Effects of Cyclic Electron Flow Inhibitor(Antimycin A)on Photosystem Photoinhibition of Sweet Pepper Leaves upon Exposure to Chilling Stress Under Low Irradiance

In chloroplast, there were two pathways involved in the cyclic electron flow around photosystem 1 （PS 1）. One was the NADH dehydrogenase （NDH）-dependent flow and the other was the ferredoxin quinone reductase-dependent flow. It was proposed that the NDH-dependent cyclic electron flow around PSI was related to the xanthophyll cycle-dependent non-photochemical quenching （NPQ） at chilling temperature under low irradiance （CL）. The function of the chloroplastic cyclic electron flow around PS 1 was examined by comparing sweet pepper （Capsicum annuum L.） control with its antimycin A （AA）-fed leaves upon exposure to CL stress. During CL stress, the maximum photochemical efficiency of PS2 （Fv/Fm） decreased markedly in both controls and AA-fed leaves, and P700＋ was also lower in AA-fed leaves than in controls. These results implied that cyclic electron flow around PS 1 functioned to protect the photosynthetic apparatus from CL stress. Under such stress, NPQ and PS2-driven electron transport rate were different between AA-fed leaves and controls. The lower NPQ in AA-fed leaves might be related to an inefficient proton gradient across thylakoid membranes （ApH） because of inhibiting cyclic electron flow around PS 1 under CL stress.

Schamel equation in an inhomogeneous magnetized sheared flow plasma with q-nonextensive trapped electrons

An investigation is carried out for understanding the properties of ion–acoustic（IA） solitary waves in an inhomogeneous magnetized electron-ion plasma with field-aligned sheared flow under the impact of q-nonextensive trapped electrons. The Schamel equation and its stationary solution in the form of solitary waves are obtained for this inhomogeneous plasma. It is shown that the amplitude of IA solitary waves increases with higher trapping efficiency（β）, while the width remains almost the same. Further, it is found that the amplitude of the solitary waves decreases with enhanced normalized drift speed, shear flow parameter and the population of the energetic particles. The size of the nonlinear solitary structures is calculated to be a few hundred meters and it is pointed out that the present results are useful to understand the solar wind plasma.

Evaluation of Carbon and Electron Flow in Lactobacillus brevis as a Potential Host for Heterologous 1-Butanol Biosynthesis

Heterofermentative lactic acid bacterium Lactobacillus brevis may be considered as a promising host for heterologous butanol synthesis because of tolerance to butanol and ability to ferment pentose and hexose sugars from wood hydrolysates that are cheap and renewable carbohydrate source. Carbon and electron flow was evaluated in two L. brevis strains in order to assess metabolic potential of these bacteria for heterologous butanol synthesis. Conditions required for generation of acetyl-CoA and NADH which are necessary for butanol biosynthesis have been determined. Key enzymes controlling direction of metabolic fluxes in L. brevis in various redox conditions were defined. In anaerobic glucose fermentation, the carbon flow through acetyl-CoA is regulated by aldehyde dehydrogenase ALDH possessing low affinity to NADH and activity (KmNADH= 200 μM, Vmax= 0.03 U/mg of total cell protein). Aerobically, the NADH-oxidase NOX (KmNADH= 25 μM, Vmax = 1.7 U/mg) efficiently competes with ALDH for NADH that results in formation of acetate instead of acetyl-CoA. In general, external electron acceptors (oxygen, fructose) and pentoses decrease NADH availability for native ethanol and recombinant butanol enzymes and therefore reduce carbon flux through acetyl-CoA. Pyruvate metabolism was studied in order to reveal redirection possibilities of competitive carbon fluxes towards butanol synthesis. The study provides a basis for the rational development of L. brevis strains producing butanol from wood hydrolysate.

Development of tailored TiO_2 mesocrystals for solar driven photocatalysis

Ordered metal oxides superstructures have attracted much more attention in the fields of fuel generation and environmental purification owing to their unique physiochemical characteristics such as large surface area, fine pore structure, efficient electronic mobility, and good stability. Very recently, TiOmesocrystals（TMCs） having superstructures self-assembled by TiOnanoparticle building blocks, are of considerable interest in current research and application ranging from UV to visible light attributed to their efficient charge separation and superior photocatalytic activity. In this review, we describe the common procedures to prepare unique TMCs and overview of recent developments of TMCs during last 3 years, especially the structure-related or electronic-effected mechanism in photocatalytic reaction. Further, we introduce the characterization and fundamental properties of modified TMCs by the means of single-particle fluorescence microscopy for unraveling the charge transport and photocatalytic properties of individual TMCs and time-resolved diffuse reflectance spectroscopy（TDR） for monitoring the charge transfer dynamics. Finally, various aspects on TMCs are discussed for the future developments of energy and environmental fields.

Chemical Reactivity Description in Density-Functional and Information Theories

In Quantum Information Theory(QIT) the classical measures of information content in probability distributions are replaced by the corresponding resultant entropic descriptors containing the nonclassical terms generated by the state phase or its gradient(electronic current). The classical Shannon(S[p]) and Fisher(I[p]) information terms probe the entropic content of incoherent local events of the particle localization, embodied in the probability distribution p, while their nonclassical phase-companions, S[ Φ ] and I[ Φ ], provide relevant coherence information supplements.Thermodynamic-like couplings between the entropic and energetic descriptors of molecular states are shown to be precluded by the principles of quantum mechanics. The maximum of resultant entropy determines the phase-equilibrium state, defined by "thermodynamic" phase related to electronic density,which can be used to describe reactants in hypothetical stages of a bimolecular chemical reaction.Information channels of molecular systems and their entropic bond indices are summarized, the complete-bridge propagations are examined, and sequential cascades involving the complete sets of the atomic-orbital intermediates are interpreted as Markov chains. The QIT description is applied to reactive systems R = A―B, composed of the Acidic(A) and Basic(B) reactants. The electronegativity equalization processes are investigated and implications of the concerted patterns of electronic flows in equilibrium states of the complementarily arranged substrates are investigated. Quantum communications between reactants are explored and the QIT descriptors of the A―B bond multiplicity/composition are extracted.

Molecular Functions of Oxygen-Evolving Complex Family Proteins in Photosynthetic Electron Flow

Oxygen-evolving complex （OEC） protein is the original name for membrane-peripheral subunits of photosystem （PS） II. Recently, multiple isoforms and homologs for OEC proteins have been iden- tified in the chloroplast thylakoid lumen, indicating that functional diversification has occurred in the OEC family. Gene expression profiles suggest that the Arabidopsis OEC proteins are roughly categorized into three groups： the authentic OEC group, the stressresponsive group, and the group including proteins related to the chloroplast NAD（P）H dehydrogenase （NDH） complex involved in cyclic electron transport around PSI. Based on the above gene expression profiles, molecular functions of the OEC family proteins are discussed together with our current knowledge about their functions.

Regulation of pepc gene expression in Anabaena sp. PCC 7120 and its effects on cyclic electron flow around photosystem I and tolerances to environmental stresses

Since pepc gene encoding phosphoenolpyruvate carboxylase （PEPCase） has been cloned from Anabaena sp. PCC 7120 and other cyanobacteria, the effects of pepc gene expression on photosynthesis have not been reported yet. In this study, we constructed mutants containing either upregu-lated （forward） or downregulated （reverse） pepc gene in Anabaena sp. PCC 7120. Results from real‐time quantitative polymerase chain reaction （RT‐qPCR）, Western blot and enzymatic analysis showed that PEPCase activity was signifi-cantly reduced in the reverse mutant compared with the wild type, and that of the forward mutant was obviously increased. Interestingly, the net photosynthesis in both the reverse mutant and the forward mutant were higher than that of the wild type, but dark respiration was decreased only in the reverse mutant. The absorbance changes of P700 upon saturation pulse showed the photosystem I （PSI） activity was inhibited, as reflected by Y（I）, and Y（NA） was elevated, and＆amp;nbsp;dark reduction of P700t was stimulated, indicating enhanced cyclic electron flow （CEF） around PSI in the reverse mutant. Additional y, the reverse mutant photosynthesis was higher than that of the wild type in low temperature, low and high pH, and high salinity, and this implies increased tolerance in the reverse mutant through downregulated pepc gene.

Feasibility assessment of up-flow anaerobic sludge blanket treatment of sulfamethoxazole pharmaceutical wastewater

Treatment of sulfamethoxazole pharmaceutical wastewater is a big challenge.In this study,a series of anaerobic evaluation tests on pharmaceutical wastewater from different operating units was conducted to evaluate the feasibility of using anaerobic digestion,and the results indicated that the key refractory factor for anaerobic treatment of this wastewater was the high sulfate concentration.A laboratory-scale up-flow anaerobic sludge blanket(UASB)reactor was operated for 195 days to investigate the effects of the influent chemical oxygen demand(COD),organic loading rate(OLR),and COD/SO_(4)^(2-) ratio on the biodegradation of sulfamethoxazole in pharmaceutical wastewater and the process performance.The electron flow indicated that methanogenesis was still the dominant reaction although sulfidogenesis was enhanced with a stepwise decrease in the influent COD/SO_(4)^(2-) ratio.For the treated sulfamethoxazole pharmaceutical wastewater,a COD of 4983 mg/L(diluted by 50%),OLR of 2.5 kg COD/(m^(3)·d),and COD/SO_(4)^(2-) ratio of more than 5 were suitable for practical applications.The recovery performance indicated that the system could resume operation quickly even if production was halted for a few days.

Plasticity of photorespiratory carbon concentration mechanism in Sedobassia sedoides(Pall.)Freitag&G.Kadereit under elevated CO_(2)concentration and salinity

Rising atmospheric CO_(2)(carbon dioxide)concentrations and salinization are manifestations of climate change that affect plant growth and productivity.Species with an intermediate C_(3)-C_(4)type of photosynthesis live in a wide range of precipitation,temperature,and soil quality,but are more often found in warm and dry habitats.One of the intermediate C_(3)-C_(4)photosynthetic type is C_(2)photosynthesis with a carbon concentration mechanism(CCM)that reassimilates CO_(2)released via photorespiration.However,the ecological significance under which C_(2)photosynthesis has advantages over C_(3)and C_(4)plants remains largely unexplored.Salt tolerance and functioning of CCM were studied in plants from two populations(P1 and P2)of Sedobassia sedoides(Pall.)Freitag&G.Kadereit Asch.species with C_(2)photosynthesis exposed to 4 d and 10 d salinity(200 mM NaCl)at ambient(785.7 mg/m^(3),aCO_(2)and elevated(1571.4 mg/m^(3),eCO_(2))CO_(2).On the fourth day of salinity,an increase in Na+content,activity catalase,and superoxide dismutase was observed in both populations.P2 plants showed an increase in proline content and a decrease in photosynthetic enzyme content:rubisco,phosphoenolpyruvate carboxylase(PEPC),and glycine decarboxylase(GDC),which indicated a weakening of C_(2)and C_(4)characteristics under salinity.Treatment under 10 d salinity led to an increased Na^(+)content and activity of cyclic electron flow around photosystem I(PSI CEF),a decreased content of K^(+)and GDC in both populations.P1 plants showed greater salt tolerance,which was assessed by the degree of reduction in photosynthetic enzyme content,PSI CEF activity,and changes in relative growth rate(RGR).Differences between populations were evident under the combination of eCO_(2)and salinity.Under long-term salinity and eCO_(2),more salt-tolerant P1 plants had a higher dry biomass(DW),which was positively correlated with PSI CEF activity.In less salt-tolerant P2 plants,DW correlated with transpiration and dark respiration.Thus,S.sedoides showed a high degree of photosynthetic plasticity under the influence of salinity and eCO_(2)through strengthening(P1 plants)and weakening C_(4)characteristics(P2 plants).

Stop flow lithography synthesis of non-spherical metal oxide particles

Non-spherical micron and hand-sized particles and their composites have become essential in select application areas of optics, wear resistance, personnel protection, chemical mechanical polishing, and biomedicine. In this paper, the synthesis of composite and ceramic non-spherical particles using stop flow lithography is reported. Precursor suspensions of poly（ethylene glycol） diacrylate, 2-hydroxy- 2-methylpropiophenone and SiO2 or Al2O3 are prepared. The precursor suspension flows through a microfluidic device mounted on an upright microscope and is polymerized in an automated process. A photomask patterned with transparent geometric features, which define the cross-sectional shapes of the particles, masks the UV light to synthesize micron sized particles. Particles with axial dimensions ranging from 35 to 167μm were synthesized. Control of device channel depth and objective lens magnification enables the manipulation of the particle size. Composite particles in triangular, square, pentagonal, hexagonal, and circular cross sections were synthesized. Subsequently, the transformation of the composite particles into the corresponding metal oxide particles was achieved through polymer burn-offand sintering.

Structural insights into photosynthetic cyclic electron transport

During photosynthesis,light energy is utilized to drive sophisticated biochemical chains of electron transfers,converting solar energy into chemical energy that feeds most life on earth.Cyclic electron transfer/flow(CET/CEF)plays an essential role in efficient photosynthesis,as it balances the ATP/NADPH ratio required in various regulatory and metabolic pathways.Photosystem I,cytochrome b6f,and NADH dehydrogenase(NDH)are large multisubunit protein complexes embedded in the thylakoid membrane of the chloroplast and key players in NDH-dependent CEF pathway.Furthermore,small mobile electron carriers serve as shuttles for electrons between these membrane protein complexes.Efficient electron transfer requires transient interactions between these electron donors and acceptors.Structural biology has been a powerful tool to advance our knowledge of this important biological process.A number of structures of the membrane-embedded complexes,soluble electron carrier proteins,and transient complexes composed of both have now been determined.These structural data reveal detailed interacting patterns of these electron donor-acceptor pairs,thus allowing us to visualize the different parts of the electron transfer process.This review summarizes the current state of structural knowledge of three membrane complexes and their interaction patterns with mobile electron carrier proteins.

Simulation of electron behavior in PIG ion source for 9 MeV cyclotron

In this paper, we focus on a PIG source for producing intense H-ions inside a 9 MeV cyclotron. The properties of the PIG ion source were simulated for a variety of electric field distributions and magnetic field strengths using a CST particle studio. After analyzing the secondary electron emission（SEE） as a function of both magnetic and electric field strengths, we found that for the modeled PIG geometry, a magnetic field strength of 0.2 T provided the best results in terms of the number of secondary electrons. Furthermore, at 0.2 T, the number of secondary electrons proved to be greatest regardless of the cathode potential. Also, the modified PIG ion source with quartz insulation tubes was tested in a KIRAMS-13 cyclotron by varying the gas flow rate and arc current, respectively.The capacity of the designed ion source was also demonstrated by producing plasma inside the constructed 9 MeV cyclotron. As a result, the ion source is verified as being capable of producing an intense H-beam and high ion beam current for the desired 9 MeV cyclotron. The simulation results provide experimental constraints for optimizing the strength of the plasma and final ion beam current at a target inside a cyclotron.

Supramolecular assembly of chloroplast NADH dehydrogenase-like complex with photosystem Ⅰfrom Arabidopsis thaliana

Cyclic electron transport/flow(CET/CEF)in chloroplasts is a regulatory process essential for the optimization of plant photosynthetic efficiency.A crucial CEF pathway is catalyzed by a membrane-embedded NADH dehydrogenase-like(NDH)complex that contains at least 29 protein subunits and associates with photosystem I(PSI)to form the NDH-PSI supercomplex.Here,we report the 3.9Åresolution structure of the Arabidopsis thaliana NDH-PSI(AtNDH-PSI)supercomplex.We constructed structural models for 26 AtNDH subunits,among which 11 are unique to chloroplasts and stabilize the core part of the NDH complex.In the supercomplex,one NDH can bind up to two PSI-light-harvesting complex I(PSI-LHCI)complexes at both sides of its membrane arm.Two minor LHCIs,Lhca5 and Lhca6,each present in one PSI-LHCI,interact with NDH and contribute to supercomplex formation and stabilization.Collectively,our study reveals the structural details of the AtNDH-PSI supercomplex assembly and provides a molecular basis for further investigation of the regulatory mechanism of CEF in plants.

Improvement potential of today＇s WEEE recycling performance： The case of LCD TVs in Belgium

Waste of electrical and electronic equipment （WEEE） constitutes one of the most relevant waste streams because of the quantity and presence of valuable materials. However, there is limited knowledge on the resource potential of urban mining WEEE, as data on material composition, and the efficiency of current recycling treatments are still scarce. In this article, an evaluationof the recycling performance at a national level for one of the fastest growing e-waste streams： LCD TVs is carried out through the following four steps. Firstly, material characterisation is performed by means of sampling of the waste stream. Secondly, a material flow analysis is conducted by evaluating the separation performance of a recycling plant in Belgium..Thirdly, the recovered economic value and avoided environmental impact （EI） of the analysed recycling system is assessed. Finally, the potential of urban mining for Belgium is forecasted. The analysis shows that while recycling performance for ferrous metals and aluminium are relatively high; there is substantial room to better close the material loops for precious metals （PM） and plastics. PMs and plastics account for 66 % of the economic value in LCD TVs and 57% of the El. With the current, commonly applied recycling technology only one-third of the PM and housing plastics are recycled; meaning that for＇these material＇s, at a national level for Belgium, there is a potential for improvement that represents 3.3 million euros in 2016 and 6.8 million euros in 2025.