212 research outputs found

    Where are noble gases trapped in Yamato-74063 (unique) ?

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    Yamato-74063,a primitive achondrite with affinities to Acapulco, has been analyzed for noble gas isotopes by laser ablation mass spectrometry. Some grains released huge amounts of trapped Xe as well as trapped Ar and Kr. Among them, an orthopyroxene grain containing abundant inclusions of tiny metal spherules released equally large amounts of Xe as found for carbon residues of ureilites and carbonaceous chondrites, with ^Ar/^Xe=11. In contrast, other grains including silicates, Fe-Ni metal and troilite released negligible amounts of trapped gases. Mineralogical studies of polished thin sections, prepared from the same chip as was analyzed for noble gases, indicate that the silicate grains containing the tiny metal inclusions also contain abundant tiny voids, one to several μm across. Originally these voids must have been filled with gases or/and fluids. We propose bubbles as a candidate of hosts that trap large amounts of noble gases in the silicate. With data on noble gas behavior in bubbles, although available only for andesite melt, the extremely low ^Ar/^Xe ratio in the silicate phase of Y-74063 can be understood in terms of the bubble hypothesis

    Image preference estimation with a data-driven approach: A comparative study between gaze and image features

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    Understanding how humans subjectively look at and evaluate images is an important task for various applications in the field of multimedia interaction. While it has been repeatedly pointed out that eye movements can be used to infer the internal states of humans, not many successes have been reported concerning image understanding. We investigate the possibility of image preference estimation based on a person’s eye movements in a supervised manner in this paper. A dataset of eye movements is collected while the participants are viewing pairs of natural images, and it is used to train image preference label classifiers. The input feature is defined as a combination of various fixation and saccade event statistics, and the use of the random forest algorithm allows us to quantitatively assess how each of the statistics contributes to the classification task. We show that the gaze-based classifier had a higher level of accuracy than metadata-based baseline methods and a simple rule-based classifier throughout the experiments. We also present a quantitative comparison with image-based preference classifiers and discuss the potential and limitations of the gaze-based preference estimator

    Spontaneous Iron Accumulation in Hepatocytes of a 7-Week-Old Female Rat

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    Abstract: Spontaneous iron accumulation in hepatocytes was observed in a 7-week-old female Han Wistar GALAS rat. Very fine yellowish brown pigments, which showed a positive reaction with Berlin Blue stain, were apparent in the cytoplasm close to the bile canaliculi, with a diminishing periportal-to-centrilobular gradient. There were also differences in distribution between and within lobes. Transmission electron microscopy revealed cytosolic ferritin and pericanalicular siderosomes in hepatocytes. No degeneration or necrotic changes were observed, and non-hepatocyte cells did not demonstrate any obvious accumulation of iron. There were no abnormalities in the animal other than this finding in the liver

    A newly-developed guide can create tibial tunnel at an optimal position during medial meniscus posterior root repairs

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    Background During transtibial pullout repair of medial meniscus (MM) posterior root tears (MMPRTs), accurate tibial tunnel creation within the anatomic MM posterior root attachment seems critical. This study aimed to evaluate the tibial tunnel position created by a newly-developed Precision guide during pullout repair of MMPRTs. Methods In 40 patients who underwent transtibial pullout repairs, the tibial tunnel was created using the Unicorn Meniscal Root (UMR) (n = 20) or Precision guide (n = 20). Three-dimensional computed tomography images of the tibial surface were evaluated postoperatively, using Tsukada's measurement method. The expected anatomic center of the MM posterior root attachment was defined as the center of three tangential lines corresponding to anatomic bony landmarks. The expected anatomic center (AC) and the tibial tunnel center (TC) were evaluated using the percentage-based posterolateral location on the tibial surface. The difference in the mediolateral and anteroposterior percentage distance between the AC and TC was calculated, as was the absolute distance between the AC and TC. Results The mean AC was located 77.4% posterior and 40.1% lateral. The mean TC was similar in the UMR and Precision guide groups. There was no significant difference in the mediolateral percentage distance (UMR 3.9% vs. Precision 3.6%, p = 0.405), but a significant difference was observed in the anteroposterior percentage distance (UMR 3.5% vs. Precision 2.6%, p = 0.031). The mean absolute distance between the AC and TC was 3.9 mm and 3.5 mm (UMR and Precision guide groups, respectively) (p = 0.364). Conclusions The new Precision guide can create tibial tunnel in an optimal and stable position during pullout repair of MMPRTs

    Hip Fractures after Intramedullary Nailing Fixation for Atypical Femoral Fractures: Three Cases

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    Secondary hip fractures (SHFs) rarely occur after intramedullary nailing (IMN) fixation without femoral neck fixation for atypical femoral fractures (AFFs). We report three cases of older Japanese women who sustained SHFs presumably caused by osteoporosis and peri-implant stress concentration around the femoral neck after undergoing IMN without femoral neck fixation for AFF. All cases were fixed with malalignment. In AFF patients, postoperative changes due to postoperative femoral bone malalignment may affect the peri-implant mechanical environment around the femoral neck, which can result in insufficiency fractures. At the first AFF surgery, we recommend femoral neck fixation after adequate reduction is achieved

    Small sensor probe for measuring plasma waves in space Space science

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    Background: Since conventional one-point observations of plasma phenomena in space cannot distinguish between time and spatial variations, the missions on the basis of multiple-point observations have become the trend. We propose a new system for multiple-point observation referred to as the monitor system for space electromagnetic environments (MSEE). Findings: The MSEE consists of small sensor probes that have a capability to measure electromagnetic waves and transfer received data to the central station through wireless communication. We developed the prototype model of the MSEE sensor probe. The sensor probe includes a plasma wave receiver, the microcontroller, the wireless communication module, and the battery in the 75-mm cubic housing. In addition, loop antennas, dipole antennas, and actuators that are used for expanding dipole antennas are attached on the housing. The whole mass of the sensor probe is 692 g, and the total power consumption is 462 mW. The sensor probe can work with both inner battery and external power supply. The maximum continuous operation time on battery power is more than 6 h. We verified the total performance for electric field measurements by inputting signal to preamplifier. In this test, we found that analog components had enough characteristics to measure electric fields, and the A/D conversion and the wireless transmission worked correctly. In the whole performance for electric fields, the sensor probe has equivalent noise level of - 135 dBV/m/√Hz. Conclusions: We succeed in developing the prototype model of the small sensor probe that had enough sensitivity for electric field to measure plasma waves and the ability to transfer observation data through wireless communication. The success in developing the small sensor probe for the measurement of plasma waves leads to the realization of the multiple-point observations using a lot of small probes scattered in space

    Medial meniscus posterior root repairs: A comparison among three surgical techniques in short-term clinical outcomes and arthroscopic meniscal healing scores

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    Background Medial meniscus (MM) posterior root repairs lead to favorable clinical outcomes in patients with MM posterior root tears (MMPRTs). However, there are few comparative studies in evaluating the superiority among several pullout repair techniques such as modified Mason–Allen suture, simple stitch, and concomitant posteromedial pullout repair. We hypothesized that an additional pullout suture at the MM posteromedial part would have clinical advantages in transtibial pullout repairs of the MMPRTs. The aim of this study was to compare the clinical usefulness among several types of pullout repair techniques in patients with MMPRTs. Methods Eighty-three patients who underwent arthroscopic pullout repairs of the MMPRTs were investigated. Patients were divided into three groups using different pullout repair techniques: a modified Mason–Allen suture using FasT-Fix all-inside meniscal repair device (F-MMA, n = 28), two simple stitches (TSS, n = 30), and TSS concomitant with posteromedial pullout repair using all-inside meniscal repair device (TSS-PM, n = 25). Postoperative clinical outcomes and semi-quantitative arthroscopic meniscal healing scores (0–10 points) were evaluated at second-look arthroscopies. Results No significant differences among the three groups were observed in patient demographics and preoperative clinical scores, except for preoperative Lysholm scores. At second-look arthroscopies, there were no significant differences among the three techniques in postoperative clinical outcomes and meniscal healing scores. Conclusions This study demonstrated that the TSS-PM pullout repair technique did not show better scores in postoperative clinical outcomes and meniscal healings compared with the F-MMA and TSS techniques. Our results suggest that the concomitant posteromedial pullout suture may have no clinical advantage in the conventional pullout repairs for the patients with MMPRTs

    Steep posterior slope of the medial tibial plateau is associated with ramp lesions of the medial meniscus and a concomitant anterior cruciate ligament injury

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    Background: Medial meniscus (MM) tears are associated with both acute and chronic anterior cruciate ligament (ACL) insufficiency and can lead to degenerative changes in the knee. ACL reconstruction (ACLR) combined with the meniscal repair was reported to result in decreased anterior knee joint laxity with evidence of improved patient-reported outcomes in the long term. However, a subtle tear of the MM posterior segment, also known as a ramp lesion, is difficult to detect on conventional magnetic resonance imaging (MRI) and is frequently missed in ACL-deficient knees. However, there are few studies about the associations between bone geometry and ramp lesion of the MM. This study aimed to compare sagittal medial tibial slope (MTS), medial tibial plateau depth (MTPD), and coronal tibial slope (CTS) between ACL-injured knees with and without ramp lesion of the MM. We hypothesised that patients with ramp lesion of the MM and a concomitant ACL injury have a steeper MTS and shallower MTPD than those without ramp lesion of the MM. Methods: Twenty-seven patients who underwent ACLR (group A), and 15 patients with combined MM repair (group AM) were included in the study. Anterior tibial translation (ATT) was measured under general anaesthesia just before surgery using a knee arthrometer. MRI was performed in the 10 degrees-knee-flexed position. The MTS and MTPD were measured on sagittal view, and the CTS was measured on coronal view. These parameters were compared between the groups. Differences in MRI measurements or patient demographics between the groups were evaluated using the Mann-Whitney U test. Results: No significant difference was observed in demographic data and post-operative side-to-side difference in ATT between both groups. Pre-operative ATT was significantly higher in group AM than in group A (P = 5.0 degrees than in those with MTS = 5.0 degrees, an occult MM ramp lesion should be strongly suspected, and surgeons should prepare for MM repair in combination with ACLR

    Two simple stitches for medial meniscus posterior root repair prevents the progression of meniscal extrusion and reduces intrameniscal signal intensity better than modified Mason-Allen sutures

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    Purpose Medial meniscus posterior root tears (MMPRTs) can cause severe medial extrusion of the medial meniscus (MMME) and the progression of knee degenerative changes, inducing a high signal intensity of the meniscus on magnetic resonance imaging (MRI). Although MMME and intrameniscal signal intensity (IMSI) reportedly decreased within 3 months after MMPRT repair, no previous studies have reported these changes after a 1-year follow-up. This study aimed to investigate the 1-year postoperative changes in MMME and IMSI on MRI after using different suture techniques. Methods Overall, 33 patients with MMPRT were evaluated, 22 underwent FasT-Fix-dependent modified Mason–Allen suture (F-MMA) repair, and 11 underwent two simple stitches (TSS) repair. MRI examinations were performed preoperatively and 1 year postoperatively. MMME and IMSI were determined using MRI. Results A significant decrease in postoperative MMME was observed in the TSS group (4.1 ± 1.0) relative to that in the F-MMA group (5.1 ± 1.4, P = 0.03). A significant decrease in postoperative IMSI (0.75 ± 0.14) was observed relative to preoperative IMSI in the TSS group (P  Conclusions The most important finding of this study is that TSS repair yielded a greater decrease in MMME and IMSI than F-MMA repair in patients with MMPRT. These results suggest that TSS repair is more useful for restoring loading stress to the posterior horn of the medial meniscus

    Estimation of the emission factors of PAHs by the traffic activities with the model of atmospheric dispersion and deposition from heavy traffic road

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    In order to consider the total atmospheric loadings of the PAHs (polycyclic aromatic hydrocarbons) from traffic activities, the emission factors of PAHs were estimated and from the obtained emission factors and vehicle transportation statistics, total atmospheric loadings were integrated and the loadings into the water body were estimated on a regional scale. The atmospheric concentration of PAHs was measured at the roadside of a heavy traffic road in the Hiroshima area in Japan. The samplings were conducted in summer and winter. Atmospheric particulate matters (fine particle, 0.6~ 7 μm; coarse particle, over 7 μm) and their PAH concentration were measured. Also, four major emission sources (gasoline and diesel vehicle emissions, tire and asphalt debris) were assumed for vehicle transportation activities, the chemical mass balance method was applied and the source partitioning at the roadside was estimated. Furthermore, the dispersion of atmospheric particles from the vehicles was modelled and the emission factors of the sources were determined by the comparison to the chemical mass balance results. Based on emission factors derived from the modelling, an atmospheric dispersion model of nationwide scale (National Institute of Advanced Industrial Science and Technology - Atmospheric Dispersion Model for Exposure and Risk assessment: AIST-ADMER) was applied, and the atmospheric concentration and loading to the ground were calculated for the Hiroshima bay watershed area
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