Dissolutionof La in KCl-NaCl and LaCl_3-KCl-NaCl melts has been investigated by means of a transparent cell,cyclic voltammetry and EHMO of quantum chemistry.It is shown that the La dissolved in KCl-NaCl melt exists in...Dissolutionof La in KCl-NaCl and LaCl_3-KCl-NaCl melts has been investigated by means of a transparent cell,cyclic voltammetry and EHMO of quantum chemistry.It is shown that the La dissolved in KCl-NaCl melt exists in a metallic state,the La dissolved in LaCl_3-KCl-NaCl melt can be ionized into La^(2+) as a result of reaction with La^(3+), furthermore,the La^(2+) reacts with La^(3+) forming atom cluster La_m^(n+) which is a stable state in the melt.展开更多
The structure of the La-LaCl_3-KCl molten system at 1223K has been investigated by computer simulation using Monte Carlo method.The partial radial distribution functions of some ion pair as well as the potential and i...The structure of the La-LaCl_3-KCl molten system at 1223K has been investigated by computer simulation using Monte Carlo method.The partial radial distribution functions of some ion pair as well as the potential and internal energy of the system at 1223K have been calculated.The results implies that about 50% of La(Ⅲ)is six coordinated and LaCl_4^(2-) tetrahedron is the predominant configuration for La(Ⅱ). It is also concluded that the distribution of free space in the molten system is not uniform.There exist many fissures and empty holes in the molten salt.展开更多
本文利用盆栽实验研究了 L a Cl3对烟草幼苗的生物效应。在烟苗长到 3～ 4片叶时 ,用不同浓度的 L a-Cl3溶液喷施 ,实验结果表明 :2 5～ 75 m g/ L L a Cl3的溶液均能促进烟苗的生长 ,增加株高、单株干重和根干重 ,提高根 /冠比 ,增加...本文利用盆栽实验研究了 L a Cl3对烟草幼苗的生物效应。在烟苗长到 3～ 4片叶时 ,用不同浓度的 L a-Cl3溶液喷施 ,实验结果表明 :2 5～ 75 m g/ L L a Cl3的溶液均能促进烟苗的生长 ,增加株高、单株干重和根干重 ,提高根 /冠比 ,增加叶片的叶绿素含量和提高叶片的净光合速率。处理的烟苗抗寒性也有所增强。烟苗在 0～ 2℃的低温下 ,原生质结构破坏的程度减轻 ,外渗物质的量减少 ,处理的比对照的电导率减少 0 .0 1～ 0 .18× 10 - 4 s/ m。喷 L a Cl3溶液的烟苗叶片总含水量有所下降 ,但束缚水含量提高 。展开更多
Cucumber seedlings were sprayed with different concentrations of LaCl_3 for 3 d continuously. After 7 d of this treatment, the plants were treated with 1200 mg·L^(-1) 2,4-dichlorophennoxy(2,4-D) for 24 h. The lea...Cucumber seedlings were sprayed with different concentrations of LaCl_3 for 3 d continuously. After 7 d of this treatment, the plants were treated with 1200 mg·L^(-1) 2,4-dichlorophennoxy(2,4-D) for 24 h. The leaves were harvested and rinsed with 5 mmol·L^(-1) EDTA. The concentrations of photosynthetic pigments, soluble protein and metabolites related to oxidative stress and the activities of antioxidant enzymes in leaves were assayed. The results show that the treatment with appropriate concentration of LaCl_3 has resistant effect on oxidative stress induced by 2, 4-D. Proper concentration of LaCl_3 promotes the activity of antioxidant system in plants and alleviates the damage caused by 2, 4-D.展开更多
Two surfaces correponding to LaCl_3 and α-solid solution(MgCl_2.LiCl) respectively: and one secondary crystallization curve with a minimum M at 63.8 wt-％ LaCl_3,2.0 wt-％ MgCl_2,34.2 wt-％ LiCl and 492℃ were fonud ...Two surfaces correponding to LaCl_3 and α-solid solution(MgCl_2.LiCl) respectively: and one secondary crystallization curve with a minimum M at 63.8 wt-％ LaCl_3,2.0 wt-％ MgCl_2,34.2 wt-％ LiCl and 492℃ were fonud by means of DTA.In combination with liquidus determination.an approach was also made to the alteration in LnCl_3-MgCl_2-LiCl svstem,where Lu denotes La.Ce.Pr or Nd.展开更多
1.IntroductionDunn and Farrington[1]found that theNa ion in Naβ″-alumina single crystal canbe exchanged completely or partially withGd;,Nd;,Eu;,Yb;,Sm;,Tb;,Dy;,Bi;and Pr;ions,but no reports havebeen published about ...1.IntroductionDunn and Farrington[1]found that theNa ion in Naβ″-alumina single crystal canbe exchanged completely or partially withGd;,Nd;,Eu;,Yb;,Sm;,Tb;,Dy;,Bi;and Pr;ions,but no reports havebeen published about the ion exchange reac-tion between La3+ and Naβ″-alumina.If anion exchanged polycrystalline β″-alumina isavailable and its ionic conductivity is highenough to be applied as a solid electrolyte inthe galvanic cell,it can be used in various展开更多
The effect and the action mechanism of lanthanum on GF_(43) plantlet in vitro were studied. The results of experiments show that root growth rate and dry weight of GF_(43) by LaCl_3 treatments increase. The activities...The effect and the action mechanism of lanthanum on GF_(43) plantlet in vitro were studied. The results of experiments show that root growth rate and dry weight of GF_(43) by LaCl_3 treatments increase. The activities of antioxidant enzymes in root system such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) apparently enhance. Moreover ·O^-_2 and malond ialdehyde (MDA) contents and cell membrane permeability of GF_(43) are decreased by LaCl_3. The relatively stable membrane structure of cell could also be maintained and the root ageing of GF_(43) plantlet in vitro delays.展开更多
The knowledge on the ionic structure of YCl_(3)-KCl molten system is of guiding significance for the practical production of yttrium metals and yttrium alloys via molten salt electrolysis using this system as electrol...The knowledge on the ionic structure of YCl_(3)-KCl molten system is of guiding significance for the practical production of yttrium metals and yttrium alloys via molten salt electrolysis using this system as electrolyte.In this paper,the theoretical Raman spectra of the ionic groups which may exist in YCl_(3)-KCl molten system are simulated by quantum chemical calculation using Gaussian09 and Gauss View 5.0 programs based on density functional theory(DFT).Then the ionic structures of 20 mol%-60 mol%YCl_(3)-KCl molten salt systems are studied by comparing the Raman shift values of the bands in the theoretical Raman spectra of different ionic groups with the experimental spectra of this system.YCl_(6)^(3-),Y_(2)Cl_(7)^(-),Y_(2)Cl_(8)^(2-)and Y_(2)Cl_(9)^(3-)are thought to exist in the molten system.With the increase of temperature,the relative content of YCl_(6)^(3-)ionic groups increases while those of Y_(2)Cl_(7)^(-),Y_(2)Cl_(8)^(2-)and Y_(2)Cl_(9)^(3-)ionic groups decrease.Moreover,the"lifetime"of all ionic groups decreases within the temperature range of 692-730℃.Meanwhile,the relative contents of Y_(2)Cl_(7)^(-),Y_(2)Cl_(8)^(2-)and Y_(2)Cl_(9)^(3-)increase with the increase of YCl_(3)content,while that of YCl_(6)^(3-)decreases.The wave function analysis of the four ionic groups(YCl_(6)^(3-),Y_(2)Cl_(7)^(-),Y_(2)Cl_(8)^(2-),and Y_(2)Cl_(9)^(3-))is carried out by Multiwfn program.The net charge in each group,the direction of electron migration during the formation of each group,the sites where electrophilic and nucleophilic reactions are most likely to occur in each ionic group,and the order of bond breaking during chemical reactions for the four groups are obtained.展开更多
Marine natural products have become an increasingly important source of new drug leads during recent years.In an attempt to identify novel anti-microbial natural products by bioprospecting deep-sea Actinobacteria,thre...Marine natural products have become an increasingly important source of new drug leads during recent years.In an attempt to identify novel anti-microbial natural products by bioprospecting deep-sea Actinobacteria,three new angucyclines,nocardiopsistins A-C,were isolated from Nocardiopsis sp.strain HB-J378.Notably,the supplementation of the rare earth salt Lanthanum chloride(LaCl3)during fermentation of HB-J378 significantly increased the yield of these angucyclines.The structures of nocardiopsistins A-C were identified by 1D and 2D NMR and HR-MS data.Nocardiopsistins A-C have activity against MRSA(methicillin-resistant Staphylococcus aureus)with MICs of 3.12–12.5μg/mL;the potency of nocardiopsistin B is similar to that of the positive control,chloramphenicol.Bioinformatic analysis of the draft genome of HB-J378 identified a set of three core genes in a biosynthetic gene cluster that encode a typical aromatic or type II polyketide synthase(PKS)system,including ketoacyl:ACP synthaseα-subunit(KSα),β-subunit(KSβ)and acyl carrier protein(ACP).The production of nocardiopsistins A-C was abolished when the three genes were knocked out,indicating their indispensable role in the production of nocardiopsistins.展开更多
文摘Dissolutionof La in KCl-NaCl and LaCl_3-KCl-NaCl melts has been investigated by means of a transparent cell,cyclic voltammetry and EHMO of quantum chemistry.It is shown that the La dissolved in KCl-NaCl melt exists in a metallic state,the La dissolved in LaCl_3-KCl-NaCl melt can be ionized into La^(2+) as a result of reaction with La^(3+), furthermore,the La^(2+) reacts with La^(3+) forming atom cluster La_m^(n+) which is a stable state in the melt.
文摘The structure of the La-LaCl_3-KCl molten system at 1223K has been investigated by computer simulation using Monte Carlo method.The partial radial distribution functions of some ion pair as well as the potential and internal energy of the system at 1223K have been calculated.The results implies that about 50% of La(Ⅲ)is six coordinated and LaCl_4^(2-) tetrahedron is the predominant configuration for La(Ⅱ). It is also concluded that the distribution of free space in the molten system is not uniform.There exist many fissures and empty holes in the molten salt.
文摘本文利用盆栽实验研究了 L a Cl3对烟草幼苗的生物效应。在烟苗长到 3～ 4片叶时 ,用不同浓度的 L a-Cl3溶液喷施 ,实验结果表明 :2 5～ 75 m g/ L L a Cl3的溶液均能促进烟苗的生长 ,增加株高、单株干重和根干重 ,提高根 /冠比 ,增加叶片的叶绿素含量和提高叶片的净光合速率。处理的烟苗抗寒性也有所增强。烟苗在 0～ 2℃的低温下 ,原生质结构破坏的程度减轻 ,外渗物质的量减少 ,处理的比对照的电导率减少 0 .0 1～ 0 .18× 10 - 4 s/ m。喷 L a Cl3溶液的烟苗叶片总含水量有所下降 ,但束缚水含量提高 。
文摘Cucumber seedlings were sprayed with different concentrations of LaCl_3 for 3 d continuously. After 7 d of this treatment, the plants were treated with 1200 mg·L^(-1) 2,4-dichlorophennoxy(2,4-D) for 24 h. The leaves were harvested and rinsed with 5 mmol·L^(-1) EDTA. The concentrations of photosynthetic pigments, soluble protein and metabolites related to oxidative stress and the activities of antioxidant enzymes in leaves were assayed. The results show that the treatment with appropriate concentration of LaCl_3 has resistant effect on oxidative stress induced by 2, 4-D. Proper concentration of LaCl_3 promotes the activity of antioxidant system in plants and alleviates the damage caused by 2, 4-D.
文摘Two surfaces correponding to LaCl_3 and α-solid solution(MgCl_2.LiCl) respectively: and one secondary crystallization curve with a minimum M at 63.8 wt-％ LaCl_3,2.0 wt-％ MgCl_2,34.2 wt-％ LiCl and 492℃ were fonud by means of DTA.In combination with liquidus determination.an approach was also made to the alteration in LnCl_3-MgCl_2-LiCl svstem,where Lu denotes La.Ce.Pr or Nd.
文摘1.IntroductionDunn and Farrington[1]found that theNa ion in Naβ″-alumina single crystal canbe exchanged completely or partially withGd;,Nd;,Eu;,Yb;,Sm;,Tb;,Dy;,Bi;and Pr;ions,but no reports havebeen published about the ion exchange reac-tion between La3+ and Naβ″-alumina.If anion exchanged polycrystalline β″-alumina isavailable and its ionic conductivity is highenough to be applied as a solid electrolyte inthe galvanic cell,it can be used in various
文摘The effect and the action mechanism of lanthanum on GF_(43) plantlet in vitro were studied. The results of experiments show that root growth rate and dry weight of GF_(43) by LaCl_3 treatments increase. The activities of antioxidant enzymes in root system such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) apparently enhance. Moreover ·O^-_2 and malond ialdehyde (MDA) contents and cell membrane permeability of GF_(43) are decreased by LaCl_3. The relatively stable membrane structure of cell could also be maintained and the root ageing of GF_(43) plantlet in vitro delays.
基金financially supported by the National Natural Science Foundation of China (No.51974081)the Fundamental Research Funds for the Central Universities (No.N2225045)MOE of China and WEIQIAO Industry-Education Cooperation Project (No.2021021800102)。
文摘The knowledge on the ionic structure of YCl_(3)-KCl molten system is of guiding significance for the practical production of yttrium metals and yttrium alloys via molten salt electrolysis using this system as electrolyte.In this paper,the theoretical Raman spectra of the ionic groups which may exist in YCl_(3)-KCl molten system are simulated by quantum chemical calculation using Gaussian09 and Gauss View 5.0 programs based on density functional theory(DFT).Then the ionic structures of 20 mol%-60 mol%YCl_(3)-KCl molten salt systems are studied by comparing the Raman shift values of the bands in the theoretical Raman spectra of different ionic groups with the experimental spectra of this system.YCl_(6)^(3-),Y_(2)Cl_(7)^(-),Y_(2)Cl_(8)^(2-)and Y_(2)Cl_(9)^(3-)are thought to exist in the molten system.With the increase of temperature,the relative content of YCl_(6)^(3-)ionic groups increases while those of Y_(2)Cl_(7)^(-),Y_(2)Cl_(8)^(2-)and Y_(2)Cl_(9)^(3-)ionic groups decrease.Moreover,the"lifetime"of all ionic groups decreases within the temperature range of 692-730℃.Meanwhile,the relative contents of Y_(2)Cl_(7)^(-),Y_(2)Cl_(8)^(2-)and Y_(2)Cl_(9)^(3-)increase with the increase of YCl_(3)content,while that of YCl_(6)^(3-)decreases.The wave function analysis of the four ionic groups(YCl_(6)^(3-),Y_(2)Cl_(7)^(-),Y_(2)Cl_(8)^(2-),and Y_(2)Cl_(9)^(3-))is carried out by Multiwfn program.The net charge in each group,the direction of electron migration during the formation of each group,the sites where electrophilic and nucleophilic reactions are most likely to occur in each ionic group,and the order of bond breaking during chemical reactions for the four groups are obtained.
基金This work was supported in part by the NIH grant CA209189.
文摘Marine natural products have become an increasingly important source of new drug leads during recent years.In an attempt to identify novel anti-microbial natural products by bioprospecting deep-sea Actinobacteria,three new angucyclines,nocardiopsistins A-C,were isolated from Nocardiopsis sp.strain HB-J378.Notably,the supplementation of the rare earth salt Lanthanum chloride(LaCl3)during fermentation of HB-J378 significantly increased the yield of these angucyclines.The structures of nocardiopsistins A-C were identified by 1D and 2D NMR and HR-MS data.Nocardiopsistins A-C have activity against MRSA(methicillin-resistant Staphylococcus aureus)with MICs of 3.12–12.5μg/mL;the potency of nocardiopsistin B is similar to that of the positive control,chloramphenicol.Bioinformatic analysis of the draft genome of HB-J378 identified a set of three core genes in a biosynthetic gene cluster that encode a typical aromatic or type II polyketide synthase(PKS)system,including ketoacyl:ACP synthaseα-subunit(KSα),β-subunit(KSβ)and acyl carrier protein(ACP).The production of nocardiopsistins A-C was abolished when the three genes were knocked out,indicating their indispensable role in the production of nocardiopsistins.
