为了有效分析机载雷达杂波抑制特性和提高目标检测性能。建立了天线行子阵和列子阵的天线发射方向图模型,同时采用空时自适应处理(Space Time Adaptive Processing,STAP)的机载雷达杂波分析方法,根据目标的导向矢量和杂波与噪声的协方...为了有效分析机载雷达杂波抑制特性和提高目标检测性能。建立了天线行子阵和列子阵的天线发射方向图模型,同时采用空时自适应处理(Space Time Adaptive Processing,STAP)的机载雷达杂波分析方法,根据目标的导向矢量和杂波与噪声的协方差矩阵建立了杂波功率谱的数学模型,选取不同的脉冲重复频率仿真分析了杂波的特征值谱和改善因子以及杂波空时谱。仿真结果表明:低脉冲重复频率和中脉冲重复频率使杂波谱扩散;随着脉冲重复频率的减少,杂波的相关度减少;STAP法适合高脉冲重复频率的情形,为抑制雷达杂波提供了依据。展开更多
The MtN3/saliva/SWEET-type genes, existing either alone or in a family group, are found in diverse organisms, from monocellular protozoa to higher eukaryotes, indicating their importance in cellular organisms. These g...The MtN3/saliva/SWEET-type genes, existing either alone or in a family group, are found in diverse organisms, from monocellular protozoa to higher eukaryotes, indicating their importance in cellular organisms. These genes encode polytopic membrane proteins that feature an MtN3/saliva domain, also known as a PQ loop repeat, The rice MtN3/saliva/SWEET gene family consists of 21 members and is among the largest families in sequenced organisms. Accumulating data suggest that these genes are involved in multiple physiological processes, including reproductive development, senescence, environmental adaptation, and host-pathogen interaction, in different species. In rice, some members of the family, including Xa13/Os8N3/OsSWEET11, which is essential for reproductive development, are used by the pathogenic bacterium Xanthomonas oryzae pv. oryzae to invade its host. Emerging data have also revealed that at least some MtN3/saliva/SWEET-type proteins may regulate different physiological processes by facilitating ion transport via interaction with ion transporters or as sugar transporters. The accumulating knowledge about MtN3/saliva/SWEET- type genes will help to elucidate the molecular bases of their function in different organisms.展开更多
目的:通过研究口内数字化扫描仪多次扫描的重复性来评价其扫描精度。方法:根据原始研究模型上牙备后基牙的分布不同分为5小组(1.右侧上颌中切牙为牙备后形态,余牙完整;2.右侧上颌第一磨牙为牙备后形态,余牙完整;3.右侧上颌中切牙和尖牙...目的:通过研究口内数字化扫描仪多次扫描的重复性来评价其扫描精度。方法:根据原始研究模型上牙备后基牙的分布不同分为5小组(1.右侧上颌中切牙为牙备后形态,余牙完整;2.右侧上颌第一磨牙为牙备后形态,余牙完整;3.右侧上颌中切牙和尖牙为牙备后形态,上颌侧切牙缺失,余牙完整;4.右侧上颌7颗牙齿为牙备后形态,左半侧完整;5.上颌全部牙齿为牙备后形态)。实验组中,每一小组的研究模型均用TRIOS口内扫描仪10次;对照组中,每一小组的研究模型先分别翻制10副石膏模型,再用3Shape口外扫描仪扫描。实验组和对照组分别得到扫描生成的50个STL三维图像文件,将总共100个STL文件通过Geomagic Studio 12软件进行处理和分析来评价两组扫描的重复性和精度。结果:实验组(口内组)3D标准偏差分别是第1小组:13.33μm,第2小组:7.0μm,第3小组:16.33μm,第4小组:41.56μm,第5小组:88.44μm。对照组的3D标准偏差分别是第1小组:14.89μm,第2小组:8.67μm,第3小组:24.33μm,第4小组:14.22μm,第5小组:12.67μm。实验组和对照组的3D标准偏差在第2,3,4,5小组中有统计学差异(P<0.05)。结论:口内数字化印模扫描精度随着牙弓扫描范围增大而降低,其在扫描范围小于半个牙弓时表现出的精度符合临床要求;而口外台式扫描仪在扫描任意范围牙弓时均表现出较好的精度。展开更多
AIM: To correlate the length of the telomere to microsatellite instability (MSI) and loss of heterozygosity (LOH) of APC, MCC and DCC genes in gastric carcinomas. METHODS: Telomeric restriction fragment (TRF) length o...AIM: To correlate the length of the telomere to microsatellite instability (MSI) and loss of heterozygosity (LOH) of APC, MCC and DCC genes in gastric carcinomas. METHODS: Telomeric restriction fragment (TRF) length of gastric cancer was measured with Southern blot. LOH of APC, MCC and DCC genes, microsatellite instability (MSI) and frameshift mutation of hMSH6, TGF-betaRII and BAX genes were analyzed by PCR-based methods. RESULTS: Sixty-eight cases of sporadic gastric carcinoma were studied for MSI using five microsatellite markers. MSI in at least one locus was detected in 17 (25%) of 68 tumors analyzed. Frameshift mutations of hMSH6, TGF-betaRII and BAX were detected in 2,6 and 3 of gastric carcinomas respectively showing high MSI (】 or = 2 loci, n = 8), but none was found in those showing low MSI (only one locus, n = 9) or MSS (tumor lacking MSI or stable, n = 51). Thirty-five cases, including all high MSI and low MSI, were studied for TRF. The mean TRF length was not correlated with clinicopathological parameters. No association was observed between TRF length and MSI or frameshift mutation. On the contrary, LOH at the DCC locus was related to telomere shortening (P【0.01). This tendency was also observed in APC and MCC genes, although there was no statistical significance. CONCLUSION: The development of gastric cancer can arise through two different genetic pathways. In high MSI gastric cancers, defective mismatch repair allows mutations to accumulate and generate the high MSI phenotype. In gastric cancers showing either low MSI or MSS, multiple deletions may represent the LOH pathway. Telomere erosion is independent of high MSI phenotype but related to the LOH pathway in gastric cancer.展开更多
The first seedling or all-stage resistance （R） R gene against stripe rust isolated from Moro wheat （Triticum aes- tivum L.） using a map-based cloning approach was identified as Yr10. Clone 4B of this gene encodes ...The first seedling or all-stage resistance （R） R gene against stripe rust isolated from Moro wheat （Triticum aes- tivum L.） using a map-based cloning approach was identified as Yr10. Clone 4B of this gene encodes a highly evolutionary- conserved and unique CC-NBS-LRR sequence. Clone 4E, a homolog of Yr10, but lacking transcription start site （TSS） and putative TATA-box and CAAT-box, is likely a non-expressed pseudogene. Clones 4B and 4E are 84% identical and divergent in the intron and the LRR domain. Gene silencing and transgenesis were used in conjunction with inoculation with differen- tially avirulent and virulent stripe rust strains to demonstrate Yr10 functionality. The Yr10 CC-NBS-LRR sequence is unique among known CC-NBS-LRR R genes in wheat but highly conserved homologs （E = 0.0） were identified in Aegilops tauschii and other monocots including Hordeum vulgare and Brachypodium distachyon. Related sequences were also identified in genomic databases of maize, rice, and in sorghum. This is the first report of a CC-NBS-LRR resistance gene in plants with limited homologies in its native host, but with numerous homologous R genes in related monocots that are either host or non-hosts for stripe rust. These results represent a unique example of gene evolution and dispersion across species.展开更多
文摘为了有效分析机载雷达杂波抑制特性和提高目标检测性能。建立了天线行子阵和列子阵的天线发射方向图模型,同时采用空时自适应处理(Space Time Adaptive Processing,STAP)的机载雷达杂波分析方法,根据目标的导向矢量和杂波与噪声的协方差矩阵建立了杂波功率谱的数学模型,选取不同的脉冲重复频率仿真分析了杂波的特征值谱和改善因子以及杂波空时谱。仿真结果表明:低脉冲重复频率和中脉冲重复频率使杂波谱扩散;随着脉冲重复频率的减少,杂波的相关度减少;STAP法适合高脉冲重复频率的情形,为抑制雷达杂波提供了依据。
基金This work was supported by grants from the National Program on the Development of Basic Research in China （2012CB114005）the National Program of High Technology Development of China （2012AA10A303） and the National Natural Science Foundation of China （31100875）No conflict of interest declared.
文摘The MtN3/saliva/SWEET-type genes, existing either alone or in a family group, are found in diverse organisms, from monocellular protozoa to higher eukaryotes, indicating their importance in cellular organisms. These genes encode polytopic membrane proteins that feature an MtN3/saliva domain, also known as a PQ loop repeat, The rice MtN3/saliva/SWEET gene family consists of 21 members and is among the largest families in sequenced organisms. Accumulating data suggest that these genes are involved in multiple physiological processes, including reproductive development, senescence, environmental adaptation, and host-pathogen interaction, in different species. In rice, some members of the family, including Xa13/Os8N3/OsSWEET11, which is essential for reproductive development, are used by the pathogenic bacterium Xanthomonas oryzae pv. oryzae to invade its host. Emerging data have also revealed that at least some MtN3/saliva/SWEET-type proteins may regulate different physiological processes by facilitating ion transport via interaction with ion transporters or as sugar transporters. The accumulating knowledge about MtN3/saliva/SWEET- type genes will help to elucidate the molecular bases of their function in different organisms.
文摘目的:通过研究口内数字化扫描仪多次扫描的重复性来评价其扫描精度。方法:根据原始研究模型上牙备后基牙的分布不同分为5小组(1.右侧上颌中切牙为牙备后形态,余牙完整;2.右侧上颌第一磨牙为牙备后形态,余牙完整;3.右侧上颌中切牙和尖牙为牙备后形态,上颌侧切牙缺失,余牙完整;4.右侧上颌7颗牙齿为牙备后形态,左半侧完整;5.上颌全部牙齿为牙备后形态)。实验组中,每一小组的研究模型均用TRIOS口内扫描仪10次;对照组中,每一小组的研究模型先分别翻制10副石膏模型,再用3Shape口外扫描仪扫描。实验组和对照组分别得到扫描生成的50个STL三维图像文件,将总共100个STL文件通过Geomagic Studio 12软件进行处理和分析来评价两组扫描的重复性和精度。结果:实验组(口内组)3D标准偏差分别是第1小组:13.33μm,第2小组:7.0μm,第3小组:16.33μm,第4小组:41.56μm,第5小组:88.44μm。对照组的3D标准偏差分别是第1小组:14.89μm,第2小组:8.67μm,第3小组:24.33μm,第4小组:14.22μm,第5小组:12.67μm。实验组和对照组的3D标准偏差在第2,3,4,5小组中有统计学差异(P<0.05)。结论:口内数字化印模扫描精度随着牙弓扫描范围增大而降低,其在扫描范围小于半个牙弓时表现出的精度符合临床要求;而口外台式扫描仪在扫描任意范围牙弓时均表现出较好的精度。
基金National Natural Science Foundation of China,No.30070043"10.5"Scientific Research Foundation of PLA,No.01Z075
文摘AIM: To correlate the length of the telomere to microsatellite instability (MSI) and loss of heterozygosity (LOH) of APC, MCC and DCC genes in gastric carcinomas. METHODS: Telomeric restriction fragment (TRF) length of gastric cancer was measured with Southern blot. LOH of APC, MCC and DCC genes, microsatellite instability (MSI) and frameshift mutation of hMSH6, TGF-betaRII and BAX genes were analyzed by PCR-based methods. RESULTS: Sixty-eight cases of sporadic gastric carcinoma were studied for MSI using five microsatellite markers. MSI in at least one locus was detected in 17 (25%) of 68 tumors analyzed. Frameshift mutations of hMSH6, TGF-betaRII and BAX were detected in 2,6 and 3 of gastric carcinomas respectively showing high MSI (】 or = 2 loci, n = 8), but none was found in those showing low MSI (only one locus, n = 9) or MSS (tumor lacking MSI or stable, n = 51). Thirty-five cases, including all high MSI and low MSI, were studied for TRF. The mean TRF length was not correlated with clinicopathological parameters. No association was observed between TRF length and MSI or frameshift mutation. On the contrary, LOH at the DCC locus was related to telomere shortening (P【0.01). This tendency was also observed in APC and MCC genes, although there was no statistical significance. CONCLUSION: The development of gastric cancer can arise through two different genetic pathways. In high MSI gastric cancers, defective mismatch repair allows mutations to accumulate and generate the high MSI phenotype. In gastric cancers showing either low MSI or MSS, multiple deletions may represent the LOH pathway. Telomere erosion is independent of high MSI phenotype but related to the LOH pathway in gastric cancer.
文摘The first seedling or all-stage resistance （R） R gene against stripe rust isolated from Moro wheat （Triticum aes- tivum L.） using a map-based cloning approach was identified as Yr10. Clone 4B of this gene encodes a highly evolutionary- conserved and unique CC-NBS-LRR sequence. Clone 4E, a homolog of Yr10, but lacking transcription start site （TSS） and putative TATA-box and CAAT-box, is likely a non-expressed pseudogene. Clones 4B and 4E are 84% identical and divergent in the intron and the LRR domain. Gene silencing and transgenesis were used in conjunction with inoculation with differen- tially avirulent and virulent stripe rust strains to demonstrate Yr10 functionality. The Yr10 CC-NBS-LRR sequence is unique among known CC-NBS-LRR R genes in wheat but highly conserved homologs （E = 0.0） were identified in Aegilops tauschii and other monocots including Hordeum vulgare and Brachypodium distachyon. Related sequences were also identified in genomic databases of maize, rice, and in sorghum. This is the first report of a CC-NBS-LRR resistance gene in plants with limited homologies in its native host, but with numerous homologous R genes in related monocots that are either host or non-hosts for stripe rust. These results represent a unique example of gene evolution and dispersion across species.
