A Tri-Band Low-Profile High-Gain Planar Antenna Using Fabry-Perot Cavity

A tri-band high-gain antenna with a planar structure and low profile is proposed. The principle of operation is explained. It is based on Fary-Perot cavity antenna (FPCA) with two frequency selective surface (FSS) layers. Two different resonant frequencies are generated by the two resonant cavities formed by the ground plane and each of the two FSS layers, respectively. A third resonant frequency is produced by combining the two FSS layers together. Advantages of this tri-band antenna includes low profile, high gain, easy fabrication and low cost. Low profile is achieved by designing the combined FSS layers as an artificial magnetic conductor (AMC) with a reflection coefficient having 0o phase shift and high magnitude. In addition, a large frequency ratio, which is often a problem for multiband array antennas, can be achieved here. To verify this concept, a C/X/Ku band FPCA is designed and one prototype is fabricated and tested. Experimental results agree well with the simulated results. High gain performance with good impedance matching in three bands is obtained, which reaches a peak gain of 14.2 dBi at 5.2 GHz, 18.9 dBi at 9.6 GHz and 19.8 dBi at 14.7 GHz, respectively. The overall height of antenna is only 20.2 mm, which is about 1/3 wavelength at its lowest operating frequency, which means a reduction of 30% compared to the height of traditional FPCA antenna

Genetic characterization of wild-type measles viruses isolated in China, 2006-2007

Molecular characterization of wild-type measles viruses in China during 1995-2004 demonstrated that genotype H1 was endemic and widely distributed throughout the country. H1-associated cases and outbreaks caused a resurgence of measles beginning in 2005. A total of 210,094 measles cases and 101 deaths were reported by National Notifiable Diseases Reporting System (NNDRS) and Chinese Measles Laboratory Network (LabNet) from 2006 to 2007, and the incidences of measles were 6.8/100,000 population and 7.2/100,000 population in 2006 and 2007, respectively. Five hundred and sixty-five wild-type measles viruses were isolated from 24 of 31 provinces in mainland China during 2006 and 2007, and all of the wild type virus isolates belonged to cluster 1 of genotype H1. These results indicated that H1-cluster 1 viruses were the predominant viruses circulating in China from 2006 to 2007. This study contributes to previous efforts to generate critical baseline data about circulating wild-type measles viruses in China that will allow molecular epidemiologic studies to help measure the progress made toward China's goal of measles elimination by 2012

The Rice HGW Gene Encodes a Ubiquitin-Associated (UBA) Domain Protein That Regulates Heading Date and Grain Weight

Heading date and grain weight are two determining agronomic traits of crop yield. To date, molecular factors controlling both heading date and grain weight have not been identified. Here we report the isolation of a hemizygous mutation, heading and grain weight (hgw), which delays heading and reduces grain weight in rice. Analysis of hgw mutant phenotypes indicate that the hemizygous hgw mutation decreases latitudinal cell number in the lemma and palea, both composing the spikelet hull that is known to determine the size and shape of brown grain. Molecular cloning and characterization of the HGW gene showed that it encodes a novel plant-specific ubiquitin-associated (UBA) domain protein localized in the cytoplasm and nucleus, and functions as a key upstream regulator to promote expressions of heading date- and grain weight-related genes. Moreover, co-expression analysis in rice and Arabidopsis indicated that HGW and its Arabidopsis homolog are co-expressed with genes encoding various components of ubiquitination machinery, implying a fundamental role for the ubiquitination pathway in heading date and grain weight control

Single Endemic Genotype of Measles Virus Continuously Circulating in China for at Least 16 Years

The incidence of measles in China from 1991 to 2008 was reviewed, and the nucleotide sequences from 1507 measles viruses (MeV) isolated during 1993 to 2008 were phylogenetically analyzed. The results showed that measles epidemics peaked approximately every 3 to 5 years with the range of measles cases detected between 56,850 and 140,048 per year. The Chinese MeV strains represented three genotypes; 1501 H1, 1 H2 and 5 A. Genotype H1 was the predominant genotype throughout China continuously circulating for at least 16 years. Genotype H1 sequences could be divided into two distinct clusters, H1a and H1b. A 4.2% average nucleotide divergence was found between the H1a and H1b clusters, and the nucleotide sequence and predicted amino acid homologies of H1a viruses were 92.3%–100% and 84.7%–100%, H1b were 97.1%–100% and 95.3%–100%, respectively. Viruses from both clusters were distributed throughout China with no apparent geographic restriction and multiple co-circulating lineages were present in many provinces. Cluster H1a and H1b viruses were co-circulating during 1993 to 2005, while no H1b viruses were detected after 2005 and the transmission of that cluster has presumably been interrupted. Analysis of the nucleotide and predicted amino acid changes in the N proteins of H1a and H1b viruses showed no evidence of selective pressure. This study investigated the genotype and cluster distribution of MeV in China over a 16-year period to establish a genetic baseline before MeV elimination in Western Pacific Region (WPR). Continuous and extensive MeV surveillance and the ability to quickly identify imported cases of measles will become more critical as measles elimination goals are achieved in China in the near future. This is the first report that a single endemic genotype of measles virus has been found to be continuously circulating in one country for at least 16 years

Panicle Morphology Mutant 1 (PMM1) determines the inflorescence architecture of rice by controlling brassinosteroid biosynthesis

Abstract Background Panicle architecture is one of the main important agronomical traits that determine branch number and grain number in rice. Although a large number of genes involved in panicle development have been identified in recent years, the complex processes of inflorescence patterning need to be further characterized in rice. Brassinosteroids (BRs) are a class of steroid phytohormones. A great understanding of how BRs contribute to plant height and leaf erectness have been reported, however, the molecular and genetic mechanisms of panicle architecture influenced by BRs remain unclear. Results Here, we identified PMM1, encoding a cytochrome P450 protein involved in BRs biosynthesis, and characterized its role in panicle architecture in rice. Three alleles of pmm1 were identified from our T-DNA insertional mutant library. Map-based cloning revealed that a large fragment deletion from the 2nd to 9th exons of PMM1 was responsible for the clustered primary branch morphology in pmm1–1. PMM1 is a new allele of DWARF11 (D11) PMM1 transcripts are preferentially expressed in young panicles, particularly expressed in the primordia of branches and spikelets during inflorescence development. Furthermore, overexpression of OsDWARF4 (D4), another gene encoding cytochrome P450, completely rescued the abnormal panicle phenotype of pmm1–1. Overall, it can be concluded that PMM1 is an important gene involved in BRs biosynthesis and affecting the differentiation of spikelet primordia and patterns of panicle branches in rice. Conclusions PMM1 is a new allele of D11, which encodes a cytochrome P450 protein involved in BRs biosynthesis pathway. Overexpression of D4 could successfully rescue the abnormal panicle architecture of pmm1 plants, indicating that PMM1/D11 and D4 function redundantly in BRs biosynthesis. Thus, our results demonstrated that PMM1 determines the inflorescence architecture by controlling brassinosteroid biosynthesis in rice

Rice <i>RBH1</i> Encoding A Pectate Lyase is Critical for Apical Panicle Development

Panicle morphology is one of the main determinants of the rice yield. Panicle abortion, a typical panicle morphological defect results in yield reduction due to defective spikelet development. To further elucidate the molecular mechanism of panicle abortion in rice, a rice panicle bald head 1 (rbh1) mutant with transfer DNA (T-DNA) insertion showing severely aborted apical spikelets during panicle development was identified and characterized. The rbh1-1 mutant showed obviously altered cell morphology and structure in the degenerated spikelet. Molecular genetic studies revealed that RBH1 encodes a pectate lyase protein. Pectate lyase-specific activity of Rice panicle Bald Head 1 (RBH1) protein assay using polygalacturonic acid (PGA) as substrates illustrated that the enzyme retained a significant capacity to degrade PGA. In addition, immunohistochemical analysis showed that the degradation of pectin is inhibited in the rbh1-1 mutant. Further analysis revealed that a significant increase in reactive oxygen species (ROS) level was found in degenerated rbh1-1 spikelets. Taken together, our findings suggest that RBH1 is required for the formation of panicle and for preventing panicle abortion