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Volatile and organic-rich C-type asteroids may have been one of the main sources of Earth’s water. Our best insight into their chemistry is currently provided by carbonaceous chondritic meteorites, but the meteorite record is biased: only the strongest types survive atmospheric entry and are then modified by interaction with the terrestrial environment. Here we present the results of a detailed bulk and microanalytical study of pristine Ryugu particles, brought to Earth by the Hayabusa2 spacecraft. Ryugu particles display a close compositional match with the chemically unfractionated, but aqueously altered, CI (Ivuna-type) chondrites, which are widely used as a proxy for the bulk Solar System composition. The sample shows an intricate spatial relationship between aliphatic-rich organics and phyllosilicates and indicates maximum temperatures of ~30 °C during aqueous alteration. We find that heavy hydrogen and nitrogen abundances are consistent with an outer Solar System origin. Ryugu particles are the most uncontaminated and unfractionated extraterrestrial materials studied so far, and provide the best available match to the bulk Solar System composition.

Presented here are the observations and interpretations from a comprehensive analysis of 16 representative particles returned from the C-type asteroid Ryugu by the Hayabusa2 mission. On average Ryugu particles consist of 50% phyllosilicate matrix, 41% porosity and 9% minor phases, including organic matter. The abundances of 70 elements from the particles are in close agreement with those of CI chondrites. Bulk Ryugu particles show higher δ18O, Δ17O, and ε54Cr values than CI chondrites. As such, Ryugu sampled the most primitive and least-thermally processed protosolar nebula reservoirs. Such a finding is consistent with multi-scale H-C-N isotopic compositions that are compatible with an origin for Ryugu organic matter within both the protosolar nebula and the interstellar medium. The analytical data obtained here, suggests that complex soluble organic matter formed during aqueous alteration on the Ryugu progenitor planetesimal (several 10’s of km)

International audience; INTRODUCTION: Organic compounds in asteroids and comets contain information about the early history of the Solar System. They could also have delivered organic material to early Earth. The Hayabusa2 spacecraft visited the carbonaceous asteroid Ryugu and collected samples of its surface materials, which were brought to Earth in December 2020. RATIONALE: We investigated the macromolecular organic matter in the Ryugu samples, measuring its elemental, isotopic, and functional group compositions along with its small-scale structures and morphologies. Analytical methods used included spectro-microscopies, electron microscopy, and isotopic microscopy. We examined intact Ryugu grains and insoluble carbonaceous residues isolated by acid treatment of the Ryugu samples. RESULTS: Organic matter is abundant in the Ryugu grains, distributed as submicrometersized organic grains and as organic matter dispersed in matrix. The Ryugu organic matter consists of aromatic carbons, aliphatic carbons, ketones, and carboxyls. The functional group

C-type asteroids1 are considered to be primitive small Solar System bodies enriched in water and organics, providing clues to the origin and evolution of the Solar System and the building blocks of life. C-type asteroid 162173 Ryugu has been characterized by remote sensing2–7 and on-asteroid measurements8,9 with Hayabusa2 (ref. 10). However, the ground truth provided by laboratory analysis of returned samples is invaluable to determine the fine properties of asteroids and other planetary bodies. We report preliminary results of analyses on returned samples from Ryugu of the particle size distribution, density and porosity, spectral properties and textural properties, and the results of a search for Ca–Al-rich inclusions (CAIs) and chondrules. The bulk sample mainly consists of rugged and smooth particles of millimetre to submillimetre size, confirming that the physical and chemical properties were not altered during the return from the asteroid. The power index of its size distribution is shallower than that of the surface boulder observed on Ryugu11, indicating differences in the returned Ryugu samples. The average of the estimated bulk densities of Ryugu sample particles is 1,282 ± 231 kg m−3, which is lower than that of meteorites12, suggesting a high microporosity down to the millimetre scale, extending centimetre-scale estimates from thermal measurements5,9. The extremely dark optical to near-infrared reflectance and spectral profile with weak absorptions at 2.7 and 3.4 μm imply a carbonaceous composition with indigenous aqueous alteration, matching the global average of Ryugu3,4 and confirming that the sample is representative of the asteroid. Together with the absence of submillimetre CAIs and chondrules, these features indicate that Ryugu is most similar to CI chondrites but has lower albedo, higher porosity and more fragile characteristics.

Without a protective atmosphere, space-exposed surfaces of airless Solar System bodies gradually experience an alteration in composition, structure and optical properties through a collective process called space weathering. The return of samples from near-Earth asteroid (162173) Ryugu by Hayabusa2 provides the first opportunity for laboratory study of space-weathering signatures on the most abundant type of inner solar system body: a C-type asteroid, composed of materials largely unchanged since the formation of the Solar System. Weathered Ryugu grains show areas of surface amorphization and partial melting of phyllosilicates, in which reduction from Fe3+ to Fe2+ and dehydration developed. Space weathering probably contributed to dehydration by dehydroxylation of Ryugu surface phyllosilicates that had already lost interlayer water molecules and to weakening of the 2.7 µm hydroxyl (–OH) band in reflectance spectra. For C-type asteroids in general, this indicates that a weak 2.7 µm band can signify space-weathering-induced surface dehydration, rather than bulk volatile loss.

Carbonaceous meteorites are thought to be fragments of C-type (carbonaceous) asteroids. Samples of the C-type asteroid (162173) Ryugu were retrieved by the Hayabusa2 spacecraft. We measured the mineralogy and bulk chemical and isotopic compositions of Ryugu samples. The samples are mainly composed of materials similar to those of carbonaceous chondrite meteorites, particularly the CI (Ivuna-type) group. The samples consist predominantly of minerals formed in aqueous fluid on a parent planetesimal. The primary minerals were altered by fluids at a temperature of 37° ± 10°C, about 5.2 − 0.7 + 0.8 million (statistical) or 5.2 − 2.1 + 1.6 million (systematic) years after the formation of the first solids in the Solar System. After aqueous alteration, the Ryugu samples were likely never heated above ~100°C. The samples have a chemical composition that more closely resembles that of the Sun’s photosphere than other natural samples do.

C-type asteroids likely formed in the outer Solar System and were then scattered inwards during giant planet migration (Walsh et al., 2011). They may have transported volatiles to the inner Solar System and created the conditions suitable for life on Earth(Alexander, 2017). Carbonaceous chondrites are fragments from C-type asteroids and provide evidence that these generally organic-rich (Garvie and Buseck, 2007) bodies experienced extensive aqueous alteration early in Solar System history (Alexander et al., 2014). On 6th December 2020, ~5.4g of material was delivered to Earth from the C-type asteroid 162173 Ryugu by the Hayabusa2 spacecraft (Yada et al., 2021). Here we present the results of an integrated bulk and micro-analytical study of Ryugu particles, which provides a unique insight into the interrelationship between aliphatic-rich organics and surrounding hydrous minerals at a sub-micrometer scale. This dataset has clear implications for better understanding the origin and early evolution of Solar System organic matter and demonstrates that Ryugu particles are among the most uncontaminated extraterrestrial materials so far studied.

C-type asteroids are considered to be primitive small Solar-System bodies enriched in water and organics, providing clues for understanding the origin and evolution of the Solar System and the building blocks of life. C-type asteroid 162173 Ryugu has been characterized by remote sensing and on-asteroid measurements with Hayabusa2, but further studies are expected by direct analyses of returned samples. Here we describe the bulk sample mainly consisting of rugged and smooth particles of millimeter to submillimeter size, preserving physical and chemical properties as they were on the asteroid. The particle size distribution is found steeper than that of surface boulders11. Estimated grain densities of the samples have a peak around 1350 kg m-3, which is lower than that of meteorites suggests a high micro-porosity down to millimeter-scale, as estimated at centimeter-scale by thermal measurements. The extremely dark optical to near-infrared reflectance and the spectral profile with weak absorptions at 2.7 and 3.4 microns implying carbonaceous composition with indigenous aqueous alteration, respectively, match the global average of Ryugu, confirming the sample’s representativeness. Together with the absence of chondrule and Ca-Al-rich inclusion of larger than sub-mm, these features indicate Ryugu is most similar to CI chondrites but with darker, more porous and fragile characteristics.

Aims Anomalous origin of the coronary artery (AOCA) with an inter-arterial course (IAC) between the great vessels poses a risk for a life-threatening cardiovascular event. We assessed, in a registry-based study, the clinical features, treatment strategies, and prognoses of life-threatening cardiovascular events ensuant to AOCA. Methods and results Included were 65 AOCA patients (48 men/17 women, aged 41 ± 23 years) from 40 clinical centres who had experienced sudden cardiac arrest (SCA) (n = 30), acute myocardial infarction (AMI) (n = 5), angina (n = 23), or syncope (n = 7). The anomalous vessel was the right coronary artery in 72% of patients and left coronary artery in 28%; the ostium was slit-like in 42%. Coronary luminal narrowing ≥75% was absent in patients with SCA or syncope (86% and 57%, respectively), but occlusion or narrowing was seen in those with AMI (100%) or angina (52%). Age ≤40 years, male sex, sporting activity, absence of prodromal symptoms, acutely angled (≤30°) take-off from the aorta, and absence of luminal narrowing of the IAC segment were associated with SCA in this patient group. Coronary vasospasm was inducible in 12 of 17 patients without coronary narrowing. Management included surgical revascularization (n = 26) percutaneous coronary intervention (n = 9), and medical treatment (n = 26). Four SCA patients died while hospitalized; no others died during the median 5.0 (range, 1.8–7.0)-year follow-up period. Conclusions In patients with AOCA, age ≤40 years, male sex, sporting activity, and an acute take-off angle appear to be risk factors for SCA. Appropriate management can be beneficial. Confirmation in a large-scale study is warranted.

With the increasing prevalence of severe obesity worldwide, surgical treatment for severely obese patients is becoming more popular. Bariatric surgery has occasionally been performed as a precursor to major operations for serious diseases to make these difficult surgeries safer for severely obese patients. We present the case of a severely obese patient with a dissected abdominal aortic aneurysm and left iliac artery aneurysm. Initially, we performed bariatric surgery on this patient to reduce perioperative risk and then subsequently performed bifurcated graft replacement. A 54-year-old man presented at our hospital for bariatric surgery before open abdominal aortic aneurysm repair. Laparoscopic sleeve gastrectomy was performed; 15 months later, the patient's weight and BMI had decreased from 139.0 kg to 97.6 kg and from 48.7 kg/m(2) to 34.2 kg/m(2) , respectively. Bifurcated graft replacement was performed safely without postoperative complications. Bariatric surgery was also effective in controlling the patient's blood pressure during the interval between surgeries.

Background: In small children, conduits for right ventricular out ow tract reconstruction are limited because of patient size and conduit resources, particularly in Japan. Methods: Since 2007, we have performed the Rastelli-type procedure using 16-mm hand-made trilea et expanded polytetra uoroethylene (ePTFE) conduits in nine approximately 1-year-old children. e median age and body weight at surgery was 17.3 months (range: 10~22 months) and 8.9 kg (range: 6.8~11 kg), respectively. e patient diagnoses were double-outlet right ventricle (DORV) with pulmonary stenosis (PS) in four, pulmonary atresia with ventricular septal defect (PA/VSD) and major aortopulmonary collateral arteries (MAPCA) in four, and PA/VSD in one patient. All patients had undergone previous surgical procedures, including modi ed Blalock shunt in ve and unifocalization of MAPCA and modi ed Blalock shunt in four patients. Conduit function, re-intervention, and right ventricular function were retrospectively investigated. Results: ere was no early or late mortality. During the median follow-up of 45 months (range: 18~79 months), balloon dilation for conduit stenosis was performed in two patients at 47 and 51 months post surgery, respectively. One of these patients required conduit replacement 27 months a er balloon dilation. Excluding this patient, the most recent echocardiographic pressure gradients of the conduits were 0~20 mmHg in four, 21~40 mmHg in four, and no patient had conduit stenosis with the pressure gradients over 41 mmHg. Conduit regurgitation was trivial in four, mild in two, and moderate in two patients. Conclusion: e Rastelli-type procedure using 16-mm hand-made trilea et ePTFE conduits in approximately 1-year-old infants showed acceptable mid-term results. Conduit stenosis gradually developed over 5~6 years. Balloon dilation for conduit stenosis has the potential to delay conduit replacement without increasing conduit regurgitation.

In this paper, we describe the development of a needle based dispenser for high-viscosity liquid, and pick & place of micro objects using capillary force. Recently, miniaturization of portable devices and their electronic parts has been remarkable. So we think that there are a lot of needs for micro manipulation for making more complex and smaller devices. There are a lot of possibilities to manipulate complex-shaped micro objects by using liquid because it changes its shape flexibly according to the shape of the contact surface. We have developed a unique surface mounting technology which is based on a movable shaft driven by a piezoelectric linear motor. We can simply apply high-viscosity liquid drops by stamping the wet tip of the shaft on a substrate, and we confirm that the device is able to apply a liquid the viscosity of which is about 1200Pas. We have studied the relation between viscosity and diameters of applied liquid drops via several experiments. We have also conducted interesting experiments in which we pick and place some small and complex-shaped objects using capillary force. We confirmed that if capillary force between the shaft and micro object is larger than that between the substrate and the micro object, we are able to place a chip-capacitor weighing below 1 mg. This simple method is very effective because any shaped object can be mounted. However, fast control and accurate control of the shaft are needed for efficient production and accurate mounting. To realize this, we developed a PID controller for the dispenser with an optical liner encoder with a resolution of 30 nm. We confirm that settling time becomes less than 50 ms when the shaft moves 5 mm with 1 micrometre accuracy.

症例は13歳，女児．くり返す運動後の失神を認めたため，当センターに紹介された．経胸壁心エコー検査で心機能に異常は認めなかったものの，24時間ホルター心電図で心拍の上昇に伴う ST 低下，およびトレッドミル負荷心筋シンチで同様の ST 低下を伴う心電図異常とともに左室前壁に虚血所見を認めた．冠動脈 CT 検査では左冠動脈主幹部低形成が認められたため，心筋虚血に伴う心原性失神と診断された．手術は非体外循環下で左内胸動脈-前下行枝の1枝バイパスを施行した．術後のストレスシンチでは心電図異常および心筋虚血の所見も認められず，冠動脈 CT 検査においてもグラフトの開存は良好であった．現在運動後の失神発作などは全く認められていない．学童期に失神を契機に発見された左冠動脈主幹部低形成の1手術例を報告した．冠動脈の形態異常に伴う心原性失神は非常に希であるが，放置すれば突然死などの原因となり，失神の鑑別診断として注意しておくべきである．また本症例のように，虚血が関与するくり返す失神に関しては積極的な冠動脈バイパス術が考慮されるべきであると考えられた．

A resonant circuit is expected to be used as a heating source for hyperthermia implants, because the circuit can be effectively heated by an applied ac magnetic field. In order to realize a less invasive delivery of the implant through a catheter or injection needle, its miniaturization down to 1 mm or less is essential. However, the heating temperature of the resonant circuit is reduced by downsizing of the size of the circuit. A ferrite core in a coil is employed in order to obtain higher induced voltage in the inductor, resulting in the higher temperature rise of the resonant circuit. The resonant circuit implant consisting of the core coil has been prepared. Its diameter is 0.9 mm and the implant can be delivered through an 18 G needle.

A 78-year-old woman with a history of mitral valve stenosis underwent open mitral commissurotomy in 1976. In 1990, she underwent mitral valve replacement (Medtronic-Hall 29 mm), tricuspid annuloplasty(DeVega method), and pacemaker implantation for bradycardiac atrial fibrillation. However, in June 2012, she developed anemia of unknown cause. Prosthetic valve dysfunction was suspected, because intermittent changes in the left ventricular inflow was detected by echocardiography. Fluoroscopy actually confirmed the presence of prosthetic valve dysfunction. Therefore mitral valve re-replacement(ATS Medical, Inc. 29 mm) and tricuspid annuloplasty (Cosgrove ring 30 mm) were performed. Monitoring the changes in the left ventricular inflow is recommended when prosthetic valve dysfunction in a single leaflet is suspected.

We used 790-nm, 130-fs laser pulses for micromachining transparent materials including acrylic resin, quartz, diamond, and polyvinyl chloride. Using this technique, even 20 mm thick acrylic resin could bedrilled in 15 minutes, while a precise cut 20μm in width was produced in acrylic resin 0.5 mm thick. However, cracks were produced by the technique when used to drill or cut quartz plate. A 1-mm micro-gear was fabricated using acrylic resin.

In this paper, we have described newly developed wet tweezers based on capillary force for micro-assembly of complex-shaped objects. The tweezers are composed of two movable rods driven by a piezoelectric linear motor and two thin tubes. The two rods penetrate the liquids in the thin tubes. If we simply stamp the rods on a base, we can apply a drop of even high viscosity liquids. If we contact them to an object, we can pick it up by capillary force. Because we use the pair of the rods for picking up, posture of objects are fixed. That is important for accurate micro-assembly. To investigate generative force of the wet tweezers, we study relationship among viscosity, surface tension, and shape of meniscus of the liquid. We also formulate the capillary force as a function of gap distance between the rod and the object with three different liquids. In several experiments, we have confirmed the wet tweezers have good assembling accuracy and possibility to realize heterogeneous and complex-shaped micro-assembly.

Recently pericardial drainage after cardiac surgery has been done using silicon tubes of small diameter. For more effective drainage, we set one of the drainage tubes circularly, coursing behind the left ventricle, through the transverse sinus, and ending at the right side of the atrium (circular pericardial drainage). As compared to conventional drainage using 28 Fr chloroethilene tubes, drainage time was shorter and no late tamponade had occurred. Circular pericardial drainage may be useful.

A 14-year-old girl was admitted to our hospital with a history of syncope and chest pain on exercise. Multi-slice coronary computed tomography (CT) demonstrated ostial stenosis of the left main trunk as well as wall thickening in the ascending aorta. Magnetic resonance imaging (MRI) also showed occlusion of the left carotid artery. She was diagnosed as having angina pectoris caused by aortitis syndrome. We performed off-pump coronary artery bypass grafting (OPCAB) with the left internal thoracic artery to the left anterior descending artery. The postoperative course was uneventful and coronary CT demonstrated good graft patency. We herein report successful OPCAB in a patient with left coronary main trunk ostial stenosis with aortitis syndrome.

Auditory brain stem responses were recorded in 20 patients with anorexia nervosa and 10 normal control subjects. Twenty patients were studied during two phases of illness, 1) anorexia nervosa group with under weight (U-AN group), and 2) anorexia nervosa group with recovered normal weight (N-AN group). Absolute latencies, interwave latencies, absolute amplitudes, and amplitude ratios were investigated. A nonsignificant difference was found among these groups as far as the latencies were concerned. Both the patients in the U-AN group and those in the N-AN group had significantly smaller amplitude ratios (III/I, IV.V/I) and absolute amplitude (V) than did the control subjects. Furthermore, a nonsignificant difference was found between the U-AN group and the N-AN group. It suggests that some dysfunction might exist in the region of the brain stem.

The Hayabusa2 spacecraft returned to Earth from the asteroid 162173 Ryugu on 6 December 2020. One day after the recovery, the gas species retained in the sample container were extracted and measured on-site and stored in gas collection bottles. The container gas consists of helium and neon with an extraterrestrial ³He/⁴He and ²⁰Ne/²²Ne ratios, along with some contaminant terrestrial atmospheric gases. A mixture of solar and Earth’s atmospheric gas is the best explanation for the container gas composition. Fragmentation of Ryugu grains within the sample container is discussed on the basis of the estimated amount of indigenous He and the size distribution of the recovered Ryugu grains. This is the first successful return of gas species from a near-Earth asteroid., 「はやぶさ2」ミッションによる世界初の小惑星からのガスサンプル：リュウグウからのたまて箱. 京都大学プレスリリース. 2022-10-21.