目的报告一种新的基因芯片荧光标记技术:通用引物U2联合标记技术(universal primer U2 labeling ,UPL);比较UPL与随机引物等其他标记方法的效率和可重复性。方法流感病毒RNA用四种标记方法处理后与流感病毒寡核苷酸检测芯片杂交,用Spss1...目的报告一种新的基因芯片荧光标记技术:通用引物U2联合标记技术(universal primer U2 labeling ,UPL);比较UPL与随机引物等其他标记方法的效率和可重复性。方法流感病毒RNA用四种标记方法处理后与流感病毒寡核苷酸检测芯片杂交,用Spss10.0对杂交结果进行分析。结果UPL方法在标记物杂交的荧光强度、信噪比、探针真阳性率和可重复性等方面均高于随机引物逆转录掺入标记法,而与其他两种RD标记方法相当,但标记过程相对更加简单。结论UPL方法可用于基因芯片研究和应用。展开更多
Efficiency and power loss in the microelectronic devices is a major issue in power electronics applications. The engineers are challenged every year to increase power density and at the same time reduce the amount of ...Efficiency and power loss in the microelectronic devices is a major issue in power electronics applications. The engineers are challenged every year to increase power density and at the same time reduce the amount of power dissipated in the applications to keep the maximum temperatures under specifications. This situation drives a constant demand for better efficiencies in smaller packages. Traditional approaches to improve efficiency in DC/DC synchronous buck converters include reducing conduction losses in the MOSFETs （metal oxide semiconductor field effect transistors） through lower RDS （ON） （resistance drain to source in the ON state） devices and lowering switching losses through low-frequency operation. However, the incremental improvements in RDS （ON） are at a point of diminishing returns and low RDS （ON） devices have large parasitic capacitances that do not facilitate the high-frequency operation required to improve power density. The drive for higher efficiency and increased power in smaller packages is being addressed by advancements in both silicon and packaging technologies. The NexFET power block combines these two technologies to achieve higher levels of performance, and in half the space versus discrete MOSFETs. This article explains these new technologies and highlights their performance advantage.展开更多
The 60mer oligonucleotide microarray was designed and applied to detecting of SARS (severe acute respiratory syndrome) coronavirus. Thirty 60mer specific oligos were designed to cover the whole genome of the first sub...The 60mer oligonucleotide microarray was designed and applied to detecting of SARS (severe acute respiratory syndrome) coronavirus. Thirty 60mer specific oligos were designed to cover the whole genome of the first submitted coronavirus strain, according to the sequence of TOR2 (GENEBANK Accession: AY274119). These primers were synthesized and printed into a microarray with 12×12 spots. RNAs were extracted from the throat swab and gargling fluid of SARS patients and reverse-transcripted into the double strand cDNAs. The cDNAs were prepared as restricted cDNA fragments by the restriction display (RD) technique and labeled by PCR with the Cy5-universal primer. The labeled samples were then applied to the oligo microarray for hybridization. The diagnostic capability of the microarray was evaluated after the washing and scanning steps. The scanning result showed that samples of SARS patients were hybridized with multiple SARS probes on the microarray, and there is no signal on the negative and blank controls. These results indicate that the genome of SARS coronavirus can be detected in parallel by the 60mer oligonucleotide microarray, which can improve the positive ratio of the diagnosis. The oligo microarray can also be used for monitoring the behavior of the virus genes in different stages of the disease status.展开更多
文摘目的报告一种新的基因芯片荧光标记技术:通用引物U2联合标记技术(universal primer U2 labeling ,UPL);比较UPL与随机引物等其他标记方法的效率和可重复性。方法流感病毒RNA用四种标记方法处理后与流感病毒寡核苷酸检测芯片杂交,用Spss10.0对杂交结果进行分析。结果UPL方法在标记物杂交的荧光强度、信噪比、探针真阳性率和可重复性等方面均高于随机引物逆转录掺入标记法,而与其他两种RD标记方法相当,但标记过程相对更加简单。结论UPL方法可用于基因芯片研究和应用。
文摘Efficiency and power loss in the microelectronic devices is a major issue in power electronics applications. The engineers are challenged every year to increase power density and at the same time reduce the amount of power dissipated in the applications to keep the maximum temperatures under specifications. This situation drives a constant demand for better efficiencies in smaller packages. Traditional approaches to improve efficiency in DC/DC synchronous buck converters include reducing conduction losses in the MOSFETs （metal oxide semiconductor field effect transistors） through lower RDS （ON） （resistance drain to source in the ON state） devices and lowering switching losses through low-frequency operation. However, the incremental improvements in RDS （ON） are at a point of diminishing returns and low RDS （ON） devices have large parasitic capacitances that do not facilitate the high-frequency operation required to improve power density. The drive for higher efficiency and increased power in smaller packages is being addressed by advancements in both silicon and packaging technologies. The NexFET power block combines these two technologies to achieve higher levels of performance, and in half the space versus discrete MOSFETs. This article explains these new technologies and highlights their performance advantage.
文摘The 60mer oligonucleotide microarray was designed and applied to detecting of SARS (severe acute respiratory syndrome) coronavirus. Thirty 60mer specific oligos were designed to cover the whole genome of the first submitted coronavirus strain, according to the sequence of TOR2 (GENEBANK Accession: AY274119). These primers were synthesized and printed into a microarray with 12×12 spots. RNAs were extracted from the throat swab and gargling fluid of SARS patients and reverse-transcripted into the double strand cDNAs. The cDNAs were prepared as restricted cDNA fragments by the restriction display (RD) technique and labeled by PCR with the Cy5-universal primer. The labeled samples were then applied to the oligo microarray for hybridization. The diagnostic capability of the microarray was evaluated after the washing and scanning steps. The scanning result showed that samples of SARS patients were hybridized with multiple SARS probes on the microarray, and there is no signal on the negative and blank controls. These results indicate that the genome of SARS coronavirus can be detected in parallel by the 60mer oligonucleotide microarray, which can improve the positive ratio of the diagnosis. The oligo microarray can also be used for monitoring the behavior of the virus genes in different stages of the disease status.
