62 research outputs found

    Plane Formation by Synchronous Mobile Robots without Chirality

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    We consider a distributed system consisting of autonomous mobile computing entities called robots moving in the three-dimensional space (3D-space). The robots are anonymous, oblivious, fully-synchronous and have neither any access to the global coordinate system nor any explicit communication medium. Each robot cooperates with other robots by observing the positions of other robots in its local coordinate system. One of the most fundamental agreement problems in 3D-space is the plane formation problem that requires the robots to land on a common plane, that is not predefined. This problem is not always solvable because of the impossibility of symmetry breaking. While existing results assume that the robots agree on the handedness of their local coordinate systems, we remove the assumption and consider the robots without chirality. The robots without chirality can never break the symmetry consisting of rotation symmetry and reflection symmetry. Such symmetry in 3D-space is fully described by 17 symmetry types each of which forms a group. We extend the notion of symmetricity [Suzuki and Yamashita, SIAM J. Compt. 1999] [Yamauchi et al., PODC 2016] to cover these 17 symmetry groups. Then we give a characterization of initial configurations from which the fully-synchronous robots without chirality can form a plane in terms of symmetricity

    Microwave Spectroscopy of a Single Permalloy Chiral Metamolecule on a Coplanar Waveguide

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    We investigate the microwave spectroscopies of a micrometer-sized single permalloy (Py) chiral structure on coplanar waveguides (CPWs). Under an external dc magnetic field applied in a direction perpendicular to the microwave propagation, the Py chiral structure loaded on the center of the CPW signal line shows Kittel-mode ferromagnetic resonance. Contrastingly, the structure on the signal-line edge highlights two additional resonances: spin-wave resonance at a higher frequency, and unique resonance at a lower frequency of approximately 7.8 GHz. The resonance signal at 7.8 GHz originates from magnetically induced, geometry-driven resonance, although the resonance frequency does not depend on the external magnetic field. Moreover, the displacement of the Py structures on the signal line results in nonreciprocal microwave transmission, which is traced back to the edge-guide mode

    Effects of monthly intravenous ibandronate on bone mineral density and microstructure in patients with primary osteoporosis after teriparatide treatment: The MONUMENT study

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    Purpose: To investigate the effects of sequential therapy with monthly intravenous ibandronate on bone mineral density (BMD) and microstructure in patients with primary osteoporosis who received teriparatide treatment. Methods: Sixty-six patients with primary osteoporosis who had undergone teriparatide treatment for more than 12 months (mean 18.6 months) received sequential therapy with 1 mg/month intravenous ibandronate for 12 months. The patients were evaluated using dual-energy X-ray absorptiometry (DXA), quantitative ultrasound, bone turnover markers, and high-resolution peripheral quantitative computed tomography (HR-pQCT) at baseline and 6 and 12 months after beginning administration. Results: At 12 months after beginning sequential therapy,the bone resorption marker, tartrate-resistant acid phosphatase-5b, decreased by 39.5%, with 82.3% of the patients exhibiting levels within the normal limit. DXA revealed that the BMD of the lumbar spine increased by 3.2%, with 79.0% of the patients exhibiting a response, and 40.3% experiencing an increase in BMD over 5%. HR-pQCT revealed that the cortical thickness of the distal tibia was increased by 2.6%. The cortical area increased by 2.5%, and the buckling ratio (an index of cortical instability) decreased by 2.5%. Most parameters of the trabecular bone showed no significant changes. These changes in the cortical bone were observed in both the distal radius and tibia and appeared beginning 6 months after treatment initiation. Conclusions: Sequential therapy with monthly intravenous ibandronate increased the BMD and improved the cortical bone microstructure of osteoporotic patients who had undergone teriparatide treatment

    Randomized controlled trial of daily teriparatide, weekly high-dose teriparatide, or bisphosphonate in patients with postmenopausal osteoporosis: The TERABIT study

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    Purpose: The effects of daily teriparatide (20 μg) (D-PTH), weekly high-dose teriparatide (56.5 μg) (W-PTH), or bisphosphonates (BPs) on areal bone mineral density (aBMD), bone turnover markers (BTMs), volumetric BMD (vBMD), microarchitecture, and estimated strength were investigated in postmenopausal osteoporosis patients.Methods: The study participants were 131 women with a history of fragility fractures. They were randomized to receive D-PTH, W-PTH, or BPs (alendronate or risedronate) for 18 months. Dual-energy X-ray absorptiometry (DXA), BTMs, and high-resolution peripheral quantitative CT (HR-pQCT) parameters were evaluated at baseline and after 6 and 18 months of treatment. The primary endpoint was the change (%) in cortical thickness (Ct.Th) after 18 months\u27 treatment compared with baseline.Results: DXA showed that D-PTH, W-PTH, and BPs increased lumbar spine aBMD (+12.0%, +8.5%, and +6.8%) and total hip aBMD (+3.0%, +2.1%, and +3.0%), but D-PTH and W-PTH decreased 1/3 radius aBMD (− 4.1%, − 3.0%, − 1.4%) after 18 months. On HR-pQCT, D-PTH increased trabecular vBMD (Tb.vBMD) at the distal radius and tibia after 18 months (+6.4%, +3.7%) compared with the BPs group, decreased cortical volumetric tissue mineral density (Ct.vTMD) (− 1.8%, − 0.9%) compared with the other groups, increased Ct.Th (+1.3%, +3.9%), and increased failure load (FL) (+4.7%, +4.4%). W-PTH increased Tb.vBMD (+5.3%, +1.9%), maintained Ct.vTMD (− 0.7%, +0.2%) compared with D-PTH, increased Ct.Th (+0.6%, +3.6%), and increased FL (+4.9%, +4.5%). The BPs increased Tb.vBMD only in the radius (+2.0%, +0.2%), maintained Ct.vTMD (− 0.6%, +0.3%), increased Ct.Th (+0.5%, +3.4%), and increased FL (+3.9%, +2.8%).Conclusions: D-PTH and W-PTH comparably increased Ct.Th, the primary endpoint. D-PTH had a strong effect on trabecular bone. Although D-PTH decreased Ct.vTMD, it increased Ct.Th and total bone strength. W-PTH had a moderate effect on trabecular bone, maintained Ct.vTMD, and increased Ct.Th and total bone strength to the same extent as D-PTH

    Non-Perfusion Area Index for Prognostic Prediction in Diabetic Retinopathy

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    Fundus fluorescent angiography is a standard examination in Japan that can directly visualize the circulatory failure in diabetic retinopathy but is not used in Western countries. In this study, we examine the relationship between the non-perfusion area in fundus fluorescent angiography and the progression of diabetic retinopathy. We evaluated 22 eyes between 22 patients who had their first fundus fluorescent angiography during a clinical episode at Keio University Hospital from January 2012 to May 2015, were diagnosed as having preproliferative diabetic retinopathy, and could be followed for at least three years. The non-perfusion area index (%) in nine segmented fundi in the initial fundus fluorescent angiography was calculated, and the progression to proliferative diabetic retinopathy over three years was evaluated. Three out of the 22 eyes (13.6%) developed proliferative diabetic retinopathy over three years. The non-perfusion area index for the initial fundus fluorescent angiography was significantly associated with progression to proliferative diabetic retinopathy. The non-perfusion area index in the posterior pole was most strongly correlated with the progression to proliferative diabetic retinopathy. Thus, the non-perfusion area index in the posterior pole among those with preproliferative diabetic retinopathy may predict the progression to proliferative diabetic retinopathy in the subsequent three years
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