Time-resolved resonant soft X-ray scattering combined with MHz synchrotron X-ray and laser pulses at the Photon Factory.

A picosecond pump-probe resonant soft X-ray scattering measurement system has been developed at the Photon Factory storage ring for highly efficient data collection. A high-repetition-rate high-power compact laser system has been installed to improve efficiency via flexible data acquisition to a sub-MHz frequency in time-resolved experiments. Data are acquired by gating the signal of a channel electron multiplier with a pulse-counting mode capable of discriminating single-bunch soft X-ray pulses in the dark gap of the hybrid operation mode in the storage ring. The photoinduced dynamics of magnetic order for multiferroic manganite SmMn2O5 are clearly demonstrated by the detection of transient changes in the resonant soft X-ray scattering intensity around the Mn LIII- and O K-edges.

Linearity and Chemical Bond of UO22+ Revisited: A Comparison Study with UN2 and UE22+ (E = S, Se, and Te) Based on Relativistic Calculations.

The stability and electronic structure of UO22+ are compared with those of UN2 and UE22+ (E = S, Se, and Te) based on four- and two-component relativistic Hamiltonians. We observed that the Hartree-Fock method overestimates the stability of the linear structures of UO22+ and UN2. In addition to the conventional mechanism based on valence orbitals, we proposed another mechanism wherein the small energy difference between U's 6p3/2 and O's σ(2s) orbitals destabilizes the bent structure of UO22+. The validity of the analysis based on the DFT method was evaluated using the coupled-cluster method. The slightly bent structures of UO22+ and UN2 are feasible from the viewpoint of energetic stability: the destabilized energy at 160° is 0.144 and 0.059 eV for UO22+ and UN2, respectively. The U-X bond (X = N,O) is rigid in the slightly bent structure, and it corresponds to the conservation of the feature of the chemical bond. For UE22+, core-valence orbitals mainly affect the stability of these molecules, like UO22+ and UN2. In UE22+, the 6p hole is fairly modest, and the 6p hole in UO22+ is a unique feature in uranium-chalcogen systems.

Sr(ii) extraction by crown ether in HFC: entropy driven mechanism through H2PFTOUD.

The solvent extraction of Sr(ii) was carried out using dicyclohexano-18-crown-6 (DCH18C6) and two HFC mixed solvents MS1 and MS2, where MS1 was composed of 30/60 (w/w)% trans-1,2-dichloroethylene/HFC-43 (HFC-43: 1,1,1,2,2,3,4,5,5,5-decafluoropentane) and MS2 was 5/95 (w/w)% heptane/HFC-43. Nitric acid and perfuruoro-3-6-9-trioxaundecane-1,11-dioic acid (H2PFTOUD) were used to study the effect of acid on the extraction. The maximum distribution ratio of Sr(ii) (D Sr) observed for H2PFTOUD conditions was ∼180, and >10 times larger than aqueous nitric acid conditions. The D Sr value was influenced by concentrations of the DCH18C6, Sr(ii), and acid, and by temperature. The composition of extracted complexes was estimated using slope analysis as an Sr(ii)-anion-DCH18C6 ratio of ∼1 : 2 : 1. From the extended X-ray absorption fine structure (EXAFS) measurements of Sr(ii) in the aqueous and organic phases, it is inferred that regardless of the acid used, DCH18C6 coordinates to the first coordination sphere of the Sr(ii) extracted complexes and Sr(ii) is hydrated (complexation with H2PFTOUD cannot be distinguished) in the aqueous phase. Thermodynamic data were significantly changed by choice of acid, i.e., both enthalpy and entropy values were negative for nitric acid conditions, on the other hand, entropy values were large and positive for H2PFTOUD conditions. These results have demonstrated that the combination of HFC solvent and crown ether is applicable for metal extraction.

X-ray study of ferroic octupole order producing anomalous Hall effect.

Recently found anomalous Hall, Nernst, magnetooptical Kerr, and spin Hall effects in the antiferromagnets Mn3X (X = Sn, Ge) are attracting much attention for spintronics and energy harvesting. Since these materials are antiferromagnets, the origin of these functionalities is expected to be different from that of conventional ferromagnets. Here, we report the observation of ferroic order of magnetic octupole in Mn3Sn by X-ray magnetic circular dichroism, which is only predicted theoretically so far. The observed signals are clearly decoupled with the behaviors of uniform magnetization, indicating that the present X-ray magnetic circular dichroism is not arising from the conventional magnetization. We have found that the appearance of this anomalous signal coincides with the time reversal symmetry broken cluster magnetic octupole order. Our study demonstrates that the exotic material functionalities are closely related to the multipole order, which can produce unconventional cross correlation functionalities.

Discovery of the Pt-Based Superconductor LaPt5As.

A novel superconductor, LaPt5As, which exhibits a new crystal structure was discovered by high-pressure synthesis using a Kawai-type apparatus. A superconducting transition temperature was observed at 2.6 K. Depending on the sintering pressure, LaPt5As has superconducting and non-superconducting phases with different crystal structures. A sintering pressure of around 10 GPa is effective to form single-phase superconducting LaPt5As. This material has a very unique crystal structure with an extremely long c lattice parameter of over 60 Å and corner-sharing tetrahedrons composed of network-like Pt layers. Density functional theory calculations have suggested that the superconducting current flows through these Pt layers. Also, this unique layered structure characteristic of LaPt5As is thought to play a key role in the emergence of superconductivity. Furthermore, due to a stacking structure which makes up layers, various structural modifications for the LaPt5As family are conceivable. Since such a high-pressure synthesis using a Kawai-type apparatus is not common in the field of materials science, there is large room for further exploration of unknown phases which are induced by high pressure in various materials.

Leigh syndrome with Fukuyama congenital muscular dystrophy: a case report.

We report the first case of Leigh syndrome (LS) with Fukuyama congenital muscular dystrophy (FCMD). A neonate suffered from lactic acidosis and subsequently presented with poor feeding, muscle weakness, hypotonia, cardiopulmonary dysfunction, and hydrocephalus. He died at 17 months. The findings of brain magnetic resonance imaging indicated some specific features of both LS and FCMD, and FCMD gene mutation was detected. Decreased mitochondrial respiratory complex I and II activity was noted. Mitochondrial DNA sequencing showed no pathogenic mutation. A case with complex I+II deficiency has rarely been reported, suggesting a nuclear gene mutation.

Altered distribution of extracellular matrix proteins in the periodontal ligament of periostin-deficient mice.

Verifying whether periostin affects the distribution of type I collagen, fibronectin and tenascin C in the periodontal ligament (PDL) is important to contribute to a more thorough understanding of that protein's functions. In this study, we have histologically examined incisor PDL of mandibles in 20 week-old male wild-type and periostin-deficient (periostin-/-) mice, by means of type I collagen, fibronectin, tenascin C, proliferating cell nuclear antigen, matrix metallo-proteinase (MMP)-1 and F4/80-positive monocyte/macrophage immunostaining, transmission electron microscopy and quantitative analysis of cell proliferation. Wild-type PDL featured well-arranged layers of collagen bundles intertwined with PDL cells, whose longitudinal axis ran parallel to the collagen fibers. However, cells in the periostin-/- PDL were irregularly distributed among collagen fibrils, which were also haphazardly arranged. Type I collagen and fibronectin reactivity was seen throughout the wild-type PDL, while in the periostin-/- PDL, only focal, uneven staining for these proteins could be seen. Similarly, tenascin C staining was evenly distributed in the wild-type PDL, but hardly seen in the periostin-/- PDL. MMP-1 immunoreactivity was uniformly distributed in the wild-type PDL, but only dotted staining could be discerned in the periostin-/- PDL. F4/80-positive monocyte/macrophages were found midway between tooth- and bone-related regions in the wild-type PDL, a pattern that could not be observed in the periostin-/- PDL. In summary, periostin deficiency may not only cause PDL collagen fibril disorganization, but could also affect the distribution of other major extracellular matrix proteins such as fibronectin and tenascin C.

Altered distribution of bone matrix proteins and defective bone mineralization in klotho-deficient mice.

In an attempt to identify the histological properties of the klotho-deficient (kl/kl) bone matrix, bone mineralization and the localization of Ca(2+)-binding bone matrix proteins - osteocalcin, dentin matrix protein-1 (DMP-1) and matrix Gla protein (MGP) - were examined in kl/kl tibiae. While a widespread osteocalcin staining could be verified in the wild-type bone matrix, localization of the same protein in the kl/kl tibiae seemed rather restricted to osteocytes with only a faint staining of the whole bone matrix. In wild-type mice, MGP immunoreactivity was present at the junction between the epiphyseal bone and cartilage, and at the insertion of the cruciate ligaments. In kl/kl mice, however, MGP was seen around the cartilaginous cores of the metaphyseal trabeculae and in the periphery of some cells of the bone surface. DMP-1 was identified in the osteocytic canalicular system of wild-type tibiae, but in the kl/kl tibiae this protein was mostly found in the osteocytic lacunae and in the periphery of some cells of the bone surface. Mineralization of the kl/kl bone seemed somewhat defective, with broad unmineralized areas within its matrix. In these areas, mineralized osteocytes along with their lacunae and osteocytic cytoplasmic processes were found to have intense osteocalcin and DMP-1 staining. Taken together, it might be that the excessive production of Ca(2+)-binding molecules such as osteocalcin and DMP-1 by osteocytes concentrates mineralization around such cells, disturbing the completeness of mineralization in the kl/kl bone matrix.

Histological examination on osteoblastic activities in the alveolar bone of transgenic mice with induced ablation of osteocytes.

The purpose of this study was to examine histological alterations on osteoblasts from the alveolar bone of transgenic mice with targeted ablation of osteoctyes. Eighteen weeks-old transgenic mice based on the diphtheria toxin (DT) receptor-mediated cell knockout (TRECK) system were used in these experiments. Mice were injected intraperitoneally with 50 µg/kg of DT in PBS, or only PBS as control. Two weeks after injections, mice were subjected to transcardiac perfusion with 4% paraformaldehyde in 0.1M phosphate buffer (pH 7.4), and the available alveolar bone was removed for histochemical analyses. Approximately 75% of osteocytes from alveolar bones became apoptotic after DT administration, and most osteocytic lacunae became empty. Osteoblastic numbers and alkaline phosphatase (ALP) activity were markedly reduced at the endosteum of alveolar bone after DT administration compared with the control. Osteoblastic ALP activity in the periodontal ligament region, on the other hand, hardly showed any differences between the two groups even though numbers were reduced in the experiment group. Silver impregnation showed a difference in the distribution of bone canaliculi between the portions near the endosteum and the periodontal ligament: the former appeared regularly arranged in contrast to the latter's irregular distribution. Under transmission electron microscopy (TEM), the osteoblasts in the periodontal ligament showed direct contact with the Sharpey's fibers. Thus, osteoblastic activity was affected by osteocyte ablation in general, but osteoblasts in contact with the periodontal ligament were less affected than endosteal osteoblasts.

Immunolocalization of sclerostin synthesized by osteocytes in relation to bone remodeling in the interradicular septa of ovariectomized rats.

This study aimed at elucidating whether estrogen deficiency would affect the synthesis of an osteocyte-derived factor, sclerostin, in the mesial region of alveolar bone. Eight 9-week-old Wistar female rats were ovariectomized (OVX) and eight other rats were Sham-operated (Sham). After 4 weeks, the interradicular septa of mandibular first molar were embedded in paraffin and then histochemically examined. Sclerostin-positive osteocytes were located in the superficial layer of the mesial region of Sham bones, whereas the OVX mesial region showed less sclerostin-reactive osteocytes. There was no significant difference in the distribution of estrogen receptor α and terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick end-labeling -positive cells in the groups studied. The Sham mesial region featured many osteoclasts, and OVX specimens showed numerous osteoclasts in association with intense immunolabeling of the receptor activator of the nuclear factor kB ligand. Contrary to the observations in Sham specimens, a complex meshwork of cement lines was seen in the OVX mesial region, accompanied by an irregularly distributed osteocytic lacunar-canalicular system. In conclusion, estrogen deficiency appears to inhibit osteocyte-derived sclerostin synthesis in the mesial region of the interradicular septum, in a process that seems to be mediated by accelerated bone remodeling rather than by direct effects on osteocytes.

Structure and formation of the twisted plywood pattern of collagen fibrils in rat lamellar bone.

This study was designed to elucidate details of the structure and formation process of the alternate lamellar pattern known to exist in lamellar bone. For this purpose, we examined basic internal lamellae in femurs of young rats by transmission and scanning electron microscopy, the latter employing two different macerations with NaOH at concentrations of 10 and 24%. Observations after the maceration with 10% NaOH showed that the regular and periodic rotation of collagen fibrils caused an alternation between two types of lamellae: one consisting of transversely and nearly transversely cut fibrils, and the other consisting of longitudinally and nearly longitudinally cut fibrils. This finding confirms the consistency of the twisted plywood model. The maceration method with 24% NaOH removed bone components other than cells, thus allowing for three-dimensional observations of osteoblast morphology. Osteoblasts extended finger-like processes paralleling the inner bone surface, and grouped in such a way that, within a group, the processes arranged in a similar direction. Transmission electron microscopy showed that newly deposited fibrils were arranged alongside these processes. For the formation of the alternating pattern, our findings suggest that: (1) osteoblasts control the collagen fibril arrangement through their finger-like process position; (2) osteoblasts behave similarly within a group; (3) osteoblasts move their processes synchronously and periodically to promote alternating different fibril orientation; and (4) this dynamic sequential deposition of fibrils results in the alternate lamellar (or twisted plywood) pattern.

Morphological assessment of bone mineralization in tibial metaphyses of ascorbic acid-deficient ODS rats.

Osteogenic disorder shionogi (ODS) rats carry a hereditary defect in ascorbic acid synthesis, mimicking human scurvy when fed with an ascorbic acid-deficient (aa-def) diet. As aa-def ODS rats were shown to feature disordered bone formation, we have examined the bone mineralization in this rat model. A fibrous tissue layer surrounding the trabeculae of tibial metaphyses was found in aa-def ODS rats, and this layer showed intense alkaline phosphatase activity and proliferating cell nuclear antigen-immunopositivity. Many osteoblasts detached from the bone surfaces and were characterized by round-shaped rough endoplasmic reticulum (rER), suggesting accumulation of malformed collagen inside the rER. Accordingly, fine, fragile fibrillar collagenous structures without evident striation were found in aa-def bones, which may result from misassembling of the triple helices of collagenous α-chains. Despite a marked reduction in bone formation, ascorbic acid deprivation seemed to have no effect on mineralization: while reduced in number, normal matrix vesicles and mineralized nodules could be seen in aa-def bones. Fine needle-like mineral crystals extended from these mineralized nodules, and were apparently bound to collagenous fibrillar structures. In summary, collagen mineralization seems unaffected by ascorbic acid deficiency in spite of the fine, fragile collagenous fibrils identified in the bones of our animal model.

Eldecalcitol, a second-generation vitamin D analog, drives bone minimodeling and reduces osteoclastic number in trabecular bone of ovariectomized rats.

To elucidate the histological events that follow administration of eldecalcitol, a second-generation of vitamin D analog currently awaiting approval as a drug for treatment of osteoporosis, we employed the ovariectomy (OVX) rat model. OVX rats received vehicle or 30ng/kg of eldecalcitol, and sham-operated animals received vehicle only. Rats were sacrificed after 12weeks and had their femora and tibiae removed and processed for histochemical and histomorphometrical analyses. When compared with OVX group, osteoclastic number and bone resorption parameters were significantly reduced in eldecalcitol-treated rats, accompanied by decreased bone formation parameters. The preosteoblastic layer, with which osteoclastic precursors interact for mutual differentiation, was poorly developed in the eldecalcitol group, indicating less cell-to-cell contact between preosteoblasts and osteoclast precursors. Interestingly, eldecalcitol did promote a type of focal bone formation that is independent of bone resorption, a process known as bone minimodeling. While the number of ED-1-positive macrophages was higher in the bone marrow of treated rats, though osteoclastic number was deceased. Taken together, our findings suggest that eldecalcitol stimulates preosteoblastic differentiation rather than their proliferation, which in turn may prevent or diminish cell-to-cell contact between preosteoblasts and osteoclastic precursors, and therefore, lead to lower osteoclast numbers and decreased bone resorption.

[Animal models for bone and joint disease. Bone disease of osteoprotegerin deficient mouse].

Osteoprotegerin (OPG) acts as a decoy receptor for the receptor activator of the nuclear factor κ B (RANK) ligand (RANKL) , preventing its association with RANK and inhibiting osteoclastogenesis. Therefore, mice homozygous for targeted disruption of the OPG gene reveal stimulated bone resorption and bone formation, resulting in enhanced bone remodeling. The OPG deficient (OPG( - / - )) mouse showed the diturbed distribution of collagen fibers and complex meshwork of cement lines, which implies weakened strength of OPG( - / - ) bone against mechanical stress. In addition, the abnormally promoted remodeling of the OPG( - / - ) bone caused the disorganized distribution of osteocyte lacunar canalicular system (OLCS) . Histochemical assessment revealed the markedly reduced synthesis of sclerostin in the OPG( - / - ) OLCS while the synthesis of dentin matrix protein-1 was not extremely affected by the OPG deficiency. Taken together, OPG deficient mouse appears to be a valid model for extremely-stimulated bone remodeling, and would provided important clues for better understanding for activities of bone cells in a pathological state in bone.