GaN-based waveguide devices for long-wavelength optical communications

This is the published version. Copyright © 2003 American Institute of PhysicsRefractive indices of AlxGa1−xN with different Al concentrations have been measured in infrared wavelength regions. Single-mode ridged optical waveguidedevices using GaN/AlGaN heterostructures have been designed, fabricated, and characterized for operation in 1550 nm wavelength window. The feasibility of developing photonic integrated circuits based on III-nitride wide-band-gap semiconductors for fiber-optical communications has been discussed

Efficient isolation of high quality RNA from tropical palms for RNA-seq analysis

Currently, RNA-seq as a high throughput technology is being widely applied to various species to elucidate the complexity of the transcriptome and to discover large number of novel genes. However, the technology has had poor success in elucidating the transcriptome of tropical palms, as it is difficult to isolate high quality RNA from tropical palm tissues due to their high polysaccharide and polyphenol content. Here, we developed an RNA-isolation protocol for tropical palms, the MRIP method (Methods for RNA Isolation from Palms). The integrity of the RNA molecules extracted using this protocol was determined to be of high quality by means of gel electrophoresis and Agilent 2100 Bioanalyzer microfluidic electrophoresis chip examination with a RIN (RNA Integrity Number) value of more than 9, indicating that the mRNAs were of good integrity. Subsequently the isolated RNA was used for transcription analysis without further purification. With Illumina sequencing, we obtained 54.9 million short reads and then conducted de novo assembly to gain 57,304 unigenes with an average length of 752 base pairs. Moreover, the RNA isolated with this protocol was also successfully used for real-time RT-PCR. These results suggested that the RNA isolated was suitable for Illumina RNA sequencing and quantitative real-time RT-PCR. Furthermore, this method was also successful in isolating total RNA from the leaves of various Palmaceae species

The phenotype and genotype of fibrodysplasia ossificans progressiva in China: A report of 72 cases

AbstractFibrodysplasia ossificans progressiva, an ultra-rare and disabling genetic disorder of skeletal malformations and progressive heterotopic ossification (HO), is the most catastrophic condition of skeletal metamorphosis in humans. We studied 72 patients with FOP in China and analyzed their phenotypes and genotypes comprising the world's largest ethnically homogeneous population of FOP patients. Ninety-nine percent of patients (71/72 cases) were of Han nationality; and 1% of patients (1/72 cases) were of Hui nationality. Based on clinical examination, 92% of patients (66/72 cases) had classic FOP; 4% of patients (3/72 cases) were FOP-plus; and 4% of patients (3/72) were FOP variants. Importantly, all individuals with FOP had mutations in the protein-coding region of activin A receptor, type I/activin-like kinase 2 (ACVR1/ALK2). Ninety-seven percent of FOP patients (70/72 cases) had the canonical c.617G>A (p.R206H) mutation, while 3% of FOP patients (2/72 cases) had variant mutations in ACVR1/ALK2. Taken together, the genotypes and phenotypes of individuals with FOP from the Han nationality in China are similar to those reported elsewhere and support the fidelity of this ultra-rare disorder in the world's most highly populated nation and across wide racial, ethnic, gender and geographic distributions

Internal photoemission from plasmonic nanoparticles: comparison between surface and volume photoelectric effects

We study emission of photoelectrons from plasmonic nanoparticles into surrounding matrix. We consider two mechanisms of the photoelectric effect from nanoparticles - surface and volume ones, and use models of these two effects which allow us to obtain analytical results for the photoelectron emission rates from nanoparticle. Calculations have been done for the step potential at surface of spherical nanoparticle, and the simple model for the hot electron cooling have been used. We highlight the effect of the discontinuity of the dielectric permittivity at the nanoparticle boundary in the surface mechanism, which leads to substantial (by 5 times) increase of photoelectron emission rate from nanoparticle compared to the case when such discontinuity is absent. For plasmonic nanoparticle, a comparison of two mechanisms of the photoeffect was done for the first time and showed that surface photoeffect, at least, does not concede the volume one, which agrees with results for the flat metal surface first formulated by Tamm and Schubin in their pioneering development of quantum-mechanical theory of photoeffect in 1931. In accordance with our calculations, this predominance of the surface effect is a result of effective cooling of hot carriers, during their propagation from volume of the nanoparticle to its surface in the scenario of the volume mechanism. Taking into account both mechanisms is essential in development of devices based on the photoelectric effect and in usage of hot electrons from plasmonic nanoantenna.Comment: 13 pages, 10 figures, 61 reference

Nested reconfigurable robots: theory, design, and realization

Rather than the conventional classification method, we propose to divide modular and reconfigurable robots into intra-, inter-, and nested reconfigurations. We suggest designing the robot with nested reconfigurability, which utilizes individual robots with intra-reconfigurability capable of combining with other homogeneous/heterogeneous robots (inter-reconfigurability). The objective of this approach is to generate more complex morphologies for performing specific tasks that are far from the capabilities of a single module or to respond to programmable assembly requirements. In this paper, we discuss the theory, concept, and initial mechanical design of Hinged-Tetro, a self-reconfigurable module conceived for the study of nested reconfiguration. Hinged-Tetro is a mobile robot that uses the principle of hinged dissection of polyominoes to transform itself into any of the seven one-sided tetrominoes in a straightforward way. The robot can also combine with other modules for shaping complex structures or giving rise to a robot with new capabilities. Finally, the validation experiments verify the nested reconfigurability of Hinged-Tetro. Extensive tests and analyses of intra-reconfiguration are provided in terms of energy and time consumptions. Experiments using two robots validate the inter-reconfigurability of the proposed module

The emission positions of kHz QPOs and Kerr spacetime influence

Based the Alfven wave oscillation model (AWOM) and relativistic precession model (RPM) for twin kHz QPOs, we estimate the emission positions of most detected kHz QPOs to be at r=18+-3 km (R/15km) except Cir X-1 at r = 30\+-5 km (R/15km). For the proposed Keplerian frequency as an upper limit to kHz QPO, the spin effects in Kerr Spacetime are discussed, which have about a 5% (2%) modification for that of the Schwarzchild case for the spin frequency of 1000 (400) Hz.The application to the four typical QPO sources, Cir X-1, Sco X-1, SAX J1808.4-3658 and XTE 1807-294, is mentioned.Comment: Science China, Physics, Mechanics & Astronomy, 2010, 53, NO.

An Unified Approach To Pseudo Scalar Meson Photoproductions Off Nucleons In The Quark Model

An unified approach to the pseudo scalar meson ($\pi, \eta$, and $K$) photoproduction off nucleons are presented. It begins with the low energy QCD Lagrangian, and the resonances in the s- and u- channels are treated in the framework of the quark model The duality hypothesis is imposed to limit the number of the t-channel exchanges. The CGLN amplitudes for each reaction are evaluated, which include both proton and neutron targets. The important role by the S-wave resonances in the second resonance region is discussed, it is particularly important for the $K, \eta$ and $\eta^\prime$ photoproductions.Comment: 31 pages in Latex fil