Development of bifunctional oriented bioactive glass/poly(lactic acid) composite scaffolds to control osteoblast alignment and proliferation

During the bone regeneration process, the anisotropic microstructure of bone tissue (bone quality) recovers much later than bone mass (bone quantity), resulting in severe mechanical dysfunction in the bone. Hence, restoration of bone microstructure in parallel with bone mass is necessary for ideal bone tissue regeneration; for this, development of advanced bifunctional biomaterials, which control both the quality and quantity in regenerated bone, is required. We developed novel oriented bioactive glass/poly(lactic acid) composite scaffolds by introducing an effective methodology for controlling cell alignment and proliferation, which play important roles for achieving bone anisotropy and bone mass, respectively. Our strategy is to manipulate the cell alignment and proliferation by the morphological control of the scaffolds in combination with controlled ion release from bioactive glasses. We quantitatively controlled the morphology of fibermats containing bioactive glasses by electrospinning, which successfully induced cell alignment along the fibermats. Also, the substitution of CaO in Bioglass®(45S5) with MgO and SrO improved osteoblast proliferation, indicating that dissolved Mg 2+ and Sr 2+ ions promoted cell adhesion and proliferation. Our results indicate that the fibermats developed in this work are candidates for the scaffolds to bone tissue regeneration that enable recovery of both bone quality and bone quantity. © 2019 The Authors. journal Of Biomedical Materials Research Part A Published By Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1031–1041, 2019.Lee S., Matsugaki A., Kasuga T., et al. Development of bifunctional oriented bioactive glass/poly(lactic acid) composite scaffolds to control osteoblast alignment and proliferation. Journal of Biomedical Materials Research - Part A, 107, 5, 1031. https://doi.org/10.1002/jbm.a.36619

Oriented siloxane-containing vaterite/poly(lactic acid) composite scaffolds for controlling osteoblast alignment and proliferation

Bone tissue has an anisotropic structure, which is strongly associated with the collagen fibril orientation and the direction of the c-axis of the bone apatite crystal. The bone regeneration process contains two main phases: bone mineral density (BMD; bone quantity) restoration and reconstruction of the bone apatite c-axis orientation (bone quality), which is the dominant factor for the mechanical properties of bone. Hence, restoration of the bone quality and quantity is required for bone tissue regeneration. In this work, novel, oriented siloxane-containing vaterite/poly(lactic acid) composite scaffolds were developed by controlling the cell alignment and proliferation, which play an important role in regenerating the bone quality and quantity, respectively. Our strategy controlled the cell alignment and proliferation using a morphological design of the scaffolds and the ions released from the siloxane-containing vaterite. The scaffolds were designed to control of the cell alignment, which successfully induced cell orientation along the fibermats. In addition, the released ions from the siloxane-containing vaterite improved osteoblast proliferation, indicating that the released Mg 2+ and silicate ions stimulated cell adhesion and proliferation. These results indicated that the fibermats developed in this work could be used for bone tissue regeneration scaffolds that enable the recovery of bone quality and quantity.Lee S., Kiyokane Y., Kasuga T., et al. Oriented siloxane-containing vaterite/poly(lactic acid) composite scaffolds for controlling osteoblast alignment and proliferation. Journal of Asian Ceramic Societies, 7, 2, 228. https://doi.org/10.1080/21870764.2019.1599528

KAgoshima Galactic Object survey with Nobeyama 45-metre telescope by Mapping in Ammonia lines (KAGONMA): Discovery of parsec-scale CO depletion in the Canis Major star-forming region

In observational studies of infrared dark clouds, the number of detections of CO freeze-out onto dust grains (CO depletion) at pc-scale is extremely limited, and the conditions for its occurrence are, therefore, still unknown. We report a new object where pc-scale CO depletion is expected. As a part of Kagoshima Galactic Object survey with Nobeyama 45-m telescope by Mapping in Ammonia lines (KAGONMA), we have made mapping observations of NH3 inversion transition lines towards the star-forming region associated with the CMa OB1 including IRAS 07077-1026, IRAS 07081-1028, and PGCC G224.28-0.82. By comparing the spatial distributions of the NH3 (1,1) and C18O (J=1-0), an intensity anti-correlation was found in IRAS 07077-1026 and IRAS 07081-1028 on the ~1 pc scale. Furthermore, we obtained a lower abundance of C18O at least in IRAS 07077-1026 than in the other parts of the star-forming region. After examining high density gas dissipation, photodissociation, and CO depletion, we concluded that the intensity anti-correlation in IRAS 07077-1026 is due to CO depletion. On the other hand, in the vicinity of the centre of PGCC G224.28-0.82, the emission line intensities of both the NH3 (1,1) and C18O (J=1-0) were strongly detected, although the gas temperature and density were similar to IRAS 07077-1026. This indicates that there are situations where C18O (J=1-0) cannot trace dense gas on the pc scale and implies that the conditional differences that C18O (J=1-0) can and cannot trace dense gas are unclear.Comment: 19 pages, 15 figures, 4 tables, accepted for Publications of the Astronomical Society of Japan (PASJ). The version 1 is the Author's Original Version. My accepted manuscript will be publicly available on the arXiv one year after publication in the PAS

Development of orthophosphosilicate glass/poly(lactic acid) composite anisotropic scaffolds for simultaneous reconstruction of bone quality and quantity

Reconstruction of organ-specific architecture is necessary to recover the original organ function. The anisotropic structure of bone tissue is strongly related to the collagen fibril alignment and bone apatite crystal direction. Bone regeneration indicates following two main process; first, restoration of bone mineral density (BMD; bone quantity), and second, restoring bone apatite c-axis orientation (bone quality). In addition to BMD, bone quality is the most important factor among bone mechanical properties. Recovery of the original bone function requires development of novel scaffolds with simultaneous reconstruction of bone quality and quantity. Herein, novel orthophosphosilicate glass (PSG)/poly(lactic acid) composite anisotropic scaffolds were developed to control cell alignment and enhance bone formation, which are important for the simultaneous reconstruction of bone quality and quantity. The strategy to control cell alignment and bone formation involved designing anisotropic scaffolds in combination with the release of therapeutic ions by PSGs. The morphology of fibrous scaffolds containing PSGs was quantitatively designed using electrospinning. This successfully modulated cell alignment and subsequent bone apatite c-axis orientation along the fiber-oriented direction. The released silicate and Mg2+ ions from PSGs in scaffolds improved cell adhesion, proliferation, and calcification. To best of our knowledge, this is the first report demonstrating that the anisotropic scaffolds containing bioactive glasses regenerate bone tissues with simultaneous reconstruction of bone quality and quantity via stimulating osteoblasts by inorganic ions and designing morphology of scaffolds.Lee S., Nagata F., Kato K., et al. Development of orthophosphosilicate glass/poly(lactic acid) composite anisotropic scaffolds for simultaneous reconstruction of bone quality and quantity. Journal of Biomedical Materials Research - Part A, 109, 5, 788. https://doi.org/10.1002/jbm.a.37067

Structures and dissolution behaviors of quaternary CaO-SrO-P₂O₅-TiO₂ glasses

Calcium phosphate glasses have a high potential for use as biomaterials because their composition is similar to that of the mineral phase of bone. Phosphate glasses can dissolve completely in aqueous solution and can contain various elements owing to their acidity. Thus, the glass can be a candidate for therapeutic ion carriers. Recently, we focused on the effect of strontium ions for bone formation, which exhibited dual effects of stimulating bone formation and inhibiting bone resorption. However, large amounts of strontium ions may induce a cytotoxic effect, and there is a need to control their releasing amount. This work reports fundamental data for designing quaternary CaO-SrO-P₂O₅-TiO₂ glasses with pyro- and meta-phosphate compositions to control strontium ion-releasing behavior. The glasses were prepared by substituting CaO by SrO using the melt-quenching method. The SrO/CaO mixed composition exhibited a mixed cation effect on the glassification degree and ion-releasing behavior, which showed non-linear properties with mixed cation compositions of the glasses. Sr²⁺ ions have smaller field strength than Ca²⁺ ions, and the glass network structure may be weakened by the substitution of CaO by SrO. However, glassification degree and chemical durability of pyro- and meta-phosphate glasses increased with substituted all CaO by SrO. This is because titanium groups in the glasses are closely related to their glass network structure by SrO substitution. The P-O-Ti bonds in pyrophosphate glass series and TiO₄ tetrahedra in metaphosphate glass series increased with substitution by SrO. The titanium groups in the glasses were crosslink and/or coordinate phosphate groups to improve glassification degree and chemical durability. Sr²⁺ ion releasing amount of pyrophosphate glasses with >83% SrO substitution was larger than 0.1 mM at day seven, an amount that reported enhanced bone formation by stimulation of osteogenic markers.Lee S., Nagata F., Kato K., et al. Structures and dissolution behaviors of quaternary CaO-SrO-P₂O₅-TiO₂ glasses. Materials, 14, 7, 1736. https://doi.org/10.3390/ma14071736

Program study of mountaineering as outdoor education - The example of safety management that uses physiological index -

The purpose of this study was to practice the effects of outdoor education in college students who participated in a 4-days nature recreational trekking course. Mountaineering or trekking mountain contains very important activities for understanding the nature. Understanding of the nature in the world can draw the interest in environmental disruption. The mountaineering or trekking activities include of outdoor education programs can help improving the quality of environment and life style by students. It is important to consider carefully our spiritual health,social.health ,and even wellness life style through the mountaineering or trekking activites proguram. The intensity of heart rates in physical exercise is the important index to understand safety mountaineering or trekking activities program. And oxygen saturation is the important index of mountain sickness as hypoxia. In this program we recognize the safety management that uses physiological index heart rates and oxygen saturation for physical stress. The educational effect of outdoor activity in the physical education of liberal arts is to understand natural environment,and also to understand the safe range of physical activity. Although muscular fatigue was observed,the subjective symptoms of acute mountain sickness were not observed. It is concluded that measurements of physiological parameters during mountain climbing is useful for risk management in outdoor education

Ammonia mapping observations of the Galactic infrared bubble N49: Three NH3_3 clumps along the molecular filament

We have carried out the NH$_3$ $(J,K)=(1,1),(2,2),$ and $(3,3)$ mapping observations toward the Galactic infrared bubble N49 (G28.83-0.25) using the Nobeyama 45 m telescope. Three NH$_3$ clumps (A, B, and C) were discovered along the molecular filament with the radial velocities of $\sim$ 96, 87, and 89 km s$^{-1}$, respectively. The kinetic temperature derived from the NH$_3$ (2,2)/NH$_3$ (1,1) shows $T_{\rm kin} = 27.0 \pm 0.6$ K enhanced at Clump B in the eastern edge of the bubble, where position coincides with massive young stellar objects (MYSOs) associated with the 6.7 GHz class II methanol maser source. This result shows the dense clump is locally heated by stellar feedback from the embedded MYSOs. The NH$_3$ Clump B also exists at the 88 km s$^{-1}$ and 95 km s$^{-1}$ molecular filament intersection. We therefore suggest that the NH$_3$ dense gas formation in Clump B can be explained by a filament-filament interaction scenario. On the other hand, NH$_3$ Clump A and C at the northern and southern side of the molecular filament might be the sites of spontaneous star formation because these clumps are located $\sim$5$-$10 pc away from the edge of the bubble.Comment: 29 pages, 13 figures, 3 tables, accepted for Publications of the Astronomical Society of Japan (PASJ