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1.
Rhinology ; 2024 Jul 26.
Article in English | MEDLINE | ID: mdl-39058315

ABSTRACT

BACKGROUND: This randomised, double-blind, placebo-controlled, parallel-group, 52-week Phase III study (MERIT; NCT04607005) assessed mepolizumab efficacy and safety in patients with chronic rhinosinusitis with nasal polyps (CRSwNP)/eosinophilic CRS (ECRS) in Japan, Russia, and China, for which data are limited. METHODOLOGY: Eligible patients (enrolled at 60 centres) had blood eosinophil count >2%, endoscopic bilateral NP score ≥5, nasal obstruction visual analogue scale (VAS) score >5, ≥2 sinonasal symptoms, and either previous sinus surgery or systemic corticosteroid use/intolerance. Patients were randomised (1:1) to receive mepolizumab 100 mg subcutaneously or placebo every 4 weeks, plus standard of care. Co-primary endpoints: change from baseline in total endoscopic NP score (ENPS) (Week 52) and nasal obstruction VAS score (Weeks 49-52). Post hoc analyses conducted in a modified intent-to-treat (mITT) population excluded patients from two study sites, related to Good Clinical Practice violations by the Site Management Organisation overseeing these sites. These were considered the primary efficacy analyses. RESULTS: In the mITT population, mepolizumab (n=80) versus placebo (n=83) significantly improved nasal obstruction VAS score from baseline to Week 49-52 and was associated with a trend of total ENPS improvements at Week 52. Mepolizumab/placebo on-treatment adverse events (AEs) occurred in 68/84 and 65/85 patients in the safety population (treatment-related AEs: 2/84 and 5/85, respectively), and on-treatment serious AEs in 0/84 and 4/85 patients, respectively (no fatalities reported). CONCLUSIONS: Mepolizumab was effective and well-tolerated in patients with CRSwNP/ECRS from Japan, Russia, and China.

2.
Community Dent Health ; 36(4): 275-279, 2019 Nov 28.
Article in English | MEDLINE | ID: mdl-31670918

ABSTRACT

OBJECTIVE: Vertical jump height and oral function affect the general muscle condition. This study aimed to evaluate the association between vertical jump height and oral function among healthy older individuals. BASIC RESEARCH DESIGN: Cross-sectional analytic study. PARTICIPANTS: 231 independent older people (mean age, 74.4 ± 5.6 years) who participated in the Kyoto Elders Physical Fitness Measurement Research Project. Individuals with partial or complete edentulousness who did not use a prosthetic device or complained of oral/maxillofacial pain were excluded from the study. INTERVENTIONS: Grip strength was measured using a Smedley Hand Dynamometer. To measure masticatory performance, the participants were instructed to chew a gummy jelly on their habitual chewing side (left or right) for 20 s. Occlusal force, contact area, and pressure were also assessed. MAIN OUTCOME MEASURES: The outcome variable was vertical jump height. The predictor variables were physical status (age, body mass index, and grip strength), oral status (number of present teeth and denture use), and oral function (masticatory performance, occlusal force, occlusal contact area, occlusal pressure, and tongue pressure). These relationships were evaluated with univariate analysis, and then multiple regression analysis was performed with age as the covariate for each male and female participant. RESULTS: Vertical jump height was significantly associated with grip strength in both men and women. Moreover, in women, it was associated with masticatory performance, occlusal force, and occlusal contact area. CONCLUSIONS: Vertical jump height was closely associated with oral function among healthy older women.


Subject(s)
Bite Force , Tongue , Aged , Aged, 80 and over , Cross-Sectional Studies , Female , Humans , Japan , Male , Mastication , Pressure
3.
Lupus ; 27(7): 1202-1206, 2018 Jun.
Article in English | MEDLINE | ID: mdl-29523055

ABSTRACT

It has been reported that T helper 17 cells are involved in the pathogenesis of systemic lupus erythematosus, but there is no report on interleukin-17-targeted therapy. We report a case of a 62-year-old female who presented with psoriasis vulgaris and refractory lupus nephritis. Because her conditions were resistant to conventional treatment, and flow cytometry confirmed the proliferation of activated T helper 17 cells in peripheral blood, and examination of a renal biopsy tissue sample confirmed infiltration of numerous interleukin-17-positive lymphocytes to the renal interstitium, administration of the anti-interleukin-17A antibody secukinumab was initiated. After starting secukinumab the clinical and biological features were improved.


Subject(s)
Antibodies, Monoclonal/therapeutic use , Interleukin-17/antagonists & inhibitors , Lupus Nephritis/complications , Psoriasis/drug therapy , Antibodies, Monoclonal, Humanized , Female , Humans , Interleukin-17/blood , Middle Aged
4.
Lupus ; 27(5): 802-811, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29308726

ABSTRACT

Objective We examined the efficacy and safety of rituximab in patients with refractory systemic lupus erythematosus (SLE). Methods The study enrolled 63 SLE patients who were treated with rituximab between 2002 and 2015. The participants underwent a battery of tests before treatment and at one year. Treatment ranged from two to four times at 500 or 1000 mg. Results Baseline characteristics were males:females = 6:57, age 33.9 years, and disease duration 87.2 months. The primary endpoint: The rate of major clinical response (MCR) was 60% while the partial clinical response (PCR) was 25%. Thirty of 36 (83%) patients with lupus nephritis (WHO II: 2, III: 5, IV: 22, V: 4, IV+V: 2, not assessed: 1) and 22 of 24 patients (92%) with neuropsychiatric SLE, who could be followed at one year, showed changes from BILAG A or B score to C or D score at one year. Multivariate analysis identified high anti-dsDNA antibody and shorter disease duration as significant determinants of MCR at one year. Repeat examination was conducted at five years. Primary failure was recorded in 8.8% and secondary failure in 32.4% (time to relapse: 24.4 months). Rituximab was well tolerated although 65 adverse events, mostly infections, were recorded within one year. Conclusion Rituximab is potentially efficacious for the treatment of patients with refractory SLE.


Subject(s)
Immunosuppressive Agents/therapeutic use , Lupus Erythematosus, Systemic/drug therapy , Lupus Nephritis/drug therapy , Lupus Vasculitis, Central Nervous System/drug therapy , Rituximab/therapeutic use , Adolescent , Adult , Aged , Chi-Square Distribution , Female , Humans , Immunosuppressive Agents/adverse effects , Japan , Lupus Erythematosus, Systemic/diagnosis , Lupus Erythematosus, Systemic/immunology , Lupus Nephritis/diagnosis , Lupus Nephritis/immunology , Lupus Vasculitis, Central Nervous System/diagnosis , Lupus Vasculitis, Central Nervous System/immunology , Male , Middle Aged , Multivariate Analysis , Recurrence , Remission Induction , Retrospective Studies , Risk Factors , Rituximab/adverse effects , Time Factors , Treatment Outcome , Young Adult
5.
Oral Dis ; 23(4): 511-517, 2017 May.
Article in English | MEDLINE | ID: mdl-28117549

ABSTRACT

OBJECTIVES: The purpose of this study was to determine whether rebamipide, an antistomach ulcer agent, ameliorated benzodiazepine-induced hyposalivation in rat parotid gland (PG) and submandibular gland (SMG). METHODS: Saliva was collected from PG and SMG through a capillary cannula inserted into the parotid duct and sublingual papillae, respectively, every 15 min for 1 h after stimulation with pilocarpine dissolved in physiological saline and intraperitoneally administered at 1 mg kg-1 . Diazepam (DZP) was administered intraperitoneally at a dose of 0.2 mg kg-1 twice daily for 7 days. Rebamipide was administered at 10, 20, 30, or 100 mg kg-1 concomitantly with DZP to determine its effect on hyposalivation. The effect of rebamipide on movement of intracellular calcium ([Ca2+ ]i) in isolated parotid acinar cells was analyzed using Fluo4, a fluorescent dye used to detect Ca2+ . RESULTS: Repetitive administration of DZP decreased salivary secretion in PG and SMG. This inhibitory effect was weakened by administration of rebamipide. Prior administration of DZP (10-6 M) significantly suppressed carbachol (10-7 M)-induced increase in [Ca2+ ]i. This inhibitory effect was ameliorated by combined use with rebamipide (5 × 10-4 M). CONCLUSION: This findings suggest that rebamipide weakens the downregulatory effect of DZP on salivary secretion by preventing DZP-induced suppression of increase in [Ca2+ ]i.


Subject(s)
Alanine/analogs & derivatives , Anti-Ulcer Agents/therapeutic use , Central Nervous System Agents/adverse effects , Diazepam/adverse effects , Quinolones/therapeutic use , Xerostomia/chemically induced , Xerostomia/drug therapy , Alanine/therapeutic use , Animals , Central Nervous System Agents/administration & dosage , Diazepam/administration & dosage , Dose-Response Relationship, Drug , Drug Administration Schedule , Male , Rats , Rats, Wistar , Treatment Outcome
6.
Allergy ; 70(8): 995-1003, 2015 Aug.
Article in English | MEDLINE | ID: mdl-25945591

ABSTRACT

BACKGROUND: Chronic rhinosinusitis (CRS) can be classified into CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). CRSwNP displays more intense eosinophilic infiltration and the presence of Th2 cytokines. Mucosal eosinophilia is associated with more severe symptoms and often requires multiple surgeries because of recurrence; however, even in eosinophilic CRS (ECRS), clinical course is variable. In this study, we wanted to set objective clinical criteria for the diagnosis of refractory CRS. METHODS: This was a retrospective study conducted by 15 institutions participating in the Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis (JESREC). We evaluated patients with CRS treated with endoscopic sinus surgery (ESS), and risk of recurrence was estimated using Cox proportional hazard models. Multiple logistic regression models and receiver operating characteristics curves were constructed to create the diagnostic criterion for ECRS. RESULTS: We analyzed 1716 patients treated with ESS. To diagnose ECRS, the JESREC scoring system assessed unilateral or bilateral disease, the presence of nasal polyps, blood eosinophilia, and dominant shadow of ethmoid sinuses in computed tomography (CT) scans. The cutoff value of the score was 11 points (sensitivity: 83%, specificity: 66%). Blood eosinophilia (>5%), ethmoid sinus disease detected by CT scan, bronchial asthma, aspirin, and nonsteroidal anti-inflammatory drugs intolerance were associated significantly with recurrence. CONCLUSION: We subdivided CRSwNP in non-ECRS, mild, moderate, and severe ECRS according to our algorithm. This classification was significantly correlated with prognosis. It is notable that this algorithm may give useful information to clinicians in the refractoriness of CRS before ESS or biopsy.


Subject(s)
Rhinitis/classification , Rhinitis/epidemiology , Sinusitis/classification , Sinusitis/epidemiology , Adult , Age Distribution , Age of Onset , Aged , Algorithms , Chronic Disease , Cohort Studies , Eosinophilia/immunology , Female , Humans , Incidence , Japan/epidemiology , Male , Middle Aged , Multivariate Analysis , Prognosis , Proportional Hazards Models , Retrospective Studies , Rhinitis/immunology , Risk Assessment , Severity of Illness Index , Sex Distribution , Sinusitis/immunology , Young Adult
7.
Lupus ; 24(7): 695-704, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25432781

ABSTRACT

OBJECTIVE: Activation of B cells is a hallmark of systemic lupus erythematosus (SLE). Syk and TRAF6 are key signaling molecules in B-cell activation through BCR and CD40/TLR, respectively. Nevertheless, whether expression of Syk and TRAF6 is altered in SLE B cells remains unknown. METHODS: Phosphorylation and/or expression of Syk and TRAF6 were analyzed by flow cytometry in peripheral blood mononuclear cells isolated from SLE patients. RESULTS: Pronounced phosphorylation and expression of Syk were noted in B cells from SLE patients compared with healthy donors. Levels of Syk phosphorylation correlated with the disease activity score. TRAF6 was significantly over-expressed in B cells of SLE patients as compared with healthy donors, and significant correlation of levels of TRAF6 expression and Syk phosphorylation was observed in SLE patients. Levels of TRAF6 expression were more pronounced in CD27+ memory B cells than in CD27-naïve B cells. In vitro treatment of SLE B cells with a Syk inhibitor (BAY61-3606) reduced Syk phosphorylation as well as TRAF6 expression. CONCLUSION: Our results suggest that the activated Syk-mediated TRAF6 pathway leads to aberrant activation of B cells in SLE, and also highlight Syk as a potential target for B-cell-mediated processes in SLE.


Subject(s)
B-Lymphocytes/metabolism , Intracellular Signaling Peptides and Proteins/biosynthesis , Intracellular Signaling Peptides and Proteins/metabolism , Lupus Erythematosus, Systemic/metabolism , Neoplasm Proteins/biosynthesis , Protein-Tyrosine Kinases/metabolism , Adolescent , Adult , Antigens, CD19/metabolism , B-Lymphocytes/enzymology , B-Lymphocytes/immunology , Case-Control Studies , Female , Flow Cytometry , Humans , Intracellular Signaling Peptides and Proteins/antagonists & inhibitors , Intracellular Signaling Peptides and Proteins/immunology , Lupus Erythematosus, Systemic/enzymology , Lupus Erythematosus, Systemic/immunology , Lymphocyte Activation , Male , Middle Aged , Niacinamide/analogs & derivatives , Niacinamide/pharmacology , Phosphorylation/drug effects , Protein-Tyrosine Kinases/antagonists & inhibitors , Protein-Tyrosine Kinases/immunology , Pyrimidines/pharmacology , Syk Kinase , Tumor Necrosis Factor Receptor Superfamily, Member 7/biosynthesis , Tumor Necrosis Factor Receptor Superfamily, Member 7/immunology , Young Adult
8.
J Fish Biol ; 83(3): 588-97, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23991876

ABSTRACT

To assess the relationship between growth rate of body mass and sex in the Japanese eel Anguilla japonica in the early life stage; the growth rates of males and females were compared under experimental conditions. The mean growth rate of females was significantly slower than that of males. To assess the relative priority of growth rate and sex, growth was delayed by restricted feeding, resulting in a significantly higher proportion of females in the delayed than in the normal growth group. These findings indicate that the mean growth rate of A. japonica is slower in females than in males in the early life stage around sex determination and differentiation under experimental rearing conditions. Moreover, growth rate probably has priority over sex determination, with slow growth rate increasing the probability of being female.


Subject(s)
Anguilla/growth & development , Sex Characteristics , Animals , Body Size , Female , Male , Sex Determination Processes
9.
Child Abuse Negl ; 135: 105997, 2023 01.
Article in English | MEDLINE | ID: mdl-36528934

ABSTRACT

BACKGROUND: In the wake of the COVID-19 pandemic, concerns have been raised that the pandemic may derail global efforts against child sexual abuse (CSA). OBJECTIVES: This study examines the prevalence and associated factors of sexual abuse among adolescent girls in the context of the COVID-19 pandemic in Ghana. PARTICIPANTS AND SETTING: The sample comprised 853 adolescent girls aged 13-19 (16.03 ± 2.04 years) in Ghana. METHODS: The study employed a concurrent mixed-method design. RESULTS: Overall, the prevalence of CSA during the COVID-19 lockdown and school closures was 32.5 %. Protective factors for CSA were feeling safe in neighbourhood (AOR = 0.526, 95 % CI = [0.325, 0.850]) and parents often listen to opinions (AOR = 0.446, 95 % CI = [0.241, 0.826]). Risk factors for CSA were physical activity (AOR = 1.649, OR = 1.783, 95 % CIAOR = [1.093, 2.487, 95 % CIOR = [1.241, 2.561]), parents sometimes listen to opinions (AOR = 1.199, OR = 1.924, 95 % CIAOR = [0.504, 2.853], 95 % CIOR = [1.034, 3.582]), living with another relative (AOR = 2.352, OR = 2.484, 95 % CIAOR = [0.270, 20.523], 95 % CIOR = [0.317, 19.475]), Akan ethnicity (AOR = 1.576, OR = 1.437, 95 % CIAOR = [0.307, 8.091], 95 % CIOR = [0.316, 6.534]), having no disability (AOR = 1.099, OR = 1.138, 95 % CIAOR = [0.679, 1.581], 95 % CIOR = [0.786, 1.649]) and having a close relationship with parents (AOR = 1.334, OR = 1.752, 95 % CIAOR = [0.746, 2.385], 95 % CIOR = [1.096, 2.802]). CONCLUSION: Knowledge of the risk and protective factors identified in this study can guide and inform the development of CSA prevention programmes during disruptive occurrences like school closures and lockdown.


Subject(s)
COVID-19 , Child Abuse, Sexual , Child , Female , Humans , Adolescent , COVID-19/epidemiology , COVID-19/prevention & control , Ghana/epidemiology , Prevalence , Pandemics/prevention & control , Communicable Disease Control , Schools
10.
Vox Sang ; 102(2): 93-9, 2012 Feb.
Article in English | MEDLINE | ID: mdl-21781123

ABSTRACT

BACKGROUND AND OBJECTIVES: Our previous report showed that parvovirus B19 genotype 1 in different solutions derived from plasma preparations showed different heat-sensitivity patterns during liquid-heating. In this study, we similarly examined B19 genotype 2. MATERIALS AND METHODS: Two plasma samples one containing B19 genotype 1 and the other genotype 2 DNA were used. Four process samples collected immediately before the heat treatment step in the manufacture of albumin, immunoglobulin, haptoglobin and antithrombin preparations were spiked with B19 and subsequently treated at 60°C for 10 h. A low pH immunoglobulin solution was also spiked with B19 and treated at room temperature for 14 days. Infectivity was then measured. RESULTS: B19 genotype 2, similar to genotype 1, showed three patterns of inactivation: (i) a rapid inactivation in the albumin and immunoglobulin preparations, (ii) a slow inactivation in the haptoglobin preparation and (iii) only limited inactivation in the antithrombin preparation. Its sensitivity in the low pH immunoglobulin solutions also resembled that of genotype 1. CONCLUSION: Both genotypes 1 and 2 of B19 varied in sensitivity to liquid-heating and low pH among different plasma preparations.


Subject(s)
Blood Safety/methods , Parvovirus B19, Human/physiology , Plasma/virology , Virus Inactivation , Cloning, Molecular , Electrophoresis, Polyacrylamide Gel , Genotype , Heating , Hot Temperature , Humans , Immunoglobulins, Intravenous/pharmacology , Microscopy, Electron , Parvovirus B19, Human/drug effects , Parvovirus B19, Human/genetics
11.
Rev Sci Instrum ; 93(12): 123507, 2022 Dec 01.
Article in English | MEDLINE | ID: mdl-36586932

ABSTRACT

A Ku-band (12-18 GHz) multichannel Doppler reflectometer (DR) has been developed in the GAMMA 10/potential control and divertor simulating experiment (PDX) tandem mirror device to improve the applicability of DR measurement for simultaneous monitoring of velocity of electron density turbulence at different locations. Our previous single-channel DR circuit has been replaced by the multichannel microwave system using a nonlinear transmission line based comb generator with heterodyne technique. The multichannel DR system has been installed in the central cell of GAMMA 10/PDX. Initial results of application to GAMMA 10/PDX plasma are presented, showing Doppler frequency shifts during an additional ion cyclotron resonance frequency heating and gas-puffing experiment.

12.
Rhinology ; 49(4): 392-6, 2011 Oct.
Article in English | MEDLINE | ID: mdl-21991563

ABSTRACT

BACKGROUND: Eosinophils and nasal polyps are believed to affect the surgical outcome of chronic rhinosinusitis (CRS). CRS is classified based on the presence of nasal polyps in western countries. The majority of patients with CRS with nasal polyps (CRS with NP) are characterized by predominantly eosinophilic inflammation. However, Asian patients with CRS with NP show characteristics indicative of neutrophilic inflammation. Therefore, are eosinophils or nasal polyps more important for the classification of CRS? METHODS: A prospective cohort study conducted from April 2007 to March 2008 classified patients with CRS based on the presence of nasal polyps and mucosal eosinophilia. The recurrence rate of nasal polyps was compared between the groups. Recurrence rate was analysed as a time-dependent variable by the Kaplan-Meier method. RESULTS: Eosinophilic inflammation was found in 59.6% of patients with CRS with NP. Patients with mucosal eosinophilia had higher polyp recurrence rate than patients without mucosal eosinophilia, whereas patients with nasal polyps did not have higher polyp recurrence rate than patients without nasal polyps. CONCLUSIONS: Presence of mucosal eosinophilia is a more important factor than nasal polyps for classifying CRS in terms of the surgical outcome.


Subject(s)
Eosinophilia/epidemiology , Rhinitis/classification , Rhinitis/epidemiology , Sinusitis/classification , Sinusitis/epidemiology , Adult , Aged , Chronic Disease , Female , Humans , Male , Middle Aged , Nasal Mucosa , Nasal Polyps/epidemiology , Prognosis , Prospective Studies , Recurrence
13.
J Oral Rehabil ; 38(9): 680-5, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21284690

ABSTRACT

Tongue pressure measured with a disposable hand-held balloon probe has been used for assessing tongue function; however, no diagnostic standard for assessing other oral functions exists currently. In this study, to develop a method for multifactorial manometric evaluation of oral functions, 20 men and 20 women (21-32 years of age) were instructed to apply 7-s maximal voluntary muscular effort on a hand-held balloon probe placed against the anterior and lateral parts of the palate, buccal surface of the molars on the habitual chewing side and labial surface of the anterior teeth for measuring anterior and posterior tongue, cheek and lip pressures (LPs), respectively. Intra-session reproducibility was determined by three repeated measurements, and associations between the obtained and the conventional data on oral diadochokinesis were tested. The men exhibited higher values of all the pressure types. Further, both genders showed a positive correlation between anterior and posterior tongue pressures (PTPs) (P < 0·05), but only the women exhibited positive correlations between anterior tongue and cheek pressures, cheek and PTPs, anterior tongue and LPs, and cheek and LPs (P < 0·05). No statistically significant correlation was found between the pressures and the number of syllabic articulations, except between LP and the number of /pa/ articulations in the women (r = 0·524, P < 0·05). In conclusion, the balloon probe method enables objective manometric evaluation of oral functions and could be an effective tool for clinical epidemiological studies and evidence-based decision-making in nursing care.


Subject(s)
Cheek/physiology , Kinesis/physiology , Mouth/physiology , Adult , Female , Humans , Japan , Lip/physiology , Male , Manometry/instrumentation , Mouth/physiopathology , Pressure , Sex Factors , Tongue/physiology , Young Adult
14.
Kyobu Geka ; 64(7): 594-7, 2011 Jul.
Article in Japanese | MEDLINE | ID: mdl-21766715

ABSTRACT

A 76-year-old woman with recurrent ball-like thrombus in right atrium after primary repair of atrial septal defect (ASD) and tricuspid annuloplasty was successfully treated by surgical resection and strict management of anticoagulation and antiarrhythmics. A routine follow-up echocardiography, 27 months after initial operation, showed a swinging ball mass looks like a myxoma in the right atrium. Intra-operative findings showed the mass attached the free wall of right atrium with a 5 mm stalk, which was far from the ASD patch, initial suture lines, and the tricuspid annulus. Histological examination revealed the round and smooth mass was thrombus. She was successfully discharged 13 days after the 2nd operation without any complaint. A postoperative laboratory check demonstrated normal coagulability. Despite the patient was prescribed warfarin potassium and aspirin, the follow-up echocardiography at 3 months showed a recurrent thrombus in the right atrium. However the strict anticoagulation therapy with warfarin potassium and aspirin induced thrombolysis and prevent any embolic event, 1 month later. It is important to continue a strict anticoagulant therapy and prevent arrhythmia to avoid recurrence thrombus.


Subject(s)
Heart Diseases/etiology , Heart Septal Defects, Atrial/surgery , Thrombosis/etiology , Aged , Anticoagulants/therapeutic use , Female , Follow-Up Studies , Heart Atria , Heart Diseases/drug therapy , Humans , Postoperative Complications , Recurrence , Thrombosis/drug therapy
15.
Rev Sci Instrum ; 92(3): 033515, 2021 Mar 01.
Article in English | MEDLINE | ID: mdl-33820074

ABSTRACT

The multipass Thomson scattering (MPTS) technique is one of the most useful methods for measuring low-electron-density plasmas. The MPTS system increases Thomson scattering (TS) signal intensities by integrating all multipass (MP) signals and improving the TS time resolution by analyzing each pass signal. The fully coaxial MPTS system developed in GAMMA 10/potential-control and diverter-simulator experiments has a polarization-based configuration with image-relaying optics. The MPTS system can enhance Thomson scattered signals for improving the measurement accuracy and megahertz-order time resolution. In this study, we develop a new MPTS system comprising a laser amplification system to obtain continuous MP signals. The laser amplification system can improve degraded laser power and return an amplified laser to the MP system. We obtain continuous MP signals from the laser amplification system by improving the laser beam profile adjuster in gas scattering experiments. Moreover, we demonstrate that more MP signals and stronger amplified MP signals can be achieved via multiple laser injections to the laser amplification system in the developed MP system comprising a laser amplification system.

16.
Rev Sci Instrum ; 92(5): 053506, 2021 May 01.
Article in English | MEDLINE | ID: mdl-34243319

ABSTRACT

In the GAMMA 10/PDX tandem mirror, plasma with strong ion-temperature anisotropy is produced by using the ion cyclotron range of frequency waves. This anisotropy of ion temperature causes several Alfvén-Ion-Cyclotron (AIC) waves to spontaneously excite in the frequency range just below the ion cyclotron frequency. In addition, difference-frequency (DF) waves are excited in the radial inner region of the plasma by wave-wave coupling among the AIC waves. The radial density profiles were measured at multi-axial positions using a frequency-modulation reflectometer with an axial array of microwave antennas, and an axial variation of the density was found to be significant. In addition, a relative phase difference of the DF wave between axially separated two points was first obtained by finely choosing the probing frequency of the reflectometers with a maximum coherence used as a measure, indicating that the DF wave is a propagating wave, while the pump AIC waves are standing waves in the axial region of measurement.

17.
Nat Commun ; 11(1): 2655, 2020 05 27.
Article in English | MEDLINE | ID: mdl-32461569

ABSTRACT

Asteroid shapes and hydration levels can serve as tracers of their history and origin. For instance, the asteroids (162173) Ryugu and (101955) Bennu have an oblate spheroidal shape with a pronounced equator, but contain different surface hydration levels. Here we show, through numerical simulations of large asteroid disruptions, that oblate spheroids, some of which have a pronounced equator defining a spinning top shape, can form directly through gravitational reaccumulation. We further show that rubble piles formed in a single disruption can have similar porosities but variable degrees of hydration. The direct formation of top shapes from single disruption alone can explain the relatively old crater-retention ages of the equatorial features of Ryugu and Bennu. Two separate parent-body disruptions are not necessarily required to explain their different hydration levels.

18.
Science ; 368(6486): 67-71, 2020 04 03.
Article in English | MEDLINE | ID: mdl-32193363

ABSTRACT

The Hayabusa2 spacecraft investigated the small asteroid Ryugu, which has a rubble-pile structure. We describe an impact experiment on Ryugu using Hayabusa2's Small Carry-on Impactor. The impact produced an artificial crater with a diameter >10 meters, which has a semicircular shape, an elevated rim, and a central pit. Images of the impact and resulting ejecta were recorded by the Deployable CAMera 3 for >8 minutes, showing the growth of an ejecta curtain (the outer edge of the ejecta) and deposition of ejecta onto the surface. The ejecta curtain was asymmetric and heterogeneous and it never fully detached from the surface. The crater formed in the gravity-dominated regime; in other words, crater growth was limited by gravity not surface strength. We discuss implications for Ryugu's surface age.

19.
Science ; 364(6437): 268-272, 2019 04 19.
Article in English | MEDLINE | ID: mdl-30890588

ABSTRACT

The Hayabusa2 spacecraft arrived at the near-Earth carbonaceous asteroid 162173 Ryugu in 2018. We present Hayabusa2 observations of Ryugu's shape, mass, and geomorphology. Ryugu has an oblate "spinning top" shape, with a prominent circular equatorial ridge. Its bulk density, 1.19 ± 0.02 grams per cubic centimeter, indicates a high-porosity (>50%) interior. Large surface boulders suggest a rubble-pile structure. Surface slope analysis shows Ryugu's shape may have been produced from having once spun at twice the current rate. Coupled with the observed global material homogeneity, this suggests that Ryugu was reshaped by centrifugally induced deformation during a period of rapid rotation. From these remote-sensing investigations, we identified a suitable sample collection site on the equatorial ridge.

20.
Science ; 365(6455): 817-820, 2019 08 23.
Article in English | MEDLINE | ID: mdl-31439797

ABSTRACT

The near-Earth asteroid (162173) Ryugu is a 900-m-diameter dark object expected to contain primordial material from the solar nebula. The Mobile Asteroid Surface Scout (MASCOT) landed on Ryugu's surface on 3 October 2018. We present images from the MASCOT camera (MASCam) taken during the descent and while on the surface. The surface is covered by decimeter- to meter-sized rocks, with no deposits of fine-grained material. Rocks appear either bright, with smooth faces and sharp edges, or dark, with a cauliflower-like, crumbly surface. Close-up images of a rock of the latter type reveal a dark matrix with small, bright, spectrally different inclusions, implying that it did not experience extensive aqueous alteration. The inclusions appear similar to those in carbonaceous chondrite meteorites.

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