Photoreceptor Cell Rescue at Early and Late RPE-Cell Transplantation Periods During Retinal Disease in RCS Dystrophic Rats

Maximal PRC rescue was affected by RPE-cell transplantation in retinas of RCS dystrophic rats at early stages of the retinal disease, while little or no rescue was detected when transplantation was performed at late time periods

High-precision RCS measurement of aircraft’s weak scattering source

AbstractThe radar cross section (RCS) of weak scattering source on the surface of an aircraft is usually less than −40dBsm. How to accurately measure the RCS characteristics of weak scattering source is a technical challenge for the aircraft’s RCS measurement. This paper proposes separating and extracting the two-dimensional (2D) reflectivity distribution of the weak scattering source with the microwave imaging algorithm and spectral transform so as to enhance its measurement precision. Firstly, we performed the 2D microwave imaging of the target and then used the 2D gating function to separate and extract the reflectivity distribution of the weak scattering source. Secondly, we carried out the spectral transform of the reflectivity distribution and eventually obtained the RCS of the weak scattering source through calibration. The prototype experimental results and their analysis show that the measurement method is effective. The experiments on an aircraft’s low-scattering conformal antenna verify that the measurement method can eliminate the clutter on the surface of aircraft. The precision of measuring a −40dBsm target is 3–5dB better than the existing RCS measurement methods. The measurement method can more accurately obtain the weak scattering source’s RCS characteristics

MimicPlay: Long-Horizon Imitation Learning by Watching Human Play

Imitation learning from human demonstrations is a promising paradigm for teaching robots manipulation skills in the real world. However, learning complex long-horizon tasks often requires an unattainable amount of demonstrations. To reduce the high data requirement, we resort to human play data - video sequences of people freely interacting with the environment using their hands. Even with different morphologies, we hypothesize that human play data contain rich and salient information about physical interactions that can readily facilitate robot policy learning. Motivated by this, we introduce a hierarchical learning framework named MimicPlay that learns latent plans from human play data to guide low-level visuomotor control trained on a small number of teleoperated demonstrations. With systematic evaluations of 14 long-horizon manipulation tasks in the real world, we show that MimicPlay outperforms state-of-the-art imitation learning methods in task success rate, generalization ability, and robustness to disturbances. Code and videos are available at https://mimic-play.github.ioComment: 7th Conference on Robot Learning (CoRL 2023 oral presentation

Genome-wide identification and expression profiling of B3 transcription factor genes in Populus alba × Populus glandulosa

B3-domain containing transcription factors (TFs) are well known to play important roles in various developmental processes, including embryogenesis, seed germination, etc. Characterizations and functional studies of the B3 TF superfamily in poplar are still limited, especially on their roles in wood formation. In this study, we conducted comprehensive bioinformatics and expression analysis of B3 TF genes in Populus alba × Populus glandulosa. A total of 160 B3 TF genes were identified in the genome of this hybrid poplar, and their chromosomal locations, syntenic relationships, gene structures, and promoter cis-acting elements were analyzed. Through domain structure and phylogenetic relationship analyses, these proteins were classified into four families LAV, RAV, ARF, and REM. Domain and conservation analyses revealed different gene numbers and different DNA-binding domains among families. Syntenic relationship analysis suggested that approximately 87% of the genes resulted from genome duplication (segmental or tandem), contributing to the expansion of the B3 family in P. alba × P. glandulosa. Phylogeny in seven species revealed the evolutionary relationship of B3 TF genes across different species. B3 domains among the eighteen proteins that were highly expressed in differentiating xylem had a high synteny, suggesting a common ancestor for these seven species. We performed co-expression analysis on the representative genes in two different ages of poplar, followed by pathways analysis. Among those genes co-expressed with four B3 genes, 14 were involved in lignin synthases and secondary cell walls biosynthesis, including PagCOMT2, PagCAD1, PagCCR2, PagCAD1, PagCCoAOMT1, PagSND2, and PagNST1. Our results provide valuable information for the B3 TF family in poplar and show the potential of B3 TF genes in engineering to improve wood properties

Acoustic waves for active reduction of droplet impact contact time

Minimizing droplet impact contact time is critical for applications such as self-cleaning, antierosion or anti-icing. Recent studies have used the texturing of surfaces to split droplets during impact or inducing asymmetric spreading, but these require specifically designed substrates that cannot be easily reconfigured. A key challenge is to realize an effective reduction in contact time during droplet impingement on a smooth surface without texturing but with active and programmable control. Our experimental results show that surface acoustic waves (SAWs), generated at a location distant from a point of droplet impact, can be used to minimize contact time by as much as 35% without requiring a textured surface. Additionally, the ability to switch on and off the SAWs means that a reduction in droplet impact contact time on a surface can be controlled in a programmable manner. Moreover, our results show that, by applying acoustic waves, the impact regime of the droplet on the solid surface can be changed from deposition or partial rebound to complete rebound. To study the dynamics of droplet impact, we develop a numerical model for multiphase flow and simulate different droplet impingement scenarios. Numerical results reveal that the acoustic waves can be used to modify and control the internal velocity fields inside the droplet. By breaking the symmetry of the internal recirculation patterns inside the droplet, the kinetic energy recovered from interfacial energy during the retraction process is increased, and the droplet can be fully separated from the surface with a much shorter contact time. Our work opens up opportunities to use SAW devices to minimize the contact time, change the droplet impact regime, and program or control the droplet’s rebounding on smooth or planar and curved surfaces, as well as rough or textured surfaces

Secondary infection with Streptococcus suis serotype 7 increases the virulence of highly pathogenic porcine reproductive and respiratory syndrome virus in pigs

<p>Abstract</p> <p>Background</p> <p>Porcine reproductive and respiratory syndrome virus (PRRSV) and <it>Streptococcus suis </it>are common pathogens in pigs. In samples collected during the porcine high fever syndrome (PHFS) outbreak in many parts of China, PRRSV and <it>S. suis </it>serotype 7 (SS7) have always been isolated together. To determine whether PRRSV-SS7 coinfection was the cause of the PHFS outbreak, we evaluated the pathogenicity of PRRSV and/or SS7 in a pig model of single and mixed infection.</p> <p>Results</p> <p>Respiratory disease, diarrhea, and anorexia were observed in all infected pigs. Signs of central nervous system (CNS) disease were observed in the highly pathogenic PRRSV (HP-PRRSV)-infected pigs (4/12) and the coinfected pigs (8/10); however, the symptoms of the coinfected pigs were clearly more severe than those of the HP-PRRSV-infected pigs. The mortality rate was significantly higher in the coinfected pigs (8/10) than in the HP-PRRSV- (2/12) and SS7-infected pigs (0/10). The deceased pigs of the coinfected group had symptoms typical of PHFS, such as high fever, anorexia, and red coloration of the ears and the body. The isolation rates of HP-PRRSV and SS7 were higher and the lesion severity was greater in the coinfected pigs than in monoinfected pigs.</p> <p>Conclusion</p> <p>HP-PRRSV infection increased susceptibility to SS7 infection, and coinfection of HP-PRRSV with SS7 significantly increased the pathogenicity of SS7 to pigs.</p

VIMA: General Robot Manipulation with Multimodal Prompts

Prompt-based learning has emerged as a successful paradigm in natural language processing, where a single general-purpose language model can be instructed to perform any task specified by input prompts. Yet task specification in robotics comes in various forms, such as imitating one-shot demonstrations, following language instructions, and reaching visual goals. They are often considered different tasks and tackled by specialized models. We show that a wide spectrum of robot manipulation tasks can be expressed with multimodal prompts, interleaving textual and visual tokens. Accordingly, we develop a new simulation benchmark that consists of thousands of procedurally-generated tabletop tasks with multimodal prompts, 600K+ expert trajectories for imitation learning, and a four-level evaluation protocol for systematic generalization. We design a transformer-based robot agent, VIMA, that processes these prompts and outputs motor actions autoregressively. VIMA features a recipe that achieves strong model scalability and data efficiency. It outperforms alternative designs in the hardest zero-shot generalization setting by up to $2.9\times$ task success rate given the same training data. With $10\times$ less training data, VIMA still performs $2.7\times$ better than the best competing variant. Code and video demos are available at https://vimalabs.github.io/Comment: ICML 2023 Camera-ready version. Project website: https://vimalabs.github.io

The State of Grasslands across Inner Mongolia and Mongolia

Grasslands across Inner Mongolia and Mongolia, with their long history of nomadic livestock grazing, are very important natural resources for animal husbandry and environmental services. The main types of grasslands are meadow steppe (forest steppe), typical steppe (steppe) and desert steppe. Most of the grasslands are degraded due to over-grazing, which reduces animal production and the values of environmental services. Overgrazing decreases plant production, species biodiversity, ecosystem stability, soil fertility & structure, and lowers animal productivity leading to reduced household incomes. In pastoral areas across Inner Mongolia and Mongolia, degraded grasslands can be rehabilitated by better managing stocking rates. Our surveys, experiments and farm demonstrations have found that, in degraded grasslands, lower stocking rates had benefits for animal production, net incomes and environmental services. To implement these improvements across Inner Mongolia and Mongolia will be challenging to avoid deleterious trade-offs with livelihoods as it will require changes in herder practices. Further research and demonstration are required to develop locally relevant systems

Wide range of droplet jetting angles by thin-film based surface acoustic waves

Nozzleless jetting of droplets with different jetting angles is a crucial requirement for 2D and 3D printing/bioprinting applications, and Rayleigh mode surface acoustic waves (SAWs) could be a potential technique for achieving this purpose. Currently, it is critical to vary the jetting angles of liquid droplets induced by SAWs and control the liquid jet directions. Generally, the direction of the liquid jet induced by SAWs generated from a bulk piezoelectric substrate such as LiNbO3 is along the theoretical Rayleigh angle of ~22o. In this study, we designed and manufactured thin-film SAW devices by depositing ZnO films on different substrates (including silicon and aluminium) to realize a wide range of jetting angles from ~16o to 55o using propagating waves generated from one interdigital transducer (IDT). We then systematically investigated different factors affecting the jetting angles, including liquid properties, applied SAW power and SAW device resonant frequency. Finally, we proposed various methods using thin-film SAW devices together with different transducer designs for realizing a wide range of jetting angles within the 3D domain