A new baccharane-type triterpene, 3-acetoxy-9(11)-baccharene(1),as well as a known compound, a-amyrin(2), has been isolated from the ether extract of the roots of Saussurea lappa C. B. Clarke. The structure of the new...A new baccharane-type triterpene, 3-acetoxy-9(11)-baccharene(1),as well as a known compound, a-amyrin(2), has been isolated from the ether extract of the roots of Saussurea lappa C. B. Clarke. The structure of the new compound was identified by spectrum analysis.展开更多
Nanocrystalline,single-phase undoped In 2O 3 was prepared by a polymer-network synthesis technique with indium nitrate as the starting material;several methods such as X-ray diffractometry (XRD) and transmission ele...Nanocrystalline,single-phase undoped In 2O 3 was prepared by a polymer-network synthesis technique with indium nitrate as the starting material;several methods such as X-ray diffractometry (XRD) and transmission electron microscopy (TEM) were employed to obtain detailed information on the crystallography and microstructual appearance of In 2O 3 superfine powders. The influence of the concentration of starting solution,calcination temperature and time on the particle size was also that investigated by means of the XRD patterns. Results indicate that the obtained powders are mostly crystalline single phase with uniform size and also that the size of the products can be controlled under proper condition.展开更多
Generally, FD coefficients can be obtained by using Taylor series expansion （TE） or optimization methods to minimize the dispersion error. However, the TE-based FD method only achieves high modeling precision over a...Generally, FD coefficients can be obtained by using Taylor series expansion （TE） or optimization methods to minimize the dispersion error. However, the TE-based FD method only achieves high modeling precision over a limited range of wavenumbers, and produces large numerical dispersion beyond this range. The optimal FD scheme based on least squares （LS） can guarantee high precision over a larger range of wavenumbers and obtain the best optimization solution at small computational cost. We extend the LS-based optimal FD scheme from two-dimensional （2D） forward modeling to three-dimensional （3D） and develop a 3D acoustic optimal FD method with high efficiency, wide range of high accuracy and adaptability to parallel computing. Dispersion analysis and forward modeling demonstrate that the developed FD method suppresses numerical dispersion. Finally, we use the developed FD method to source wavefield extrapolation and receiver wavefield extrapolation in 3D RTM. To decrease the computation time and storage requirements, the 3D RTM is implemented by combining the efficient boundary storage with checkpointing strategies on GPU. 3D RTM imaging results suggest that the 3D optimal FD method has higher precision than conventional methods.展开更多
A new triterpenoid, methyl buergericate (12a), which was elucidated as 2 alpha, 3 alpha, 19 alpha, 24-tetrahydroxyl olean-12-en-28-oic acid methyl ester by spectroscopic methods, together with eleven known triterpenoi...A new triterpenoid, methyl buergericate (12a), which was elucidated as 2 alpha, 3 alpha, 19 alpha, 24-tetrahydroxyl olean-12-en-28-oic acid methyl ester by spectroscopic methods, together with eleven known triterpenoids was isolated from Rubus buergeri Miq. The isolation of the above chemical constituents from this plant was reported for the first time.展开更多
To improve the data quality of converted waves, and better identify and suppress the strong ground-roll interference in three-component （3C） seismic recordings on land, we present an adaptive polarization filtering ...To improve the data quality of converted waves, and better identify and suppress the strong ground-roll interference in three-component （3C） seismic recordings on land, we present an adaptive polarization filtering method, which can effectively separate the ground- roll interference by combining complex polarization and instantaneous polarization analysis. The ground roll noise is characterized by elliptical plane polarization, strong energy, low apparent velocity, and low frequency. After low-pass filtering of the 3C data input within a given time-window of the ground roll, the complex covariance matrix is decomposed using the sliding time window with overlapping data and length that depends on the dominant ground-roll frequency. The ground-roll model is established using the main eigenvectors, and the ground roll is detected and identified using the instantaneous polarization area attributes and average energy constraints of the ground-roll zone. Finally, the ground roll is subtracted. The threshold of the method is stable and easy to select, and offers good ground- roll detection. The method is a robust polarization filtering method. Model calculations and actual data indicate that the method can effectively identify and attenuate ground roll while preserving the effective signals.展开更多
The phase equilibria and compositions in Mg-rich side at 300 ℃ were investigated in Mg-Zn-Ca ternary system through the equilibrated alloy method by using scanning electron microscopy,electron probe microanalysis,X-r...The phase equilibria and compositions in Mg-rich side at 300 ℃ were investigated in Mg-Zn-Ca ternary system through the equilibrated alloy method by using scanning electron microscopy,electron probe microanalysis,X-ray diffraction and transmission electron microscopy.The results show that two ternary compounds T1 and T2 can be in equilibrium with the Mg-based solid solution in Mg-Zn-Ca system.T1 phase is a linear compound with the composition region（molar fraction） of 15% Ca,20.5%-48.9% Zn and balanced Mg at 300 ℃.Its hexagonal structure parameters decrease with increasing Zn content,i.e.a=0.992-0.945 nm,c=1.034-1.003 nm.T2 phase has hexagonal structure with the composition region of 26.4%-28.4% Mg,63.2%-65.5% Zn and 7.1%-8.4% Ca.At 300 ℃,the solubility of Zn in the Mg-based solid solution increases for the addition of Ca,the maximum solubility of Zn is 3.7%.Three-phase fields consisting of--Mg＋Mg2Ca＋T1,--Mg＋T1＋T2,--Mg＋T2＋MgZn and MgZn＋T2＋Mg2Zn3 exist in the Mg-Zn-Ca system at 300 ℃.展开更多
The thermal decomposition kinetics of high iron gibbsite ore was investigated under non-isothermal conditions.Popescu method was applied to analyzing the thermal decomposition mechanism.The results show that the most ...The thermal decomposition kinetics of high iron gibbsite ore was investigated under non-isothermal conditions.Popescu method was applied to analyzing the thermal decomposition mechanism.The results show that the most probable thermal decomposition mechanism is the three-dimensional diffusion model of Jander equation,and the mechanism code is D3.The activation energy and pre-exponential factor for thermal decomposition of high iron gibbsite ore calculated by the Popescu method are 75.36 kJ/mol and 1.51×10-5 s-（-1）,respectively.The correctness of the obtained mechanism function is validated by the activation energy acquired by the iso-conversional method.Popescu method is a rational and reliable method for the analysis of the thermal decomposition mechanism of high iron gibbsite ore.展开更多
[Objective] This study was to obseve the flower bud differentiation process of Gentiana triflora Pall., and to clarify the flower bud development law and the correlation between flower buds differentiation and externa...[Objective] This study was to obseve the flower bud differentiation process of Gentiana triflora Pall., and to clarify the flower bud development law and the correlation between flower buds differentiation and external morphology. [Method] The paraffin section method was used to observe the flower bud of Gentiana triflora un- der microscope. [Result] The flower bud differentiation process of Gentiana triflora could be divided into six stages： the undifferentiated stage, initial differentiation stage, sepal primordia differentiation stage, petal primordia differentiation stage, stamen pri- mordia differentiation stage and the pistil primordia differentiation stage. The flower bud differentiation started from early May, when the plant had 10-11 stem nodes, and completed in early June, lasted about 40 d. The effect of plant height on flower bud differentiation was not significant. [Conclusion] The study provided theoretical basis for the high-yield cultivation, variety selection and flowering regulation of Gentiana triflora.展开更多
Seasonal dynamics of above- and belowground biomass and nutrient characteristics （nitrogen, carbon, and phosphorus） of Carex lasiocarpa were investigated in the typical wetland of Sanjiang Plain, China from May 2007...Seasonal dynamics of above- and belowground biomass and nutrient characteristics （nitrogen, carbon, and phosphorus） of Carex lasiocarpa were investigated in the typical wetland of Sanjiang Plain, China from May 2007 to September 2008. The results show that the changes of aboveground biomass during the growing season are best described by the twice function curve model, whereas the changes of belowground biomass follow the exponential increase curve model. Both the organic carbon contents in the above- and belowground plant parts show significant positive linear correlations with the growing time, and the coefficients R2 are 0.983 and 0.746, respectively. The carbon accu-mulations of the above- and belowground plant parts during the growing season show the same dynamics as those of the biomass. However, the nitrogen contents and accumulation in C. lasiocarpa aboveground and belowground parts show exponential increase during the growing season. The dynamics of C. lasiocarpa phosphorus contents follows the twice function curve model, whereas the accumulation of phosphorus shows the linear increase. The ratios of C/N in different parts of C. lasiocarpa fit the negative linear relations with total nitrogen content in the growing season. Moreover, the ratios of C/P in C. lasiocarpa plant also fit the negative linear relations with total phosphorus content. The results show that nitrogen is the primary limiting nutrient for C. lasiocarpa growth as compared with carbon and phosphorus.展开更多
From the fruit of Rosa davidii Crep., eleven compounds were isolated and identified by spectral evidence, viz. 2 alpha, 3 beta, 19 beta -trihydroxyl-olean-12-en-28-oic acid (1), 2 alpha, 3 beta -dihydroxyl-urs-28 (13)...From the fruit of Rosa davidii Crep., eleven compounds were isolated and identified by spectral evidence, viz. 2 alpha, 3 beta, 19 beta -trihydroxyl-olean-12-en-28-oic acid (1), 2 alpha, 3 beta -dihydroxyl-urs-28 (13)-lactone (2), arjunic acid (3), euscaphic acid (4), 2 alpha, 3 beta -dihydroxyl-urs-12-en-28-oic acid (5), oleanolic acid (6), kaempferol (7), tiliroside (8), quercetin (9), daucosterol (10) and beta -sitosterol (11). Among them, 1 and 2 were new compounds.展开更多
Objective: To detect the action of arsenic trioxide (As_2O_3) on theexpression of Tumor drug-resistant molecule. Methods: APL cell line MR_2 resistant to all-transretin-oic acid (ATRA ) was put into research, while AP...Objective: To detect the action of arsenic trioxide (As_2O_3) on theexpression of Tumor drug-resistant molecule. Methods: APL cell line MR_2 resistant to all-transretin-oic acid (ATRA ) was put into research, while APL cell line NB_4 was used for control. Theim-munocytochemical assays were used to detect the expressions of P-glycoprotein (P_(gp)) andGluta-thione S-transferase ( GST) . Results: Not only the expression of P_(gp) in MR_2 cell line(30%-40%) was significantly higher than that in NB4 cell line (10%-20% ) (P < 0.001), but also theexpression of GST in MR_2 cell line (60. 4 +- 4.0 )-( 66.5 +- 4.4) was significantly higher thanthat in NB4 cell line (28.3 +- 5.6)-(31.2 +- 5. l)(P < 0.05). As_2O_3 at the concentration of0.5-2.0 μmol/l could significantly decrease the expression of P_(gp) and GSTπ, but could donothing about the expression of GSTα and GSTμ. Conclusion: The lower expression of P_(gp) andGSTπ might be the sensitive indications of frustrating drug-resistance, while GSTα and GSTμ mightnot be the case. ATRA might be the substrates of P_(gp) transmission and GSTπ catalysis .展开更多
Depositing a cocatalyst has proven to be an important strategy for improving the photoelectrochemical(PEC)water-splitting efficiency of photoanodes.In this study,Ni(OH)2 quantum dots(Ni(OH)2 QDs)were deposited in situ...Depositing a cocatalyst has proven to be an important strategy for improving the photoelectrochemical(PEC)water-splitting efficiency of photoanodes.In this study,Ni(OH)2 quantum dots(Ni(OH)2 QDs)were deposited in situ onto anα-Fe_(2)O_(3)photoanode via a chelation-mediated hydrolysis method.The photocurrent density of the Ni(OH)2 QDs/α-Fe_(2)O_(3)photoanode reached 1.93 mA·cm^(−2)at 1.23 V vs.RHE,which is 3.5 times that ofα-Fe_(2)O_(3),and an onset potential with a negative shift of ca.100 mV was achieved.More importantly,the Ni(OH)2 QDs exhibited excellent stability in maintaining PEC water oxidation at a high current density,which is attributed to the ultra-small crystalline size,allowing for the rapid acceptance of holes fromα-Fe_(2)O_(3)to Ni(OH)_(2)QDs,formation of active sites for water oxidation,and hole transfer from the active sites to water molecules.Further(photo)electrochemical analysis suggests that Ni(OH)_(2)QDs not only provide maximal active sites for water oxidation but also suppress charge recombination by passivating the surface states ofα-Fe_(2)O_(3),thereby significantly enhancing the water oxidation kinetics over theα-Fe_(2)O_(3)surface.展开更多
Twenty-four compounds including eight steroids （1-8）, nine triterpenoids （9-16, 24）, three flavonoids （20-22）, and four benzenecarboxylic derivatives （17-19, 23） were isolated and identified from stems and twi...Twenty-four compounds including eight steroids （1-8）, nine triterpenoids （9-16, 24）, three flavonoids （20-22）, and four benzenecarboxylic derivatives （17-19, 23） were isolated and identified from stems and twigs of medicinal mangrove plant Sonneratia caseolaris. The structures of the isolated compounds were determined by extensive analysis of their spectroscopic data. Among these rnetabolites, compounds 1, 4-20 and 22-24 were isolated and identified for the first time from S. caseolaris. In the in vitro cytotoxic assay against SMMC-7721 human hepatoma cells, compound 21 （3＇,4＇,5,7-tetrahydroxyflavone） exhibited significant activity with IC50 2.8 μg/mL, while oleanolic acid （14）, 3,3＇-di-O-methyl ether ellagic acid （18）, and 3,3＇,4-O-tri-O-methyl ether ellagic acid （19） showed weak activity. None of these compounds displayed significant antibacterial activites.展开更多
基金This work was supported by the Kunming Institute of Botany,Chinese Academy of Sciences.
文摘A new baccharane-type triterpene, 3-acetoxy-9(11)-baccharene(1),as well as a known compound, a-amyrin(2), has been isolated from the ether extract of the roots of Saussurea lappa C. B. Clarke. The structure of the new compound was identified by spectrum analysis.
基金TheScientificResearchFoundationfortheReturnedOverseasChineseScholars ,StateEducationMinistry (No . [2 0 0 2 ]2 47)
文摘Nanocrystalline,single-phase undoped In 2O 3 was prepared by a polymer-network synthesis technique with indium nitrate as the starting material;several methods such as X-ray diffractometry (XRD) and transmission electron microscopy (TEM) were employed to obtain detailed information on the crystallography and microstructual appearance of In 2O 3 superfine powders. The influence of the concentration of starting solution,calcination temperature and time on the particle size was also that investigated by means of the XRD patterns. Results indicate that the obtained powders are mostly crystalline single phase with uniform size and also that the size of the products can be controlled under proper condition.
基金supported by the National Natural Science Foundation of China(No.41474110)Shell Ph.D. Scholarship to support excellence in geophysical research
文摘Generally, FD coefficients can be obtained by using Taylor series expansion （TE） or optimization methods to minimize the dispersion error. However, the TE-based FD method only achieves high modeling precision over a limited range of wavenumbers, and produces large numerical dispersion beyond this range. The optimal FD scheme based on least squares （LS） can guarantee high precision over a larger range of wavenumbers and obtain the best optimization solution at small computational cost. We extend the LS-based optimal FD scheme from two-dimensional （2D） forward modeling to three-dimensional （3D） and develop a 3D acoustic optimal FD method with high efficiency, wide range of high accuracy and adaptability to parallel computing. Dispersion analysis and forward modeling demonstrate that the developed FD method suppresses numerical dispersion. Finally, we use the developed FD method to source wavefield extrapolation and receiver wavefield extrapolation in 3D RTM. To decrease the computation time and storage requirements, the 3D RTM is implemented by combining the efficient boundary storage with checkpointing strategies on GPU. 3D RTM imaging results suggest that the 3D optimal FD method has higher precision than conventional methods.
文摘A new triterpenoid, methyl buergericate (12a), which was elucidated as 2 alpha, 3 alpha, 19 alpha, 24-tetrahydroxyl olean-12-en-28-oic acid methyl ester by spectroscopic methods, together with eleven known triterpenoids was isolated from Rubus buergeri Miq. The isolation of the above chemical constituents from this plant was reported for the first time.
基金supported by the National Natural Science Foundation of China(No.41074080)the Important National Science&Technology Specific Projects(No.2011ZX05019-008)
文摘To improve the data quality of converted waves, and better identify and suppress the strong ground-roll interference in three-component （3C） seismic recordings on land, we present an adaptive polarization filtering method, which can effectively separate the ground- roll interference by combining complex polarization and instantaneous polarization analysis. The ground roll noise is characterized by elliptical plane polarization, strong energy, low apparent velocity, and low frequency. After low-pass filtering of the 3C data input within a given time-window of the ground roll, the complex covariance matrix is decomposed using the sliding time window with overlapping data and length that depends on the dominant ground-roll frequency. The ground-roll model is established using the main eigenvectors, and the ground roll is detected and identified using the instantaneous polarization area attributes and average energy constraints of the ground-roll zone. Finally, the ground roll is subtracted. The threshold of the method is stable and easy to select, and offers good ground- roll detection. The method is a robust polarization filtering method. Model calculations and actual data indicate that the method can effectively identify and attenuate ground roll while preserving the effective signals.
基金Project(50731002) supported by the National Natural Science Foundation of ChinaProject(20082030) supported by the Natural Science Foundation of Liaoning Province,China
文摘The phase equilibria and compositions in Mg-rich side at 300 ℃ were investigated in Mg-Zn-Ca ternary system through the equilibrated alloy method by using scanning electron microscopy,electron probe microanalysis,X-ray diffraction and transmission electron microscopy.The results show that two ternary compounds T1 and T2 can be in equilibrium with the Mg-based solid solution in Mg-Zn-Ca system.T1 phase is a linear compound with the composition region（molar fraction） of 15% Ca,20.5%-48.9% Zn and balanced Mg at 300 ℃.Its hexagonal structure parameters decrease with increasing Zn content,i.e.a=0.992-0.945 nm,c=1.034-1.003 nm.T2 phase has hexagonal structure with the composition region of 26.4%-28.4% Mg,63.2%-65.5% Zn and 7.1%-8.4% Ca.At 300 ℃,the solubility of Zn in the Mg-based solid solution increases for the addition of Ca,the maximum solubility of Zn is 3.7%.Three-phase fields consisting of--Mg＋Mg2Ca＋T1,--Mg＋T1＋T2,--Mg＋T2＋MgZn and MgZn＋T2＋Mg2Zn3 exist in the Mg-Zn-Ca system at 300 ℃.
基金Project(51374058)supported by the National Natural Science Foundation of China
文摘The thermal decomposition kinetics of high iron gibbsite ore was investigated under non-isothermal conditions.Popescu method was applied to analyzing the thermal decomposition mechanism.The results show that the most probable thermal decomposition mechanism is the three-dimensional diffusion model of Jander equation,and the mechanism code is D3.The activation energy and pre-exponential factor for thermal decomposition of high iron gibbsite ore calculated by the Popescu method are 75.36 kJ/mol and 1.51×10-5 s-（-1）,respectively.The correctness of the obtained mechanism function is validated by the activation energy acquired by the iso-conversional method.Popescu method is a rational and reliable method for the analysis of the thermal decomposition mechanism of high iron gibbsite ore.
基金Supported by the Youth Fund of Heilongjiang University,China~~
文摘[Objective] This study was to obseve the flower bud differentiation process of Gentiana triflora Pall., and to clarify the flower bud development law and the correlation between flower buds differentiation and external morphology. [Method] The paraffin section method was used to observe the flower bud of Gentiana triflora un- der microscope. [Result] The flower bud differentiation process of Gentiana triflora could be divided into six stages： the undifferentiated stage, initial differentiation stage, sepal primordia differentiation stage, petal primordia differentiation stage, stamen pri- mordia differentiation stage and the pistil primordia differentiation stage. The flower bud differentiation started from early May, when the plant had 10-11 stem nodes, and completed in early June, lasted about 40 d. The effect of plant height on flower bud differentiation was not significant. [Conclusion] The study provided theoretical basis for the high-yield cultivation, variety selection and flowering regulation of Gentiana triflora.
基金This research was supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (No.KZCX2–YW–309)the Major State Basic Research Development Program of China (973 Program No. 2004CB418507)
文摘Seasonal dynamics of above- and belowground biomass and nutrient characteristics （nitrogen, carbon, and phosphorus） of Carex lasiocarpa were investigated in the typical wetland of Sanjiang Plain, China from May 2007 to September 2008. The results show that the changes of aboveground biomass during the growing season are best described by the twice function curve model, whereas the changes of belowground biomass follow the exponential increase curve model. Both the organic carbon contents in the above- and belowground plant parts show significant positive linear correlations with the growing time, and the coefficients R2 are 0.983 and 0.746, respectively. The carbon accu-mulations of the above- and belowground plant parts during the growing season show the same dynamics as those of the biomass. However, the nitrogen contents and accumulation in C. lasiocarpa aboveground and belowground parts show exponential increase during the growing season. The dynamics of C. lasiocarpa phosphorus contents follows the twice function curve model, whereas the accumulation of phosphorus shows the linear increase. The ratios of C/N in different parts of C. lasiocarpa fit the negative linear relations with total nitrogen content in the growing season. Moreover, the ratios of C/P in C. lasiocarpa plant also fit the negative linear relations with total phosphorus content. The results show that nitrogen is the primary limiting nutrient for C. lasiocarpa growth as compared with carbon and phosphorus.
文摘Objective: To detect the action of arsenic trioxide (As_2O_3) on theexpression of Tumor drug-resistant molecule. Methods: APL cell line MR_2 resistant to all-transretin-oic acid (ATRA ) was put into research, while APL cell line NB_4 was used for control. Theim-munocytochemical assays were used to detect the expressions of P-glycoprotein (P_(gp)) andGluta-thione S-transferase ( GST) . Results: Not only the expression of P_(gp) in MR_2 cell line(30%-40%) was significantly higher than that in NB4 cell line (10%-20% ) (P < 0.001), but also theexpression of GST in MR_2 cell line (60. 4 +- 4.0 )-( 66.5 +- 4.4) was significantly higher thanthat in NB4 cell line (28.3 +- 5.6)-(31.2 +- 5. l)(P < 0.05). As_2O_3 at the concentration of0.5-2.0 μmol/l could significantly decrease the expression of P_(gp) and GSTπ, but could donothing about the expression of GSTα and GSTμ. Conclusion: The lower expression of P_(gp) andGSTπ might be the sensitive indications of frustrating drug-resistance, while GSTα and GSTμ mightnot be the case. ATRA might be the substrates of P_(gp) transmission and GSTπ catalysis .
文摘Depositing a cocatalyst has proven to be an important strategy for improving the photoelectrochemical(PEC)water-splitting efficiency of photoanodes.In this study,Ni(OH)2 quantum dots(Ni(OH)2 QDs)were deposited in situ onto anα-Fe_(2)O_(3)photoanode via a chelation-mediated hydrolysis method.The photocurrent density of the Ni(OH)2 QDs/α-Fe_(2)O_(3)photoanode reached 1.93 mA·cm^(−2)at 1.23 V vs.RHE,which is 3.5 times that ofα-Fe_(2)O_(3),and an onset potential with a negative shift of ca.100 mV was achieved.More importantly,the Ni(OH)2 QDs exhibited excellent stability in maintaining PEC water oxidation at a high current density,which is attributed to the ultra-small crystalline size,allowing for the rapid acceptance of holes fromα-Fe_(2)O_(3)to Ni(OH)_(2)QDs,formation of active sites for water oxidation,and hole transfer from the active sites to water molecules.Further(photo)electrochemical analysis suggests that Ni(OH)_(2)QDs not only provide maximal active sites for water oxidation but also suppress charge recombination by passivating the surface states ofα-Fe_(2)O_(3),thereby significantly enhancing the water oxidation kinetics over theα-Fe_(2)O_(3)surface.
基金Supported by the National Natural Science Foundation of China (No. 30770234)Knowledge Innovation Program of Chinese Academy of Sciences (KZCX2-YW-211-04)Department of Science and Technology of Shandong Province (No.2006GG2205023)
文摘Twenty-four compounds including eight steroids （1-8）, nine triterpenoids （9-16, 24）, three flavonoids （20-22）, and four benzenecarboxylic derivatives （17-19, 23） were isolated and identified from stems and twigs of medicinal mangrove plant Sonneratia caseolaris. The structures of the isolated compounds were determined by extensive analysis of their spectroscopic data. Among these rnetabolites, compounds 1, 4-20 and 22-24 were isolated and identified for the first time from S. caseolaris. In the in vitro cytotoxic assay against SMMC-7721 human hepatoma cells, compound 21 （3＇,4＇,5,7-tetrahydroxyflavone） exhibited significant activity with IC50 2.8 μg/mL, while oleanolic acid （14）, 3,3＇-di-O-methyl ether ellagic acid （18）, and 3,3＇,4-O-tri-O-methyl ether ellagic acid （19） showed weak activity. None of these compounds displayed significant antibacterial activites.
