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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, β-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. [ABSTRACT FROM AUTHOR]

Calcium phosphate forms particles under excessive urinary excretion of phosphate in the kidney. While the formation of calcium phosphate particles (CaPs) has been implicated in the damage to renal tubular cells and renal dysfunction, clarifying the ultrastructural information and the elemental composition of the small CaPs in the wide areas of kidney tissue has been technically difficult. This study introduces correlative and sequential light as well as electron microscopic CaP observation in the kidney tissue by combining fluorescent staining for CaPs and energy-dispersive X-ray spectroscopy (EDS) in scanning electron microscopy (SEM) on resin sections prepared using high-pressure freezing and freeze substitution. CaPs formed in mouse kidneys under long-term feeding of a high-phosphate diet were clearly visualized on resin sections by fluorescence-conjugated alendronate derivatives and toluidine blue metachromasia. These CaPs were verified by correlative observation with EDS. Furthermore, small CaPs formed in the kidney under short-term feeding were detected using fluorescent probes. The elemental composition of the particles, including calcium and magnesium, was identified following EDS analyses. These results suggest that the correlative microscopy approach is helpful for observing in situ distribution and elemental composition of CaPs in the kidney and contributing to studies regarding CaP formation-associated pathophysiology. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

We herein report a concept study of a transition edge sensor (TES) X-ray microcalorimeter array with two different thickness absorbers. We developed an energy-dispersive X-ray spectroscope (EDS) with a 64-pixel TES array and installed it on a scanning transmission electron microscope (STEM) for material analysis. One of the key applications of the proposed system is the microanalysis of astromaterials, for which the relative abundance of light elements such as boron, carbon, and oxygen against silicon are crucial. However, the line sensitivity below ∼ 500 eV for the our STEM TES EDS system was not enough to detect the X-ray from light elements because of the relatively high continuum emission and low detection efficiency, which occurs due to the X-ray window and the optical blocking filters. A simple solution to increase line sensitivity at low energy is the adoption of thin X-ray absorbers that leads to an improvement in the energy resolution. However, doing so causes the sensitivity to decrease for high energy lines. Utilizing the spot-size dependence of the polycapillary X-ray optics on energy, which are used in the STEM TES EDS system, we studied a design in which thin absorbers are distributed on the outer area of detector. We optimized the design using the raytracing analysis of optics. A thin (300 nm) absorber is placed on the 52 outer pixels, while a thick (3.5 μ m) absorber is placed on the central 12 pixels. The thin pixels detect approximately 50–60% of the total counts in 0.1–2 keV, while the central thick pixels detect approximately 50–80% of the total counts in 2–10 keV. We also demonstrated the fabrication process of two-thickness absorber arrays. [ABSTRACT FROM AUTHOR]

The remineralization mechanism in dental caries lesions is not completely understood. This study reports on ultrastructural and chemical changes observed within arrested caries lesions. Carious human teeth were observed using scanning electron microscopy (SEM) and focused-ion-beam (FIB)-SEM. The crystals detected in the caries lesions were characterized by transmission electron microscopy (TEM), along with chemical element mapping using energy-dispersive spectroscopy (EDS)-STEM. FIB-SEM 3D reconstructions revealed a severely damaged dentin surface abundantly covered by bacteria. Although the dentin tubules were clogged up to a depth of 100 μm, bacterial invasion into dentin tubules was not observed. TEM crystal analysis and EDS-STEM revealed the presence of Ca and P, as well as of Mg within the HAp crystals deposited inside the dentin tubules. It was concluded that extensive remineralization with deposition of Mg-HAp crystals had occurred in dentin tubules of caries-arrested dentin. Understanding the natural remineralization process is thought to be helpful for developing clinical biomimetic remineralization protocols. [ABSTRACT FROM AUTHOR]

X-ray free-electron lasers (XFELs)1,2 are widely operated on the basis of self-amplified spontaneous emission (SASE)3,4, where spontaneous radiation from the electron beam is amplified along the magnetic field in undulators. Despite their high intensities, SASE-XFELs have a broad spectrum due to the stochastic starting-up process5. To narrow the bandwidth, self-seeding has been proposed6,7 and recently demonstrated8,9, where the seed pulse produced by monochromatizing the SASE-XFELs from the first section of undulators using a thin crystal in transmission geometry is amplified in the remaining undulators. Here, we present an efficient self-seeding scheme using the Bragg reflection to produce a seed pulse. We applied this scheme to SPring-8 Angstrom Compact free-electron LAser (SACLA)10, and produced nearly Fourier-transform-limited XFEL pulses that correspond to an increase in spectral brightness by a factor of six compared with SASE-XFELs. This achievement will not only enhance the throughput of present XFEL experiments but also should open new opportunities for X-ray science. A nearly Fourier-limited X-ray free-electron laser beam is generated by a self-seeding scheme. The beam in the first half of the undulators is monochromatized via Bragg reflection, and is subsequently amplified in the remaining undulators. [ABSTRACT FROM AUTHOR]

A detector head for an energy-dispersive X-ray spectroscopy (EDS) for a scanning transmission electron microscope (STEM) was designed, fabricated, and tested. A 64-pixel TES X-ray microcalorimeter and 64 SQUID array amplifiers (SAAs) are mounted on a detector head which is cooled to about 100 mK. The body of the detector head is a copper rod of about 1cm2 cross section and 10 cm length with 3 cm cubic structure at the bottom. The TES microcalorimeter is mounted at the top of the rod while the SAAs are mounted on the four side surfaces of the cubic structure. In order to reduce the number of wire bondings, we adopted a flip-chip bonding for the SAAs. In order to reduce the stress imposed on the flip-chip bondings due to the difference in the linear thermal expansion of the SAA chip and the mounting surfaces, we mounted the SAAs and connectors to the room-temperature electronics on sapphire circuit board and mounted the SAAs and connectors using a superconducting flip-chip bonding technology. Then, both the TES and the sapphire circuit board were mounted on the rod and are connected to the print circuit like superconducting wires, which are created on the multiple surfaces of the rod, with Al wire bondings. We reduced the number of wire bondings from 768 to 256. The yield of the flip-chip bonding was not perfect but relatively high. We installed the detector head in the STEM EDS system, confirmed that the energy resolution and counting requirements, ΔE<10eV with 5 kcps were fulfilled. [ABSTRACT FROM AUTHOR]

The structure and dynamics of submicrometre magnetic domains are the main factors determining the physical properties of magnetic materials. Here, we report the first observation of skyrmion-like magnetic nanodomains in a ferromagnetic manganite, La0.5Ba0.5MnO3, using Lorentz transmission electron microscopy (LTEM). The skyrmion-like magnetic domains appear as clusters above the Curie temperature. We found that the repeated reversal of magnetic chirality is caused by thermal fluctuation. The closely spaced clusters exhibit dynamic coupling, and the repeated magnetization reversal becomes fully synchronized with the same chirality. Quantitative analysis of such dynamics was performed by LTEM to directly determine the barrier energy for the magnetization reversal of skyrmion-like nanometre domains. This study is expected to pave the way for further investigation of the unresolved nature and dynamics of magnetic vortex-like nanodomains. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Hoolock hoolock (the western hoolock gibbon) is a species of the family Hylobatidae (small apes), which constitutes the superfamily Hominoidea (hominoids) together with Hominidae (great apes and human). Here, we report that centromeres or their vicinities in this gibbon species contain tandem repeat sequences that consist of 35-50-bp repeat units, and exhibit a sequence similarity with the variable number of tandem repeat (VNTR) region of the SVA, LAVA and PVA transposons. SVA is a composite retrotransposon thought to have been formed by fusion of three solo elements in the common ancestor of hominoids. LAVA and PVA are recently identified retrotransposons that have the same basic structure as SVA. Thus, the large-scale tandem repeats in the centromere region may have been derived from one or more of SVA-type transposons, including the three mentioned above and other yet unknown elements, or the repeat sequences could have served as a source for such elements. Amplification of VNTR-related sequences in another gibbon species, Hoolock leuconedys (eastern hoolock gibbon), has recently been reported, but it is yet to be examined whether the large-scale tandem repeats observed in the two species originated from a single event that occurred in their common ancestor. The repeat sequences in the western hoolock gibbon are mostly 40 kb or more in length, are present in 28 of the 38 chromosomes of the somatic cells, and are homozygous for chromosomal presence/absence. [ABSTRACT FROM AUTHOR]

The free-electron laser, first proposed by Madey in 1971, has significantly reduced laser wavelengths to the vacuum ultraviolet and soft X-ray regions. Recently, an X-ray free-electron laser (XFEL) was operated at 1.2 Å at the Linac Coherent Light Source (LCLS). Here, we report the successful generation of sub-ångström laser light using a compact XFEL source, combining a short-period undulator with an 8 GeV electron beam. The shortest wavelength attained-0.634 Å (63.4 pm)-is four orders of magnitude smaller than the 694 nm generated by Maiman's first laser. The maximum power exceeded 10 GW with a pulse duration of 10?14 s. This achievement will contribute to the widespread use of XFEL sources and provide broad opportunities for exploring new fields in science. [ABSTRACT FROM AUTHOR]

The martensitic transformation and shape memory effect of Ti(Pt, Ir) with 5-37.5 at. pct Ir were investigated using differential thermal analysis (DTA), high-temperature X-ray diffraction (HT-XRD), and compression tests. The austenite finish temperature, A, increased with increasing Ir content from 1331 K (1058 °C) in Ti-50 at. pct Pt to 1491 K (1218 °C) in Ti-12.5Pt-37.5Ir. The structure of the parent and martensite phases was identified as B2 and B19 in all tested alloys. A large strain recovery rate was obtained in Ti(Pt, Ir) with 10 to 30 at. pct Ir. The highest shape recovery ratio was 57 pct in Ti-25Pt-25Ir after deformation at 1123 K (850 °C), followed by heating to above A. Using HT-XRD, the dependence of lattice parameter change on Ir content and temperature was investigated. The volume change during phase transformation from B2 to B19 was estimated using the lattice parameter of the B2 and B19 phases. Strain recovery is discussed along with volume change and lattice parameter change. [ABSTRACT FROM AUTHOR]

Single-pass free-electron lasers based on self-amplified spontaneous emission are enabling the generation of laser light at ever shorter wavelengths, including extreme ultraviolet, soft X-rays and even hard X-rays. A typical X-ray free-electron laser is a few kilometres in length and requires an electron-beam energy higher than 10 GeV (refs 6, 8). If such light sources are to become accessible to more researchers, a significant reduction in scale is desirable Here, we report observations of brilliant extreme-ultraviolet radiation from a 55-m-long compact self-amplified spontaneous-emission source, which combines short-period undulators with a high-quality electron source operating at a low acceleration energy of 250 MeV. The radiation power reaches saturation at wavelengths ranging from 51 to 61 nm with a maximum pulse energy of 30 µJ. The ultralow emittance (0.6π mm mrad) of the electron beam from a CeB6 thermionic cathode is barely degraded by a multiple-stage bunch compression system that dramatically enhances the beam current from 1 to 300 A. This achievement expands the potential for generating X-ray free-electron laser radiation with a compact 2-GeV machine. [ABSTRACT FROM AUTHOR]

CD40-CD40 ligand (CD40L) interaction is an important costimulatory signaling pathway in the crosstalk between T cells and antigen-presenting cells. This receptor-ligand system is known to be essential in eliciting strong cellular immunity. Here we demonstrate that murine lung cancer cells (3LLSA) transduced with the CD40L gene (3LLSA-CD40L) were rejected in syngeneic C57BL/6 mice, but grew in CD40-deficient mice to the same extent as control tumor cells. Immunohistochemical study showed that inflammatory cells, including CD4+, CD8+ T cells and NK cells, infiltrated into the inoculated 3LLSA-CD40L tumor tissue. Inoculation of 3LLSA-CD40L cells into mice resulted in the induction of 3LLSA-specific cytotoxic T-cell immunity, and the growth of parental 3LLSA tumors was inhibited when 3LLSA cells were inoculated into C57BL/6 mice mixed with 3LLSA-CD40L cells or when they were rechallenged 4 weeks after 3LLSA-CD40L cells were rejected. Furthermore, co-inoculation of interferon (IFN)-γtransduced cells (3LLSA-IFNγ) with 3LLSA-CD40L cells enhanced the antitumor immunity efficiently in viva. These results indicate that the in viva priming with CD40L- and IFN-γ gene-transduced lung cancer cells is a promising strategy for inducing antitumor immunity in the treatment of lung cancer. [ABSTRACT FROM AUTHOR]

The article offers information on the generation of fully coherent soft-X-ray pulses by a two-stage high-gain harmonic-generation (HGHG) scheme at the Free Electron Laser for Multidisciplinary Investigations (FERMI) radiation facility located in Trieste, Italy. It mentions that shortest wavelength for a HGHG free electron laser (FEL) useful for scientists whose research suffers from noisy self-amplified spontaneous emission (SASE) spectra, was generated at Fermi.

Inefficient Mg-induced p-type doping has been remained a major obstacle in the development of GaN-based electronic devices for solid-state lighting and power applications. This study reports comparative structural analysis of defects in GaN layers on freestanding GaN substrates where Mg incorporation is carried out via two approaches: ion implantation and epitaxial doping. Scanning transmission electron microscopy revealed the existence of pyramidal and line defects only in Mg-implanted sample whereas Mg-doped sample did not show presence of these defects which suggests that nature of defects depends upon incorporation method. From secondary ion mass spectrometry, a direct correspondence is observed between Mg concentrations and location and type of these defects. Our investigations suggest that these pyramidal and line defects are Mg-rich species and their formation may lead to reduced free hole densities which is still a major concern for p-GaN-based material and devices. As freestanding GaN substrates offer a platform for realization of p-n junction-based vertical devices, comparative structural investigation of defects originated due to different Mg incorporation processes in GaN layers on such substrates is likely to give more insight towards understanding Mg self-compensation mechanisms and then optimizing Mg doping and/or implantation process for the advancement of GaN-based device technology. [ABSTRACT FROM AUTHOR]

We report an unexpectedly large flux loss observed in permanent magnets in one of the undulators operated in SACLA, the x-ray free electron laser facility in Japan. Characterizations of individual magnets extracted from the relevant undulator have revealed that the flux loss was caused by a homogeneous magnetization reversal extending over a wide area, but not by demagnetization of individual magnets damaged by radiation. We show that the estimated flux-loss rate is much higher than what is reported in previous papers, and its distribution is much more localized to the upstream side. Results of numerical and experimental studies carried out to validate the magnetization reversal and quantify the flux loss are presented, together with possible countermeasures against rapid degradation of the undulator performance. [ABSTRACT FROM AUTHOR]