104 research outputs found
The Othello game on an n × n board is PSPACE-complete
AbstractGiven an arbitrary position of the Othello game played on an n × n board, the problem of determining the winner is shown to be PSPACE-complete. It can be reduced from generalized geography played on bipartite graphs with maximum degree 3
Dexterous hand-arm coordinated manipulation using active body-environment contact
Abstract-Human-symbiotic humanoid robots that can perform tasks dexterously using their hands are needed in our homes, welfare facilities, and other places. To improve their task performance, we propose a motion control scheme aimed at appropriately coordinated hand and arm motions. By observing human manual tasks, we identified active body-environment contact as a kind of human manual skill and devised a motion control scheme based on it. We also analyzed the effectiveness of active body-environment contact in glass-placing and drawer-opening tasks. We validated our motion control scheme through actual tests on a prototype human-symbiotic humanoid robot
BioGlue® coronary embolism during open heart surgery
AbstractIn cases of iatrogenic coronary embolism during cardiac surgery or percutaneous coronary intervention, small air bubbles or foreign bodies are directly injected, which usually result in serious adverse events if not treated promptly. We herein describe the case of a patient who developed acute myocardial infarction resulting in shock due to BioGlue® (CryoLife, Atlanta, GA, USA)-induced coronary embolism during the surgical repair of aortic dissection and was treated for retrieval of the material using a thrombectomy catheter.<Learning objective: Coronary embolism caused by surgical adhesives is a rare but potentially life-threatening complication. It is important for surgeons to promptly recognize and treat this serious condition in consultation with cardiologists.
Magnetized Fast Isochoric Laser Heating for Efficient Creation of Ultra-High-Energy-Density States
The quest for the inertial confinement fusion (ICF) ignition is a grand
challenge, as exemplified by extraordinary large laser facilities. Fast
isochoric heating of a pre-compressed plasma core with a high-intensity
short-pulse laser is an attractive and alternative approach to create
ultra-high-energy-density states like those found in ICF ignition sparks. This
avoids the ignition quench caused by the hot spark mixing with the surrounding
cold fuel, which is the crucial problem of the currently pursued ignition
scheme. High-intensity lasers efficiently produce relativistic electron beams
(REB). A part of the REB kinetic energy is deposited in the core, and then the
heated region becomes the hot spark to trigger the ignition. However, only a
small portion of the REB collides with the core because of its large
divergence. Here we have demonstrated enhanced laser-to-core energy coupling
with the magnetized fast isochoric heating. The method employs a
kilo-tesla-level magnetic field that is applied to the transport region from
the REB generation point to the core which results in guiding the REB along the
magnetic field lines to the core. 7.7 1.3 % of the maximum coupling was
achieved even with a relatively small radial area density core (
0.1 g/cm). The guided REB transport was clearly visualized in a
pre-compressed core by using Cu- imaging technique. A simplified
model coupled with the comprehensive diagnostics yields 6.2\% of the coupling
that agrees fairly with the measured coupling. This model also reveals that an
ignition-scale areal density core ( 0.4 g/cm) leads to much
higher laser-to-core coupling ( 15%), this is much higher than that achieved
by the current scheme
The three-dimensional structure of Drosophila melanogaster (6-4) photolyase at room temperature
(6-4) photolyases are flavoproteins that belong to the photolyase/cryptochrome family. Their function is to repair DNA lesions using visible light. Here, crystal structures of Drosophila melanogaster (6-4) photolyase [Dm(6-4)photolyase] at room and cryogenic temperatures are reported. The room-temperature structure was solved to 2.27 angstrom resolution and was obtained by serial femtosecond crystallography (SFX) using an X-ray free-electron laser. The crystallization and preparation conditions are also reported. The cryogenic structure was solved to 1.79 angstrom resolution using conventional X-ray crystallography. The structures agree with each other, indicating that the structural information obtained from crystallography at cryogenic temperature also applies at room temperature. Furthermore, UV-Vis absorption spectroscopy confirms that Dm(6-4)photolyase is photoactive in the crystals, giving a green light to time-resolved SFX studies on the protein, which can reveal the structural mechanism of the photoactivated protein in DNA repair.Peer reviewe
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Comparing serial X-ray crystallography and microcrystal electron diffraction (MicroED) as methods for routine structure determination from small macromolecular crystals.
Innovative new crystallographic methods are facilitating structural studies from ever smaller crystals of biological macromolecules. In particular, serial X-ray crystallography and microcrystal electron diffraction (MicroED) have emerged as useful methods for obtaining structural information from crystals on the nanometre to micrometre scale. Despite the utility of these methods, their implementation can often be difficult, as they present many challenges that are not encountered in traditional macromolecular crystallography experiments. Here, XFEL serial crystallography experiments and MicroED experiments using batch-grown microcrystals of the enzyme cyclophilin A are described. The results provide a roadmap for researchers hoping to design macromolecular microcrystallography experiments, and they highlight the strengths and weaknesses of the two methods. Specifically, we focus on how the different physical conditions imposed by the sample-preparation and delivery methods required for each type of experiment affect the crystal structure of the enzyme
Features of and Mechanisms Underlying Insulitis In aly/aly Male Mice as an Animal Model of Autoimmune Pancreatitis: Activation of CD11c+, CD4+, and Th2 Cells and Predominant Destruction of β-cells
Diabetes mellitus (DM) is observed in patients with autoimmune pancreatitis (AIP). The development of DM in AIP is believed to be due to blood flow obstruction of the endocrine gland that accompanies pancreatitis, as well as injury to the islets caused by inflammation. The latter is called insulitis and the detailed mechanisms underlying its development are not yet clear. The aim of the present study was to elucidate the mechanisms involved in the development of insulitis in AIP using aly mice as an animal model of AIP: results in aly/aly male mice, as the AIP group, were compared with those inaly/+ male mice as a control group. Mice in both groups were killed between 16 and 48 weeks of age, and pancreatitis and insulitis were evaluated histologically. Inflammatory and endocrine cells were evaluated by immunofluorescence staining with anti-CD4, anti-CD8, anti-CD11b, and anti-CD11c antibodies, as well as immunohistochemical analyses using insulin and glucagon antibodies. Plasma levels and the pancreatic content of interferon (IFN)-γ (as a Th1-secreted cytokine) and interleukin (IL)-4 (as a Th2-secreted cytokine) were determined. Pancreatitis was seen in aly/aly mice from 16 weeks of age and it developed gradually thereafter. Insulitis also developed gradually and was seen in mice after 24 weeks of age in association with a decrease in the number of islets. CD11c+ cells and CD4+ T cells were seen to infiltrate into the islets. Although the number of β-cells decreased with time, the number of α-cells was maintained until mice were 48 weeks of age. IFN-γ content peaked in mice at 16 weeks of age and declined rapidly from 20 weeks. There were two peaks in IL-4 content, one at 16 weeks and the other at 32 weeks, suggesting an association between IL-4 content and advanced insulitis after 32 weeks. In conclusion, the results suggest that insulitis in AIP is induced predominantly by the infiltration of CD11c+ cells and CD4+ T cells into the islets, and progression is facilitated by the imbalance of the activation of Th2 rather than Th1. Furthermore, insulitis in AIP predominantly involves β-cells rather than α-cells
Alpha-CaMKII deficiency causes immature dentate gyrus, a novel candidate endophenotype of psychiatric disorders
Elucidating the neural and genetic factors underlying psychiatric illness is hampered by current methods of clinical diagnosis. The identification and investigation of clinical endophenotypes may be one solution, but represents a considerable challenge in human subjects. Here we report that mice heterozygous for a null mutation of the alpha-isoform of calcium/calmodulin-dependent protein kinase II (alpha-CaMKII+/-) have profoundly dysregulated behaviours and impaired neuronal development in the dentate gyrus (DG). The behavioral abnormalities include a severe working memory deficit and an exaggerated infradian rhythm, which are similar to symptoms seen in schizophrenia, bipolar mood disorder and other psychiatric disorders. Transcriptome analysis of the hippocampus of these mutants revealed that the expression levels of more than 2000 genes were significantly changed. Strikingly, among the 20 most downregulated genes, 5 had highly selective expression in the DG. Whereas BrdU incorporated cells in the mutant mouse DG was increased by more than 50 percent, the number of mature neurons in the DG was dramatically decreased. Morphological and physiological features of the DG neurons in the mutants were strikingly similar to those of immature DG neurons in normal rodents. Moreover, c-Fos expression in the DG after electric footshock was almost completely and selectively abolished in the mutants. Statistical clustering of human post-mortem brains using 10 genes differentially-expressed in the mutant mice were used to classify individuals into two clusters, one of which contained 16 of 18 schizophrenic patients. Nearly half of the differentially-expressed probes in the schizophrenia-enriched cluster encoded genes that are involved in neurogenesis or in neuronal migration/maturation, including calbindin, a marker for mature DG neurons. Based on these results, we propose that an "immature DG" in adulthood might induce alterations in behavior and serve as a promising candidate endophenotype of schizophrenia and other human psychiatric disorders
Moderate Hypoxia Down-Regulates Interleukin-6 Secretion and TLR4 Expression in Human Sw.71 Placental Cells
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