dendrimers.Their unusual,tree-like topology endows these nanometre-sized macromolecules with a gradient in branch density from the interior to the exterior,which can be exploited to direct the transfer of charge and energy from the dendri...     

Organic solvent- and phase transfer catalyst-free oxida-tion of cyclohexanol to cyclo-hexanone with dilute H2O2

The oxidation of cyclohexanol to cyclohexanone with 30% aqueous hydrogen peroxide by using peroxotungstate complexes formed in situ from sodium tungstate dihydrate and various bidentate organic ligands as the catalysts, without organic solvents, halide and phase transfer catalyst has been carried out. The influence of 13 ligands on the oxidation is investigated. The maximum yield of cyclohexanone is obtained when using 1,10-phenanthroline (96%) and oxalic acid (95%) as the ligand. Very high yields (around 90%) have also been obtained for the instances of using salicylic acid, 3,5-dibromosalicylic acid, and 8-hydro- xylquinoline as ligands. A research to improve the reaction condition using cheap oxalic acid as the ligand indicates that the optimum condition is that the reaction mixture with a molar ratio of cycohexanol︰tungstate dihydrate︰oxalic acid︰30% H2O2=100︰2︰2︰120 was stirred at 85-90℃ for 12 h.     

Formation of Ferric Porphyrinoids with Unusual Electronic and Magnetic Properties

1 Results Energy levels of the metal 3d orbitals in iron(Ⅲ) porphyrinoids are controlled by various factors such as the nature and number of axial ligands, electronic and steric effects of peripheral substituents, deformation and core modification of porphyrin ring, hydrogen bonding to the axial ligand, etc. By manipulating these factors, we are now able to prepare various iron(Ⅲ) porphyrinoids withunusual electronic and magnetic properties[1]. Here, we report the formation of such complexes as ⅰ) low-s...     

Energy-Aware GPU Programming at Source-Code Levels

To enhance the energy efficiency and performance of algorithms with Graphics Processing Unit (GPU) accelerators in source-code development, we consider the power efficiency based on data transfer bandwidth and power consumption in key situations. First, a set of primitives is abstracted from program statements. Then, data transfer bandwidth and power consumption in different granularity sizes are considered and mapped into proper primitives. With these mappings, a programmer can intuitively determine the power efficiency and performance in different running states of a thread. Finally, this intuition enables the programmer to tune the algorithm in order to achieve the best energy efficiency and performance. Using these power-aware principles, two Fast Fourier Transform (FFT) methods are compared. The mapping between power consumption and primitives is helpful for algorithm tuning in source-code levels.     

量子点在荧光共振能量转移技术中的应用研究进展

Quantum dots can be overcome traditional organic fluorescent dye deficiencies,such as the narrow of absorption spectra,the tailing of emission spectrum. Therefore,quantum dots can be used as a new type of fluorescent probe in resonance energy transfer technology,instead of the traditional organic fluorescent dye. In recent years, the study of quantum dots used in resonance energy transfer technology research become more widely, this paper review the application of quantum dot used in fluorescence resonance energy transfer in recent years.     

Investigation of the kinetic mechanism of the demanganization reaction between carbon-saturated liquid iron and CaF_2–CaO–SiO_2-based slags

The demanganization reaction kinetics of carbon-saturated liquid iron with an eight-component slag consisting of CaO–SiO_2–MgO–FeO–MnO–Al_2O_3–TiO_2–CaF_2 was investigated at 1553, 1623, and 1673 K in this study. The rate-controlling step(RCS) for the demanganization reaction with regard to the hot metal pretreatment conditions was studied via kinetics analysis based on the fundamental equation of heterogeneous reaction kinetics. From the temperature dependence of the mass transfer coefficient of a transition-metal oxide(Mn O), the apparent activation energy of the demanganization reaction was estimated to be 189.46 k J·mol~(–1) in the current study, which indicated that the mass transfer of Mn O in the molten slag controlled the overall rate of the demanganization reaction. The calculated apparent activation energy was slightly lower than the values reported in the literature for mass transfer in a slag phase. This difference was attributed to an increase in the "specific reaction interface"(SRI) value, either as a result of turbulence at the reaction interface or a decrease of the absolute amount of slag phase during sampling, and to the addition of calcium fluoride to the slag.     

Significant heat transfer enhancement for R123 condensation by micromembrane cylinder

Renewable energy or low grade energy utilizations need high performance of phase change heat exchangers. Suspending micromembrane cylinder in tube(called modulated heat transfer tube) increases the void fractions or vapor qualities near the tube wall to significantly enhance heat transfer. The R123 condensation heat transfer with horizontal position was investigated. The results for the bare tube and modulated heat transfer tube were tested case by case. It is found that the modulated heat transfer tube significantly enhance the condensation heat transfer, with the heat transfer enhancement factors(EF)covering the range of 1.118–2.124. The comprehensive performance evaluation criteria(PEC) had the range of0.71–1.66, with most of runs behaving PEC larger than 1.0.For the two-phase outlet conditions, the EF values are increased with increases in the vapor mass fluxes, Gxin,where G is the mass flux and xinis the inlet vapor mass quality. The EF values are inversely related to Gxinfor the subcooled liquid outlet cases. The enhanced heat transfer mechanisms are analyzed with the observed images together with the discussion of pressure and velocity distributions.     

Applications of Transition Metals in Organic Synthesis and Polymerization

1 Results Classic oxidants require rigorous control of the experimental conditions added with the problem of lack of selectivity. Catalysis by transition metals with environmentally safe oxidants provides synthetic routes to minimize pollution by giving environmental benign by-products. Fe (Ⅵ) is a powerful and a selective oxidant with Fe(Ⅲ) as a by-product, while hydrogen peroxide is clean with water as the only by-product. Separation of sodium or potassium ferrates requires tedious processes. Association of a ferric salt with a clay support had been reported previously also[1-2],which prompted us to find out a way in which sodium ferrate could be used in solution itself. Presence of copper nano-particles adsorbed on solid support, accelerate the process. Present study[3] describes the oxidation of organic substrates with in-situ prepared Fe(Ⅵ)in combination of montmorillonite K10 and metallic copper nano-particles without following the tedious and lengthy process of separation of Fe(Ⅵ). Apart from it the catalytic activities of three transition metals palladium(Ⅱ), iridium(Ⅲ) and rhodium(Ⅲ) in solution phase and under solvent less conditions were studied in the oxidation of various organic compounds by hydrogen peroxide[4] and cerium(Ⅳ) sulphate. In the oxidation by hydrogen peroxide (with substrate: catalyst ratio 1∶62 500 to 1∶1 961) palladium(Ⅱ) was found to be the most efficient catalyst, while iridium(Ⅲ) (catalyst: substrate ratio 1∶57 to 151) was so much efficient with cerium(Ⅳ) that it oxidizes even cyclohexane and benzene giving rise to 44% and 51.8% yields of carbonyl compounds.     

Investigation of the kinetic mechanism of the demanganization reaction between carbon-saturated liquid iron and CaF2-CaO-SiO2-based slags

The demanganization reaction kinetics of carbon-saturated liquid iron with an eight-component slag consisting of CaO-SiO₂-MgO-FeO-MnO-Al₂O₃-TiO₂-CaF₂ was investigated at 1553, 1623, and 1673 K in this study. The rate-controlling step (RCS) for the demanganization reaction with regard to the hot metal pretreatment conditions was studied via kinetics analysis based on the fundamental equation of heterogeneous reaction kinetics. From the temperature dependence of the mass transfer coefficient of a transition-metal oxide (MnO), the apparent activation energy of the demanganization reaction was estimated to be 189.46 kJ·mol-1 in the current study, which indicated that the mass transfer of MnO in the molten slag controlled the overall rate of the demanganization reaction. The calculated apparent activation energy was slightly lower than the values reported in the literature for mass transfer in a slag phase. This difference was attributed to an increase in the "specific reaction interface" (SRI) value, either as a result of turbulence at the reaction interface or a decrease of the absolute amount of slag phase during sampling, and to the addition of calcium fluoride to the slag.     

Synthesis and Applications of Fluoroalkyl End-capped Oligomeric Nanoparticles

1 Results Considerable interest has been devoted in recent years to block copolymers containing fluoroalkyl groups owing to exhibiting the low surface energy and the self-assembled polymeric aggregates resembling micelle in aqueous and organic media, which cannot be achieved in the corresponding randomly fluorinated copolymers[1].In these fluorinated block copolymers, we have found that ABA triblock-type fluoroalkylated oligomers and dendritic-type fluoroalkyl end-capped block copolymers can be prepared by the use of fluoroalkanoyl peroxide as a key intermediate[2].Interestingly, these fluorinated block polymers can form the nanometer size-controlled self-assembled molecular aggregates with the aggregation of end-capped fluoroalkyl segments in aqueous and organic media[3].More interestingly, these fluorinated molecular aggregates thus obtained could interact with a variety of guest molecules such as organic dyes, low-molecular biocides, metal nanoparticles, calcium carbonates, fullerenes, single-walled carbon nanotubes, nanodiammonds and magnetites to afford stable fluorinated molecular aggregates-guest molecules nanocomposites[3].     

Excitation energy distribution between two photosystems inPorphyra yezoensis and its significance in photosynthesis evolution

Comparative investigation on energy distribution between two photosystems were carried out in the sporo- phytes and gametophytes of Porphyra yezoensis. By perfor- ming 77 K fluorescence spectra, we suggested that there probably existed a pathway for energy transfer from PSⅡ to PSⅠ to redistribute the absorbed energy in gametophytes, while no such a way or at minor level in sporophytes. Electron transfer inhibitor DCMU blocked the energy transfer from PSⅡ to PSⅠ in gametophytes, but no obvious effects on sporophytes. These indicated that excitation energy distribution between two photosystems in gametophytes was more cooperative than that in sporophytes. These data in ontogenesis reflected the evolution process of photosynthetic organisms and supported the hypothesis of independent evolution of each photosystem.     

Organic solvent- and phase transfer catalyst-free oxidation of cyclohexanol to cyclohexanone with dilute H2O2

The oxidation of cyclohexanol to cyclohexanone with 30% aqueous hydrogen peroxide by using peroxotungstate complexes formed in situ from sodium tungstate dihydrate and various bidentate organic ligands as the catalysts, without organic solvents, halide and phase transfer catalyst has been carried out. The influence of 13 ligands on the oxidation is investigated. The maximum yield of cyclohexanone is obtained when using 1,10-phenanthroline (96%) and oxalic acid (95%) as the ligand. Very high yields (around 90%) have also been obtained for the instances of using salicylic acid, 3,5-dibromosalicylic acid, and 8-hydro- xylquinoline as ligands. A research to improve the reaction condition using cheap oxalic acid as the ligand indicates that the optimum condition is that the reaction mixture with a molar ratio of cycohexanol︰tungstate dihydrate︰oxalic acid︰30% H₂O₂=100︰2︰2︰120 was stirred at 85—90℃ for 12 h. :     

ApcD is required for state transition but not involved in blue-light induced quenching in the cyanobacterium <Emphasis Type="Italic">Anabaena</Emphasis> sp. PCC7120

Pbycobilisomes （PBS） are able to transfer absorbed energy to photosystem Ⅰ and Ⅱ, and the distribution of light energy between two photosystems is regulated by state transitions. In this study we show that energy transfer from PBS to photosystem Ⅰ （PSI） requires ApcD. Cells were unable to perform state transitions in the absence of ApcD. The apcD mutant grows more slowly in light mainly absorbed by PBS, indicating that ApcD-dependent energy transfer to PSI is required for optimal growth under this condition. The apcD mutant showed normal blue-light induced quenching, suggesting that ApcD is not required for this process and state transitions are independent of blue-light induced quenching. Under nitrogen fixing condition, the growth rates of the wild type and the mutant were the same, indicating that energy transfer from PBS to PSI in heterocysts was not required for nitrogen fixation.     

Relationship between microstate number and available entransy

Based on the relationship between entransy and microstate number, we discuss the variations of the available transport entransy, the unavailable transport entransy, the available conversion entransy and the unavailable conversion entransy with the microstate number. We focus on physical processes in which heat is used for heating/cooling or doing work. When heat is transported for heating or cooling, the available transport entransy increases if the increase in microstate number is due to the increase in internal energy of the system, and decreases if the increase in microstate number is due to spontaneous heat transfer. When heat is used to do work, both the available conversion entransy and the unavailable conversion entransy increase if the increase in microstate number relates to the growth in internal energy of the system. The available conversion entransy decreases and the unavailable conversion entransy increases if the increase in microstate number results from spontaneous heat transfer.     

Hydrometallurgical recycling of valuable metals from spent lithium-ion batteries by reductive leaching with stannous chloride

The reductant is a critical factor in the hydrometallurgical recycling of valuable metals from spent lithium-ion batteries(LIBs). There is limited information regarding the use of SnCl_2 as a reductant with organic acid(maleic acid) for recovering valuable metals from spent LiCoO_2 material. In this study, the leaching efficiencies of Li and Co with 1 mol·L~(-1) of maleic acid and 0.3 mol·L~(-1) of SnCl_2 were found to be98.67% and 97.5%, respectively, at 60°C and a reaction time of 40 min. We investigated the kinetics and thermodynamics of the leaching process in this study to better understand the mechanism of the leaching process. Based on a comparison with H_2O_2 with respect to leaching efficiency, the optimal leaching parameters, and the activation energy, we determined that it is feasible to replace H_2O_2 with SnCl_2 as a leaching reductant in the leaching process. In addition, when SnCl_2 is used in the acid-leaching process, Sn residue in the leachate may have a positive effect on the re-synthesis of nickel-rich cathode materials. Therefore, the results of this study provide a potential direction for the selection of reductants in the hydrometallurgical recovery of valuable metals from spent LIBs.