Spectral-brightness optimization of an X-ray free-electron laser by machine-learning-based tuning.

A machine-learning-based beam optimizer has been implemented to maximize the spectral brightness of the X-ray free-electron laser (XFEL) pulses of SACLA. A new high-resolution single-shot inline spectrometer capable of resolving features of the order of a few electronvolts was employed to measure and evaluate XFEL pulse spectra. Compared with a simple pulse-energy-based optimization, the spectral width was narrowed by half and the spectral brightness was improved by a factor of 1.7. The optimizer significantly contributes to efficient machine tuning and improvement of XFEL performance at SACLA.

Single-shot spectrometer using diamond microcrystals for X-ray free-electron laser pulses.

A simple spectrometer using diffraction from diamond microcrystals has been developed to diagnose single-shot spectra of X-ray free-electron laser (XFEL) pulses. The large grain size and uniform lattice constant of the adopted crystals enable characterizing the XFEL spectrum at a resolution of a few eV from the peak shape of the powder diffraction profile. This single-shot spectrometer has been installed at beamline 3 of SACLA and is used for daily machine tuning.

Delayed Onset and Directionality of X-Ray-Induced Atomic Displacements Observed on Subatomic Length Scales.

Transient structural changes of Al_{2}O_{3} on subatomic length scales following irradiation with an intense x-ray laser pulse (photon energy: 8.70 keV; pulse duration: 6 fs; fluence: 8×10^{2} J/cm^{2}) have been investigated by using an x-ray pump x-ray probe technique. The measurement reveals that aluminum and oxygen atoms remain in their original positions by ∼20 fs after the intensity maximum of the pump pulse, followed by directional atomic displacements at the fixed unit cell parameters. By comparing the experimental results and theoretical simulations, we interpret that electron excitation and relaxation triggered by the pump pulse modify the potential energy surface and drives the directional atomic displacements. Our results indicate that high-resolution x-ray structural analysis with the accuracy of 0.01 Å is feasible even with intense x-ray pulses by making the pulse duration shorter than the timescale needed to complete electron excitation and relaxation processes, which usually take up to a few tens of femtoseconds.

A morphometric analysis of the osteocyte canaliculus using applied automatic semantic segmentation by machine learning.

INTRODUCTION: Osteocytes play a role as mechanosensory cells by sensing flow-induced mechanical stimuli applied on their cell processes. High-resolution imaging of osteocyte processes and the canalicular wall are necessary for the analysis of this mechanosensing mechanism. Focused ion beam-scanning electron microscopy (FIB-SEM) enabled the visualization of the structure at the nanometer scale with thousands of serial-section SEM images. We applied machine learning for the automatic semantic segmentation of osteocyte processes and canalicular wall and performed a morphometric analysis using three-dimensionally reconstructed images. MATERIALS AND METHODS: Six-week-old-mice femur were used. Osteocyte processes and canaliculi were observed at a resolution of 2 nm/voxel in a 4 × 4 µm region with 2000 serial-section SEM images. Machine learning was used for automatic semantic segmentation of the osteocyte processes and canaliculi from serial-section SEM images. The results of semantic segmentation were evaluated using the dice similarity coefficient (DSC). The segmented data were reconstructed to create three-dimensional images and a morphological analysis was performed. RESULTS: The DSC was > 83%. Using the segmented data, a three-dimensional image of approximately 3.5 µm in length was reconstructed. The morphometric analysis revealed that the median osteocyte process diameter was 73.8 ± 18.0 nm, and the median pericellular fluid space around the osteocyte process was 40.0 ± 17.5 nm. CONCLUSION: We used machine learning for the semantic segmentation of osteocyte processes and canalicular wall for the first time, and performed a morphological analysis using three-dimensionally reconstructed images.

Atomic-Scale Visualization of Ultrafast Bond Breaking in X-Ray-Excited Diamond.

Ultrafast changes of charge density distribution in diamond after irradiation with an intense x-ray pulse (photon energy, 7.8 keV; pulse duration, 6 fs; intensity, 3×10^{19} W/cm^{2}) have been visualized with the x-ray pump-x-ray probe technique. The measurement reveals that covalent bonds in diamond are broken and the electron distribution around each atom becomes almost isotropic within ∼5 fs after the intensity maximum of the x-ray pump pulse. The 15 fs time delay observed between the bond breaking and atomic disordering indicates nonisothermality of electron and lattice subsystems on this timescale. From these observations and simulation results, we interpret that the x-ray-induced change of the interatomic potential drives the ultrafast atomic disordering underway to the following nonthermal melting.

Successful treatment of aortic valve endocarditis caused by Enterococcus casseliflavus: a case report.

BACKGROUND: Enterococcus casseliflavus is rarely isolated from human specimens. To the best of our knowledge, there are no reports on its detailed treatment course and prognosis. Here, we present the first known case of E. casseliflavus endocarditis with a detailed treatment course. CASE PRESENTATION: An 86-year-old Japanese woman was transferred to the emergency department with dyspnoea, wheezing, and lumbago. Her medical history included hypertension, chronic kidney disease, idiopathic interstitial pneumonia, and rectal carcinoma. Physical examination revealed expiratory wheezes and a diastolic murmur (Levine 2/6) at the 4th right sternal border. Chest radiography revealed bilateral interstitial opacities and slight cardiac dilatation. Transthoracic echocardiography demonstrated the presence of mobile vegetation with perforation, prolapse, and regurgitation of the aortic valve. With a suspicion of infective endocarditis, we started administering intravenous ampicillin/sulbactam. Thereafter, blood cultures identified E. casseliflavus through matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. The antimicrobial treatment was then switched to ampicillin plus gentamicin. The patient underwent aortic valve replacement on the thirteenth hospital day. She was administered intravenous ampicillin and gentamicin for 6 weeks. The patient was discharged 8 weeks after admission. CONCLUSIONS: Our case demonstrated that E. casseliflavus could cause infective endocarditis, which can be successfully treated with a 6-week regimen of ampicillin and gentamicin in combination with proper surgical treatment.

Two-color X-ray free-electron laser consisting of broadband and narrowband beams.

A simple scheme is proposed and experimentally confirmed to generate X-ray free-electron lasers (XFELs) consisting of broadband and narrowband beams with a controllable intensity ratio and a large photon-energy separation. This unique two-color XFEL beam will open new opportunities for investigation of nonlinear interactions between intense X-rays and matter.

Self-healing by design: universal kinetic model of strength recovery in self-healing ceramics.

We propose a new theoretical kinetic model of strength recovery by oxidation-induced self-healing of surface cracks in composites containing a healing agent (HA). The kinetics is a key parameter in the design of structural components that can self-heal the damage done in service. Based on three-dimensional (3D) observations of crack-gap filling, two crack-gap filling models, i.e., a bridging model and a tip-to-mouth filling model, are incorporated in the proposed kinetic model. These crack-gap filling models account for the microstructural features of the fracture surfaces, crack geometry, and oxidation kinetics of the healing-agent. Hence, the minimum and maximum remaining flaw sizes in the healed crack gaps are estimated for various healing temperatures, times, and oxygen partial pressure conditions. Further, the nonlinear elastic fracture mechanics suitable for small-sized remaining flaws, together with a statistical analysis of the original Weibull-type strength distribution, enables the prediction of upper and lower strength limits of the healed composites. Three sintered alumina matrix composites containing silicon carbide (SiC)-type HAs with various volume fractions and shapes, together with monolithic SiC ceramics, are considered. The strength of the healed-composite predicted by our model agrees well with the experimental values. This theoretical approach can be applied to HAs other than SiC and enables the design of self-healing ceramic components for various applications.

The Clinical Efficacy of Endothelin Receptor Antagonists in Patients with Pulmonary Arterial Hypertension.

Therapeutic strategies for pulmonary arterial hypertension (PAH) have made remarkable progress over the last two decades. Currently, 3 types of drugs can be used to treat PAH; prostacyclins, phosphodiesterase 5 inhibitors, and endothelin receptor antagonists (ERA). In Japan, the first generation ERA bosentan was reimbursed in 2005, following which the 2nd generation ERAs ambrisentan and macitentan were reimbursed in 2009 and 2015, respectively. The efficacy of each ERA on hemodynamics in PAH patients remains to be elucidated. The aims of this study were to evaluate the hemodynamic effects of ERAs and compare these effects among each generation of ERAs.We retrospectively examined the clinical parameters of 42 PAH patients who were prescribed an ERA (15 bosentan, 12 ambrisentan, and 15 macitentan) and who underwent a hemodynamic examination before and after ERA introduction at our institution from January 2007 to July 2019.In a total of 42 patients, mean pulmonary arterial pressure (mPAP) and pulmonary vascular resistance (PVR) were significantly decreased and cardiac index was significantly increased after ERA introduction (P < 0.001) and the World Health Organization-Functional class (WHO-Fc) was significantly improved after ERA introduction (P = 0.005). Next, in a comparison between 1st and 2nd generation ERAs, 2nd generation ERAs were found to have brought about greater improvements in hemodynamic parameters (mPAP and PVR. P < 0.01), heart rate, brain natriuretic peptide, arterial oxygen saturation, and mixed venous oxygen saturation than the 1st generation ERA bosentan.We conclude that all ERAs could successfully improve the hemodynamics of PAH patients and that the newer generation ERAs, ambrisentan and macitentan, seemed to be preferable to bosentan.

Multiple-beamline operation of SACLA.

The SPring-8 Ångstrom Compact free-electron LAser (SACLA) began parallel operation of three beamlines (BL1-3) in autumn 2017 to increase the user beam time of the X-ray free-electron laser. The success of the multiple-beamline operation is based on two technological achievements: (i) the fast switching operation of the SACLA main linear accelerator, which provides BL2 and BL3 with pulse-by-pulse electron beams, and (ii) the relocation and upgrade of the SPring-8 Compact SASE Source for BL1, for the generation of a soft X-ray free-electron laser. Moreover, the photon beamlines and experimental stations were upgraded to facilitate concurrent user experiments at the three beamlines and accommodate more advanced experiments.

Observation of femtosecond X-ray interactions with matter using an X-ray-X-ray pump-probe scheme.

Resolution in the X-ray structure determination of noncrystalline samples has been limited to several tens of nanometers, because deep X-ray irradiation required for enhanced resolution causes radiation damage to samples. However, theoretical studies predict that the femtosecond (fs) durations of X-ray free-electron laser (XFEL) pulses make it possible to record scattering signals before the initiation of X-ray damage processes; thus, an ultraintense X-ray beam can be used beyond the conventional limit of radiation dose. Here, we verify this scenario by directly observing femtosecond X-ray damage processes in diamond irradiated with extraordinarily intense (∼10(19) W/cm(2)) XFEL pulses. An X-ray pump-probe diffraction scheme was developed in this study; tightly focused double-5-fs XFEL pulses with time separations ranging from sub-fs to 80 fs were used to excite (i.e., pump) the diamond and characterize (i.e., probe) the temporal changes of the crystalline structures through Bragg reflection. It was found that the pump and probe diffraction intensities remain almost constant for shorter time separations of the double pulse, whereas the probe diffraction intensities decreased after 20 fs following pump pulse irradiation due to the X-ray-induced atomic displacement. This result indicates that sub-10-fs XFEL pulses enable conductions of damageless structural determinations and supports the validity of the theoretical predictions of ultraintense X-ray-matter interactions. The X-ray pump-probe scheme demonstrated here would be effective for understanding ultraintense X-ray-matter interactions, which will greatly stimulate advanced XFEL applications, such as atomic structure determination of a single molecule and generation of exotic matters with high energy densities.

Twinning behavior of orthorhombic-α" martensite in a Ti-7.5Mo alloy.

Deformation microstructure of orthorhombic-α" martensite in a Ti-7.5Mo (wt.%) alloy was investigated by tracking a local area of microstructure using scanning electron microscopy, electron back-scattered diffraction, and transmission electron microscopy. The as-quenched α" plates contain {111}α"-type I transformation twins generated to accommodate transformation strain from bcc-ß to orthorhombic-α" martensite. Tensile deformation up to strain level of 5% induces {112}α"-type I deformation twins. The activation of {112}α"-type I deformation twinning mode is reported for the first time in α" martensite in ß-Ti alloys. {112}α"-type I twinning mode was analyzed by the crystallographic twinning theory by Bilby and Crocker and the most possible mechanism of atomic displacements (shears and shuffles) controlling the newly reported {112}α"-type I twinning were proposed.

A soft X-ray free-electron laser beamline at SACLA: the light source, photon beamline and experimental station.

The design and performance of a soft X-ray free-electron laser (FEL) beamline of the SPring-8 Compact free-electron LAser (SACLA) are described. The SPring-8 Compact SASE Source test accelerator, a prototype machine of SACLA, was relocated to the SACLA undulator hall for dedicated use for the soft X-ray FEL beamline. Since the accelerator is operated independently of the SACLA main linac that drives the two hard X-ray beamlines, it is possible to produce both soft and hard X-ray FEL simultaneously. The FEL pulse energy reached 110 µJ at a wavelength of 12.4 nm (i.e. photon energy of 100 eV) with an electron beam energy of 780 MeV.

Observation of the magnetic skyrmion lattice in a MnSi nanowire by Lorentz TEM.

We report here the real-space observation of skyrmions and helical magnetic domains in a MnSi nanowire (NW) using Lorentz transmission electron microscopy (LTEM). The MnSi NW was thinned to a rectangular cross-section by focused-ion beam milling to reduce obstructive Fresnel fringes. Helimagnetic domains, imaged as alternating bright and dark contrast stripes with an 18 nm period, were observed to be the spontaneous magnetic ground state at 6 K, while the hexagonal skyrmion lattice (SkX) with a domain diameter of 18 nm was observed under a normal magnetic field of 210 mT. Temperature-dependent measurements reveal that the SkX is stable over a larger range in this NW system (6-35 K) compared to the narrow temperature regime of skyrmion phase in bulk MnSi (26-30 K) and thin films of MnSi (5-23 K).

"Happy Heart Syndrome" Followed Up with Cardiac Magnetic Resonance Imaging.

We herein report a 49-year-old woman who developed "happy heart syndrome" while watching a family theater performance. She was followed up with cardiac magnetic resonance imaging (CMR). The time course of the CMR findings was similar to that previously reported for Takotsubo cardiomyopathy (TTC), including the form of "broken heart syndrome." CMR findings for "happy heart syndrome" have not been sufficiently investigated. However, the CMR findings in this case suggest that "happy heart syndrome" and other conventional TTC including "broken heart syndrome" are clinically a single disease, at least from an imaging aspect.

Right-sided iliac vein compression syndrome: when the vein is compressed between the internal and external iliac arteries-a case report.

Background: In its normal anatomical relationship, the inferior vena cava is located on the right side of the abdominal aorta. Iliac vein compression syndrome (IVCS) is a pathological condition in which a blood clot is formed due to blood flow obstruction when the left common iliac vein is compressed between the right common iliac artery and the vertebral body. Therefore, right-sided IVCS (RIVCS) is rare. The effectiveness of treatment for RIVCS has not been sufficiently investigated. Case summary: A 51-year-old man developed deep vein thrombosis in the right lower extremity and non-massive pulmonary embolism during steroid treatment for IgA nephropathy. Magnetic resonance angiography (MRA) suggested iliac compression syndrome. Symptoms improved with the use of direct oral anticoagulants and compression stockings. At the 8-month follow-up, the clinical course was uneventful. Discussion: The causes of RIVCS in this case are believed to be the effects of steroids, prolonged sitting, and compression of the right external iliac vein. However, considering that deep vein thrombosis did not form in the left lower limb where there was no venous compression, it can be considered that the compression of the right external iliac vein had a significant impact. This case has been followed up for 8 months with anticoagulants and is progressing well. This is the first case to report the course of RIVCS treated conservatively with anticoagulant therapy for 8 months. This case suggested that conservative treatment is effective for RIVCS.

An autopsy case of lung adenocarcinoma with immune checkpoint inhibitor-induced pneumonia and fulminant myocarditis following pembrolizumab administration: a case report.

Immune checkpoint inhibitors (ICIs) are the current standard of care for non-small-cell lung cancer (NSCLC). Myocarditis is a rare but serious immune-related adverse event (irAE) associated with ICI therapy. We present a patient who received a single dose of pembrolizumab for NSCLC and developed ICI-associated pneumonia. Although pneumonia improved with corticosteroid therapy, the patient subsequently developed ICI-associated fulminant myocarditis. Despite high-dose corticosteroid therapy, the patient died on day 30 after pembrolizumab initiation. Even if an observed irAE was effectively treated, clinicians should remain vigilant for other irAEs, especially those that are difficult to control with low-dose corticosteroids.

Detection of loci for allergic asthma using SMXA recombinant inbred strains of mice.

Asthma is regarded as a multifactorial inflammatory disorder arising as a result of inappropriate immune responses in genetically susceptible individuals to common environmental antigens. However, the precise molecular basis is unknown. To identify genes for susceptibility to three asthma-related traits, airway hyperresponsiveness (AHR), eosinophil infiltration, and allergen-specific serum IgE levels, we conducted a genetic analysis using SMXA recombinant inbred (RI) strains of mice. Quantitative trait locus analysis detected a significant locus for AHR on chromosome 17. For eosinophil infiltration, significant loci were detected on chromosomes 9 and 16. Although we could not detect any significant loci for allergen-specific serum IgE, analysis of consomic strains showed that chromosomes 17 and 19 carried genes that affected this trait. We detected genetic susceptibility loci that separately regulated the three asthma-related phenotypes. Our results suggested that different genetic mechanisms regulate these asthma-related phenotypes. Genetic analyses using murine RI and consomic strains enhance understanding of the molecular mechanisms of asthma in human.

Successful Treatment with Low-dose Crizotinib in a Patient with ROS1-rearranged Lung Cancer Who Developed Crizotinib-induced Heart Failure.

Crizotinib shows antitumor activity against C-ros oncogene 1-rearranged non-small-cell lung cancer (NSCLC). While corrected QT interval (QTc) prolongation and bradycardia are known as cardiac adverse effects, little is known about crizotinib-related heart failure. Our patient with C-ros oncogene 1-rearranged NSCLC on a reduced dose of crizotinib (200 mg twice daily) after initially experiencing bradycardia and QTc prolongation developed crizotinib-induced heart failure. With further dose reduction (250 mg once daily), there was no recurrence of any cardiac adverse effects, and the patient achieved a long-term response. Although crizotinib can cause heart failure, continuation of crizotinib at a low dose may be an effective treatment option.

Bundling of collagen fibrils influences osteocyte network formation during bone modeling.

Osteocytes form a cellular network by gap junctions between their cell processes. This network is important since intercellular communication via the network is essential for bone metabolism. However, the factors that influence the formation of this osteocyte network remain unknown. As the early stage of osteocyte network formation occurs on the bone surface, we observed a newly formed trabecular bone surface by orthogonal focused ion beam-scanning electron microscopy. The embedding late osteoblast processes tended to avoid bundled collagen fibrils and elongate into sparse collagen fibrils. Then, we examined whether the inhibition of bundling of collagen fibrils using a potent lysyl oxidase inhibitor, ß-aminopropionitrile (BAPN) changed the cellular network of the chick calvaria. The osteocyte shape of the control group was spindle-shape, while that of the BAPN group was sphere-shaped. In addition, the osteocyte processes of the control group were elongated vertically to the long axis of the cell body, whereas the osteocyte processes of the BAPN group were elongated radially. Therefore, it was suggested that the bundling of collagen fibrils influences normal osteocyte network formation during bone modeling.