为促进芯片国产化进程,解决低密度奇偶校验(Low density parity check,LDPC)码译码效率低下的问题,以空间数据咨询委员会(The consultative committee for space data systems,CCSDS)标准下的、应用于近地空间(8176,7154)的LDPC码为研...为促进芯片国产化进程,解决低密度奇偶校验(Low density parity check,LDPC)码译码效率低下的问题,以空间数据咨询委员会(The consultative committee for space data systems,CCSDS)标准下的、应用于近地空间(8176,7154)的LDPC码为研究对象,根据归一化最小和译码(Normalized minimum sum,NMS)算法理论,设计了一种尺度因子可改变的LDPC译码器。首先,利用Vivado软件编写寄存器传输级(Register-transfer level,RTL)代码并进行功能仿真。其次,利用Design Compiler工具完成RTL级代码的综合,以生成物理设计需要的门级网表,并通过Innovus工具完成对的芯片后端自动布线(Auto placement route,APR)阶段的设计。在利用Prime Time和Calibre软件分别进行时序检查和物理验证时发现,存在时序违例1132条,设计规则违例647条。以不断迭代的方式进行修复,最终消除了违例,时序和物理设计均满足要求,并生成了GDS II文件。该设计可为芯片国产化生产提供新的思路。展开更多
Objective:To evaluate the anti-bacterial and anti-oxidant activity of and rographolide(AND)and echiodinin(ECH)of Andrographis paniculata.Methods:In this study,an attempt has been made to demonstrate the anti-microbial...Objective:To evaluate the anti-bacterial and anti-oxidant activity of and rographolide(AND)and echiodinin(ECH)of Andrographis paniculata.Methods:In this study,an attempt has been made to demonstrate the anti-microbial and anti-oxidant activity of isolated AND and ECH by broth micro-dilution method and 2,2-dipheny l-2-picryl-hydrazyl(DPPH)assay,respectively.Structure elucidation was determined by electro-spray ionization-MSD,NMR(1H and13C)and IR spectra.Results:AND was effective against most of the strains tested including Mycobacterium smegmatis,showing broad spectrum of growth inhibition activity with Minimum inhibitory concentration values againstStaphylococcus aureus(100μg/mL),Streptococcus thermophilus(350μg/mL)Bacillus subtilis(100μg/mL),Escherichia coli(50μg/mL),Mycobacterium smegmatis(200μg/mL),Klebsiella pneumonia(100μg/mL),andPseudomonas aeruginosa(200μg/mL).ECH showed specific anti-bacterial activity against Staphylococcus aureus,Escherichia coli,Bacillus subtilis and Pseudomonas aeruginosaat a concentration higher than 225μg/mL.Both AND and ECH were not effective against the two yeast strains,Candida albicansand Saccharomyces cerevisiae tested in this study.Conclusion:This preliminary study showed promising anti-bacterial activity and moderate free radical scavenging activity of AND and ECH,and it may provide the scientific rationale for its popular folklore medicines.展开更多
AIM： To investigate overlapping regions of the rpoB gene previously involved with rifamycin resistance in M. tuberculosis and seek correlation between rpoB mutations in dinical MAP strains with susceptibility to RIF ...AIM： To investigate overlapping regions of the rpoB gene previously involved with rifamycin resistance in M. tuberculosis and seek correlation between rpoB mutations in dinical MAP strains with susceptibility to RIF and RFB. METHODS： We designed a molecular-based PCR method for the evaluation of rifabutin （RFB） and rifampicin （RIF） resistance based on probable determinant regions within the rpoB gene of MAP, including the 81 bp variable site located between nucleotides 1363 and 1443. The minimum inhibitory concentration （MIC） for RIF was also determined against 11 MAP isolates in attempt to seek correlation with rpoB sequences. RESULTS： We determined that MAP strain 18 had an MIC of 〉 30 mg/L and ≤ 5 mg/L for RIF and RFB respectively, and a significant and novel rpoB mutation C1367T, compared to an MIC of ≤ 1.0 mg/L for both drugs in the wild type MAP. The 30-fold increase in the MIC was a direct result of the rpoB mutation C1367T, which caused an amino acid change Thr456 to Ile456 in the drug＇s binding site. In addition, MAP strain 185 contained five silent rpoB mutations and exhibited an MIC comparable to the wild-type. Moreover, our in vitro selected mutation in MAP strain UCF5 resulted in the generation of a new resistant strain （UCF5-RIF16r） that possessed T1442C rpoB mutation and an MIC 〉 30 mg/L and 〉 10 mg/L for RIF and RFB respectively. Sequencing of the entire rpoB gene in MAP strains UCF4, 18, and UCF5-RIF16r revealed an rpoB mutation A2284C further downstream of the 81 bp variable region in UCF4, accounting for observed slight increase in MIC. In addition, no other significant mutations were found in strains 18 and UCF-RIF16r. CONCLUSION： The data clearly illustrates that clinical and in vitro-selected MAP mutants with rpoB mutations result in resistance to RIF and RFB, and that a single amino acid change in the beta subunit may have a significant impact on RIF resistance. Unconventional drug susceptibility testing such as our molecular approach will be beneficial for evaluation of antibiotic effectiveness. This molecular approach may also serve as a model for other drugs used for treatment of MAP infections.展开更多
根据在重庆大学多功能人工气候室内对高海拔条件下 10 k V合成绝缘子的覆冰试验研究结果 ,分析了覆冰量、覆冰状态及海拔高度 (或气压 )对 10 k V合成绝缘子最低交流闪络特性的影响及闪络过程 ,提出了 10 k V合成绝缘子在高海拔和覆冰...根据在重庆大学多功能人工气候室内对高海拔条件下 10 k V合成绝缘子的覆冰试验研究结果 ,分析了覆冰量、覆冰状态及海拔高度 (或气压 )对 10 k V合成绝缘子最低交流闪络特性的影响及闪络过程 ,提出了 10 k V合成绝缘子在高海拔和覆冰分别及综合作用下闪络电压的校正公式。展开更多
文摘为促进芯片国产化进程,解决低密度奇偶校验(Low density parity check,LDPC)码译码效率低下的问题,以空间数据咨询委员会(The consultative committee for space data systems,CCSDS)标准下的、应用于近地空间(8176,7154)的LDPC码为研究对象,根据归一化最小和译码(Normalized minimum sum,NMS)算法理论,设计了一种尺度因子可改变的LDPC译码器。首先,利用Vivado软件编写寄存器传输级(Register-transfer level,RTL)代码并进行功能仿真。其次,利用Design Compiler工具完成RTL级代码的综合,以生成物理设计需要的门级网表,并通过Innovus工具完成对的芯片后端自动布线(Auto placement route,APR)阶段的设计。在利用Prime Time和Calibre软件分别进行时序检查和物理验证时发现,存在时序违例1132条,设计规则违例647条。以不断迭代的方式进行修复,最终消除了违例,时序和物理设计均满足要求,并生成了GDS II文件。该设计可为芯片国产化生产提供新的思路。
基金Financially supported by Universiti Malaysia Kelantan(Grant No.R/SGJP/A07.00/00710A/001/2012/000081)
文摘Objective:To evaluate the anti-bacterial and anti-oxidant activity of and rographolide(AND)and echiodinin(ECH)of Andrographis paniculata.Methods:In this study,an attempt has been made to demonstrate the anti-microbial and anti-oxidant activity of isolated AND and ECH by broth micro-dilution method and 2,2-dipheny l-2-picryl-hydrazyl(DPPH)assay,respectively.Structure elucidation was determined by electro-spray ionization-MSD,NMR(1H and13C)and IR spectra.Results:AND was effective against most of the strains tested including Mycobacterium smegmatis,showing broad spectrum of growth inhibition activity with Minimum inhibitory concentration values againstStaphylococcus aureus(100μg/mL),Streptococcus thermophilus(350μg/mL)Bacillus subtilis(100μg/mL),Escherichia coli(50μg/mL),Mycobacterium smegmatis(200μg/mL),Klebsiella pneumonia(100μg/mL),andPseudomonas aeruginosa(200μg/mL).ECH showed specific anti-bacterial activity against Staphylococcus aureus,Escherichia coli,Bacillus subtilis and Pseudomonas aeruginosaat a concentration higher than 225μg/mL.Both AND and ECH were not effective against the two yeast strains,Candida albicansand Saccharomyces cerevisiae tested in this study.Conclusion:This preliminary study showed promising anti-bacterial activity and moderate free radical scavenging activity of AND and ECH,and it may provide the scientific rationale for its popular folklore medicines.
基金Supported by Grant RO1-AI51251-01 from NIH-NIAID
文摘AIM： To investigate overlapping regions of the rpoB gene previously involved with rifamycin resistance in M. tuberculosis and seek correlation between rpoB mutations in dinical MAP strains with susceptibility to RIF and RFB. METHODS： We designed a molecular-based PCR method for the evaluation of rifabutin （RFB） and rifampicin （RIF） resistance based on probable determinant regions within the rpoB gene of MAP, including the 81 bp variable site located between nucleotides 1363 and 1443. The minimum inhibitory concentration （MIC） for RIF was also determined against 11 MAP isolates in attempt to seek correlation with rpoB sequences. RESULTS： We determined that MAP strain 18 had an MIC of 〉 30 mg/L and ≤ 5 mg/L for RIF and RFB respectively, and a significant and novel rpoB mutation C1367T, compared to an MIC of ≤ 1.0 mg/L for both drugs in the wild type MAP. The 30-fold increase in the MIC was a direct result of the rpoB mutation C1367T, which caused an amino acid change Thr456 to Ile456 in the drug＇s binding site. In addition, MAP strain 185 contained five silent rpoB mutations and exhibited an MIC comparable to the wild-type. Moreover, our in vitro selected mutation in MAP strain UCF5 resulted in the generation of a new resistant strain （UCF5-RIF16r） that possessed T1442C rpoB mutation and an MIC 〉 30 mg/L and 〉 10 mg/L for RIF and RFB respectively. Sequencing of the entire rpoB gene in MAP strains UCF4, 18, and UCF5-RIF16r revealed an rpoB mutation A2284C further downstream of the 81 bp variable region in UCF4, accounting for observed slight increase in MIC. In addition, no other significant mutations were found in strains 18 and UCF-RIF16r. CONCLUSION： The data clearly illustrates that clinical and in vitro-selected MAP mutants with rpoB mutations result in resistance to RIF and RFB, and that a single amino acid change in the beta subunit may have a significant impact on RIF resistance. Unconventional drug susceptibility testing such as our molecular approach will be beneficial for evaluation of antibiotic effectiveness. This molecular approach may also serve as a model for other drugs used for treatment of MAP infections.
