SE Process Research Articles

Hydrochar produced from mixed feedstocks as efficient adsorbent for selenium and chromium removal from acidic wastewater

Selenium (Se) and chromium (Cr) in water might be harmful because of their high toxicity in the aquatic environment. Efficient removal of their hexavalent forms (Se(VI) and Cr(VI)) from extreme acidic wastewater is still challenging. Therefore, several new hydrochars suited for efficient removal of trace Se(VI) and Cr(VI) from acidic wastewater were fabricated from biomass through a hydrothermal method. Most functional groups were retained in the hydrochar, which gave it an excellent adsorption capacity (43.2 mg·g−1 and 132 mg·g−1 for Se(VI) and Cr(VI), respectively). After one batch treatment at exceptionally low pH and a hydrochar dose of 0.2 g·L−1, Se(VI) and Cr(VI) could be removed from 1 mg·L−1 to 6 μg·L−1 and 15 μg·L−1, respectively. The mechanism of adsorption at various pH was elucidated by Scanning Electron Microscopy, Thermogravimetry, Fourier Transform Infrared Spectrometer, X-Ray Photoelectron Spectroscopy and density functional theory (DFT) calculation. The adsorption mechanism for Se(VI) in acidic solution involved the binding of SeO42− with protonated amino groups (−NH3+) of Mix hydrochar. In the pH range of 6.5 to 7, Cr(VI) combined with −NH3+ functional groups primarily in the form of CrO42−. When the pH fell below 6.5, Cr(VI) bound with both −NH3+ and carbonyl groups (−C=O) in the form of HCrO4−. Fast kinetics were observed during the removal process of Se(VI) and Cr(VI). The hydrochar adsorbent showed good stability under acidic environments and during long-term adsorption cycles. These findings may provide theoretical basis for design of adsorption materials for acidic wastewater treatment.

Fabrication of sulfur-based functionalized activated carbon as solid phase extraction adsorbent for selective analysis of selenite in water

Based on the important feature of sulfur with excellent selectivity toward selenite in the presence of selenate, a simple and low-cost adsorbent of solid phase extraction known as sulfur loading activated carbon (SAC-6) was successfully prepared and applied for selenite (Se(IV)) analysis in water. Microstructure and morphological characteristics of SAC-6 had been identified by XRD, TEM, BET and FT-IR. In the static adsorption experiments, Se(IV) could be separated in a wide range of pH values (pH=3–11). The retention process of Se(IV) onto SAC-6 was characterized as spontaneous exothermic reaction. An obvious change of adsorption mechanism occurred in static and dynamic adsorption processes shown that the behaviors followed monolayer and hybrid adsorption. The theoretical maximum adsorption capacity of SAC-6 calculated by Langmuir-Freundlich was 13.48 mg/g. The microcolumn filled with SAC-6 was applied to extract Se(IV) in water solution. The detection limit of Se(IV) analytical procedure was confirmed as 0.27 μg/L within a linear range of 10–1000 μg/L. A good precision with relative standard deviation of 1.34 % (100 μg/L, n = 6) was achieved. The high adaptability and accuracy of SAC-6 microcolumn was validated by analyzing natural water samples and certified reference materials. Our work successfully excavated the application value of the sulfur selectivity, and also provided a new adsorbent for Se(IV) extraction and analysis.

How do school experiences in adolescence affect educational investment in adulthood? The case of parental investment in private tutoring in Germany

AbstractThis article examines the role of parents’ school experiences in adolescence on their educational investment strategies for their own children in middle adulthood. We focus our analysis on the parents’ decision to organize private tutoring (also called shadow education) for their children. Previous international research largely agrees that families with a high socioeconomic status (SES) are more likely to invest in tutoring to achieve competitive advantages in the educational race for higher credentials and maintain a high social status. In Germany, however, recent studies suggest that tutoring in Germany primarily serves underperforming children from les educated families to acquire relatively higher school degrees by compensating the higher demands of academic school tracks. We propose a theoretical decision model based on rational choice and life course theory incorporating psychological factors related to school performance of the parents (such as performance anxiety and ability self-concept) and operationalize four components that are intended to explain the (un)equal use of tutoring: (1) children’s school background, (2) parents’ cost and (3) benefit considerations, as well as (4) parents’ school biography. In addition, we hypothesize on the intergenerational transmission of performance-related factors from parents to their children and how this affects SE investment. We test our hypotheses quantitatively through logit regressions and a structural equation model using unique longitudinal data for 558 families (parents and their children) from the German “LifE” study (1979–2012). Our study produced two key findings: On the one hand, the parents’ previous school performance plays a direct role in the extent to which they themselves are able to provide their children with the necessary support in the event of poor performance. On the other hand, the performance-related experiences of the parents during school are to a certain extent transmitted to their children and thus influence their grades, ability self-concept and performance anxiety. These factors, in turn, are decisive for the decision to organize SE. Our findings indicate that instead of reducing the decision-making process for SE to absolute dimensions of student performance and parents’ SES and related cost-benefit calculations, dynamic factors behind this family decision related to intergenerational transmission and individual characteristics should be considered.

Enhancing the mechanical strength of corrugated medium paper through instant catapult steam explosion pretreatment of tobacco stem

The decline in mechanical properties of secondary fiber upon multiple recycling iterations necessitates the incorporation of cost-effective and environmentally friendly fibers to counterbalance strength loss. In this study, an orthogonal experiment design was employed to optimize the SE process to acquire tabocco stem pulp (TSP). The study systematically investigated the influence of steam pressure, residence time, and alkali dosage employed during impregnation were investigated. Notably, the research identified alkali dosage as the most significant parameter impacting system performance. Under optimized conditions (1.2 MPa, 5 min, and 5 %), the prepared paper using 100 % TSP exhibited the capability to attain Grade C corrugated medium. TSP, subsequently, served as a compensatory material for mitigating the loss of strength observed in low-quality secondary fibers (LSF). Remarkably, the introduction of 20 wt% TSP resulted in the production of grade B products, showcasing exceptional enhancement in ring-crush strength. The breaking length of paper was increased with an additional 0.5 wt% PAE added, resulting in all criteria achieving the highest grade A. In conclusion, the study elucidated the synergistic and complementary effects of TSP and LSF, wherein stiff TSP fiber bundles formed a network that effectively supported LSF filling. This study identified the relationship between SE parameters and fiber properties, conclusively establishing waste tobacco stem as a quality fiber source conducive to producing high-quality paper.

Integration analysis of transcriptome and proteome profiles brings new insights of somatic embryogenesis of two eucalyptus species

BackgroundSomatic embryogenesis (SE) is recognized as a promising technology for plant vegetative propagation. Although previous studies have identified some key regulators involved in the SE process in plant, our knowledge about the molecular changes in the SE process and key regulators associated with high embryogenic potential is still poor, especially in the important fiber and energy source tree – eucalyptus.ResultsIn this study, we analyzed the transcriptome and proteome profiles of E. camaldulensis (with high embryogenic potential) and E. grandis x urophylla (with low embryogenic potential) in SE process: callus induction and development. A total of 12,121 differentially expressed genes (DEGs) and 3,922 differentially expressed proteins (DEPs) were identified in the SE of the two eucalyptus species. Integration analysis identified 1,353 (131 to 546) DEGs/DEPs shared by the two eucalyptus species in the SE process, including 142, 13 and 186 DEGs/DEPs commonly upregulated in the callus induction, maturation and development, respectively. Further, we found that the trihelix transcription factor ASR3 isoform X2 was commonly upregulated in the callus induction of the two eucalyptus species. The SOX30 and WRKY40 TFs were specifically upregulated in the callus induction of E. camaldulensis. Three TFs (bHLH62, bHLH35 isoform X2, RAP2-1) were specifically downregulated in the callus induction of E. grandis x urophylla. WGCNA identified 125 and 26 genes/proteins with high correlation (Pearson correlation > 0.8 or < -0.8) with ASR3 TF in the SE of E. camaldulensis and E. grandis x urophylla, respectively. The potential target gene expression patterns of ASR3 TF were then validated using qRT-PCR in the material.ConclusionsThis is the first time to integrate multiple omics technologies to study the SE of eucalyptus. The findings will enhance our understanding of molecular regulation mechanisms of SE in eucalyptus. The output will also benefit the eucalyptus breeding program.

Bioreduction of Se(IV) by Lactiplantibacillus plantarum NML21 and synthesis of selenium nanospheres Se(0)

Selenium nanospheres (SeNPs) show less toxicity and greater bioavailability than selenite salts. This research demonstrated the substantial tolerance and efficient conversion of Se(IV) into SeNPs by Lactiplantibacillus plantarum NML21. The bioreduction process of Se(IV) and the properties of SeNPs, including their morphology, particle size, and stability, were investigated with techniques including SEM, EDX, TEM, XPS, FT-IR, dynamic light scattering, XRD, and Raman spectroscopy. Under high selenium stress, certain cells displayed significant deformation and rupture, and released SeNPs as the main product of the bioreduction of Se(IV). These SeNPs were red, amorphous, zero-valent, and spherical, with an average diameter of 160 nm. Spectroscopic analysis highlighted that the functional groups of CO and CO are key to the bioreduction of Se(IV). The study suggested preliminary mechanisms for the bioreduction of Se(IV) and the formation and release of SeNPs by lactic acid bacteria. NML21 may therefore be a promising candidate for SeNPs synthesis.

Adsorption mechanism and influencing factors of selenium under the coexistence of nanoparticles and microplastics

Microplastics (MPs), as a common “vector” of pollutants in the aquatic environment, have a significant impact on the migration and transformation of heavy metals. In order to explore the mechanism and the influencing factors of the adsorption behavior of microplastics (MPs) on selenium (Se) in aqueous solution under the coexistence of nanoparticles, polystyrene microplastics (PS), nano-titanium dioxide particles (TiO2) and their coexisting compounds (PS+TiO2) were used as adsorbents to investigate the adsorption kinetics, isotherms and thermodynamic processes of Se. The effects of pH, humic acid concentration and coexisting ions on the adsorption behavior of Se(VI) were also analyzed. The results showed that the adsorption process of Se(VI) by PS and PS+TiO2 could be well fitted by pseudo-second-order kinetic model and Freundlich isotherm model, and it was an endothermic reaction with increased entropy. The adsorption capacity of Se(VI) by PS, TiO2, and PS+TiO2 were decreased with the increase of solution pH. Humic acid and Ca2+ promoted the adsorption of Se(VI), while PO43- significantly inhibited the adsorption of Se(VI) in the above three systems. The main adsorption mechanism of PS on Se(VI) was electrostatic adsorption and hydrogen bonding. The TiO2 adsorbed on the surface of PS mainly affected the adsorption behavior of PS on Se(VI) through hydrogen bonding.

Selenium in Photochemical Vapor Generation: Mechanism Study and Potential Nonchromatographic Speciation Analysis.

The mechanism of selenium in the UV photochemical vapor generation (PVG) process was investigated by the use of multiple analytical methods. It was found that the UV-induced photooxidation trapping of the generated volatile SeH2 should be responsible for the previous opinion of relative inertness of Se(VI) in PVG with formic acid. Furthermore, the formation of Se(IV) was found during the PVG process, and the comproportionation of Se(IV) with SeH2 and the photooxidation of Se(IV) into Se(VI) were investigated. Then, a preliminary model was proposed for the PVG process of Se(VI) and Se(IV) with low-molecular-weight organic acids. Then, a novel, simple, and green photocontrolled method without any photocatalyst was thus proposed for the nonchromatographic speciation analysis of Se(IV) and Se(VI), with a limit of detection of 0.2 and 5 ng/mL, respectively.

Efficient adsorption of selenium (Se(IV) and Se(VI)) from water using Acacia senegal polysaccharide with multiple amine groups: Synthesis and application

In this study, an amine-rich gel (ARAS) was prepared by chemically altering Acacia senegal (AS). ARAS acts as an adsorbent for selenium. Owing to the introduction of amino functional groups and a remarkable specific surface area (91.89 g/m2), ARAS shows maximum adsorption capacities at 75 and 130 mg g−1 for Se(IV) and Se(VI), respectively. The removal efficiency of ARAS is higher (ωSeIV = 98.2 % and ωSeVI = 98.6 %) at lower concentrations (CSeIV = 100 ppm and CSeVI = 95 ppm) and the adsorption equilibrium is achieved within 60 min. The adsorption process of Se (IV) and Se (VI) via ARAS is elucidated using the Quasi-Second-Order kinetic and Langmuir models. The enhanced adsorption capacity of the adsorbent could be attributed to the synergistic effects of electrostatic attraction, hydrogen bonding, and specific physicochemical properties. Thermodynamic studies reveal that the surface adsorption process is spontaneous and exothermic. Notably, ARAS maintains remarkable adsorption stability under a variety of solution conditions, including variable pH (4–11), NaCl concentrations (0–1 M), and the presence of organic solvents. It retains approximately 60 % of its initial adsorption capacity for Se(IV) and Se(VI) after three adsorption cycles. Therefore, ARAS with its cost-effectiveness and exceptional performance shows considerable potential for applications in water treatment.

Global Urban Land Expansion Tends To Be Slope Climbing: A Remotely Sensed Nighttime Light Approach

AbstractThe slope climbing of urban land expansion (SE) has become an increasingly prevalent phenomenon, and it has resulted in unique characteristics in terms of urban form, landscape, and governance with challenges for sustainable urban development worldwide. However, relatively little concern has been given to the SE with a long time series worldwide. On the basis of urban entities extracted from Suomi National Polar‐Orbiting Partnership Visible Infrared Imaging Radiometer Suite‐like (SNPP‐VIIRS‐like) data, we attempted to quantify and evaluate global SE with the help of slope spectrum analysis from different scales (e.g., global, continental, national, and city scales) during the period of 2000–2020. Our study proves that urban entities not only identify physical scopes but also reflect the intensity differences of socioeconomic development, which can provide an accurate approach to evaluate the SE. We found that global urban entities increased from 157,733 km2 in 2000 to 470,632 km2 in 2020, representing a 1.98‐fold increase. The global average slope of urban entities was on an upward trend, from 0.85° by 2000 to 0.96° by 2020, an increase of about 0.11°. Asia, Africa, and South America have experienced an evident SE process, while North America has exhibited a slow SE trend. A remarkable phenomenon has been found in China, where rapid SE has occurred due to the country's unprecedented urbanization process. The change value of the upper limit slope of urban land and the average slope climbing index of urban land have also experienced a volatile growth trend at global, continental, national, and city scales. Our study suggests that sustainable urban development should take the SE phenomenon into considerations, and that reasonable governance policies and strategies should be formulated to address its potential impacts.

The Controlling Factors of Soil Selenium Content in a Selenium-Deficient Area in Southwest China

Selenium (Se) is a beneficial microelement for humans, and its varying abundances and shortages have attracted widespread concern. The accumulation process of soil Se is quite complicated, being controlled by multiple factors. However, the influence mechanism of soil properties, climate, and topographic conditions on Se distribution is still unclear in Se-deficient areas. For this study, we collected 2804 samples from cropland soil to assess the levels of Se and the factors that influence those levels in Se-deficient areas of southwestern China. The Se content in this area (0.17 mg/kg) was less than the mean value of China as a whole (0.29 mg/kg). Moran’s I index and a random forest (RF) model showed that higher Se levels were mostly observed in the southern and northern sections of the area we studied. The RF model had excellent performance in predicting soil Se content, with an accuracy of 64%. The use of Shapley additive explanations indicated that soil organic matter (SOM) and mean annual precipitation (MAP) were the critical factors determining Se distribution. The areas with high SOM and MAP showed high Se levels. The information obtained from this work can provide guidance for agricultural planning in Se-deficient areas.

Fine-Tuning Bi2Te3-Copper Selenide Alloys Enables an Efficient n-Type Thermoelectric Conversion

Bismuth tellurides is one of the most promising thermoelectric (TE) material candidates in low-temperature application circumstances, but the n-type thermoelectric property is relatively low compared to the p-type counterpart and still needs to be improved. Herein, we incorporated different copper selenides (CuSe, Cu3Se2 and Cu2-xSe) into a Bi2Te3 matrix to create the alloy by grinding and successive sintering to enable higher thermoelectric performance. The results demonstrated that all alloys achieved n-type TE characteristics and Bi2Te3-CuSe exhibited the best Seebeck coefficient and power factor among them. Along with the low thermal conductivity, the maximum dimensionless TE figure of merit (ZT) value of 1.64 at 573 K was delivered for Bi2Te3-CuSe alloy, which is among the best reported results in the n-type Bi2Te3-based TE materials to the best of our knowledge. The improved TE properties should be related to the co-doping process of Se and Cu. Our investigation shows a new method to enhance the performance of n-type TE materials by appropriate co-doping or alloying.

Performance Comparison of Different Approaches for State Estimation Using RTU and Phasor Measurements

This paper compares various approaches to implement state estimation with conventional (RTU) measurements and phasor measurements. This study implements two-stage Hybrid State Estimation (HSE) in order to merge RTU and PMU measurements. Non-overlapping approach for area decomposition is applied in this paper. Centralized merging of PMU measurements in the process of HSE is presented to merge conventional measurements and phasor measurements effectively in a distributed network. Further, this study applies linear state estimation in a distributed network in case of full observability with PMU. Performance of state estimator in overall power system network and distributed network is compared for all approaches in terms of mean square error of estimated states and execution time of SE process. The effectiveness of the proposed approach is demonstrated with IEEE 14 bus system and IEEE 118 bus system.

High-yield recycling and recovery of copper, indium, and gallium from waste copper indium gallium selenide thin-film solar panels

A separation process for Cu, In, Ga, and Se (CIGS)-based thin-film solar panels is proposed in this study. Initially, the separation process, by peeling off the panels in a layer-by-layer manner, was achieved by utilizing the different thermal strains of materials inside the CIGS solar panels. Subsequently, the recovery process was performed by annealing the CIGS layers for the removal of Se, and then leaching was performed with nitric acid, followed by the individual extraction of valuable metals. The pH values, concentrations of extractant, stripping agents, organic-aqueous ratios, and reaction time were investigated in detail to optimize the separation conditions for Cu, In, and Ga. First, In was extracted using di-(2-ethylhexyl) phosphoric acid into the organic phase, while Cu and Ga remained in the aqueous phase, by controlling the extraction conditions. After the extraction of In, Ga was extracted using the same extraction agent under different conditions, and nearly pure Cu remained in the residual aqueous solution. Ammonium hydroxide was added to three solutions to form metal hydroxide precipitates. Under the optimal conditions, a recovery rate of >90% could be achieved for In, Ga, and Cu. Furthermore, all as-formed hydroxides were recycled and converted into metal oxides with a purity of >99% by calcination. These findings can provide a pathway for the effective recycling and recovery of Cu, In, and Ga from waste CIGS thin-film solar panels. • A facile and practical method to separate and recover valuable metals respectively from the real commercial thin-film solar panel was demonstrated. • A novel and low-cost physical separation process was induced to peer off the solar panel layer by layer via the extremely low-temperature liquid nitrogen treatment. • An extraction and stripping process was designed to separate Cu, In, and Ga from a complicated multi-element system individually. • Highly pure valuable metal oxides were recovered as the final products, establishing a possible curcular economy model for waste solar panel recycling and recovery.

Characterization of the differentiated reduction of selenite and tellurite by a halotolerant bacterium: Process and mechanism

Se(IV)- and Te(IV)-containing wastewater usually contains salt, which reduces the activity of conventional microorganisms and may affect their microbial treatment. So far, salt-tolerant Se(IV)- and Te(IV)-reducing bacteria are very limited. Moreover, the detailed molecular response of microbial reduction of Se(IV)/Te(IV) under saline conditions has yet to be reported. In this study, the Se(IV) and Te(IV) reductive processes and mechanisms were investigated with the employment of a marine bacterium Shewanella sp. CNZ-1 (CNZ-1) using process and kinetic analyses, enzymology and RT-qPCR analyses, and differential proteomics approaches. Our results showed that CNZ-1 can effectively reduce Se(IV) and Te(IV) to Se0 and Te0 with the max k (R2) values of 0.0412 h−1 (0.86) and 0.0292 h−1 (0.91) under 2% NaCl conditions, respectively. The mechanism study showed that CNZ-1 mediated Se(IV) reduction was an enzyme-based reductive reaction, whereas CNZ-1 mediated Te(IV) reduction was more like a resistance-related detoxification process (including both bioadsorption and bioreduction). The bioreduction of Se(IV) was mainly depended on functional membrane proteins (>4-fold; e.g., nitrite reductase, polysulfide reductase and fumarate reductase), while proteins related to efflux system and stress resistance system (>2-fold; e.g., Type II secretory pathway and phage shock proteins) were essential for the Te(IV) bioreduction process. Overall, our findings expanded the understanding the fate of Se(IV) and Te(IV) in the saline environment and provided guidance for Se(IV) or Te(IV) pollution control.

Microbial oxidation of organic and elemental selenium to selenite

Selenium (Se) is an essential trace element for life. Se reduction has attracted much attention in the microbial Se cycle, but there is less evidence for Se oxidation. In particular, it is unknown whether microorganisms oxidise organic Se(-II). In this study, four strains of bacteria, namely Dyella spp. LX-1 and LX-66, and Rhodanobacter spp. LX-99 and LX-100, isolated from seleniferous soil, were involved in the oxidation of selenomethionine (SeMet), selenocystine (SeCys2), selenourea and Se(0) to selenite (Se(IV)) in pure cultures. The oxidation rates of organic Se were more rapidly than those of Se(0) in liquid media. Then Se(0) and SeMet were used as examples, microbial oxidation was the predominant process for both additional Se(0) and SeMet in sterilised alkaline or acidic soils. The Se(IV) concentrations were significantly higher at pH 8.56 than at pH 5.25. In addition, water-soluble Se (SOLSe) and exchangeable and carbonate-bound Se (EXC-Se) fractions increased dramatically with these four Se-oxidising bacteria in unsterilised seleniferous soil. To our knowledge, this is the first study to find that various bacteria are involved in the oxidation of organic Se to Se oxyanions, bridging the gap of Se redox in the Se biogeochemical cycle.

Four‐Electron Transfer Reaction Endows High Capacity for Aqueous Cu–Se Battery

AbstractSelenium as a potential alternative cathode material for storing metal ions exhibits a series of advantages such as favorable electronic conductivity, attractive volumetric specific capacity, and mass density. However, due to the shortage of feasible redox couples for conversion reactions, the development of Se‐based batteries has been seriously impeded. Herein, based on the quantitative analysis of chemical thermodynamic properties, a novel conversion‐type Cu–Se battery is constructed with Cu2+ as the variable‐valence charge carrier. Benefitting from the synergism between the variable‐valence charge carrier and the chemical stability of copper selenides, the Cu–Se battery delivers a high initial reversible capacity of 1045.4 mAh g−1 at 0.1 A g−1, exceptional long‐span cycling stability with 89.7% capacity retention over 1500 cycles at 2 A g−1, and outstanding rate performance. Under a joint theoretical and experimental study from density functional theory calculations, X‐ray diffraction, X‐ray photoelectron spectroscopy, and high‐resolution transmission electron microscopy, it is demonstrated that the energy storage mechanism is a stepwise four‐electron conversion process of Se↔CuIISe↔CuI2Se. Thus, this work establishes an available aqueous Cu–Se battery with excellent performance and paves the way for exploring more promising metal–Se batteries by screening thermodynamic parameters.

Opportunities and Challenges of Sociotechnical Systems Engineering

AbstractThe authors propose a Sociotechnical Systems Engineering (STSE) framework that elevates the requirements and concerns of external/global stakeholders to be on par with those of traditional system users and counters the argument that profit motivation should be the dominant factor when deciding which systems we should build. STSE offers a more complete perspective on what it means to deliver a balanced solution. The authors distill unique elements of Sociotechnical Systems Engineering (STSE) and an integrated framework. The framework serves as the foundation for ongoing discussion of opportunities and challenges associated with our evolving practice of SE. Traditional SE framework, practices and processes remain intact. STSE emphasizes the importance of accounting for societal considerations and hidden costs excluded from our current decision‐making consideration. Post‐deployment societal outcomes we experience may not lie in our ability to perform SE/STSE, but in the governing motivations as we do so.

In silico characterization of putative gene homologues involved in somatic embryogenesis suggests that some conifer species may lack LEC2, one of the key regulators of initiation of the process

BackgroundSomatic embryogenesis (SE) is the process in which somatic embryos develop from somatic tissue in vitro on medium in most cases supplemented with growth regulators. Knowledge of genes involved in regulation of initiation and of development of somatic embryos is crucial for application of SE as an efficient tool to enable genetic improvement across genotypes by clonal propagation.ResultsCurrent work presents in silico identification of putative homologues of central regulators of SE initiation and development in conifers focusing mainly on key transcription factors (TFs) e.g. BBM, LEC1, LEC1-LIKE, LEC2 and FUSCA3, based on sequence similarity using BLASTP. Protein sequences of well-characterised candidates genes from Arabidopsis thaliana were used to query the databases (Gymno PLAZA, Congenie, GenBank) including whole-genome sequence data from two representative species from the genus Picea (Picea abies) and Pinus (Pinus taeda), for finding putative conifer homologues, using BLASTP. Identification of corresponding conifer proteins was further confirmed by domain search (Conserved Domain Database), alignment (MUSCLE) with respective sequences of Arabidopsis thaliana proteins and phylogenetic analysis (Phylogeny.fr).ConclusionsThis in silico analysis suggests absence of LEC2 in Picea abies and Pinus taeda, the conifer species whose genomes have been sequenced. Based on available sequence data to date, LEC2 was also not detected in the other conifer species included in the study. LEC2 is one of the key TFs associated with initiation and regulation of the process of SE in angiosperms. Potential alternative mechanisms that might be functional in conifers to compensate the lack of LEC2 are discussed.

Mechanically and structurally stable Sb2Se3/carbon nanocomposite as anode for the lithium-ion batteries

Metal chalcogenides undergoing alloying and conversion mechanism can give high capacity as anode for lithium-ion batteries. However, large volume change and phase segregation lead to poor cycle performance. In this study, we focus on Sb2Se3 and develop methods to enhance its long-term stability and reversibility. In particular, we find that carbon encapsulation reduces volume change during lithiation/delithiation and facilitates the recombination process of Sb and Se even after long cycling. With an addition of 20 wt% acetylene black, the Sb2Se3/C nanocomposite material exhibits an excellent cycle performance with a charge capacity of 545 mAh g−1 at 250 mA g−1 after 1000 cycles, corresponding to a capacity retention of 99.3%. We also demonstrate a full cell with LiFePO4 cathode and Sb2Se3/C anode that is capable of delivering a stable capacity of 340 mAh g−1 at 1 A g−1 (about 3 C rate) after 300 cycles.