A Reconfigurable Soft Linkage Robot via Internal "Virtual" Joints.

Traditional robots derive their capabilities of movement through rigid structural "links" and discrete actuated "joints." Alternatively, soft robots are composed of flexible materials that permit movement across a continuous range of their body and appendages and thus are not restricted in where they can bend. While trade-offs between material choices may restrain robot functionalities within a narrow spectrum, we argue that bridging the functional gaps between soft and hard robots can be achieved from a hybrid design approach that utilizes both the reconfigurability and the controllability of traditional soft and hard robot paradigms. In this study, we present a hybrid robot with soft inflated "linkages," and rigid internal joints that can be spatially reconfigured. Our method is based on the geometric pinching of an inflatable beam to form mechanical pinch-joints connecting the inflated robot linkages. Such joints are activated and controlled via internal motorized modules that can be relocated for on-demand joint-linkage configurations. We demonstrate two applications that utilize joint reconfigurations: a deployable robot manipulator and a terrestrial crawling robot with tunable gaits.

Production of transgenic rice new germplasm with strong resistance against two isolations of Rice stripe virus by RNA interference.

Rice stripe disease, with the pathogen Rice stripe virus (RSV), is one of the most widespread and severe virus diseases. Cultivating a resistant breed is an essential and efficient method in preventing rice stripe disease. Following RNA interference (RNAi) theory, we constructed three RNAi binary vectors based on coat protein (CP), special-disease protein (SP) and chimeric CP/SP gene sequence. Transgenic lines of rice cv. Yujing6 were generated through Agrobacterium-mediated transformation. We inoculated T1 generation plants from each line derived from CP/SP, CP, and SP transgenic rice plants with two RSV isolates from Shandong Province and Jiangsu Province using viruliferous vector insects. In these resistance assays, chimeric CP/SP RNAi lines showed stronger resistance against two isolates than CP or SP single RNAi lines. Stable integration and expression of RNAi transgenes were confirmed by Southern and northern blot analysis of independent transgenic lines. In the resistant transgenic lines, lower levels of transgene transcripts and specific short interference RNAs were observed relative to the susceptible transgenic plant, which showed that virus resistance was increased by RNAi. Genetic analysis demonstrated that transgene and virus resistance was stably inherited in the T2 progeny plants.

Flexoskeleton Printing Enables Versatile Fabrication of Hybrid Soft and Rigid Robots.

One of the many secrets to the success and prevalence of insects is their versatile, robust, and complex exoskeleton morphology. A fundamental challenge in insect-inspired robotics has been the fabrication of robotic exoskeletons that can match the complexity of exoskeleton structural mechanics. Hybrid robots composed of rigid and soft elements have previously required access to expensive multi-material three-dimensional (3D) printers, multistep casting and machining processes, or limited material choice when using consumer-grade fabrication methods. In this study, we introduce a new design and fabrication process to rapidly construct flexible exoskeleton-inspired robots called "flexoskeleton printing." We modify a consumer-grade fused deposition modeling (FDM) 3D printer to deposit filament directly onto a heated thermoplastic base layer, which provides extremely strong bond strength between deposited material and the inextensible, flexible base layer. This process significantly improves the fatigue resistance of printed components and enables a new class of insect-inspired robot morphologies. We demonstrate these capabilities through design and testing of a wide library of canonical flexoskeleton elements; ultimately leading to the integration of elements into a flexoskeleton walking legged robot.

A Tunable-Color Emission Phosphor Y2O3:Eu³âº, Bi³âº with Efficient Energy Transfer for White Light Emitting Diodes.

The Eu³âº, Bi³âº ions co-doped Y2O3 phosphor has been synthesized by the conventional solid-state reaction method, and its photoluminescence (PL) spectra are investigated for application in white light emitting diode (LED). The Eu³âº, Bi³âº ions co-doped Y2O3 phosphor showed a characteristic emissions with greenish blue and red color upon the near-UV light in the range of 310-360 nm, originating from ³P1 --> ¹S0 transition of Bi³âº and 5D0 --> 7F(J) transition of Eu³âº, respectively. As 613-nm emission of Eu³âº ions is monitored, excitation spectrum consists of two broad peaks near 230 nm and 330 nm, ascribed to the Eu³âº-O²- charge transfer band (CTB) and the transition from the ground state to the excited states of Bi³âº ions, respectively. It implies that the energy transfer from Bi³âº ions to E³âº ions occur and the phosphor's color may be controlled by adjusting the concentrations of Eu³âº ions and Bi³âºons in Y202O3The availability of this strategy is demonstrated in this work, and white light can be realized with superior chromaticity coordinates of (x = 0.337, y = 0.328) and a CCT of 5284 K for Y202O3% Eu3+³âº0.1% Bi3+³âºThus, it will be a promising candidate for the ultraviolet excitation white light emitting diode (LED).

A single-phased tunable emission phosphor MgY2Si3O10: Eu(3+), Bi(3+) with efficient energy transfer for white LEDs.

A novel single-phased tunable emitting phosphor MgY2Si3O10: Bi(3+), Eu(3+) has been synthesized by a conventional high temperature solid-state method. X-ray diffraction (XRD), photoluminescence emission and excitation spectra were utilized to characterize the as-synthesized samples. Under UV-light pumping, MgY2Si3O10: Bi(3+) showed characteristic blue emission corresponding to the (3)P1→(1)S0 transition of Bi(3+) ions, and MgY2Si3O10: Eu(3+) showed characteristic red emission corresponding to the (5)D0→(7)FJ (J = 1, 2, 3, 4) transition of Eu(3+) ions. Spectra indicate that Bi(3+) ions occupy two nonequivalent sites in the MgY2Si3O10 matrix, namely, Bi(3+)(i) and Bi(3+)(ii). The two sites (Bi(3+)(i) and Bi(3+)(ii)) exhibit broad emission peaks at 411 nm and 490 nm, respectively. Efficient energy transfer between these two Bi(3+) sites has been proven using the spectra. The spectral overlap between the emission spectrum of Bi(3+) and the excitation spectrum of Eu(3+) allows for resonance-type energy transfer to occur from Bi(3+) to Eu(3+). The efficient energy transfer from Bi(3+) to Eu(3+)via a dipole-quadrupole interaction mechanism is significantly demonstrated by comparing experimental data with theoretical calculations. According to the concentration quenching-method, the critical distance of energy transfer from Bi(3+) to Eu(3+) is calculated to be 13.2 Å. As it is a new phosphor, CIE coordinates and CCT temperature, in addition to efficient energy transfer have been also investigated in detail. White light emission for MgY2Si3O10: n Bi(3+), m Eu(3+) can be realized through controlling the concentrations of Bi(3+) and Eu(3+). All of the results indicate that MgY2Si3O10: n Bi(3+), m Eu(3+) is a potential phosphor for white light UV-LEDs.

A novel green-emitting phosphor Ba2Gd2Si4O13:Eu(2+) for near UV-pumped light-emitting diodes.

A novel green-emitting phosphor Ba2Gd2Si4O13:Eu(2+) has been prepared using a conventional high-temperature solid-state method. X-ray diffraction and photoluminescence spectra were used to characterize the as-synthesized phosphor. The Ba2Gd2Si4O13:Eu(2+) phosphor exhibits a broad emission band centered at 503 nm under 365 nm excitation. Monitoring the 503 nm emission, the Ba2Gd2Si4O13:Eu(2+) phosphor shows an intense broad excitation band ranging from 200 to 410 nm. The concentration quenching mechanism has been investigated, and demonstrated to involve a dipole-dipole interaction. The critical concentration was found to be about 4 mol%. The critical distance calculated using the concentration method and spectral overlap method was 23.9 Å and 27.1 Å, respectively. The temperature-dependent photoluminescence and CIE chromaticity coordinate of the Ba2Gd2Si4O13:Eu(2+) phosphor were also investigated in this work. The results revealed that Ba2Gd2Si4O13:Eu(2+) possesses excellent thermal stability and the CIE value of the Ba2Gd2Si4O13:0.04 Eu(2+) phosphor upon 365 nm excitation is (0.211, 0.434), located in the green region. All the properties indicate that the Ba2Gd2Si4O13:Eu(2+) phosphor is a potential green-emitting phosphor fit for ultraviolet light pumped LEDs.

Production of marker-free and RSV-resistant transgenic rice using a twin T-DNA system and RNAi.

A twin T-DNA system is a convenient strategy for creating selectable marker-free transgenic plants. The standard transformation plasmid, pCAMBIA 1300, was modified into a binary vector consisting of two separate T-DNAs, one of which contained the hygromycin phosphotransferase (hpt) marker gene. Using this binary vector, we constructed two vectors that expressed inverted-repeat (IR) structures targeting the rice stripe virus (RSV) coat protein (CP) gene and the special-disease protein (SP) gene. Transgenic rice lines were obtained via Agrobacterium-mediated transformation. Seven independent clones harbouring both the hpt marker gene and the target genes (RSV CP or SP) were obtained in the primary transformants of pDTRSVCP and pDTRSVSP, respectively. The segregation frequencies of the target gene and the marker gene in the T1 plants were 8.72 percent for pDTRSVCP and 12.33 percent for pDTRSVSP. Two of the pDTRSVCP lines and three pDTRSVSP lines harbouring the homozygous target gene, but not the hpt gene, were strongly resistant to RSV. A molecular analysis of the resistant transgenic plants confirmed the stable integration and expression of the target genes. The resistant transgenic plants displayed lower levels of the transgene transcripts and specific small interfering RNAs, suggesting that RNAi induced the viral resistance.

Delimitation of the PSH1(t) gene for rice purple leaf sheath to a 23.5 kb DNA fragment.

Leaf sheath color plays an important role as a marker for rice genetic improvement. A recombinant inbred line (RIL) population consisting of 220 individuals was developed from a cross between an Oryza sativa subsp. indica variety, IRBB60, and an Oryza sativa subsp. japonica variety, 9407. Within the RIL population, a line, RI51, was found to have purple leaf sheath (PSH). To map the gene governing PSH, RI51 was crossed with 9407 green leaf sheath (GSH) to develop an F2 segregating population. The distribution of F2 plants with PSH and GSH fitted a segregation ratio of 3:1, indicating that the PSH was controlled by a major dominant gene. The gene locus for PSH, tentatively designated as PSH1(t), was identified by surveying two bulks made of the respective 40 individuals with PSH and GSH with SSR markers covering the entire rice genome. The survey indicated that the PSH1(t) region was located on chromosome 1. Further confirmation was made using a large random sample of 360 individuals from the same F2 population and the PSH1(t) locus was then mapped on chromosome 1 between SSR markers RM3475 and RM7202 with genetic distances of 2.0 and 1.1 cM, respectively. For fine mapping of PSH1(t), a large F(2:3) segregating population with 3300 individuals from the seven heterozygous F2 plants in the RM3475-RM7202 region was constructed. Analysis of recombinants in the PSH1(t) region anchored the gene locus to an interval of 23.5 kb flanked by the left marker L03 and the right marker L05. Sequence analysis of this fragment predicted six open reading frames encoding a putative trans-sialidase, a putative Plastidic ATP/ADP-transporter, and four unknown proteins. The detailed genetic and physical maps of the PSH1(t) locus will be very useful in molecular cloning of the PSH1(t) gene.