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A wideband traveling-wave circularly polarized (CP) antenna printed on a single-layer PCB for millimeter-wave (MM-Wave) applications is presented in this communication. The proposed antenna radiates the CP wave on the basis of the principle similar to the classical endfire-mode helical antenna. The proposed antenna is terminated with an absorber to realize traveling-wave radiation. The traveling-wave working mechanism causes the proposed antenna to have a frequency scanning function and higher stability compared with resonant antennas. Curved microstrip transmission lines are adopted as the CP radiation elements; the whole array antenna is etched on a single-layer substrate. A prototype operating at 30 GHz is fabricated and measured. The radiation beam of the proposed antenna scans from − 14.5° (28 GHz) to +22.5° (34 GHz), the axial ratios are lower than 3 dB, and the measured gains show a maximum value of 21.9 dBi at 33 GHz and a minimum value of 20.3 dBi at 28 GHz. The measured $| \text {S}_{11} |$ and $| \text {S}_{21} |$ are lower than −10 and −16 dB, respectively, in the frequencies mentioned above. [ABSTRACT FROM AUTHOR]

This letter presents a low-cost, single-layer, dual circularly polarized (CP) series-fed antenna based on the sequential rotation technique for millimeter-wave (MM-wave) applications. The series-fed working form endows the proposed antenna with more compact structure and lower ohmic, dielectric losses caused by the feeding network compared with parallel-fed antennas. The curved microstrip transmission lines are adopted as radiation elements; therefore, the whole antenna can be etched on a single-layer laminate using standard printed circuit board technology. These characteristics make the antenna a competitive candidate for MM-wave applications. To validate the proposed design, a dual-CP antenna operating at 30 GHz is fabricated. Based on the measurement, the proposed antenna has a 3 dB gain bandwidth of 1.97 GHz, the measured $| {{S_{21}}} |$ is lower than −20 dB, and the axial ratios are lower than 3 dB in the aforementioned frequencies. [ABSTRACT FROM AUTHOR]

This paper presents the design of dual circularly polarized (CP) series-fed arrays based on the sequential rotation (SR) technique with uniform radiation elements. The radiation elements and feeding network used in the array are uniform, which leads to the possibility of dual-CP radiation by series-fed SR arrays. Meanwhile, the elements radiate unequal powers due to this arrangement. The relationship between the axial ratio and four key parameters of the array is derived and thoroughly discussed. Good polarization purity and port isolation can be realized by optimizing these parameters. A dual-CP array working at 10 GHz is designed with the help of the analysis. The experimental results show that the proposed antenna has good properties. [ABSTRACT FROM AUTHOR]

Abstract: A substrate integrated waveguide (SIW) circularly polarized (CP) antenna with omnidirectional radiation in the azimuthal plane is proposed. The antenna consists of five identical end‐fire CP antenna elements in a pentagonal array configuration, which is loaded on a circular substrate. Each element contains an H‐plane horn antenna in SIW structure and a printed dipole antenna. Five parasitic curve elements are introduced to improve the omnidirectional property of the antenna. Combined with complementary dipoles theory and SIW technology, prototype antenna is designed, fabricated and measured. With a low profile of 0.024λ0, the antenna has a 10‐dB return‐loss impedance bandwidth of 4.08% (2.4∼2.5 GHz) and a 3‐dB axial‐ratio (AR) bandwidth of 5.76% (2.36∼2.50 GHz). The antenna works well in the 2.45 GHz ISM band, with good cross‐polarization and excellent omnidirectional property. [ABSTRACT FROM AUTHOR]

A simple structure of broadband circularly polarized slot antenna based on coplanar waveguide (CPW) feeding is proposed in this article. To obtain circular polarization with a single feed, a transition from microstrip to CPW is designed to excite the even and odd modes of the CPW simultaneously. By adjusting the relative position and dimensions of the two circular patches introduced at the end of microstrip line and CPW, a 908 phase difference between two modes can be produced. When the two modes are coupled into the wide slot antenna, broadband circular polarization operation can be realized. The 10-dB reflection coefficient bandwidth of the proposed antenna is 88.2% (2.49-6.42 GHz) and 3-dB AR bandwidth attains 50% (2.72- 4.49 GHz). [ABSTRACT FROM AUTHOR]

A slot helix antenna working in Global Positioning System (GPS) L1 and L2 bands is proposed in this paper. Adopting sequential rotation technique, the proposed antenna is equipped with six helix radiation arms and fed by a microstrip line with folded shape. The whole antenna can be built on a full printed circuit board; so, it is easy to process the proposed antenna. The circularly polarized radiation mechanism of a circular array is analyzed in a new perspective to guide the design. A double-faced slot radiation structure is also established for dual-band operation. Additionally, a traveling wave feeding network suitable for the proposed antenna is presented. The experimental results show that the proposed antenna has good properties in GPS L1 and L2 bands. [ABSTRACT FROM PUBLISHER]

Purpose: To investigate the outcomes of unilateral medial rectus resection (UMR-res) for the treatment of small to moderate angles of recurrent exotropia in children followed up for a minimum of 6 months. Methods: This study is a retrospective, consecutive, interventional case series in which 48 children who underwent UMR-res (range 4.0-7.5 mm) for recurrent exotropia [range 12-25 prism diopters (PD)] between January 2009 and February 2013 were enrolled. Of these 48 children, 32 had recurrent intermittent exotropia, and 16 had recurrent constant exotropia. A successful surgical alignment was defined as +5 to −10 PD of orthophoria in the primary position while viewing distant or near targets. Results: At a mean follow-up of 12 months, the surgical success rate was 75 % (36/48), and the undercorrection rate was 25 % (12/48). No patient exhibited overcorrection. The success rates of the UMR-res in the recurrent intermittent exotropia group and recurrent constant exotropia group were 78 % and 69 %, respectively, and were not significantly different ( P = 0.50). In the initial surgical procedure groups, the success rates of patients with bilateral lateral rectus recession, unilateral lateral rectus recession, and unilateral lateral rectus recession combined with medial rectus resection were 81.8 % (18/22), 81.25 % (13/16), and 50 % (5/10), respectively. The surgical success rates did not differ among these three groups ( P = 0.122). Conclusion: Based on our results, UMR-res would appear to be an effective and safe procedure for the treatment of intermittent or constant recurrent exotropia of ≤25 PD in children. [ABSTRACT FROM AUTHOR]

Cotton is an important strategic material related to national interest and people's livelihood. Cotton yield is affected by many factors. Through analyzing various production factors' contribution to cotton yield increase, the basic factors promoting cotton output growth were found out to provide theoretical reliance and policy support for ensuring the supply of cotton market. Based on 4 major factors affecting the cotton yield increase, i.e. land investment, material and capital investment, labor input, disaster. Using production function, this paper calculated the various factors' production elasticity and rate of contribution on cotton yield increase. The results showed that technology advance played a vital role in cotton production, land investment was the first restriction factor affecting cotton yield increase, labor force and disaster were the negative factors for cotton output. Before ending, the paper puts forward some corresponding policy suggestions. [ABSTRACT FROM AUTHOR]

The adaptive integral method (AIM) in conjunction with the asymptotic waveform evaluation (AWE) technique is presented for wide-band analysis of antennas in the presence of electrically large conducting platforms. In the AWE technique, the Padé approximation solution obtained by matching the coefficients of the Taylor series (namely, moments) is utilized to achieve fast frequency sweeping. Besides the calculation and storage of the high order frequency derivatives of impedance matrices, the AWE technique requires repeatedly solving the linear system for the moments. Thus the AIM is employed to reduce matrix storage and to accelerate all the matrix-vector multiplications in both the linear system for the moments and the iterative solver. Furthermore, a localized self-box inclusion (SBI) preconditioner is used to accelerate the solution procedure of the linear system for the moments. Finally, three numerical examples are given and discussed. The input admittance and return loss of the antennas over a given frequency band are obtained by AIM and AIM-AWE method, respectively. The good agreements show that the proposed hybrid technique can greatly reduce the computation time without loss of accuracy. [ABSTRACT FROM AUTHOR]

Invertase (INV) hydrolyzes sucrose into glucose and fructose, thereby playing key roles in primary metabolism and plant development. Based on their pH optima and sub-cellular locations, INVs are categorized into cell wall, cytoplasmic, and vacuolar subgroups, abbreviated as CWIN, CIN, and VIN, respectively. The broad importance and implications of INVs in plant development and crop productivity have attracted enormous interest to examine INV function and regulation from multiple perspectives. Here, we review some exciting advances in this area over the last two decades, focusing on (1) new or emerging roles of INV in plant development and regulation at the post-translational level through interaction with inhibitors, (2) cross-talk between INV-mediated sugar signaling and hormonal control of development, and (3) sugar- and INV-mediated responses to drought and heat stresses and their impact on seed and fruit set. Finally, we discuss major questions arising from this new progress and outline future directions for unraveling mechanisms underlying INV-mediated plant development and their potential applications in plant biotechnology and agriculture. [ABSTRACT FROM PUBLISHER]

Heterotrimeric GTP-binding proteins, which consist of Gα, Gβ, and Gγ subunits, play important roles in transducing extracellular signals perceived by cell surface receptors into intracellular physiological responses. In addition to a single prototypical Gα protein (GPA1), Arabidopsis has three unique Gα-like proteins, known as XLG1, XLG2, and XLG3, that have been found to be localized in nuclei, although their functions and mode of action remain largely unknown. Through a transcriptomic analysis, we found that XLG2 and XLG3 were rapidly induced by infection with the bacterial pathogen Pseudomonas syringae, whereas the XLG1 transcript level was not affected by pathogen infection. A reverse genetic screen revealed that the xlg2 loss-of-function mutation causes enhanced susceptibility to P. syringae. Transcriptome profiling revealed that the xlg2 mutation affects pathogen-triggered induction of a small set of defense-related genes. However, xlg1 and xlg3 mutants showed no difference from wild-type plants in resistance to P. syringae. In addition, the xlg2 xlg3 double mutant and the xlg1 xlg2 xlg3 triple mutant were not significantly different from the xlg2 single mutant in the disease resistance phenotype, suggesting that the roles of XLG1 and XLG3 in defense, if any, are less significant than for XLG2. Constitutive overexpression of XLG2 leads to the accumulation of abnormal transcripts from multiple defense-related genes. Through co-immunoprecipitation assays, XLG2 was found to interact with AGB1, the sole Gβ subunit in Arabidopsis, which has previously been found to be a positive regulator in resistance to necrotrophic fungal pathogens. However, no significant difference was found between three xlg single mutants, the xlg2 xlg3 double mutant, the xlg triple mutant, and wild-type plants in resistance to the necrotrophic fungal pathogens Botrytis cinerea or Alternaria brassicicola. These results suggest that XLG2 and AGB1 are components of a G-protein complex different from the prototypical heterotrimeric G-protein and may have distinct functions in modulating defense responses. [ABSTRACT FROM PUBLISHER]

Plants have evolved complicated regulatory systems to control immune responses. Both positive and negative signaling path- ways interplay to coordinate development of a resistance response with the appropriate amplitude and duration. AtNUDT7, a Nudix domain-containing protein in Arabidopsis (Arabidopsis thaliana) that hydrolyzes nucleotide derivatives, was found to be a negative regulator of the basal defense response, and its loss-of-function mutation results in enhanced resistance to infection by Pseudomonas syringae. The nudt7 mutation does not cause a strong constitutive disease resistance phenotype, but it leads to a heightened defense response, including accelerated activation of defense-related genes that can be triggered by pathogenic and nonpathogenic microorganisms. The nudt7 mutation enhances two distinct defense response pathways: one independent of and the other dependent on NPR1 and salicylic acid accumulation. In vitro enzymatic assays revealed that ADP-ribose and NADH are preferred substrates of NUDT7, and the hydrolysis activity of NUDT7 is essential for its biological function and is sensitive to inhibition by Ca2+. Further analyses indicate that ADP-ribose is not likely the physiological substrate of NUDT7. However, the nudt7 mutation leads to perturbation of cellular redox homeostasis and a higher level of NADH in pathogen-challenged leaves. The study suggests that the alteration in cellular antioxidant status caused by the nudt7 mutation primes the cells for the amplified defense response and NUDT7 functions to modulate the defense response to prevent excessive stimulation. [ABSTRACT FROM AUTHOR]

Mitogen-activated protein kinase (MAPK) cascades are important signaling modules in eukaryotic cells. They function downstream of sensors/receptors and regulate cellular responses to external and endogenous stimuli. Recent studies demonstrated that SIPK and WIPK, two tobacco (Nicotiana spp.) MAPKs, are involved in signaling plant defense responses to various pathogens. Ntf4, another tobacco MAPK that shares 93.6% and 72.3% identity with SIPK and WIPK, respectively, was reported to be developmentally regulated and function in pollen germination. We found that Ntf4 is also expressed in leaves and suspension-cultured cells. Genomic analysis excluded the possibility that Ntf4 and SIPK are orthologs from the two parental lines of the amphidiploid common tobacco. In vitro and in vivo phosphorylation and activation assays revealed that Ntf4 shares the same upstream MAPK kinase, NtMEK2, with SIPK and WIPK. Similar to SIPK and WIPK, Ntf4 is also stress responsive and can be activated by cryptogein, a proteinaceous elicitin from oomycetic pathogen Phytophthora cryptogea. Tobacco recognition of cryptogein induces rapid hypersensitive response (HR) cell death in tobacco. Transgenic Ntf4 plants with elevated levels of Ntf4 protein showed accelerated HR cell death when treated with cryptogein. In addition, conditional overexpression of Ntf4, which results in high cellular Ntf4 activity, is sufficient to induce HR-like cell death. Based on these results, we concluded that Ntf4 is multifunctional. In addition to its role in pollen germination, Ntf4 is also a component downstream of NtMEK2 in the MAPK cascade that regulates pathogen-induced HR cell death in tobacco. [ABSTRACT FROM AUTHOR]

A wideband antenna for DCS-1800, PCS-1900, WCDMA/IMT-2000, WLAN, and TD-SCDMA indoor applications is presented. The antenna consists of two half circle shaped radiating patches, a feeding ground and a reflector ground. The coupling between two patches is considered in the design of the antenna. The two patches are fed with 90° phase difference, which leads to down-tilted radiation patterns when the antenna is mounted on a wall. A prototype is constructed and tested. Simulated and measured results are given. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1377-1379, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25973 [ABSTRACT FROM AUTHOR]

Textured Bi-substituted Ca2Co2O5 ceramics have been prepared using a coprecipitation method combined with spark plasma sintering. The Bi substitution is effective in increasing the grain orientation of the Ca2Co2O5-based ceramics (from 0.46 to 0.85). Electrical conductivity increases obviously with partial substitution of Bi3+ for Ca2+ (from 113.9 to 142.4 S/cm at 973 K). The Ca1.92Bi0.08Co2O5 sample exhibits higher power factor (4.4×10-4 W m-1 K-2) than that of pure Ca2Co2O5 (3.2×10-4 W m-1 K-2) at 973 K, indicating that the Ca2Co2O5 system is another promising p-type material for high-temperature thermoelectric applications. [ABSTRACT FROM AUTHOR]

A low profile circularly polarized (CP) antenna based on printed monopole and sequential rotation feed network is presented. As the monopole placed on the edge of the limited floor produces an axial radiation, CP radiation will be obtained when the sequential rotation technique is introduced to enclose the 6 monopoles into a hexagon. By folding the top of the monopole elements to the center, the profile of the antenna is reduced greatly. Measurement results show that the proposed antenna has a good CP performance and a small size. The antenna operates at 1.575 GHz with profile of 7 mm and 3 dB beamwidth of 140°. [ABSTRACT FROM AUTHOR]