Ultrafast time-resolved 2D imaging of laser-driven fast electron transport in solid density matter using an x-ray free electron laser

High-power, short-pulse laser-driven fast electrons can rapidly heat and ionize a high-density target before it hydrodynamically expands. The transport of such electrons within a solid target has been studied using two-dimensional (2D) imaging of electron-induced Kα radiation. However, it is currently limited to no or picosecond scale temporal resolutions. Here, we demonstrate femtosecond time-resolved 2D imaging of fast electron transport in a solid copper foil using the SACLA x-ray free electron laser (XFEL). An unfocused collimated x-ray beam produced transmission images with sub-micron and ∼10 fs resolutions. The XFEL beam, tuned to its photon energy slightly above the Cu K-edge, enabled 2D imaging of transmission changes induced by electron isochoric heating. Time-resolved measurements obtained by varying the time delay between the x-ray probe and the optical laser show that the signature of the electron-heated region expands at ∼25% of the speed of light in a picosecond duration. Time-integrated Cu Kα images support the electron energy and propagation distance observed with the transmission imaging. The x-ray near-edge transmission imaging with a tunable XFEL beam could be broadly applicable for imaging isochorically heated targets by laser-driven relativistic electrons, energetic protons, or an intense x-ray beam.

Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide-bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu's parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate that Ryugu's parent body formed ~2 million years after the beginning of Solar System formation.

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.

POS0969 UNVEILING AXIAL INVOLVEMENT IN PSORIATIC ARTHRITIS: AN ANCILLARY ANALYSIS OF THE ASAS-perSpA STUDY

Background:

Heterogeneity in psoriatic arthritis (PsA) is a current matter of discussion, especially concerning axial involvement.

Objectives:

To determine the profile of axial PsA (axPsA) in a worldwide setting. Secondly, to identify predictive factors associated with the development of axial involvement in patients with PsA.

Methods:

Data from 3684 patients with axial spondyloarthritis (axSpA) or PsA from the ASAS-PerSpA study were analysed. The ASAS-PerSpA is an observational, cross-sectional study that recruited consecutive patients with SpA from 68 centers worldwide. For this analysis, 367 PsA patients ever presenting axial involvement according to their rheumatologist were defined as axPsA and compared with 2651 axSpA patients, using logistic regression to later identify predictive factors for rheumatologist diagnosis of axPsA. In addition, the axPsA patients were also compared with 666 PsA patients without axial involvement (pPsA) and the characteristics associated with axial manifestations were determined by logistic regression analysis.

Results:

Among all patients, 2651 were identified as axSpA and 1033 patients as PsA. Among those with axial involvement, 2651 were identified as axSpA (100% of axSpA) and 367 as axPsA (35.5 % of PsA). In comparison with axSpA, axPsA patients were less frequently males, older, less frequently HLA-B27 positive and had a higher body mass index (Table 1). Additionally, while patients with axPsA had more peripheral manifestations and psoriasis, concomitant IBD and uveitis were higher in axSpA. In the multivariable analysis, older age at diagnosis (OR= 1.04), peripheral arthritis (OR= 7.32) and dactylitis (OR= 2.82) were significantly associated with a diagnosis of axPsA. However, uveitis (OR= 0.22), IBD (OR= 0.12) or HLA*B27 carriership (OR= 0.26) were inversely associated with axPsA diagnosis as compared to axSpA. Furthermore, axial involvement in patients with PsA was significantly associated with male gender (OR= 1.68), elevated CRP (OR= 2.87), and the absence of psoriasis (OR= 0.33).

Conclusion:

In this worldwide setting, axPsA was defined by rheumatologists as a unique phenotype, with disease features lying between axSpA and pure pPsA. Male gender, elevated CRP and the absence of psoriasis were associated with axial involvement in patients with PsA.

Table 1.

Demographic and disease characteristics of patients with axial involvement included in the ASAS PerSpA study. Results shown as absolute numbers (percentages) or as the mean ± standard deviation

axSpAn= 2651axPsAn= 367p-valueSex (male)1816 (68.5) 196 (53.4)<0.001Age at study visit42.1(13.0)50.0 (12.7)<0.001Body Mass Index25.9 (5.1)27.4 (5.7)<0.001Family history of SpA944 (35.6)135 (36.8)0.684Past history or current symptoms of back pain2625 (99.0)358 (97.5)0.04Inflammatory back pain (ASAS definition), n/N(%)2500/2632 (94.9)317/362 (87.6)<0.001Sacroiliitis on imaging, n/N (%) by: xRay mNY criteria1997/2586 (77.2)185/298 (62.1)<0.001 MRI-SIJ, ASAS definition1449/1757 (82.4)141/225 (62.6)<0.001 mNY criteria or ASAS definition2446/2634 (92.9)243/339 (71.7)<0.001HLA B27 positive1674 /2126 (78.7)54/182 (29.6)<0.001Elevated CRP (>5 mg/dL)1863/2569 (72.5)274/356 (76.9)0.2Classification criteria ASAS criteria2339 (88.2)185 (50.4)<0.001 CASPAR criteria123 (4.6)274 (74.4)<0.001Peripheral Arthritis946 (35.7)318 (86.6)<0.001Enthesitis1086 (41.0)198 (54.0)<0.001Dactylitis155 (5.8)125 (34.1)<0.001Psoriasis185 (7.0)324 (88.3)<0.001IBD129 (4.9)3 (0.8)<0.001Uveitis576(21.7)13 (3.5)<0.001csDMARD (ever)1359 (51.3)339 (92.4)<0.001bDMARD (ever)1585 (59.8)263 (71.7)<0.001Specific drug for axial involvementNSAIDs2465 (98.6)317 (96.1)0.002csDMARD828 (33.1)187 (56.7)<0.001bDMARD1288 (51.5)180 (54.4)0.32

axSpA: axial spondyloarthritis; axPsA: axial psoriatic arthritis; IBD: Inflammatory Bowel Disease; CRP: C-Reactive Protein; mNY: modified New York; csDMARDs: conventional synthetic DMARDs; bDMARDs: biological DMARDs; NSAID: Non-steroidal anti-inflammatory drugs

Disclosure of Interests:

Diego Benavent: None declared, Chamaida Plasencia: None declared, Denis Poddubnyy: None declared, Mitsumasa Kishimoto Consultant of: AbbVie, Amgen-Astellas BioPharma, Asahi-Kasei Pharma, Astellas, Ayumi Pharma, BMS, Chugai, Daiichi-Sankyo, Eisai, Eli Lilly, Gilead, Janssen, Kyowa Kirin, Novartis, Ono Pharma, Pfizer, Tanabe-Mitsubishi, Teijin Pharma, and UCB Pharma., Fabian Proft Grant/research support from: AbbVie, AMGEN, BMS, Celgene, MSD, Novartis, Pfizer, Roche, UCB, Haruki Sawada: None declared, Clementina López-Medina: None declared, Maxime Dougados: None declared, Victoria Navarro-Compán: None declared.

Unveiling axial involvement in psoriatic arthritis: An ancillary analysis of the ASAS-perSpA study

OBJECTIVE

To determine the clinical profile of axial psoriatic arthritis (PsA) in a worldwide setting. Secondly, to identify factors associated with the development of axial involvement in patients with PsA.

METHODS

Data from 3684 patients with axial spondyloarthritis (axSpA) or PsA from the ASAS-perSpA study were analysed. The ASAS-perSpA is a cross-sectional study that recruited consecutive patients with SpA (as diagnosed by their rheumatologist) from 68 centers worldwide and collected patient and disease data. First, 2651 axSpA patients and 367 PsA patients with any history of axial involvement (axPsA) were compared using logistic regression to later identify predictive factors for rheumatologist diagnosis of axPsA. Secondly, 367 axPsA patients were compared with 666 PsA patients lacking axial involvement (peripheral PsA [pPsA]) and the characteristics associated with axial manifestations were explored by logistic regression analysis.

RESULTS

Patients with axPsA were older and less frequently males or HLA*B27 positive in comparison with axSpA patients. Additionally, while patients with axPsA had more peripheral manifestations and psoriasis, other extra-musculoskeletal manifestations (IBD and uveitis) were more frequent in those with axSpA. In the multivariable analysis, older age at diagnosis (OR = 1.04), peripheral arthritis (OR = 7.32) and dactylitis (OR = 2.82) were significantly associated with the diagnosis of axPsA. However, uveitis (OR = 0.22), IBD (OR = 0.12), HLA*B27 carriership (OR = 0.26) or sacroiliitis on imaging (OR = 0.5) were inversely associated with axPsA diagnosis as compared to axSpA. Axial involvement in patients with PsA was significantly associated with male gender (OR = 1.68), elevated CRP (OR = 2.87) and the absence of psoriasis (OR = 0.33).

CONCLUSION

In this worldwide setting axPsA was defined by rheumatologists as a unique phenotype, with disease features lying between axSpA and pure pPsA.

2D monochromatic x-ray imaging for beam monitoring of an x-ray free electron laser and a high-power femtosecond laser

In pump-probe experiments with an X-ray Free Electron Laser (XFEL) and a high-power optical laser, spatial overlap of the two beams must be ensured to probe a pumped area with the x-ray beam. A beam monitoring diagnostic is particularly important in short-pulse laser experiments where a tightly focused beam is required to achieve a relativistic laser intensity for generation of energetic particles. Here, we report the demonstration of on-shot beam pointing measurements of an XFEL and a terawatt class femtosecond laser using 2D monochromatic Kα imaging at the Matter in Extreme Conditions end-station of the Linac Coherent Light Source. A thin solid titanium foil was irradiated by a 25-TW laser for fast electron isochoric heating, while a 7.0 keV XFEL beam was used to probe the laser-heated region. Using a spherical crystal imager (SCI), the beam overlap was examined by measuring 4.51 keV Kα x rays produced by laser-accelerated fast electrons and the x-ray beam. Measurements were made for XFEL-only at various focus lens positions, laser-only, and two-beam shots. Successful beam overlapping was observed on ∼58% of all two-beam shots for 10 μm thick samples. It is found that large spatial offsets of laser-induced Kα spots are attributed to imprecise target positioning rather than shot-to-shot laser pointing variations. By applying the Kα measurements to x-ray Thomson scattering measurements, we found an optimum x-ray beam spot size that maximizes scattering signals. Monochromatic x-ray imaging with the SCI could be used as an on-shot beam pointing monitor for XFEL-laser or multiple short-pulse laser experiments.

Differential impact of target vessel on the diagnostic performance of resting full-cycle ratio as non-hyperemic physiological assessment

Background

Recently, wire-based resting indices have been recognized as gold standard for evaluating physiological lesion assessment. The resting full-cycle ratio (RFR) is a unique resting index which is calculated as the point of absolutely lowest distal pressure to aortic pressure during entire cardiac cycle. It is unclear whether the diagnostic performance of RFR for detecting functional coronary artery stenosis is similar in each coronary artery. The aim of this study is to compare the diagnostic performance of RFR based on target coronary vessel.

Method

This study was a prospectively enrolled observational study. A total of 156 consecutive patients with 220 intermediate lesions were enrolled in this study. The RFR was measured after adequately waiting for stable condition, while FFR was measured after intravenous administration of ATP (180mcg/kg/min). Lesions with FFR ≤0.80 were considered functionally significant coronary artery stenosis.

Results

In all lesions, reference diameter, diameter stenosis, lesion length, RFR, and FFR were 3.0±0.7mm, 45±13%, 13.0±8.8mm, 0.90±0.09, and 0.82±0.10, respectively. Functional significance was observed in 88 lesions (40%) of all lesions. RFR showed a significant correlation with FFR in overall lesions (r=0.774, p&lt;0.001). The ROC curve analysis of RFR showed good accuracy for predicting functional significance (AUC 0.87, diagnostic accuracy 81%) in all subjects. Regarding each target vessel, there were similar and significant positive correlation between RFR and FFR (LAD; r=0.733, p&lt;0.001, LCX; r=0.771, p&lt;0.001, RCA; r=0.769, p&lt;0.001, respectively). The prevalence of discordant between RFR and FFR was significantly different among 3 vessels (LAD 26%, LCX 12%, RCA 13%, respectively, p&lt;0.05 for among 3 groups). Regarding the comparison of ROC curves according to lesion location, AUC was significantly lower in LAD than in LCX and RCA (LAD 0.780, LCX 0.947, RCA 0.926, p&lt;0.01 for LAD compared to LCX, p&lt;0.01 for LAD compared to RCA, respectively). Furthermore, the diagnostic accuracy was significantly different according to target vessel (LAD 74%, LCX 88%, RCA 87%, respectively, p&lt;0.05 for among 3 vessels).

Conclusion

RFR demonstrated better diagnostic accuracy for evaluating functional lesion severity. The diagnostic performance of RFR was different based on target vessel. RFR is a unique and useful resting index, and it may detect functionally significant coronary stenosis that cannot be detected with other resting indices in daily practice.

Funding Acknowledgement

Type of funding source: None

Discordance predictor between fractional flow reserve and resting full-cycle ratio in clinical characteristics

Introduction

Fractional flow reserve (FFR) is a gold standard method to evaluate functional lesion severity in daily clinical practice. Recently, the resting full-cycle ratio (RFR) which was newly developed resting indices was launched. Unlike other resting indices evaluated in diastolic phase, RFR is evaluated during entire cardiac phase. Previous studies showed discordance predictors between FFR and instantaneous wave-free ratio. However, it is previously unreported what predictor cause discordant outcome between FFR and RFR.

Purpose

The purpose of this study was to evaluate clinical predictors of discordance between FFR and RFR.

Methods

A total of 156 patients with 220 lesions were prospectively enrolled in this study. RFR was evaluated before inducing hyperemia. FFR was measured after intravenous adenosine triphosphate administration (180 mcg/kg/min). According to FFR and RFR values, the patients and lesions were classified into 4 groups: Concordant negative (Group-1 [n=114]: FFR &gt;0.80, RFR &gt;0.89); negative FFR and positive RFR (Group-2 [n=18]: FFR &gt;0.80, RFR ≤0.89); positive FFR and negative RFR (Group-3 [n=25]: FFR ≤0.80, RFR &gt;0.89); Concordant positive (Group-4 [n=63]: FFR ≤0.80, RFR ≤0.89). Among them, discordance predictors with clinical characteristics between RFR and FFR were compared using by two separate logistic regression analyses. (Group-1 vs. Group-2, Group-3 vs. Group-4, respectively). Age, sex and those predictors with a p value ≤0.10 were included in a multivariate regression analysis using by forward stepwise selection to identify independent predictors of discordance.

Results

On multiple regression analysis, hemodialysis (HD) (OR:6.072 [1.090–33.836]), peripheral artery disease (PAD) (OR:9.053 [1.776–46.162]) and left anterior descending artery (LAD) (OR:9.264 [2.092–41.031]) were significantly associated with positive RFR among negative FFR groups (Groupe 2 discordance). Conversely, diabetes mellitus (DM) (OR:0.212 [0.062–0.721]) and Hb (OR:1.480 [1.102–1.987]) were significantly associated with negative RFR among positive FFR groups (Groupe 3 discordance)

Conclusions

Since the clinical characteristics with HD, PAD, LAD, DM and Hb may influence concordant with FFR during RFR evaluation, it should be considered when interpreting RFR.

Distribution and independent predictors

Funding Acknowledgement

Type of funding source: None

Diagnostic feasibility of resting full-cycle ratio between systole and diastole to assess functional lesion severity of intermediate coronary artery stenosis

Background

Recently, non-hyperemic physiologic indices have become widespread for evaluating physiological lesion assessment. The resting full-cycle ratio (RFR) is a unique non-hyperemic index which is calculated as the point of absolutely lowest distal pressure to aortic pressure during entire cardiac cycle. It is unclear whether RFR may detect functionally significant coronary stenosis that cannot be detected with other resting indices due to differences in the cardiac cycle. The aim of this study is to compare the diagnostic performance of RFR based on cardiac cycle.

Method

This study was a prospectively enrolled observational study. A total of 156 consecutive patients with 220 intermediate lesions were enrolled in this study. The RFR was measured after adequately waiting for stable condition, while FFR was measured after intravenous administration of ATP (180mcg/kg/min). Lesions with FFR ≤0.80 were considered functionally significant coronary artery stenosis.

Results

In all lesions, reference diameter, diameter stenosis, lesion length, RFR, and FFR were 3.0±0.7mm, 45±13%, 13.0±8.8mm, 0.90±0.09, and 0.82±0.10, respectively. Functional significance was observed in 88 lesions (40%) of all lesions. RFR systole was observed in 24 lesions (10.9%). Regarding to the coronary lesions, RFR systole was more frequent in non-LAD (LAD; 4.2%, left circumflex artery (LCX); 9.8%, and right coronary artery (RCA); 30.4%, respectively, p&lt;0.018). RFR showed a significant correlation with FFR in both systole and diastole (R = 0.918, p&lt;0.001, R = 0.733, p&lt;0.001, respectively). The ROC curve analysis showed similar agreement in both systole and diastole (AUC: 0.881, p&lt;0.001, AUC: 0.864, p&lt;0.001, respectively). RFR provided a good diagnostic accuracy and no difference in both systole and diastole (79.6% and 87.5%, respectively, p=0.58).

Conclusion

RFR is feasible and reliable non-hyperemic index regardless of the difference of cardiac cycle to evaluate physiological lesion severity in daily practice.

Funding Acknowledgement

Type of funding source: None

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.

P5628Resolution of incomplete stent apposition in the early phase after stent implantation: serial optical coherence tomography analyses at 2-week and 4-month

Background

Previous optical coherence tomography (OCT) study demonstrated that the incomplete stent apposition (ISA) distance <355 μm immediately after an index procedure was the corresponding cut-off point for predicting the resolution of ISA at 8–12 months follow-up in the second-generation DES. However, the natural course of acute ISA in the earlier phase remains unknown. The aim of the present study is to evaluate the natural course of acute ISA in the early phase after second-generation everolimus-eluting stent (EES) using serial OCT analyses at 2-week and 4-month.

Methods

From the population of the ACS-OCT trial, we identified a total of 45 patients who successfully underwent serial OCT examinations at post-stenting, 2-week follow-up, and 4-month follow-up. The presence of ISA was assessed in the OCT images, and ISA distance was measured within the stented segment. The target site for OCT analysis was the cross-section at the proximal edge of implanted stent. Serial OCT images at post-stenting, 2-week follow-up and 4-month follow-up were reviewed side by side on the screen, and maximum ISA distance and cross-sectional ISA area were measured.

Results

Incomplete stent apposition was observed in all EES at post-stenting, and it was persistent in 37.8% at 2-week follow-up and 11.1% at 4-month follow-up. Maximum ISA distance was significantly decreased over time (post-stenting, 144±150mm; 2-week follow-up, 88±146mm; 4-month follow-up, 34±111mm). Receiver-operating curve analysis identified that the best cut-off value of OCT-estimated ISA distance at post-stenting for predicting persistent ISA at 2-week follow-up and 4-month follow-up was >140μm and >215μm, respectively.

ROC curve analysis

Conclusion

ISA distance at post-stenting is an useful predictor for the resolution of ISA in the early phase after EES implantation.

P5633Diagnostic impact of resting full-cycle ratio as newly developed non-hyperemic indices for physiological lesion assessment

Background

Although fractional flow reserve (FFR) is a gold standard method to evaluate functional lesion severity in the catheterization laboratory, the need of hyperemic condition limits the widespread adoption of FFR. Recently, the resting full-cycle ratio (RFR) which was newly developed resting indices was launched. It is unclear whether RFR as resting condition could assess physiological lesion severity of coronary artery stenosis. The aim of this study was to evaluate the diagnostic impact of RFR compared to FFR in entire range of coronary artery stenosis.

Method

A total of 53 patients with 70 lesions were enrolled in this study. The RFR was measured after adequately waiting for stable condition, while FFR was measured after intravenous administration of ATP (180mcg/kg/min). Lesions with FFR ≤0.80 were considered functionally significant coronary artery stenosis.

Results

In all lesions, reference diameter, diameter stenosis, lesion length, RFR, and FFR were 3.3±0.8mm, 44±12%, 14.6±7.2mm, 0.90±0.11, and 0.83±0.11, respectively. Functional significance was observed in 24 lesions (34%) of all lesions. The RFR showed a significant correlation with FFR (y = 0.800x + 0.239, R = 0.817, p<0.001). The Bland-Altman plot demonstrated a good agreement with a mean difference of 0.07 and a standard deviation of 0.06 between RFR and FFR across entire range of coronary artery stenosis. ROC curve analysis showed an excellent accuracy of RFR cut-off of ≤0.90 in predicting FFR ≤0.80 which had 78% sensitivity and 87% specificity (AUC 0.87, diagnostic accuracy 84%).

Conclusion

The RFR as newly resting indices is reliable to the assessment of functional lesion severity. This physiology-based approach may be a possible alternative method for FFR measurements in daily practice.

The response function of Fujifilm BAS-TR imaging plates to laser-accelerated titanium ions

Calibrated diagnostics for energetic particle detection allow for the systematic study of charged particle sources. The Fujifilm BAS-TR imaging plate (IP) is a reusable phosphorescent detector for radiation applications such as x-ray and particle beam detection. The BAS-TR IP has been absolutely calibrated to many low-Z (low proton number) ions, and extending these calibrations to the mid-Z regime is beneficial for the study of laser-driven ion sources. The Texas Petawatt Laser was used to generate energetic ions from a 100 nm titanium foil, and charge states Ti¹⁰⁺ through Ti¹²⁺, ranging from 6 to 27 MeV, were analyzed for calibration. A plastic detector of CR-39 with evenly placed slots was mounted in front of the IP to count the number of ions that correspond with the IP levels of photo-stimulated luminescence (PSL). A response curve was fitted to the data, yielding a model of the PSL signal vs ion energy. Comparisons to other published response curves are also presented, illustrating the trend of PSL/nucleon decreasing with increasing ion mass.

Monochromatic 2D Kα Emission Images Revealing Short-Pulse Laser Isochoric Heating Mechanism

The rapid heating of a thin titanium foil by a high intensity, subpicosecond laser is studied by using a 2D narrow-band x-ray imaging and x-ray spectroscopy. A novel monochromatic imaging diagnostic tuned to 4.51 keV Ti Kα was used to successfully visualize a significantly ionized area (⟨Z⟩>17±1) of the solid density plasma to be within a ∼35  μm diameter spot in the transverse direction and 2  μm in depth. The measurements and a 2D collisional particle-in-cell simulation reveal that, in the fast isochoric heating of solid foil by an intense laser light, such a high ionization state in solid titanium is achieved by thermal diffusion from the hot preplasma in a few picoseconds after the pulse ends. The shift of Kα and formation of a missing Kα cannot be explained with the present atomic physics model. The measured Kα image is reproduced only when a phenomenological model for the Kα shift with a threshold ionization of ⟨Z⟩=17 is included. This work reveals how the ionization state and electron temperature of the isochorically heated nonequilibrium plasma are independently increased.

Hayabusa2 arrives at the carbonaceous asteroid 162173 Ryugu-A spinning top-shaped rubble pile

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.

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.

Imaging the atomic structure and local chemistry of platelets in natural type Ia diamond

In the past decades, many efforts have been devoted to characterizing {001} platelet defects in type Ia diamond. It is known that N is concentrated at the defect core. However, an accurate description of the atomic structure of the defect and the role that N plays in it is still unknown. Here, by using aberration-corrected transmission electron microscopy and electron energy-loss spectroscopy we have determined the atomic arrangement within platelet defects in a natural type Ia diamond and matched it to a prevalent theoretical model. The platelet has an anisotropic atomic structure with a zigzag ordering of defect pairs along the defect line. The electron energy-loss near-edge fine structure of both carbon K- and nitrogen K-edges obtained from the platelet core is consistent with a trigonal bonding arrangement at interstitial sites. The experimental observations support an interstitial aggregate mode of formation for platelet defects in natural diamond.

An optical configuration for fastidious STEM detector calibration and the effect of the objective-lens pre-field

In the scanning transmission electron microscope, an accurate knowledge of detector collection angles is paramount in order to quantify signals on an absolute scale. Here we present an optical configuration designed for the accurate measurement of collection angles for both image-detectors and energy-loss spectrometers. By deflecting a parallel electron beam, carefully calibrated using a diffraction pattern from a known material, we can directly observe the projection-distortion in the post-specimen lenses of probe-corrected instruments, the 3-fold caustic when an image-corrector is fitted, and any misalignment of imaging detectors or spectrometer apertures. We also discuss for the first time, the effect that higher-order aberrations in the objective-lens pre-field has on such an angle-based detector mapping procedure.

Two-color monochromatic x-ray imaging with a single short-pulse laser

Simultaneous monochromatic crystal imaging at 4.5 and 8.0 keV with x-rays produced by a single short-pulse laser is presented. A layered target consisting of thin foils of titanium and copper glued together is irradiated by the 50 TW Leopard short-pulse laser housed at the Nevada Terawatt Facility. Laser-accelerated MeV fast electrons transmitting through the target induce Kα fluorescence from both foils. Two energy-selective curved crystals in the imaging diagnostic form separate monochromatic images on a single imaging detector. The experiment demonstrates simultaneous two-color monochromatic imaging of the foils on a single detector as well as Kα x-ray production at two different photon energies with a single laser beam. Application of the diagnostic technique to x-ray radiography of a high density plasma is also presented.

Collimated Propagation of Fast Electron Beams Accelerated by High-Contrast Laser Pulses in Highly Resistive Shocked Carbon

Collimated transport of ultrahigh intensity electron current was observed in cold and in laser-shocked vitreous carbon, in agreement with simulation predictions. The fast electron beams were created by coupling high-intensity and high-contrast laser pulses onto copper-coated cones drilled into the carbon samples. The guiding mechanism-observed only for times before the shock breakout at the inner cone tip-is due to self-generated resistive magnetic fields of ∼0.5-1  kT arising from the intense currents of fast electrons in vitreous carbon, by virtue of its specific high resistivity over the range of explored background temperatures. The spatial distribution of the electron beams, injected through the samples at different stages of compression, was characterized by side-on imaging of hard x-ray fluorescence.

Calibration and characterization of a highly efficient spectrometer in von Hamos geometry for 7-10 keV x-rays

We have built an absolutely calibrated, highly efficient, Bragg crystal spectrometer in von Hamos geometry. This zinc von Hamos spectrometer uses a crystal made from highly oriented pyrolytic graphite that is cylindrically bent along the non-dispersive axis. It is tuned to measure x-ray spectra in the 7-10 keV range and has been designed to be used on a Ten Inch Manipulator for the Omega and OmegaEP target chambers at the Laboratory for Laser Energetics in Rochester, USA. Significant shielding strategies and fluorescence mitigation have been implemented in addition to an imaging plate detector making it well suited for experiments in high-intensity environments. Here we present the design and absolute calibration as well as mosaicity and integrated reflectivity measurements.

Lipopolysaccharide-induced vacuoles in macrophages: Their origin is plasma membrane-derived organelles and endoplasmic reticulum, but not lysosomes

Lipopolysaccharide (LPS) is one of the potent activators of macrophages. LPS was shown to induce cell spreading and large vacuoles in the cytoplasm of a macrophage-like cell line, JY3. These vacuoles were negative for acid phosphatase histochemistry and did not take up Lucifer yellow added to the medium. Latex beads were incorporated into cytoplasmic vesicles distinct from the vacuoles. These results indicated that the vacuoles are neither phagosomes nor lysosomes.

DiIC18(3), a specific marker of endoplasmic reticulum (ER), stained the vacuoles intensely, and DiOC6(3) stained the vacuoles at a density similar to nuclear envelope, suggesting ER origin of their membrane. Glucose-6-phosphatase, however, was not detected histochemically.

Vacuoles were also stained with wheat germ agglutinin-horseradish peroxidase (WGA-HRP) or WGA-biotin, suggesting that the vacuoles originated from plasma membrane-endosome-trans Golgi network-secretory granule pathway. Golgi markers, TPPase or BODIPY-ceramide were not localized to the vacuolar membrane.

These results indicate that the vacuoles may have dual origins; ER and plasma membrane-derived organelles.

High-contrast laser acceleration of relativistic electrons in solid cone-wire targets

The consequences of small scale-length precursor plasmas on high-intensity laser-driven relativistic electrons are studied via experiments and simulations. Longer scale-length plasmas are shown to dramatically increase the efficiency of electron acceleration, yet, if too long, they reduce the coupling of these electrons into the solid target. Evidence for the existence of an optimal plasma scale-length is presented and estimated to be from 1 to 5μm. Experiments on the Trident laser (I=5×10(19)W/cm(2)) diagnosed via Kα emission from Cu wires attached to Au cones are quantitively reproduced using 2D particle-in-cell simulations that capture the full temporal and spatial scale of the nonlinear laser interaction and electron transport. The simulations indicate that 32%±8%(6.5%±2%) of the laser energy is coupled into electrons of all energies (1-3 MeV) reaching the inner cone tip and that, with an optimized scale-length, this could increase to 35% (9%).

Inhibition of Rho-associated kinases disturbs the collective cell migration of stratified TE-10 cells

Background

The collective cell migration of stratified epithelial cells is considered to be an important phenomenon in wound healing, development, and cancer invasion; however, little is known about the mechanisms involved. Furthermore, whereas Rho family proteins, including RhoA, play important roles in cell migration, the exact role of Rho-associated coiled coil-containing protein kinases (ROCKs) in cell migration is controversial and might be cell-type dependent. Here, we report the development of a novel modified scratch assay that was used to observe the collective cell migration of stratified TE-10 cells derived from a human esophageal cancer specimen.

Results

Desmosomes were found between the TE-10 cells and microvilli of the surface of the cell sheet. The leading edge of cells in the cell sheet formed a simple layer and moved forward regularly; these rows were followed by the stratified epithelium. ROCK inhibitors and ROCK small interfering RNAs (siRNAs) disturbed not only the collective migration of the leading edge of this cell sheet, but also the stratified layer in the rear. In contrast, RhoA siRNA treatment resulted in more rapid migration of the leading rows and disturbed movement of the stratified portion.

Conclusions

The data presented in this study suggest that ROCKs play an important role in mediating the collective migration of TE-10 cell sheets. In addition, differences between the effects of siRNAs targeting either RhoA or ROCKs suggested that distinct mechanisms regulate the collective cell migration in the simple epithelium of the wound edge versus the stratified layer of the epithelium.

Electronic supplementary material

The online version of this article (doi:10.1186/s40659-015-0039-2) contains supplementary material, which is available to authorized users.

Atomic-Resolution STEM Imaging of Graphene at Low Voltage of 30 kV with Resolution Enhancement by Using Large Convergence Angle

Atomic resolution at a low accelerating voltage with aberration correction is required to reduce the electron irradiation damage in scanning transmission electron microscopy imaging. However, the reduction in resolution caused by the diffraction limit becomes severe with increasing electron wavelength at low accelerating voltages. The developed aberration corrector can compensate for higher-order aberration in scanning transmission electron microscopy to expand the uniform phase angle. The resolution for imaging graphene at 30 kV is evaluated by changing the convergence angle for a probe-forming system with a higher-order aberration corrector. A single-carbon atom on graphene is successfully imaged at atomic resolution with a cold-field emission gun by dark-field imaging at an accelerating voltage of 30 kV.

Enhanced relativistic-electron-beam energy loss in warm dense aluminum

Energy loss in the transport of a beam of relativistic electrons in warm dense aluminum is measured in the regime of ultrahigh electron beam current density over 2×10^{11}  A/cm^{2} (time averaged). The samples are heated by shock compression. Comparing to undriven cold solid targets, the roles of the different initial resistivity and of the transient resistivity (upon target heating during electron transport) are directly observable in the experimental data, and are reproduced by a comprehensive set of simulations describing the hydrodynamics of the shock compression and electron beam generation and transport. We measured a 19% increase in electron resistive energy loss in warm dense compared to cold solid samples of identical areal mass.

Effects of lactic acid bacteria on low-density lipoprotein susceptibility to oxidation and aortic fatty lesion formation in hyperlipidemic hamsters

We investigated the effects of Streptococcus thermophilus YIT 2001, a strain of lactic acid bacteria, on the susceptibility of low-density lipoprotein (LDL) to oxidation and the formation of aortic fatty lesions in hyperlipidemic hamsters. S. thermophilus YIT 2001 had the highest in vitro antioxidative activity against LDL oxidation among the 79 strains of lactic acid bacteria and bifidobacteria tested, which was about twice that of S. thermophilus YIT 2084. The lag time of LDL oxidation in the YIT 2001 feeding group was significantly longer than in controls, but was unchanged in the YIT 2084 group. After the feeding of YIT 2001, lag times were prolonged and areas of aortic fatty lesions were dose-dependently attenuated, although there were no effects on plasma lipid levels. These results suggest that YIT 2001 has the potential to prevent the formation of aortic fatty lesions by inhibiting LDL oxidation.

Investigation of fast-electron-induced Kα x rays in laser-produced blow-off plasma

Refluxing of fast electrons generated by high-intensity, short-pulse lasers was investigated by measuring electron-induced Kα x rays from a buried tracer layer. Using planar foils of Au/Cu/CH, the 150-J, 0.7-ps TITAN short-pulse laser was focused on the gold foil to generate fast electrons and the 3-ns, 300-J long pulse beam irradiated on the CH side to create expanding plasma as a conducting medium. By delaying the short-pulse beam timing from the long pulse laser irradiation, the plasma size was varied to change electron refluxing in the target rear. The total yields and two-dimensional images of 8.05-keV Cu-Kα x ray were recorded with an x-ray spectrometer and two monochromatic crystal imagers. The measurements show that the integrated yields decrease by a factor of 10 from refluxing to the nonrefluxing limit. Similar radial profiles of the Kα images in the rear were observed at all delays. Hybrid-particle-in-cell simulations using plasma profiles calculated by a radiation-hydrodynamic code HYDRA agree well with the measured Kα yields. The simulations suggest that conducting plasma with the size of ∼300 μm in the laser direction and ∼600 μm in the lateral direction at the density of 2 × 1020 1/cm3 is sufficiently large to prevent electrons from refluxing in the target. The parameters found in this study can be useful in designing experiments utilizing a Kα x-ray source in refluxing regime or a tracer layer in nonrefluxing regime.

Human parvovirus B19 infection mimicking systemic lupus erythematosus

Abstract Although several recent reports have discussed the similarities between human parvovirus B19 (HPV-B19) infection and systemic lupus erythematosus (SLE), the relationship between these conditions has not been established owing to the small number of patients investigated. In 1998-1999, an outbreak of Erythema infectiosum occurred close to our hospital, enabling us to investigate the clinical, hematological, and serological findings, including serum complement and antinuclear antibodies (ANA), in 22 patients with acute HPV-B19 infection. The principal symptoms included rash (86.3%), edema (59%), arthralgia (45.4%) and fever (31.8%). Lymphadenopathy was seen in three of the 22 cases. The laboratory findings showed high incidences of leukopenia (50%), hypocomplementemia (95%), and ANA (64.7%). At the time of disease onset, patients with acute HPV-B19 infection presented with features which were similar to those of SLE. The possibility of HPV-B19 infection should therefore be considered in patients presenting with SLE-like features.