Pebbles and sand on asteroid (162173) Ryugu: In situ observation and particles returned to Earth.

The Hayabusa2 spacecraft investigated the C-type (carbonaceous) asteroid (162173) Ryugu. The mission performed two landing operations to collect samples of surface and subsurface material, the latter exposed by an artificial impact. We present images of the second touchdown site, finding that ejecta from the impact crater was present at the sample location. Surface pebbles at both landing sites show morphological variations ranging from rugged to smooth, similar to Ryugu's boulders, and shapes from quasi-spherical to flattened. The samples were returned to Earth on 6 December 2020. We describe the morphology of >5 grams of returned pebbles and sand. Their diverse color, shape, and structure are consistent with the observed materials of Ryugu; we conclude that they are a representative sample of the asteroid.

From decimeter-scale elevated ionic conductivity regions in the cloud to lightning initiation.

In this work, we represent the lightning initiation scenario as a sequence of two transitions of discharge activity to progressively larger spatial scales: the first one is from small-scale avalanches to intermediate-scale streamers; and the second one is from streamers to the lightning seed. We postulate the existence of ion production centers in the cloud, whose occurrence is caused by electric field bursts accompanying hydrometeor collisions (or near collisions) in the turbulent thundercloud environment. When a new ion production center is created inside (fully or partially) the residual ion spot left behind by a previously established center, there is a cumulative effect in the increasing of ion concentration. As a result, the essentially non-conducting thundercloud becomes seeded by elevated ion-conductivity regions (EICRs) with spatial extent of 0.1-1 m and a lifetime of 1-10 s. The electric field on the surface of an EICR (due to its conductivity being at least 4 orders of magnitude higher than ambient) is a factor of 3 or more higher than ambient. For a maximum ambient electric field of 100 kV/m typically measured in thunderclouds, such field enhancement is sufficient for initiation of positive streamers and their propagation over distances of the order of decimeters, and this will be happening naturally, without any external agents (e.g., superenergetic cosmic ray particles) or extraordinary in-cloud conditions, such as very high potential differences or very large hydrometeors. Provided that each EICR generates at least one streamer during its lifetime, the streamers will form a 3D network, some parts of which will contain hot channel segments created via the cumulative heating and/or thermal-ionizational instability. These hot channel segments will polarize, interact with each other, and cluster, forming longer conducting structures in the cloud. When the ambient potential difference bridged by such a conducting structure exceeds 3 MV, we assume that the lightning seed, capable of self-sustained bidirectional extension, is formed.

Transient ischemic attack without self-awareness of symptoms witnessed by bystanders: analysis of the PROMISE-TIA registry.

BACKGROUND AND PURPOSE: A transient ischemic attack (TIA) can occur without self-awareness of symptoms. We aimed to investigate characteristics of patients with a tissue-based diagnosis of TIA but having no self-awareness of their symptoms and whose symptoms were witnessed by bystanders. METHODS: We used data from the multicenter registry of 1414 patients with a clinical diagnosis of TIA. For patients without evidence of ischemic lesions on imaging, clinical characteristics were compared between patients with and without self-awareness of their TIA symptoms. RESULTS: Among 896 patients (559 men, median age of 70 years), 59 (6.6%) were unaware of their TIA symptoms, but had those symptoms witnessed by bystanders. Patients without self-awareness of symptoms were older and more frequently female, and more likely to have previous history of stroke, premorbid disability, and atrial fibrillation, but less likely to have dyslipidemia than those with self-awareness. Patients without self-awareness of symptoms arrive at hospitals earlier than those with self-awareness (P < 0.001). ABCD2 score was higher in patients without self-awareness of symptoms than those with self-awareness (median 5 vs. 4, P = 0.002). Having no self-awareness of symptoms was a significant predictor of ischemic stroke within 1 year after adjustment for sex, ABCD2 score, and onset to arrival time (hazard ratio = 2.44, 95% confidential interval: 1.10-4.83), but was not significant after further adjustment for arterial stenosis or occlusion. CONCLUSIONS: Patients with a TIA but having no self-awareness of their symptoms might have higher risk of subsequent ischemic stroke rather than those with self-awareness, suggesting urgent management is needed even if patients have no self-awareness of symptoms.

Sample collection from asteroid (162173) Ryugu by Hayabusa2: Implications for surface evolution.

The near-Earth asteroid (162173) Ryugu is thought to be a primitive carbonaceous object that contains hydrated minerals and organic molecules. We report sample collection from Ryugu's surface by the Hayabusa2 spacecraft on 21 February 2019. Touchdown images and global observations of surface colors are used to investigate the stratigraphy of the surface around the sample location and across Ryugu. Latitudinal color variations suggest the reddening of exposed surface material by solar heating and/or space weathering. Immediately after touchdown, Hayabusa2's thrusters disturbed dark, fine grains that originate from the redder materials. The stratigraphic relationship between identified craters and the redder material indicates that surface reddening occurred over a short period of time. We suggest that Ryugu previously experienced an orbital excursion near the Sun.

An artificial impact on the asteroid (162173) Ryugu formed a crater in the gravity-dominated regime.

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.

The surface composition of asteroid 162173 Ryugu from Hayabusa2 near-infrared spectroscopy.

The near-Earth asteroid 162173 Ryugu, the target of the Hayabusa2 sample-return mission, is thought to be a primitive carbonaceous object. We report reflectance spectra of Ryugu's surface acquired with the Near-Infrared Spectrometer (NIRS3) on Hayabusa2, to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micrometers was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, which is consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.

The geomorphology, color, and thermal properties of Ryugu: Implications for parent-body processes.

The near-Earth carbonaceous asteroid 162173 Ryugu is thought to have been produced from a parent body that contained water ice and organic molecules. The Hayabusa2 spacecraft has obtained global multicolor images of Ryugu. Geomorphological features present include a circum-equatorial ridge, east-west dichotomy, high boulder abundances across the entire surface, and impact craters. Age estimates from the craters indicate a resurfacing age of [Formula: see text] years for the top 1-meter layer. Ryugu is among the darkest known bodies in the Solar System. The high abundance and spectral properties of boulders are consistent with moderately dehydrated materials, analogous to thermally metamorphosed meteorites found on Earth. The general uniformity in color across Ryugu's surface supports partial dehydration due to internal heating of the asteroid's parent body.

Risk stratification for congenital diaphragmatic hernia by factors within 24 h after birth.

OBJECTIVE: To establish a simple risk stratification system for patients with congenital diaphragmatic hernia (CDH) based on postnatal information within 24 h after birth. STUDY DESIGN: A multi-institutional retrospective cohort study was conducted including 348 neonates who had isolated CDH born between 2006 and 2010. Based on the two most powerful variables for 90-day survival selected by multivariate analyses, a risk stratification system was established. RESULTS: Multiple logistic regression analysis identified two adverse prognostic factors: an Apgar score at 1 min (Ap1) of 0-4 (odds ratio (OR) 3.3, P=0.004), and a best oxygenation index (OI) ⩾8.0 (OR 11.4, P<0.001). Based on a combinations of these two factors, patients were classified into three risk categories. The 90-day survival rates in categories 1-3 were 100, 88 and 52%, respectively (P<0.001). CONCLUSION: Our simple risk stratification system based on Ap1 and best OI was capable of predicting mortality well.

Mutant botrocetin-2 inhibits von Willebrand factor-induced platelet agglutination.

Essentials Botrocetin-2 (Bot2) binds to von Willebrand factor (VWF) and induces platelet agglutination. We identified Bot2 residues that are required for binding to VWF and glycoprotein (GP) Ib. We produced a mutant Bot2 that binds to VWF but inhibits platelet agglutination. Mutant Bot2 could be used as a potential anti-thrombotic reagent to block VWF-GPIb interaction. SUMMARY: Background Botrocetin-2 (Bot2) is a botrocetin-like protein composed of α and ß subunits that have been cloned from the snake Bothrops jararaca. Bot2 binds specifically to von Willebrand factor (VWF), and the complex induces glycoprotein (GP) Ib-dependent platelet agglutination. Objectives To exploit Bot2's VWF-binding capacity in order to attempt to create a mutant Bot2 that binds to VWF but inhibits platelet agglutination. Methods and Results Several point mutations were introduced into Bot2 cDNA, and the recombinant protein (recombinant Bot2 [rBot2]) was purified on an anti-botrocetin column. The mutant rBot2 with either Ala at Asp70 in the ß subunit (Aspß70Ala), or Argß115Ala and Lysß117Ala, showed reduced platelet agglutination-inducing activity. rBot2 with Aspß70Ala showed little binding activity towards immobilized VWF on an ELISA plate, whereas rBot2 with Argß115Ala/Lysß117Ala showed reduced binding activity towards GPIb (glycocalicin) after forming a complex with VWF. rBot2 point-mutated to oppositely charged Glu at both Argß115 and Lysß117 showed normal binding activity towards VWF but no platelet-agglutinating activity. Furthermore, this doubly mutated protein inhibited ristocetin-induced or high shear stress-induced platelet aggregation, and restrained thrombus formation under flow conditions. Conclusions Asp70 in the ß subunit of botrocetin is important for VWF binding, and Arg115 and Lys117 in the ß subunit are essential for interaction with GPIb. Doubly mutated rBot2, with Argß115Glu and Lysß117Glu, repels GPIb and might have potential as an antithrombotic reagent that specifically blocks VWF function. This is the first report on an artificial botrocetin that can inhibit the VWF-GPIb interaction.

The relationship between three signs of fetal magnetic resonance imaging and severity of congenital diaphragmatic hernia.

OBJECTIVE: To seek a simple approach for prenatally classifying congenital diaphragmatic hernia (CDH) severity using fetal magnetic resonance imaging (MRI) markers. STUDY DESIGN: A retrospective, multicenter study using questionnaires to investigate fetal MRI findings. We included fetuses prenatally diagnosed with isolated left-sided CDH and delivered after 36 weeks of gestation. We focused on three fetal MRI morphological signs: incomplete pulmonary baseline (IPB), liver up (LU) and retrocardiac stomach (RCS). We also evaluated the fetal MRI score defined as the total number of positive signs; the primary outcome was survival at discharge. RESULTS: In 256 patients (from 56 institutions), IPB, LU and RCS findings correlated with lower survival: odds ratio (95% confidence interval), 0.16 (0.08 to 0.33); 0.24 (0.12 to 0.51); and 0.14 (0.07 to 0.28); respectively. Patients with higher fetal MRI scores had a higher mortality rate. CONCLUSION: IPB, LU and RCS on fetal MRI are related to CDH severity.

Increase in disaster-related deaths: risks and social impacts of evacuation.

In Fukushima Prefecture, disaster-related death is a social problem for individuals who were forced to leave their hometowns as a result of the Great East Japan Earthquake and the accident at Fukushima Daiichi nuclear power plant. Disaster-related death is caused by stress, exhaustion, and worsening of pre-existing illnesses due to evacuation. The number of disaster-related deaths has reached almost 2000, and continues to rise. Prolonged uncertainty and deteriorating living conditions suggest no end to such deaths, although response measures have been taken to improve the situation. It is said that insufficient response measures were taken, in particular, during the transitional period between the emergency phase and the reconstruction phase. There is a need to apply the lessons learned in planning for evacuation after a nuclear hazard, considering radiological protection as well as risks associated with evacuation.

Multicenter observational study comparing sedation/analgesia protocols for laser photocoagulation treatment of retinopathy of prematurity.

OBJECTIVE: The aim of this study was to identify the best sedation/analgesia protocol for laser photocoagulation (PC) of retinopathy of prematurity (ROP). STUDY DESIGN: This multicenter observational study included five hospitals, each using a specific sedation/analgesia protocol: local anesthesia with oxybuprocaine hydrochloride (Group L); intravenous pentazocine (Group P); intravenous fentanyl (Group F); air, oxygen and sevoflurane (AOS) inhalation (Group I). The groups were compared for pain responses, vital signs and adverse events. RESULTS: Heart rates and systemic blood pressures were elevated by PC in Groups L and P and Groups L, P and F, respectively. Moreover, poor analgesic efficacy was recognized in Groups L, P and F. In contrast, Group I experienced hypothermia, enteral feeding intolerance and apnea more frequently. CONCLUSION: From the viewpoint of sedation/pain relief, AOS anesthesia should be the best protocol. However, considering all the various factors together, the most reasonable one can be varied based on the patient's condition and hospital.

Paradoxical downward seizure pattern on amplitude-integrated electroencephalogram.

The use of amplitude-integrated electroencephalography (aEEG) to assess brain function and detect seizures has been increasing worldwide. Results from previous studies have demonstrated that seizure patterns can be recognized as transient rises on aEEG traces. We report here a case of an infant with neonatal seizures that showed paradoxical transient drops on aEEG traces. The ictal EEG showed initial low-amplitude fast rhythmic activity followed by epileptic recruiting rhythms and high-voltage slow waves. Therefore, downward patterns on aEEG traces should be recognized as suspected seizure patterns.

Detection of pulsation in unruptured cerebral aneurysms by ECG-gated 3D-CT angiography (4D-CTA) with 320-row area detector CT (ADCT) and follow-up evaluation results: assessment based on heart rate at the time of scanning.

PURPOSE: Many epidemiological studies on unruptured cerebral aneurysms have reported that the larger the aneurysm, the higher the risk of rupture. However, many ruptured aneurysms are not large. Electrocardiography (ECG)-gated 3D-computed tomography angiography (4D-CTA) was used to detect pulsation in unruptured cerebral aneurysms. The differences in the clinical course of patients in whom pulsation was or was not detected were then evaluated. METHODS: Forty-two patients with 62 unruptured cystiform cerebral aneurysms who underwent 4D-CTA and follow-up 3D-CTA more than 120 days later were studied. The tube voltage, tube current, and rotation speed were 120 kV, 270 mA, and 0.35 s/rot., respectively. ECG-gated reconstruction was performed, with the cardiac cycle divided into 20 phases. Patients with heart rates higher than 80 bpm were excluded, so 37 patients with 56 aneurysms were analyzed. RESULTS: Pulsation was detected in 20 of the 56 unruptured aneurysms. Of these 20 aneurysms, 6 showed a change in shape at the time of follow-up. Of the 36 aneurysms in which pulsation was not detected, 2 showed a change in shape at follow-up. There was no significant difference in the follow-up interval between the two groups. The aneurysms in which pulsation was detected were significantly more likely to show a change in shape (P = 0.04), with a higher odds ratio of 7.286. CONCLUSION: Unruptured aneurysms in which pulsation was detected by 4D-CTA were more likely to show a change in shape at follow-up, suggesting that 4D-CTA may be useful for identifying aneurysms with a higher risk of rupture.

A smartphone-based medication self-management system with realtime medication monitoring.

BACKGROUND: Most patients cannot remember their entire medication regimen and occasionally forget to take their medication. OBJECTIVES: The objective of the study was to design, develop, and demonstrate the feasibility of a new type of medication self-management system using smartphones with real-time medication monitoring. METHODS: We designed and developed a smartphone-based medication self-management system (SMSS) based on interviews of 116 patients. The system offered patients two main functions by means of smartphones: (1) storage and provision of an accurate, portable medication history and medication-taking records of patients; and (2) provision of a reminder to take medication only when the patient has forgotten to take his/her medication. These functions were realized by two data input methods: (a) reading of prescription data represented in two-dimensional barcodes using the smartphone camera and getting the photographic images of the pills; and (b) real-time medication monitoring by novel user-friendly wireless pillboxes. RESULTS: Interviews suggested that a pocket-sized pillbox was demanded to support patient's medication-taking outside the home and pillboxes for home use should be adaptable to the different means of pillbox storage. In accordance with the result, we designed and developed SMSS. Ten patients participated in the feasibility study. In 17 out of 47 cases (36.2%), patients took their medication upon being presented with reminders by the system. Correct medication-taking occurrence was improved using this system. CONCLUSIONS: The SMSS is acceptable to patients and has the advantage of supporting ubiquitous medication self-management using a smartphone. We believe that the proposed system is feasible and provides an innovative solution to encourage medication self-management.

Three-dimensional visualization of composite fillings for dental identification using CT images.

OBJECTIVES: This study aimed to discriminate between enamel and composite resins by differences in Hounsfield units shown on 16 section multidetector CT (MDCT) images taken of unidentified bodies. METHODS: First, we determined the Hounsfield units of composite resins in 15 extracted human teeth. We then filled a single cavity prepared in each of the teeth with one of five different types of composite resins, and scanned the teeth using our routine post-mortem CT protocol for the head and neck. Obtained data were transferred to a radiological workstation and reconstructed. Furthermore, post-mortem CT images of the head of three unidentified bodies were reconstructed in the same manner. RESULTS: Four types of composite resins containing radio-opaque fillers showed a constant value of 4000 HU, and one radiolucent composite resin showed values in the range of 660-800 HU in the extracted teeth. Pixels at 4000 HU indicated that the composite resins were selected and visualized as three-dimensional colour images. Composite resins could be visualized on reconstructed images of the three unidentified bodies, and the sites visualized matched those noted on the forensic dental charts. CONCLUSIONS: Discriminating enamel and composite resins containing radio-opaque materials was difficult because of their similar Hounsfield unit values. However, we did succeed in visualizing the composite resins despite limitations of the CT scale. CT reconstructed images can contribute to dental identification, particularly in cases where it is difficult to detect composite resins on external investigation, and these images can be prepared during routine dental identification work.

Comparison of cerebral aneurysm volumes as determined by digitally measured 3D rotational angiography and approximation from three diameters.

This study compared digital measurement of aneurysm volume by 3D rotational angiography (3D-RA) with an approximation technique using three diameters of an aneurysm to re-interpret previously reported optimal packing densities (volume embolization ratio, VER) in coil embolization of intracranial aneurysms. Estimation of the volume of saccular aneurysms is important for calculation of the VER, which is in turn reported to be useful for prediction of coil compaction. The conventional formula for the volume estimation is V=4/3 π(A/2) (B/2) (C/2), where A, B, and C are the aneurysmal height, length, and width measured on 3D-RA image respectively. Using 3D rotational angiography data from 74 aneurysms, the approximated volume generated using the conventional formula was directly compared with the digitally measured volume. The digitally measured volume varied from 0.003 ml to 7.935 ml, and the dome-to-neck ratio (D/N) from 0.79 up to 4.62. We found that the conventional formula almost systematically underestimated the volume by up to 50 %, particularly when the neck was large relative to the dome (D/N<2). On average, digitally measured volume was 1.26~1.29 times larger than the approximated volume obtained using the conventional formula.Conventional 2D angiography based aneurysm volume calculation tends to underestimate an aneurysm volume, so the so-called VER (volume embolization ratio) could be overestimated.