Abstract: A cellulase having improved enzymatic activity is disclosed. The cellulase has a modified amino acid sequence of SEQ ID NO: 2 or a modified amino acid sequence with at least 80% sequence identity of SEQ ID NO: 2, wherein the modification is a substitution of methionine at position 120 or a corresponding position with asparagine.

Abstract: The present application provides indexing methods and systems for indexing spatial data objects of a data space, and methods and systems for performing an operation on an index of spatial data. One of the methods includes: associating each spatial data object with one of a plurality of separations according to a size of the respective spatial data object; and mapping each spatial data object to an index key based on the separation with which the spatial data object is associated. The methods and systems for performing an operation on an index of spatial data can facilitate efficient selection or manipulation of the spatial data objects.

Abstract: Embodiment of the present invention discloses a kind of methionine lyase and its encoding gene and biosynthetic method. According to the present invention, the gene encoding methionine lyase as shown in SEQ ID No. 1 is separated from the genome of C. rosea. Embodiment of the present invention further provides an efficient biosynthetic method of methionine lyase, comprising: (1) cloning gene (shown in SEQ ID No.1) encoding methionine degradation enzyme into a yeast expression vector to construct recombinant yeast expression vector; (2) transforming the recombinant yeast expression vector into Saccharomyces cerevisiae to obtain expression strain; (3) inducing the expression strain to express the methionine lyase, collecting induced strains, purifying expressed recombinant methionine lyase. Purity of recombinant methionine lyase prepared according to the present invention is above 90%, and its efficiency of degradating methionine can reach 0.53±0.0030 ?M MTL·h?1·mg protein?1.

Abstract: A photovoltaic power generation system includes at least one photovoltaic power generation microgrid and a central server configured to communicate with the photovoltaic power generation microgrid via Internet.

Abstract: A photovoltaic power generation system includes at least one photovoltaic power generation microgrid and a central server configured to communicate with the photovoltaic power generation microgrid via Internet.

Abstract: The present invention discloses a sulfur-substituted podophyllotoxin derivative, synthesis method thereof, and use thereof. The present invention introduces a rigid aromatic heterocyclic compound, as well as a further sulfonamidated product of 3-amino-5-mercapto-1,2,4-triazole, 2-amino-5-mercapto-1,3,4-thiadiazole, 4-methylbenzenesulfonyl chloride, or 4-methoxybenzenesulfonyl chloride as a substituent group, into position 4 of the C-ring of podophyllotoxin or 4?-demethylepipodophyllotoxin to obtain the podophyllotoxin derivative shown in formula (V), said derivative having significantly increased antitumor activity and reduced toxic side effects. Experiments on in vitro tumor cell inhibition indicate that the antitumor activity of the compound of formula (V) of the present invention is significantly higher than the antitumor activity of podophyllotoxin or 4?-demethylepipodophyllotoxin.

Abstract: Embodiment of the present invention discloses a kind of methionine lyase and its encoding gene and biosynthetic method. According to the present invention, the gene encoding methionine lyase as shown in SEQ ID No. 1 is separated from the genome of C. rosea. Embodiment of the present invention further provides an efficient biosynthetic method of methionine lyase, comprising: (1) cloning gene (shown in SEQ ID No. 1) encoding methionine degradation enzyme into a yeast expression vector to construct recombinant yeast expression vector; (2) transforming the recombinant yeast expression vector into Saccharomyces cerevisiae to obtain expression strain; (3) inducing the expression strain to express the methionine lyase, collecting induced strains, purifying expressed recombinant methionine lyase. Purity of recombinant methionine lyase prepared according to the present invention is above 90%, and its efficiency of degradating methionine can reach 0.53±0.0030 ?M MTL·h?1·mg protein?1.

Abstract: The present invention discloses an anilino-substituted podophyllin derivative having antitumor activity, method for preparation thereof, and use thereof. By means of anilino reactions, the present invention introduces 4-chloro-3-methylaniline, 3-fluoro-4-methoxyaniline, 4,4?-diaminodiphenylmethane, o-anisidine, 4-chloro-2-aminoanisole, anthranilonitrile, 2,6-dichloro-4-aminophenol, N,N-dimethylamino meta-aniline, 2-ethyl-5-nitroaniline, 2 2?-diaminodiphenylsulfide, or 2-aminobenzotrifluoride into position 4 of the active C-ring of podophyllotoxin or 4?-demethylepipodophyllotoxin to obtain the aniline-substituted podophyllotoxin derivative shown in formula (V); by means of multi-pathway and multi-target effects on tumor cells, said derivative has significantly increased antitumor activity, and can be prepared as an antineoplastic drug and applied in clinical antitumor therapy.

Abstract: The present invention discloses an anilino-substituted podophyllin derivative having antitumor activity, method for preparation thereof, and use thereof. By means of anilino reactions, the present invention introduces 4-chloro-3-methylaniline, 3-fluoro-4-methoxyaniline, 4,4?-diaminodiphenylmethane, o-anisidine, 4-chloro-2-aminoanisole, anthranilonitrile, 2,6-dichloro-4-aminophenol, N,N-dimethylamino meta-aniline, 2-ethyl-5-nitroaniline, 2 2?-diaminodiphenylsulfide, or 2-aminobenzotrifluoride into position 4 of the active C-ring of podophyllotoxin or 4?-demethylepipodophyllotoxin to obtain the aniline-substituted podophyllotoxin derivative shown in formula (V); by means of multi-pathway and multi-target effects on tumor cells, said derivative has significantly increased antitumor activity, and can be prepared as an antineoplastic drug and applied in clinical antitumor therapy.

Abstract: The present invention discloses a sulfur-substituted podophyllotoxin derivative, synthesis method thereof, and use thereof. The present invention introduces a rigid aromatic heterocyclic compound, as well as a further sulfonamidated product of 3-amino-5-mercapto-1,2,4-triazole, 2-amino-5-mercapto-1,3,4-thiadiazole, 4-methylbenzenesulfonyl chloride, or 4-methoxybenzenesulfonyl chloride as a substituent group, into position 4 of the C-ring of podophyllotoxin or 4?-demethylepipodophyllotoxin to obtain the podophyllotoxin derivative shown in formula (V), said derivative having significantly increased antitumor activity and reduced toxic side effects. Experiments on in vitro tumor cell inhibition indicate that the antitumor activity of the compound of formula (V) of the present invention is significantly higher than the antitumor activity of podophyllotoxin or 4?-demethylepipodophyllotoxin.

Abstract: A 4?-demethylepipodophyllotoxin derivative of formula (III) having anti-tumor activity is provided. After the activation of hydroxyl in position C4 of 4?-demethylepipodophyllotoxin, tetramethylpyrazine is introduced by transamination to obtain the 4?-demethylepipodophyllotoxin derivative which is preferably used to inhibit gastric cancer line BGC-823.

Abstract: A 4?-demethylepipodophyllotoxin derivative of formula(III) having anti-tumor activity is provided. After the activation of hydroxyl in position C4 of 4?-demethylepipodophyllotoxin, tetramethylpyrazine is introduced by transamination to obtain the 4?-demethylepipodophyllotoxin derivative which is preferably used to inhibit gastric cancer line BGC-823.

Abstract: A 4?-demethylepipodophyllotoxin derivative of formula(III) having anti-tumor activity is provided. After the activation of hydroxyl in position C4 of 4?-demethylepipodophyllotoxin, tetramethylpyrazine is introduced by transamination to obtain the 4?-demethylepipodophyllotoxin derivative which is preferably used to inhibit gastric cancer line BGC-823.

Abstract: A 4?-demethylepipodophyllotoxin derivative of formula(III) having anti-tumor activity is provided. After the activation of hydroxyl in position C4 of 4?-demethylepipodophyllotoxin, tetramethylpyrazine is introduced by transamination to obtain the 4?-demethylepipodophyllotoxin derivative which is preferably used to inhibit gastric cancer line BGC-823.

Abstract: This invention relates to a piezoelectric ceramic material of a quarternary system, formulated on the basis of ternary system materials (PCM and PMN). Said quarternary system piezoelectric ceramic material consists of lead niobate with Mg (Pb (Mg.sub.1/3 Nb.sub.2/3)O.sub.3, lead niobate with Mn (Pb(Mn.sub.1/3 Nb.sub.2/3)O.sub.3), lead zirconate (PbZrO3) and lead titanate (PbTiO3), and possesses excellent properties for large power output purposes, and is suitable for making piezoelectric transformers of large power output. A single piece piezoelectric transformer (dimensions 100.times.25.times.36 mm3) using the material of the present invention is found to have a maximum output power of 50 W. The material according to this invention has a simple preparing process, a wider and lower sintering temperature range, is fine and compact in ceramic structure, and has a high rate of success of finished products.