Cu_(2)ZnSnSSe_(4)(CZTSSe)thin film solar cells,with adjustable bandgap and rich elemental content,hold promise in next-gen photovoltaics.Crystalline quality is pivotal for efficient light absorption and carrier transp...Cu_(2)ZnSnSSe_(4)(CZTSSe)thin film solar cells,with adjustable bandgap and rich elemental content,hold promise in next-gen photovoltaics.Crystalline quality is pivotal for efficient light absorption and carrier transport.During the post-selenization process,understanding crystal growth mechanisms,and improving layer quality are essential.We explored the effects of ramp rate and annealing temperature on CZTSSe films,using X-ray diffraction(XRD),Raman spectroscopy,scanning electron microscope(SEM),and ultraviolet-visual spectrophotometry(UV-Vis).The optimal performance occurred at 25.25°C/min ramp rate and 530°C annealing.This led to smoother surfaces,higher density,and larger grains.This condition produced a single-layer structure with large grains,no secondary phases,and a 1.14 eV bandgap,making it promising for photovoltaic applications.The study has highlighted the effect of selenization conditions on the characteristics of the CZTSSe absorber layer and has provided valuable information for developing CZTSSe thin film solar cells.展开更多
Traditional studies on transforming selenate and selenite are often limited by static measurements and low spatial resolution.They do not fully consider the impact of moisture content.This paper uses the DGT(diffusive...Traditional studies on transforming selenate and selenite are often limited by static measurements and low spatial resolution.They do not fully consider the impact of moisture content.This paper uses the DGT(diffusive gradients in thin films)technique to deeply explore how moisture changes affect the transformation of selenate and selenite in the environment(changes in properties over time).First,representative soil samples(loess)are prepared,and their moisture content is adjusted.Fixed concentrations of selenate and selenite are added,and then the DGT device simulates their migration in the natural environment.The experiment covers drought,moisture,and high moisture environments,and the experiment is repeated under each condition to ensure the accuracy of the data.The sample quality is verified and further analyzed by ion chromatography(IC)and atomic absorption spectroscopy(AAS).This article uses DGT technology to study the influence of moisture content on the migration and transformation of selenate and selenite in soil.Results indicate that increased moisture content leads to higher concentrations,diffusion rates,and DGT capture efficiency of both selenium species,highlighting the importance of moisture in their environmental behavior.When the moisture content increased from 25%to 65%,the coefficient of variation of selenate and selenite increased.The DGT technique proved effective in capturing spatial heterogeneity and providing high-precision measurements,offering robust data to advance research on selenium behavior in soils.展开更多
With the improvement of living standards, people pay more attention to the agricultural products with health protection function, and the selenium-rich agricultural products attract more and more consumers. The main b...With the improvement of living standards, people pay more attention to the agricultural products with health protection function, and the selenium-rich agricultural products attract more and more consumers. The main biological role of selenium is to resist oxidation and inflammatory response, mainly focusing on resisting aging, preventing cardiovascular disease, protecting eyesight, counteracting or destroying the toxic properties, preventing cancer and thyroid disease. In most areas of China, there is a widespread shortage of selenium, thus producing selenium-rich agricultural products to provide natural selenium-rich health food to the areas in need of selenium, has gradually become a new hot spot of China's health food industry, but high content of selenium in food is detrimental to human body, even leads to selenium intoxication, and artificially adding inorganic selenium is difficult to guarantee that the selenium content of agricultural products is not exceeded. According to human body's daily demand for selenium in dietetics and the content of selenium in agricultural products in the Chinese food composition table, we put forward the recommendations on the standard of selenium in agricultural products, in order to provide the basis for China to formulate the health standard of selenium content in selenium-rich agricultural products.展开更多
Herein,we reported a convenient and efficient multicomponent reaction of indoles,selenium powder and unactivated alkyl halides.This protocol provides a practical,and facile approach for the synthesis of 3-alkylselenin...Herein,we reported a convenient and efficient multicomponent reaction of indoles,selenium powder and unactivated alkyl halides.This protocol provides a practical,and facile approach for the synthesis of 3-alkylselenindole derivatives.The advantages of this strategy include mild and transition-metal-free conditions,broad functional group tolerance,the use of simple and easily accessible seleniium powder and alkyl halides as coupling partners.More importantly,the reaction proceeded smoothly with a large scale(>10 g,>90%yield),which further highlighted the potential application of this selenation strategy.展开更多
Soil organic matter (SOM) plays an important role in the Se dynamics in soil. The potential effects of vermicompost and digestate as important sources of SOM on selenium (Se) mobility were assessed in this study. Thre...Soil organic matter (SOM) plays an important role in the Se dynamics in soil. The potential effects of vermicompost and digestate as important sources of SOM on selenium (Se) mobility were assessed in this study. Three soils differing in their physicochemical parameters, fluvisol, chernozem, and luvisol, were chosen, and three types of vermicomposts based on various bio-waste materials as digestate (vermicompost 1), kitchen waste with woodchips (vermicompost 2), and garden bio-waste (vermicompost 3) were used due to their high organic matter content. Additionally, digestate samples alone were applied. To evaluate the potential effect of vermicompost application on sorption characteristics of soils, batch sorption experiments were performed. The results showed a predominant effect on Se species in the soils, where selenite sorbed more intensively compared to selenate, regardless of the soil and ameliorative material applied. In the control, the soil sorption ability of selenite tended to decrease in the order: fluvisol > luvisol > chernozem. However, these differences were not significant. Moreover, the effects of the ameliorative materials depended on both soil and amendment used. In fluvisol, all the amendment applications resulted in a decrease in distribution coefficient ( K d values) of Se, whereas in chernozem, this effect was observed only for the digestate-based vermicompost 1. Increasing K d levels were reported in luvisol treated with digestate;the application of garden bio-waste-based vermicompost 3 tended to decrease the K d values. Further studies are required on long-term effects of these amendments on Se mobility in soils and the role of individual organic matter fractions in this context.展开更多
Selenium is an essential trace element for humans and animals.As the active center of selenoproteins,the addition of selenium is beneficial to enhance the antioxidant ability.However,the high cost limits the applicati...Selenium is an essential trace element for humans and animals.As the active center of selenoproteins,the addition of selenium is beneficial to enhance the antioxidant ability.However,the high cost limits the application of organic Se in agriculture animal production.Selenized glucose(SeGlu)is a newly invented organoselenium material with good stability,low toxicity and low cost.This assay found that SeGlu was able to increase selenium deposition in liver of newborn broilers,and enhance the antioxidant capacity of liver by elevating the activities of antioxidant enzymes such as total superoxide dismutase and glutathione peroxidase.This paper as the first example clarifying the mechanism of SeGlu to enhance the antioxidant ability of chicks,shows that SeGlu can be used as an organic selenium enrichment additive for early nutrition of poultry.As a cross-discipline study involving chemistry,biology and agriculture animal science,the work may be beneficial for studies in related fields and prompt the development of the selenium science.展开更多
Under changing climate,trace elements like selenium(Se)have emerged as vital constituent of agro-ecosystems enabling crop plants to off-set the adverse effects of suboptimal growth conditions.The available form of sel...Under changing climate,trace elements like selenium(Se)have emerged as vital constituent of agro-ecosystems enabling crop plants to off-set the adverse effects of suboptimal growth conditions.The available form of selenium is important for boosting its bioavailability to crop plants having varied agro-botanical traits and root architectural systems.As compared to selenite,the selenate has a weaker soil bonding,higher absorption in the soil solution which results in a comparatively absorption by plant roots.Various factors including dry climate,high pH,optimal ambient air temperature,less accumulation of water,and low concentration of organic matter in the soil tend to boost the selenate ratio in the soil.The use of selenium pelleted seeds has emerged as an interesting and viable alternative to alleviate selenium deficiency in agricultural eco-systems.Similarly,the co-inoculation of a mixture of Selenobacteria and Arbuscular mycorrhizal fungi represents an evolving promising strategy for the bio-fortification of wheat plants to produce selenium-rich flour to supplement human dietary needs.Furthermore,in-depth research is required to assure the effectiveness of biological fertilization procedures in field conditions as well as to explore and increase our understanding pertaining to the underlying main mechanisms and channels of selenium absorption in plants.The focus of this review is to synthesize the recent developments on Se dynamics in soil-plant systems and emerging promising strategies to optimize its levels for crop plants.Recent developments regarding the use of micro-organisms as a biotechnological mean to enhance plant nutrition and crop quality have been objectively elaborated.The study becomes even more pertinent for arid and semi-arid agro-ecosystems owing to the potential role of selenium in providing stress tolerance to crop plants.Moreover,this review synthesizes and summarizes the recent developments on climate change and bioavailability,and the protective role of selenium in crop plants.展开更多
Selenization reaction with the in situ prepared NaHSe has been successfully developed to occur in aqueous solution.The technique affords a method to upload the bioactive Se element on cotton products in semi-industria...Selenization reaction with the in situ prepared NaHSe has been successfully developed to occur in aqueous solution.The technique affords a method to upload the bioactive Se element on cotton products in semi-industrial scale.The antibacterial tests revealed that the selenized cotton possessed a potent and prolonged antimicrobial effect against both Gram-positive S.aureus and Gram-negative E.coli bacteria.This work discloses a practical method for preparing the selenium-containing antibacterial materials concisely and directly with industrial application potential.展开更多
The effect of selenate (Na2SeO4) and sulphate (Na2SO4) was studied on growth and metabolism in two rice cultivars cv. satabdi and cv. khitish. Selenate at low concentration (2 μM) expressed growth promoting effect on...The effect of selenate (Na2SeO4) and sulphate (Na2SO4) was studied on growth and metabolism in two rice cultivars cv. satabdi and cv. khitish. Selenate at low concentration (2 μM) expressed growth promoting effect on rice seedlings as opposed to its high concentration (≥20 μM) where the test seedlings showed stunted growth with browning at the apices of both roots and shoots. The chlorophyll contents showed a dose dependent effect. Both chlorophyll a and chlorophyll b contents were inhibited with increase in selenate concentrations. The effect was more pronounced in cv. satabdi compared to cv. khitish.The level of accessory pigments was deferentially affected by selenium treatment. Simultaneously, the fluorescence intensity and Hill activity decreased with increase in selenate concentrations in the test seedlings. It is assumed that selenium plays a protective role in plants subjected to stress and prevents the formation of reactive oxygen species (ROS) in the cells. Higher selenate concentrations (≥20 μM) exerted variable effect on the activities of enzymatic antioxidants viz.;superoxide dismutase (SOD), catechol peroxidase (CPX) and catalase (CAT) in the test seedlings. The activity of SOD increased with increase in selenate concentrations, whereas activities of CAT and CPX decreased. Under high selenate concentrations, the levels of oxidative stress markers, viz.;proline, H2O2 and MDA were also enhanced. Selenium induced accumulation of total soluble sugar and increased the level of both reducing and non reducing sugars in both the test cultivars. The starch contents concomitantly decreased with rise in selenate concentrations. Moreover, the nutrient contents of test seedlings were significantly influenced by selenium. The Na and K levels gradually increased whereas Ca, Mg and Fe levels decreased on application of selenate. Joint application of 10 mM sulphate and selenate showed significant alterations on all parameters tested with respect to selenate treatment alone. Partial to complete amelioration occurred in the test seedlings treated with high concentrations of selenate and sulphate. Our study shows that selenium at low concentration had a stimulatory effect on growth and metabolism as against high concentrations which proved to be toxic to the rice seedlings obtained from both the cultivars. Effects were more pronounced in cv. satabdi than in cv. khitish which is considered to be comparatively tolerant to selenium. The dose dependent influence of selenium on the physiological and biochemical responses of test seedlings may be reversed by co-application with sulphate.展开更多
The CulnSe2 compound was prepared by selenization of Cu-In precursor, which was ultrasonic electrodeposited at constant current. CulnSe2 films were compacted to improve surface morphology. The films were characterized...The CulnSe2 compound was prepared by selenization of Cu-In precursor, which was ultrasonic electrodeposited at constant current. CulnSe2 films were compacted to improve surface morphology. The films were characterized by X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, and energy dispersive spectroscopy （EDS）. It is indicated that ideal stoichiometrie CulnSe2 films can be obtained by the selenization of Cu-In precursor deposited at a current density of 20 mA/cm^2. Single-phase CulnSe2 is formed in the selenization proeess, and it exhibits preferred orientation along the （112） plane. The CulnSe2 films with smooth surface can be obtained under the pressure of 500 MPa at 60℃.展开更多
The growth of seedlings of Townsville sytlo (Stylosanthes humilis H.B.K.) is inhibited by aluminium (Al) ions, their elongation being re-covered with sodium selenate at 1.0 μM. Methyl viologen and hydrogen peroxide, ...The growth of seedlings of Townsville sytlo (Stylosanthes humilis H.B.K.) is inhibited by aluminium (Al) ions, their elongation being re-covered with sodium selenate at 1.0 μM. Methyl viologen and hydrogen peroxide, reactive oxy-gen species (ROS)-generating compounds, also inhibited seedling elongation and again growth was relieved by selenate. Selenate, thus, seemed to be operating as a ROS quencher, since N-acetylcysteine (NAC), an antioxidant com-pound, also stimulated largely the growth of Al-inhibited seedlings. At a higher concentra-tion (0.1 mM), however, selenate inhibited seed-ling growth and elongation was recovered by NAC. Ethylene production by selenate plus NAC-treated seedlings was very higher and thus the gaseous hormone was not responsible for the seedling growth inhibition caused by sele-nate. Hence, it seems that at high levels sele-nate operates as a ROS-generating compound whose effects were counteracted by NAC. It can be deduced that, at low concentration, sele-nates behave as a ROS quencher and at high level as a ROS-promoting species.展开更多
[Objective] The paper was to understand the harms of Actias selene ningpoana Felder to plants. [Method] The larvae were cultured in five different groups: camphor tree, cherry tree, crape myrtle tree, poplar and willo...[Objective] The paper was to understand the harms of Actias selene ningpoana Felder to plants. [Method] The larvae were cultured in five different groups: camphor tree, cherry tree, crape myrtle tree, poplar and willow, to observe the growth status of larvae. [Result] The survival rates of A. selene ningpoana in cherry tree and crape myrtle tree group were higher. The larvae in cherry tree group had faster growth, and the adults were large. [Conclusion] A. selene ningpoana is most harmful to cherry trees, which should be paid special attention in cherry garden.展开更多
Effective charge separation and rapid interfacial H_(2) production are imperative for the construction of efficient photocatalysts.Compared to Pt,the metallic Ag co‐catalyst with its strong electron‐trapping ability...Effective charge separation and rapid interfacial H_(2) production are imperative for the construction of efficient photocatalysts.Compared to Pt,the metallic Ag co‐catalyst with its strong electron‐trapping ability and excellent electronic conductivity typically exhibits an extremely limited photocatalytic H_(2-)evolution rate owing to its sluggish interfacial H_(2)‐generation reaction.In this study,amorphous AgSe_(x) was incorporated in situ onto metallic Ag as a novel and excellent H_(2)‐evolution active site to boost the interfacial H_(2)‐generation rate of Ag nanoparticles in a TiO_(2)/Ag system.Core‐shell Ag@AgSe_(x)nanoparticle‐modified TiO_(2)photocatalysts were prepared via a two‐step pathway involving the photodeposition of metallic Ag and the selective surface selenization of metallic Ag to yield amorphous AgSe_(x)shells.The as‐prepared TiO_(2)/Ag@AgSe_(x)(20μL)photocatalyst exhibited an excellent H_(2‐)production performance of 853.0μmol h^(-1)g^(-1),prominently outperforming the TiO_(2)and TiO_(2)/Ag samples by factors of 11.6 and 2.4,respectively.Experimental investigations and DFT calculations revealed that the enhanced H_(2‐)generation activity of the TiO_(2)/Ag@AgSe_(x)photocatalyst could be accounted by synergistic interactions of the Ag@AgSe_(x)co‐catalyst.Essentially,the metallic Ag core could quickly capture and transport the photoinduced electrons from TiO_(2)to the amorphous AgSe_(x)shell,whereas the amorphous AgSe_(x)shell provided large active sites for boosting the interfacial H_(2)evolution.This study offers a facile route for the construction of novel core‐shell co‐catalysts for sustainable H_(2)evolution.展开更多
Bulk group IB transition-metal chalcogenides have been widely explored due to their applications in thermoelectrics.However,a layered two-dimensional form of these materials has been rarely reported.Here,we realize se...Bulk group IB transition-metal chalcogenides have been widely explored due to their applications in thermoelectrics.However,a layered two-dimensional form of these materials has been rarely reported.Here,we realize semiconducting Cu_(2)Se by direct selenization of Cu(111).Scanning tunneling microcopy measurements combined with first-principles calculations allow us to determine the structural and electronic properties of the obtained structure.X-ray photoelectron spectroscopy data reveal chemical composition of the sample,which is Cu_(2)Se.The observed moire pattern indicates a lattice mismatch between Cu_(2)Se and the underlying Cu(111)-√3×√3 surface.Differential conductivity obtained by scanning tunneling spectroscopy demonstrates that the synthesized Cu_(2)Se exhibits a band gap of 0.78 eV.Furthermore,the calculated density of states and band structure demonstrate that the isolated Cu_(2)Se is a semiconductor with an indirect band gap of-0.8 eV,which agrees quite well with the experimental results.Our study provides a simple pathway varying toward the synthesis of novel layered 2D transition chalcogenides materials.展开更多
Arsenic affects plants by disrupting their growth and metabolism while selenium, an essential micronutrient has beneficial role in stress tolerance. Owing to the antioxidative capacity of selenium, it can counteract d...Arsenic affects plants by disrupting their growth and metabolism while selenium, an essential micronutrient has beneficial role in stress tolerance. Owing to the antioxidative capacity of selenium, it can counteract detrimental effects of arsenic induced stress in plants. The interactive influence of arsenate and selenate on the growth, arsenic and selenium accumulation, activities of non-enzymatic and enzymatic antioxidants, levels of ascorbate, α-tocopherol, total glutathione and activities of glutathione regulatory enzymes along with characterization and quantification of phytochelatins in growing wheat (Triticum aestivum L.) seedlings were investigated. Rate of arsenic accumulation was increased in arsenate treated seedlings while in seedlings treated jointly with arsenate and selenate, arsenic accumulation decreased. Arsenate stress resulted decrease in ascorbate and total glutathione contents, activities of the glutathione metabolism enzymes while significantly increased the levels of α-tocopherol and phytochelatins (PC2 and PC4), along with activities of ascorbate peroxidase and ascorbic acid oxidase in the test seedlings. The effects were more pronounced in roots than in shoots. Joint application of arsenate along with selenate was able to overcome the adverse effects caused by arsenic alone to variable extents by exhibiting significant alterations of all parameters tested, imparting better growth and thiol metabolism in the test seedlings. Our results conclude that application of selenium fertilizer in arsenic contaminated soil might be favourable to improve growth and defense ability in wheat against arsenic toxicity.展开更多
Local segregation in Cu-In precursors and its effects on the element distribution and microstructures of selenized CuInSe2 thin films were investigated. Cu-In precursors with an ideal total mole ratio of Cu to In of 0...Local segregation in Cu-In precursors and its effects on the element distribution and microstructures of selenized CuInSe2 thin films were investigated. Cu-In precursors with an ideal total mole ratio of Cu to In of 0.92 were prepared by middle frequency alternating current magnetron sputtering with Cu-In alloy target, then CuInSe2 absorbers for solar cells were formed by selenization process in selenium atmosphere. Scanning electron microscope and energy dispersive X-ray spectroscope were used respectively to observe the surface morphologies and determine the compositions of both Cu-In precursors and CuInSe2 thin films. Their microstructures were characterized by X-ray diffractometry and Raman spectroscope. The results show that Cu-In precursors are mainly composed of (Cu11In9) phase with In-rich solid solution. Stoichiometric CuInSe2 thin films with a homogeneous element distribution and single chalcopyrite phase can be synthesized from a segregated Cu-In precursor film with an ideal total mole ratio of Cu to In of 0.92. CuInSe2 thin film shows P-type conductivity and its resistivity reaches 1.2×103Ω·cm.展开更多
Cu2ZnSn（S,Se）4（CZTSSe） thin film was prepared using a simple two-step approach based on the single-source evaporation and synchronous sulfo-selenization.Composition,microstructure,morphology,and properties of the ...Cu2ZnSn（S,Se）4（CZTSSe） thin film was prepared using a simple two-step approach based on the single-source evaporation and synchronous sulfo-selenization.Composition,microstructure,morphology,and properties of the asprepared CZTSSe thin films were investigated.XRD and Raman patterns confirmed the formation of single-phase CZTSSe solid solutions.SEM results showed that the CZTSSe thin film had a uniform morphology and large grains.EDS results revealed the composition of CZTSSe film was Cu：Zn：Sn：S：Se = 23.7：12.6：12.2：37.7：13.8（in at%）,which was in accordance with the stoichiometric Cu2ZnSn（S,Se）4.The optical band gap of CZTSSe thin film evaluated from its UV–Vis spectrum was 1.33 eV.The resistivity,carrier concentration,and mobility were 0.53 X cm,7.9 9 1018cm3,and 7.5 cm2/（Vs）,respectively.展开更多
By allowing H_(2)SeO_(4),Cy_(2)NH,CyNH_(2) or Bz2NH to react respectively with SnPh_(3)Cl(in methanol),SnPh_(2)Cl_(2)(in water+methanol)and MgCl_(2)·6H_(2)O(in methanol)in specific ratios,the studied complexes ar...By allowing H_(2)SeO_(4),Cy_(2)NH,CyNH_(2) or Bz2NH to react respectively with SnPh_(3)Cl(in methanol),SnPh_(2)Cl_(2)(in water+methanol)and MgCl_(2)·6H_(2)O(in methanol)in specific ratios,the studied complexes are obtained.The suggested structures are discrete and polymer,the environment of the tin center being trans trigonal bipyramidal(compound 1),tetrahedral(compound 2)and octahedral(compound 3),the anions behaving as a bidentate selenate.展开更多
基金supported by the Science and Technology Innovation Development Program(No.70304901).
文摘Cu_(2)ZnSnSSe_(4)(CZTSSe)thin film solar cells,with adjustable bandgap and rich elemental content,hold promise in next-gen photovoltaics.Crystalline quality is pivotal for efficient light absorption and carrier transport.During the post-selenization process,understanding crystal growth mechanisms,and improving layer quality are essential.We explored the effects of ramp rate and annealing temperature on CZTSSe films,using X-ray diffraction(XRD),Raman spectroscopy,scanning electron microscope(SEM),and ultraviolet-visual spectrophotometry(UV-Vis).The optimal performance occurred at 25.25°C/min ramp rate and 530°C annealing.This led to smoother surfaces,higher density,and larger grains.This condition produced a single-layer structure with large grains,no secondary phases,and a 1.14 eV bandgap,making it promising for photovoltaic applications.The study has highlighted the effect of selenization conditions on the characteristics of the CZTSSe absorber layer and has provided valuable information for developing CZTSSe thin film solar cells.
文摘Traditional studies on transforming selenate and selenite are often limited by static measurements and low spatial resolution.They do not fully consider the impact of moisture content.This paper uses the DGT(diffusive gradients in thin films)technique to deeply explore how moisture changes affect the transformation of selenate and selenite in the environment(changes in properties over time).First,representative soil samples(loess)are prepared,and their moisture content is adjusted.Fixed concentrations of selenate and selenite are added,and then the DGT device simulates their migration in the natural environment.The experiment covers drought,moisture,and high moisture environments,and the experiment is repeated under each condition to ensure the accuracy of the data.The sample quality is verified and further analyzed by ion chromatography(IC)and atomic absorption spectroscopy(AAS).This article uses DGT technology to study the influence of moisture content on the migration and transformation of selenate and selenite in soil.Results indicate that increased moisture content leads to higher concentrations,diffusion rates,and DGT capture efficiency of both selenium species,highlighting the importance of moisture in their environmental behavior.When the moisture content increased from 25%to 65%,the coefficient of variation of selenate and selenite increased.The DGT technique proved effective in capturing spatial heterogeneity and providing high-precision measurements,offering robust data to advance research on selenium behavior in soils.
基金Supported by Hunan University Innovation Team FoundationHunan Science and Technology Plan Project (2011NK3093)
文摘With the improvement of living standards, people pay more attention to the agricultural products with health protection function, and the selenium-rich agricultural products attract more and more consumers. The main biological role of selenium is to resist oxidation and inflammatory response, mainly focusing on resisting aging, preventing cardiovascular disease, protecting eyesight, counteracting or destroying the toxic properties, preventing cancer and thyroid disease. In most areas of China, there is a widespread shortage of selenium, thus producing selenium-rich agricultural products to provide natural selenium-rich health food to the areas in need of selenium, has gradually become a new hot spot of China's health food industry, but high content of selenium in food is detrimental to human body, even leads to selenium intoxication, and artificially adding inorganic selenium is difficult to guarantee that the selenium content of agricultural products is not exceeded. According to human body's daily demand for selenium in dietetics and the content of selenium in agricultural products in the Chinese food composition table, we put forward the recommendations on the standard of selenium in agricultural products, in order to provide the basis for China to formulate the health standard of selenium content in selenium-rich agricultural products.
基金the National Natural Science Foundation of China(No.21672157)PAPD,the project of scientific and technologic infrastructure of Suzhou(No.SZS201708)+1 种基金Natural Science Foundation of Jiangsu Province(No.BK20200874)Natural Science Foundation for colleges and universities in Jiangsu Province(No.20KJD150001)。
文摘Herein,we reported a convenient and efficient multicomponent reaction of indoles,selenium powder and unactivated alkyl halides.This protocol provides a practical,and facile approach for the synthesis of 3-alkylselenindole derivatives.The advantages of this strategy include mild and transition-metal-free conditions,broad functional group tolerance,the use of simple and easily accessible seleniium powder and alkyl halides as coupling partners.More importantly,the reaction proceeded smoothly with a large scale(>10 g,>90%yield),which further highlighted the potential application of this selenation strategy.
基金the Czech Science Foundation (GACR) for their financial support (Project No. 1304580S)
文摘Soil organic matter (SOM) plays an important role in the Se dynamics in soil. The potential effects of vermicompost and digestate as important sources of SOM on selenium (Se) mobility were assessed in this study. Three soils differing in their physicochemical parameters, fluvisol, chernozem, and luvisol, were chosen, and three types of vermicomposts based on various bio-waste materials as digestate (vermicompost 1), kitchen waste with woodchips (vermicompost 2), and garden bio-waste (vermicompost 3) were used due to their high organic matter content. Additionally, digestate samples alone were applied. To evaluate the potential effect of vermicompost application on sorption characteristics of soils, batch sorption experiments were performed. The results showed a predominant effect on Se species in the soils, where selenite sorbed more intensively compared to selenate, regardless of the soil and ameliorative material applied. In the control, the soil sorption ability of selenite tended to decrease in the order: fluvisol > luvisol > chernozem. However, these differences were not significant. Moreover, the effects of the ameliorative materials depended on both soil and amendment used. In fluvisol, all the amendment applications resulted in a decrease in distribution coefficient ( K d values) of Se, whereas in chernozem, this effect was observed only for the digestate-based vermicompost 1. Increasing K d levels were reported in luvisol treated with digestate;the application of garden bio-waste-based vermicompost 3 tended to decrease the K d values. Further studies are required on long-term effects of these amendments on Se mobility in soils and the role of individual organic matter fractions in this context.
基金supported by the Open Project of Jiangsu Key Laboratory of Animal genetic Breeding and Molecular Design(No.AGBMD202202)the Jiangsu Agricultural Science and Technology Innovation Fund(Nos.[CX(21)3131]and[CX(20)3010])+2 种基金the“JBGS”Project of Seed Industry Revitalization in Jiangsu Province(Nos.[JBGS[2021]027 and JBGS[2021]105])the Science and Education Integration Project of Yangzhou University(No.[KJRH202115])Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Selenium is an essential trace element for humans and animals.As the active center of selenoproteins,the addition of selenium is beneficial to enhance the antioxidant ability.However,the high cost limits the application of organic Se in agriculture animal production.Selenized glucose(SeGlu)is a newly invented organoselenium material with good stability,low toxicity and low cost.This assay found that SeGlu was able to increase selenium deposition in liver of newborn broilers,and enhance the antioxidant capacity of liver by elevating the activities of antioxidant enzymes such as total superoxide dismutase and glutathione peroxidase.This paper as the first example clarifying the mechanism of SeGlu to enhance the antioxidant ability of chicks,shows that SeGlu can be used as an organic selenium enrichment additive for early nutrition of poultry.As a cross-discipline study involving chemistry,biology and agriculture animal science,the work may be beneficial for studies in related fields and prompt the development of the selenium science.
文摘Under changing climate,trace elements like selenium(Se)have emerged as vital constituent of agro-ecosystems enabling crop plants to off-set the adverse effects of suboptimal growth conditions.The available form of selenium is important for boosting its bioavailability to crop plants having varied agro-botanical traits and root architectural systems.As compared to selenite,the selenate has a weaker soil bonding,higher absorption in the soil solution which results in a comparatively absorption by plant roots.Various factors including dry climate,high pH,optimal ambient air temperature,less accumulation of water,and low concentration of organic matter in the soil tend to boost the selenate ratio in the soil.The use of selenium pelleted seeds has emerged as an interesting and viable alternative to alleviate selenium deficiency in agricultural eco-systems.Similarly,the co-inoculation of a mixture of Selenobacteria and Arbuscular mycorrhizal fungi represents an evolving promising strategy for the bio-fortification of wheat plants to produce selenium-rich flour to supplement human dietary needs.Furthermore,in-depth research is required to assure the effectiveness of biological fertilization procedures in field conditions as well as to explore and increase our understanding pertaining to the underlying main mechanisms and channels of selenium absorption in plants.The focus of this review is to synthesize the recent developments on Se dynamics in soil-plant systems and emerging promising strategies to optimize its levels for crop plants.Recent developments regarding the use of micro-organisms as a biotechnological mean to enhance plant nutrition and crop quality have been objectively elaborated.The study becomes even more pertinent for arid and semi-arid agro-ecosystems owing to the potential role of selenium in providing stress tolerance to crop plants.Moreover,this review synthesizes and summarizes the recent developments on climate change and bioavailability,and the protective role of selenium in crop plants.
基金financially supported by the Natural Science Foundation of Jiangsu Province(Nos.BK20190909,BK20181449)Jiangsu Provincial Six Talent Peaks Project(No.XCL-090)Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Selenization reaction with the in situ prepared NaHSe has been successfully developed to occur in aqueous solution.The technique affords a method to upload the bioactive Se element on cotton products in semi-industrial scale.The antibacterial tests revealed that the selenized cotton possessed a potent and prolonged antimicrobial effect against both Gram-positive S.aureus and Gram-negative E.coli bacteria.This work discloses a practical method for preparing the selenium-containing antibacterial materials concisely and directly with industrial application potential.
文摘The effect of selenate (Na2SeO4) and sulphate (Na2SO4) was studied on growth and metabolism in two rice cultivars cv. satabdi and cv. khitish. Selenate at low concentration (2 μM) expressed growth promoting effect on rice seedlings as opposed to its high concentration (≥20 μM) where the test seedlings showed stunted growth with browning at the apices of both roots and shoots. The chlorophyll contents showed a dose dependent effect. Both chlorophyll a and chlorophyll b contents were inhibited with increase in selenate concentrations. The effect was more pronounced in cv. satabdi compared to cv. khitish.The level of accessory pigments was deferentially affected by selenium treatment. Simultaneously, the fluorescence intensity and Hill activity decreased with increase in selenate concentrations in the test seedlings. It is assumed that selenium plays a protective role in plants subjected to stress and prevents the formation of reactive oxygen species (ROS) in the cells. Higher selenate concentrations (≥20 μM) exerted variable effect on the activities of enzymatic antioxidants viz.;superoxide dismutase (SOD), catechol peroxidase (CPX) and catalase (CAT) in the test seedlings. The activity of SOD increased with increase in selenate concentrations, whereas activities of CAT and CPX decreased. Under high selenate concentrations, the levels of oxidative stress markers, viz.;proline, H2O2 and MDA were also enhanced. Selenium induced accumulation of total soluble sugar and increased the level of both reducing and non reducing sugars in both the test cultivars. The starch contents concomitantly decreased with rise in selenate concentrations. Moreover, the nutrient contents of test seedlings were significantly influenced by selenium. The Na and K levels gradually increased whereas Ca, Mg and Fe levels decreased on application of selenate. Joint application of 10 mM sulphate and selenate showed significant alterations on all parameters tested with respect to selenate treatment alone. Partial to complete amelioration occurred in the test seedlings treated with high concentrations of selenate and sulphate. Our study shows that selenium at low concentration had a stimulatory effect on growth and metabolism as against high concentrations which proved to be toxic to the rice seedlings obtained from both the cultivars. Effects were more pronounced in cv. satabdi than in cv. khitish which is considered to be comparatively tolerant to selenium. The dose dependent influence of selenium on the physiological and biochemical responses of test seedlings may be reversed by co-application with sulphate.
基金supported by the Program of Higher-Level Talents of Inner Mongolia University(Nos.Z20090144 and Z20090120)
文摘The CulnSe2 compound was prepared by selenization of Cu-In precursor, which was ultrasonic electrodeposited at constant current. CulnSe2 films were compacted to improve surface morphology. The films were characterized by X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, and energy dispersive spectroscopy （EDS）. It is indicated that ideal stoichiometrie CulnSe2 films can be obtained by the selenization of Cu-In precursor deposited at a current density of 20 mA/cm^2. Single-phase CulnSe2 is formed in the selenization proeess, and it exhibits preferred orientation along the （112） plane. The CulnSe2 films with smooth surface can be obtained under the pressure of 500 MPa at 60℃.
文摘The growth of seedlings of Townsville sytlo (Stylosanthes humilis H.B.K.) is inhibited by aluminium (Al) ions, their elongation being re-covered with sodium selenate at 1.0 μM. Methyl viologen and hydrogen peroxide, reactive oxy-gen species (ROS)-generating compounds, also inhibited seedling elongation and again growth was relieved by selenate. Selenate, thus, seemed to be operating as a ROS quencher, since N-acetylcysteine (NAC), an antioxidant com-pound, also stimulated largely the growth of Al-inhibited seedlings. At a higher concentra-tion (0.1 mM), however, selenate inhibited seed-ling growth and elongation was recovered by NAC. Ethylene production by selenate plus NAC-treated seedlings was very higher and thus the gaseous hormone was not responsible for the seedling growth inhibition caused by sele-nate. Hence, it seems that at high levels sele-nate operates as a ROS-generating compound whose effects were counteracted by NAC. It can be deduced that, at low concentration, sele-nates behave as a ROS quencher and at high level as a ROS-promoting species.
文摘[Objective] The paper was to understand the harms of Actias selene ningpoana Felder to plants. [Method] The larvae were cultured in five different groups: camphor tree, cherry tree, crape myrtle tree, poplar and willow, to observe the growth status of larvae. [Result] The survival rates of A. selene ningpoana in cherry tree and crape myrtle tree group were higher. The larvae in cherry tree group had faster growth, and the adults were large. [Conclusion] A. selene ningpoana is most harmful to cherry trees, which should be paid special attention in cherry garden.
文摘Effective charge separation and rapid interfacial H_(2) production are imperative for the construction of efficient photocatalysts.Compared to Pt,the metallic Ag co‐catalyst with its strong electron‐trapping ability and excellent electronic conductivity typically exhibits an extremely limited photocatalytic H_(2-)evolution rate owing to its sluggish interfacial H_(2)‐generation reaction.In this study,amorphous AgSe_(x) was incorporated in situ onto metallic Ag as a novel and excellent H_(2)‐evolution active site to boost the interfacial H_(2)‐generation rate of Ag nanoparticles in a TiO_(2)/Ag system.Core‐shell Ag@AgSe_(x)nanoparticle‐modified TiO_(2)photocatalysts were prepared via a two‐step pathway involving the photodeposition of metallic Ag and the selective surface selenization of metallic Ag to yield amorphous AgSe_(x)shells.The as‐prepared TiO_(2)/Ag@AgSe_(x)(20μL)photocatalyst exhibited an excellent H_(2‐)production performance of 853.0μmol h^(-1)g^(-1),prominently outperforming the TiO_(2)and TiO_(2)/Ag samples by factors of 11.6 and 2.4,respectively.Experimental investigations and DFT calculations revealed that the enhanced H_(2‐)generation activity of the TiO_(2)/Ag@AgSe_(x)photocatalyst could be accounted by synergistic interactions of the Ag@AgSe_(x)co‐catalyst.Essentially,the metallic Ag core could quickly capture and transport the photoinduced electrons from TiO_(2)to the amorphous AgSe_(x)shell,whereas the amorphous AgSe_(x)shell provided large active sites for boosting the interfacial H_(2)evolution.This study offers a facile route for the construction of novel core‐shell co‐catalysts for sustainable H_(2)evolution.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51772087,11904094,51972106,and 11804089)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB30000000)Natural Science Foundation of Hunan Province,China(Grant Nos.2019JJ50034 and 2019JJ50073).
文摘Bulk group IB transition-metal chalcogenides have been widely explored due to their applications in thermoelectrics.However,a layered two-dimensional form of these materials has been rarely reported.Here,we realize semiconducting Cu_(2)Se by direct selenization of Cu(111).Scanning tunneling microcopy measurements combined with first-principles calculations allow us to determine the structural and electronic properties of the obtained structure.X-ray photoelectron spectroscopy data reveal chemical composition of the sample,which is Cu_(2)Se.The observed moire pattern indicates a lattice mismatch between Cu_(2)Se and the underlying Cu(111)-√3×√3 surface.Differential conductivity obtained by scanning tunneling spectroscopy demonstrates that the synthesized Cu_(2)Se exhibits a band gap of 0.78 eV.Furthermore,the calculated density of states and band structure demonstrate that the isolated Cu_(2)Se is a semiconductor with an indirect band gap of-0.8 eV,which agrees quite well with the experimental results.Our study provides a simple pathway varying toward the synthesis of novel layered 2D transition chalcogenides materials.
文摘Arsenic affects plants by disrupting their growth and metabolism while selenium, an essential micronutrient has beneficial role in stress tolerance. Owing to the antioxidative capacity of selenium, it can counteract detrimental effects of arsenic induced stress in plants. The interactive influence of arsenate and selenate on the growth, arsenic and selenium accumulation, activities of non-enzymatic and enzymatic antioxidants, levels of ascorbate, α-tocopherol, total glutathione and activities of glutathione regulatory enzymes along with characterization and quantification of phytochelatins in growing wheat (Triticum aestivum L.) seedlings were investigated. Rate of arsenic accumulation was increased in arsenate treated seedlings while in seedlings treated jointly with arsenate and selenate, arsenic accumulation decreased. Arsenate stress resulted decrease in ascorbate and total glutathione contents, activities of the glutathione metabolism enzymes while significantly increased the levels of α-tocopherol and phytochelatins (PC2 and PC4), along with activities of ascorbate peroxidase and ascorbic acid oxidase in the test seedlings. The effects were more pronounced in roots than in shoots. Joint application of arsenate along with selenate was able to overcome the adverse effects caused by arsenic alone to variable extents by exhibiting significant alterations of all parameters tested, imparting better growth and thiol metabolism in the test seedlings. Our results conclude that application of selenium fertilizer in arsenic contaminated soil might be favourable to improve growth and defense ability in wheat against arsenic toxicity.
基金Project(2004AA513023) supported by the National High Technology Research and Development Program of China
文摘Local segregation in Cu-In precursors and its effects on the element distribution and microstructures of selenized CuInSe2 thin films were investigated. Cu-In precursors with an ideal total mole ratio of Cu to In of 0.92 were prepared by middle frequency alternating current magnetron sputtering with Cu-In alloy target, then CuInSe2 absorbers for solar cells were formed by selenization process in selenium atmosphere. Scanning electron microscope and energy dispersive X-ray spectroscope were used respectively to observe the surface morphologies and determine the compositions of both Cu-In precursors and CuInSe2 thin films. Their microstructures were characterized by X-ray diffractometry and Raman spectroscope. The results show that Cu-In precursors are mainly composed of (Cu11In9) phase with In-rich solid solution. Stoichiometric CuInSe2 thin films with a homogeneous element distribution and single chalcopyrite phase can be synthesized from a segregated Cu-In precursor film with an ideal total mole ratio of Cu to In of 0.92. CuInSe2 thin film shows P-type conductivity and its resistivity reaches 1.2×103Ω·cm.
基金financially supported by the National Natural Science Foundation of China (Nos.51275509 and 51175491)
文摘Cu2ZnSn（S,Se）4（CZTSSe） thin film was prepared using a simple two-step approach based on the single-source evaporation and synchronous sulfo-selenization.Composition,microstructure,morphology,and properties of the asprepared CZTSSe thin films were investigated.XRD and Raman patterns confirmed the formation of single-phase CZTSSe solid solutions.SEM results showed that the CZTSSe thin film had a uniform morphology and large grains.EDS results revealed the composition of CZTSSe film was Cu：Zn：Sn：S：Se = 23.7：12.6：12.2：37.7：13.8（in at%）,which was in accordance with the stoichiometric Cu2ZnSn（S,Se）4.The optical band gap of CZTSSe thin film evaluated from its UV–Vis spectrum was 1.33 eV.The resistivity,carrier concentration,and mobility were 0.53 X cm,7.9 9 1018cm3,and 7.5 cm2/（Vs）,respectively.
文摘By allowing H_(2)SeO_(4),Cy_(2)NH,CyNH_(2) or Bz2NH to react respectively with SnPh_(3)Cl(in methanol),SnPh_(2)Cl_(2)(in water+methanol)and MgCl_(2)·6H_(2)O(in methanol)in specific ratios,the studied complexes are obtained.The suggested structures are discrete and polymer,the environment of the tin center being trans trigonal bipyramidal(compound 1),tetrahedral(compound 2)and octahedral(compound 3),the anions behaving as a bidentate selenate.
