Nonprehensile Manipulation via Multisensory Learning from Demonstration

Dexterous manipulation problem concerns control of a robot hand to manipulate an object in a desired manner. While classical dexterous manipulation strategies are based on stable grasping (or force closure), many human-like manipulation tasks do not maintain grasp stability, and often utilize the intrinsic dynamics of the object rather than the closed form of kinematic relation between the object and the robotic fingers. Such manipulation strategies are referred as nonprehensile or dynamic dexterous manipulation in the literature. Nonprehensile manipulation typically involves fast and agile movements such as throwing and flipping. Due to the complexity of such motions (which may involve impulsive dynamics) and uncertainties associated with them, it has been challenging to realize nonprehensile manipulation tasks in a reliable way. In this paper, we propose a new control strategy to realize practical nonprehensile manipulation tasks using a robot hand. The main idea of our control strategy are two-folds. Firstly, we make explicit use of multiple modalities of sensory data for the design of control law. Specifically, force data is employed for feedforward control while the position data is used for feedback (i.e. reactive) control. Secondly, control signals (both feedback and feedforward) are obtained by the multisensory learning from demonstration (LfD) experiments which are designed and performed for specific nonprehensile manipulation tasks in concern. We utilize various LfD frameworks such as Gaussian mixture model and Gaussian mixture regression (GMM/GMR) and hidden Markov model and GMR (HMM/GMR) to reproduce generalized motion profiles from the human expert's demonstrations. The proposed control strategy has been verified by experimental results on dynamic spinning task using a sensory-rich two-finger robotic hand. The control performance (i.e. the speed and accuracy of the spinning task) has also been compared with that of the classical dexterous manipulation based on finger gating

Experimental investigation of plasmofluidic waveguides

Plasmofluidic waveguides are based on guiding light which is strongly confined in fluid with the assistance of a surface plasmon polariton. To realize plasmofluidic waveguides, metal-insulator-silicon-insulator-metal (MISIM) waveguides, which are hybrid plasmonic waveguides fabricated using standard complementary metal-oxide-semiconductor technology, are employed. The insulator of the MISIM waveguide is removed to form 30-nm-wide channels, and they are filled with fluid. The plasmofluidic waveguide has a subwavelength-scale mode area since its mode is strongly confined in the fluid. The waveguides are experimentally characterized for different fluids. When the refractive index of the fluid is 1.440, the plasmofluidic waveguide with 190-nm-wide silicon has propagation loss of 0.46 dB/mu m; the coupling loss between it and an ordinary silicon photonic waveguide is 1.79 dB. The propagation and coupling losses may be reduced if a few fabrication-induced imperfections are removed. The plasmofluidic waveguide may pave the way to a dynamically phase-tunable ultracompact device.open0

Untargeted metabolomics analysis of rat hippocampus subjected to sleep fragmentation

Sleep fragmentation (SF) commonly occurs in several pathologic conditions and is especially associated with impairments of hippocampus-dependent neurocognitive functions. Although the effects of SF on hippocampus in terms of protein or gene levels were examined in several studies, the impact of SF at the metabolite level has not been investigated. Thus, in this study, the differentially expressed large-scale metabolite profiles of hippocampus in a rat model of SF were investigated using untargeted metabolomics approaches. Forty-eight rats were divided into the following 4 groups: 4-day SF group, 4-day exercise control (EC) group, 15-day SF group, and 15-day EC group (n = 12, each). SF was accomplished by forced exercise using a walking wheel system with 30-s on/90-s off cycles, and EC condition was set at 10-min on/30-min off. The metabolite profiles of rat hippocampi in the SF and EC groups were analyzed using liquid chromatography/mass spectrometry. Multivariate analysis revealed distinctive metabolic profiles and marker signals between the SF and corresponding EC groups. Metabolic changes were significant only in the 15-day SF group. In the 15-day SF group, L-tryptophan, myristoylcarnitine, and palmitoylcarnitine were significantly increased, while adenosine monophosphate, hypoxanthine, L-glutamate, L-aspartate, L-methionine, and glycerophosphocholine were decreased compared to the EC group. The alanine, aspartate, and glutamate metabolism pathway was observed as the common key pathway in the 15-day SF groups. The results from this untargeted metabolomics study provide a perspective on metabolic impact of SF on the hippocampus.Peer reviewe

Begonia wuzhishanensis (sect. Diploclinium, Begoniaceae), a new species from Hainan Island, China

Background: Hainan is the largest island of the Indo-Burma Biodiversity Hotspot and has the best preserved and most extensive tropical forests in China. A recent study on distribution of endangered species in China identifies southern Hainan as one of eight hotspots for plant conservation in the country. In continuation of our studies of Asian Begonia, we report the discovery of an attractive undescribed species, B. wuzhishanensis C.-I Peng, X.H. Jin & S.M.Ku, from Hainan Island. Results: Living plant of the new species, Begonia wuzhishanensis, was collected in 2009 and cultivated in the experimental greenhouse for morphological and cytological studies. It flowered consecutively in 2012 and 2013 in the experimental greenhouse, Academia Sinica. It was assigned to the large, heterogeneous sect. Diploclinium. The chromosome number of this new species was determined to be 2n = 26. Conclusions: A careful study of literature, herbarium specimens and living plants, both in the wild and in cultivation, support the recognition of the new species Begonia wuzhishanensis, which is described in this paper. Begonia wuzhishanensis is currently known only from Fanyang, Wuzhishan Mountain in the center of the island. A line drawing, color plate, and a distribution map are provided to aid in identification

Scale-up study for ex-vivo expansion of allogeneic natural killer cells in stirred-tank bioreactor

Natural killer (NK) cells are a type of lymphocyte in the blood that are responsible for innate and adaptive immune response, and they mature in the liver and bone marrow. Being a key role in host defense system with direct and indirect killing of virus-infected cells or cancer cells, NK cell has been considered an attractive candidate for cancer therapy. Peripheral blood shows the low frequency of NK cells, so ex vivo expansion method is important to obtain sufficient NK cells for therapeutic use. Currently, we successfully developed bioreactor process for NK cell expansion on lab-scale. Stirred-tank bioreactor could be considered as optimal alternative system for large-scale NK cell expansion compared with other ones because it is automated, less labor intensive, scalable, well-controlled and cost-effective. In bioreactor process, agitation is one of important parameters for NK cell expansion because it is necessary to provide homogenous culture conditions. So we defined effects of agitation in bioreactor and figured out an optimum condition. After that scale-up studies were carried out with manufacturing-scale bioreactor based on these results. The results in terms of growth rate, viability cytotoxicity and purity, were comparable with lab-scale

Case Report Squamous cell carcinoma of the small bowel manifesting as a jejunal perforation: a case report

Abstract: Squamous cell carcinoma arising from the small intestine is rare and difficult to identify as a primary or metastatic feature. We report a case of small intestinal squamous cell carcinoma manifesting as subacute peritonitis due to perforation. An 80-year-old man was admitted to our hospital with intermittent postprandial abdominal pain. He was diagnosed with acute peritonitis due to gastrointestinal perforation. During explorative laparotomy, a perforation site was detected in the jejunum and segmental resection to correct the perforation was performed including the perforation site located at the 70 cm inside the jejunum from the Treitz ligament. The pathology results revealed squamous cell carcinoma in the resected segment of the jejunum with two perforation sites

Gene expression profiling of cancer stem cell in human lung adenocarcinoma A549 cells

<p>Abstract</p> <p>Background</p> <p>The studies on cancer-stem-cells (CSCs) have attracted so much attention in recent years as possible therapeutic implications. This study was carried out to investigate the gene expression profile of CSCs in human lung adenocarcinoma A549 cells.</p> <p>Results</p> <p>We isolated CSCs from A549 cell line of which side population (SP) phenotype revealed several stem cell properties. After staining the cell line with Hoechst 33342 dye, the SP and non-side population (non-SP) cells were sorted using flow cytometric analysis. The mRNA expression profiles were measured using an Affymetrix GeneChip^®oligonucleotide array. Among the sixty one differentially expressed genes, the twelve genes inclusive three poor prognostic genes; Aldo-keto reductase family 1, member C1/C2 (AKR1C1/C2), Transmembrane 4 L six family member 1 nuclear receptor (TM4SF1), and Nuclear receptor subfamily 0, group B, member 1 (NR0B1) were significantly up-regulated in SP compared to non-SP cells.</p> <p>Conclusion</p> <p>This is the first report indicating the differences of gene expression pattern between SP and non-SP cells in A549 cells. We suggest that the up-regulations of the genes AKR1C1/C2, TM4SF1 and NR0B1 in SP of human adenocarcinoma A549 cells could be a target of poor prognosis in anti-cancer therapy.</p

Silicon@porous nitrogen-doped carbon spheres through a bottom-up approach are highly robust lithium-ion battery anodes

Due to its excellent capacity, around 4000 mA h g(-1), silicon has been recognized as one of the most promising lithium-ion battery anodes, especially for future large-scale applications including electrical vehicles and utility power grids. Nevertheless, Si suffers from a short cycle life as well as limitations for scalable electrode fabrication. Herein, we report a novel design for highly robust and scalable Si anodes: Si nanoparticles embedded in porous nitrogen-doped carbon spheres (NCSs). The porous nature of NCSs buffers the volume changes of Si nanoparticles and thus resolves critical issues of Si anode operations, such as pulverization, vulnerable contacts between Si and carbon conductors, and an unstable solid-electrolyte interphase. The unique electrode structure exhibits outstanding performance with a gravimetric capacity as high as 1579 mA h g(-1) at a C/10 rate based on the mass of both Si and C, a cycle life of 300 cycles with 94% capacity retention, as well as a discharge rate capability of 6 min while retaining a capacity of 702 mA h g(-1). Significantly, the coulombic efficiencies of this structure reach 99.99%. The assembled structure suggests a design principle for high capacity alloying electrodes that suffer from volume changes during battery operations.