169 research outputs found

    Significantly high polarization degree of the very low-albedo asteroid (152679) 1998 KU2_\mathrm{2}

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    We present a unique and significant polarimetric result regarding the near-Earth asteroid (152679) 1998 KU2_\mathrm{2} , which has a very low geometric albedo. From our observations, we find that the linear polarization degrees of 1998 KU2_\mathrm{2} are 44.6 ±\pm 0.5\% in the RC_\mathrm{C} band and 44.0 ±\pm 0.6\% in the V band at a solar phase angle of 81.0\degr. These values are the highest of any known airless body in the solar system (i.e., high-polarization comets, asteroids, and planetary satellites) at similar phase angles. This polarimetric observation is not only the first for primitive asteroids at large phase angles, but also for low-albedo (< 0.1) airless bodies. Based on spectroscopic similarities and polarimetric measurements of materials that have been sorted by size in previous studies, we conjecture that 1998 KU2_\mathrm{2} has a highly microporous regolith structure comprising nano-sized carbon grains on the surface.Comment: 9 pages, 5 figures, and 3 tables, accepted for publication in A&

    Preoperative and Postoperative Pulmonary Function in Elderly Patients with Thoracolumbar Kyphoscoliosis

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    Study DesignCase series.PurposeThe objective of this study was to investigate the change in pulmonary function in adult patients with a spinal deformity who underwent spinal corrective surgery.Overview of LiteratureDegenerative lumbar and/or thoraco-lumbar deformities are is often prominent in adult spinal deformity cases, whereas a thoracic deformity involving the chest wall is inconspicuous. A lumbar spine deformity could affect the pulmonary function; however, few reports have investigated pulmonary function in adult patients with a spinal deformity.MethodsThis study included 14 adult patients with a spinal deformity who underwent posterior corrective fusion (3 males, 11 females; mean age, 67.4 years). We measured percent vital capacity (%VC) and percent forced expiratory volume in 1 second (%FEV1) before surgery and six months after surgery. We investigated the change in pulmonary function after corrective surgery and the correlation between radiographic parameters and pulmonary function.ResultsMean preoperative %VC and %FEV1 values were 99.9% and 79.3%, respectively. Two cases were diagnosed with restrictive impairment, and two cases were diagnosed with obstructive impairment before surgery. %VC improved in the restrictive impairment cases six months after surgery. However, %FEV1 did not improve significantly after surgery in the obstructive impairment cases.ConclusionsRestrictive impairment was improved in adult patients with a spinal deformity by corrective spinal surgery. However, spinal surgery did not improve obstructive impairment

    Response to: Hypoglossal Nerve Unjury after Cervical Spine Surgery

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial Licens

    Novel Measurement Technique for the Sagittal Vertical Axis and Its Clinical Application in Adult Spinal Deformity

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    Study DesignProspective physical measurement of the sagittal vertical axis (SVA).PurposeTo evaluate a simple method for measuring SVA by analyzing its relationship with radiographic measurements and clinical appearance.Overview of LiteratureNo studies have examined physical measurements using the cranial center of gravity (CCG) in a relaxed standing position.MethodsThe physical measurement of the horizontal distance between CCG and spina iliaca posterior superior (CCG-SIPS) was measured using a straight ruler in 252 healthy volunteers and 56 patients with adult spinal deformity. Health-related quality of life (HRQOL) was evaluated using the Oswestry disability index (ODI), and clinical symptoms were assessed according to standing status and the presence of gastroesophageal reflux disease (GERD).ResultsCCG-SIPS increased with age in the volunteer group and strongly correlated with radiographic SVA in the patient group (r=0.984). Differences increased between CCG-SIPS in patients in the relaxed position and radiographic SVA with an increase in sagittal malalignment (r=0.692, p120 mm) was significantly larger in the patient group than in the group with low sagittal malalignment (59.9±18.8 vs. 45.1±17.0; p=0.004); these patients (CCG-SIPS>120 mm) needed crutches or walkers for standing. The patient group with GERD had significantly larger sagittal malalignment than the group without GERD (160.3 mm vs. 81.0 mm).ConclusionsThe CCG-SIPS correlated with age and strongly reflected radiographic SVA and HRQOL in the patients. Moreover, it reflects a relaxed posture without a backward shift in the radiographic position even in patients with severe sagittal malalignment. The critical limit of CCG-SIPS can be relevant to clinical appearance, including standing assistance (>120 mm) and the existence of GERD (>150 mm). Thus, it will be a useful predictor of true SVA in clinical practice before radiographic evaluation
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