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Astrophysical reactions involving radioactive isotopes (RI) often play an important role in high-temperature stellar environments. The experimental studies on the reaction rates for those are still limited mainly due to the technical difficulties in producing high-quality RI beams. A direct measurement of those reactions would be still challenging in many cases, however, we can make a reliable evaluation of the reaction rates by an indirect method or by studying the resonance prorerties. Here we ntroduce recent examples of experimental studies on such RI-involving astrophysical reactions, performed at Center for Nuclear Study, the University of Tokyo, using the low-energy RI beam separator CRIB. One is for the neutron-induced destruction reactions of 7Be in the Big-Bang nucleosynthesis, and the other is the study on the 22Mg(α, p) reaction relevant in X-ray bursts, which was performed with the resonant scattering method from the inverse reaction channel.

The distribution of dopant atoms plays a key role in the effectiveness of doping, thereby requiring delicate characterizations. In this study, we found that energy-dispersive X-ray spectroscopy (EDX) and electron energy loss spectroscopy (EELS) techniques in scanning transmission electron microscopy (STEM) were not adequate to reveal the distribution of yttrium and the chemical composition of the ZrO2/SiO2 heterophase interface in an yttrium-doped ZrO2-SiO2 nanocrystalline glass-ceramic. Atom probe tomography (APT) is rarely utilized to characterize ceramics due to some inherent difficulties. However, we successfully revealed the three-dimensional distribution of ZrO2 nanocrystallites and SiO2 matrix at the atomic scale with APT under optimized and well-controlled conditions. We also found that the ZrO2 nanocrystallites had a special core-shell structure, with a thin Zr/Si interfacial layer as a shell and a ZrO2 solid solution as a core. Yttrium dopants showed interfacial segregation at both ZrO2 grain boundaries and the ZrO2/SiO2 heterophase interfaces.

Development of coatings with tailored surface properties that enhance bone growth is crucial to enhancing the life span of load bearing implants. Bioactive ceramic–polysaccharide hydrogel composite...

Experimental studies on astrophysical reactions involving radioactive isotopes (RI) often accompany technical challenges. Studies on such nuclear reactions have been conducted at the low-energy RI beam separator CRIB, operated by Center for Nuclear Study, the University of Tokyo. We discuss two cases of astrophysical reaction studies at CRIB; one is for the 7Be+n reactions which may affect the primordial 7Li abundance in the Big-Bang nucleosynthesis, and the other is for the 22Mg(α, p) reaction relevantin X-raybursts.

Healthcare acquired infections are a major human health problem, and are becoming increasingly troublesome with the emergence of drug resistant bacteria. Engineered surfaces that reduce the adhesion, proliferation, and spread of bacteria have promise as a mean of preventing infections and reducing the use of antibiotics. To address this need, we created a flexible plastic wrap that combines a hierarchical wrinkled structure with chemical functionalization to reduce bacterial adhesion, biofilm formation, and the transfer of bacteria through an intermediate surface. These hierarchical wraps were effective for reducing biofilm formation of World Health Organization-designated priority pathogens Gram positive methicillin-resistant Staphylococcus aureus (MRSA) and Gram negative Pseudomonas aeruginosa by 87 and 84%, respectively. In addition, these surfaces remain free of bacteria after being touched by a contaminated surface with Gram negative E. coli. We showed that these properties are the result of broad liquid repellency of the engineered surfaces and the presence of reduced anchor points for bacterial adhesion on the hierarchical structure. Such wraps are fabricated using scalable bottom-up techniques and form an effective cover on a variety of complex objects, making them superior to top-down and substrate-specific surface modification methods.

Double perovskite Eu2NiMnO6 (ENMO) Gd2NiMnO6 (GNMO) and Tb2NiMnO6 (TNMO) ceramic powder have been synthesized by solid-state reaction and their crystal structure, microstructure, cryogenic magnetic properties, and magnetocaloric performance have been investigated. Structural studies by using X-ray diffraction shows that all compounds crystallize in the monoclinic structure with a P21/n space group. A ferromagnetic to paramagnetic (FM-PM) second-order phase transition occurred in ENMO, GNMO, and TNMO around 143, 130, and 112 K, respectively. The values of maximum magnetic entropy change and relative cooling power at an applied field of 5 T are found to be 3.2, 3.8, 3.5 J/kgK and 150, 182, 176 J/kg respectively, for the studied sample. The change in structural, magnetic, and magnetocaloric effect ascribed to the superexchange mechanism of Ni2+ – O – Mn3+ and Ni2+ – O – Mn4+. Due to different atomic size of Eu, Gd, Tb changes the ratio of Mn4+/Mn3+ which is responsible for the variation of properties significantly in double perovskite.

The industrial injection of carbon dioxide into ready mixed concrete during mixing and batching can produce a measurable increase in hydration and a significant compressive strength increase. Physiochemical aspects of the mechanism were investigated through the analysis of a model tricalcium silicate system activated with a carbon dioxide addition immediately after hydration started. The attendant effects were examined through isothermal calorimetry, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). Carbonate reaction products around 70 nm were observed to have formed within 60 s of the CO2 gas injection. Within 10 min the carbonates have been covered by new hydration products. The initial product formed appears to be an amorphous or poorly crystalline calcium carbonate. The overall reaction over 24 h was the same for the hydrated and CO2-activated cases although the latter instance included the formation of carbonate reaction products.

In schistosomiasis mansoni, soluble egg antigens of the worm induce chronic T-cell-mediated granulomatous tissue responses. Since the first preparation of crude soluble egg antigen extract, a dearth of highly purified antigens has hampered the identification of granuloma inducer molecules. Here we report that a cloned 38-kDa egg polypeptide (r38) with homologies to small heat shock proteins is a strong immunogen. The recombinant and the sodium dodecyl sulfate-polyacrylamide gel electrophoresis separated and eluted native 38-kDa (p38) polypeptides, used in microgram amounts and unaided by adjuvant, sensitized mice for a Th1-type immune response, with strong interleukin-2 (IL-2) and gamma interferon secretion but no IL-4 and IL-10 secretion. Extensive cross-reactivity between these two polypeptides was evident. THis pattern was confirmed by reverse transcription-PCR that showed strong IL-2 and gamma interferon message expression but trace amounts of IL-4 message expression in r38-sensitized splenocytes. In mice, the polypeptide induced pulmonary mononuclear granuloma formation around antigen-coupled beads or worm eggs. We propose that the superior immunogenicity of r38 is linked to its relatedness to small heat shock proteins and that the 38-kDa polypeptide may induce the Th1 cytokine responses observed during the early development phase of the egg-induced granuloma.

This work presents a successful methodology to image mammalian cells adhered to nanostructured titanium by using scanning electron microscopy (SEM) operating in low-vacuum mode following ionic liquid treatment. Human osteoblast-like Saos-2 cells were treated with a room-temperature ionic liquid, 1-ethyl-3-methylimidazolium tetrafluoroborate, and subsequently imaged on titanium by SEM. Titanium substrates were modified to create laser-induced periodic surface structures (LIPSS) for visualization at the submicron scale. By using a combination of fluorescence-based cell metabolism along with light microscopy and SEM image analysis, the shape and location of irradiated cells were confirmed to be unchanged after multiple irradiation sessions; the viability of minimally irradiated cells was also unaltered. The wet imaging conditions combined with a rapid facile protocol using ionic liquid allows this technique to fulfill a niche in examining cellular behavior on biomaterials with submicron surface features. The demonstrated method to track observed cell adhesion to submicron surface features by SEM has great implications for understanding cell migration on nanostructured surfaces as well as the exploration of simpler SEM preparation methods for cellular imaging.

Post-operative therapy for joint replacement is often performed to optimize bone volume and bone-implant contact. Methods, such as pulsed therapeutic ultrasound, have been shown to be a valuable addition to regular physiotherapy to increase bone regeneration. To evaluate the efficacy of kilohertz-frequency (kHz) resonant stimuli to additively manufactured implant analogues, Saos-2 cells were seeded onto porous stainless steel scaffolds and flat substrates. Resonant frequency modes were mapped in the low kHz range, and cells were subjected to daily stimulus for 10 min at a frequency of 1.278 kHz. kHz-frequency excitation was found to increase normalized alkaline phosphatase production by almost twofold on metallic substrates relative to non-vibrated control scaffolds, while peak velocity influenced alkaline phosphatase production on porous scaffolds but not flat substrates. Total cell proliferation was downregulated by excitation, and all excited samples displayed larger variability. This work indicates that vibration within the range of 0.16–0.48 mm/s may reduce cell proliferation, but favour osteogenic gene expression. This study highlights the potential of using kHz-resonance therapy to mitigate early-onset pore occlusion to achieve uniform osseointegration through porous metallic scaffolds.

For the first time, an electrophoretic deposition (EPD) method has been developed for the deposition of polymethylmethacrylate (PMMA) and PMMA-alumina films for biomedical implant applications. The proposed biomimetic approach was based on the use of a bile salt, sodium cholate (NaCh), which served as a multifunctional solubilizing, charging, dispersing and film-forming agent. Investigations revealed PMMA-Ch- and PMMA-alumina interactions, which facilitated the deposition of PMMA and PMMA-alumina films. This approach allows for the use of a non-toxic water-ethanol solvent for PMMA. The proposed deposition strategy can also be used for co-deposition of PMMA with other functional materials. The PMMA and composite films were tested for biomedical implant applications. The PMMA-alumina films showed statistically improved metabolic results compared to both the bare stainless steel substrate and pure PMMA films. Alkaline phosphatase (ALP) activity affirmed the bioactivity and osteoconductive potential of PMMA and composite films. PMMA-alumina films showed greater ALP activity than both the PMMA-coated and uncoated stainless steel.

Reproducible and controllable methods of modifying titanium surfaces for dental and orthopaedic applications are of interest to prevent poor implant outcomes by improving osseointegration. This study made use of a femtosecond laser to generate laser-induced periodic surface structures with periodicities of 300, 620 and 760 nm on titanium substrates. The reproducible rippled patterns showed consistent submicron scale roughness and relatively hydrophobic surfaces as measured by atomic force microscopy and contact angle, respectively. Transmission electron microscopy and Auger electron spectroscopy identified a thicker oxide layer on ablated surfaces compared to controls. In vitro testing was conducted using osteosarcoma Saos-2 cells. Cell metabolism on the laser-ablated surfaces was comparable to controls and alkaline phosphatase activity was notably increased at late time points for the 620 and 760 nm surfaces compared to controls. Cells showed a more elongated shape on laser-ablated surfaces compared to controls and showed perpendicular alignment to the periodic structures. This work has demonstrated the feasibility of generating submicron features on an implant material with the ability to influence cell response and improve implant outcomes.

Bone is a complex, hierarchical structure comprised of two distinct phases: the organic, collagen– rich phase and the inorganic mineral–rich phase. This collagen–mineral arrangement has implications for bone function, aging, and disease. However, strategies to extract a single mineralized collagen fibril to investigate the interplay between components with sufficient resolution have been mostly confined to in vitro systems that only approximate the biological environment or transmission electron microscopy studies with lower spatial and chemical resolution. Therefore, there is extensive debate over the location of mineral with respect to collagen in in vivo mineralized tissues as visualization and quantification of the mineral in a living system is difficult or impossible. Herein, we have developed an approach to artificially extract a single mineralized collagen fibril from bone to analyze its composition and structure atom-by-atom with 3D resolution and sub-nanometer accuracy using atom probe tomography. This enables, for the first time, a method to probe fibril-level mineralization and collagen–mineral arrangement from an in vivo system with both the spatial and chemical precision required to comment on collagen– mineral arrangement. Using atom probe tomography, 4D (spatial + chemical) reconstructed volumes of leporine bone were generated with accuracy from correlative scanning electron microscopy. Distinct, winding collagen fibrils were identified with mineralized deposits both encapsulating and incorporated into the collagenous structures. This work demonstrates a novel fibril-level detection method that can be used to probe structural and chemical changes of bone and contribute new insights to the debate on collagen–mineral arrangement in mineralized tissues such as bones, and teeth.

To compare the efficacy and safety of transoral robotic surgery (TORS) with endoscope-guided coblation tongue base resection.Retrospective case-control study.University-based tertiary care medical center.Patients with obstructive sleep apnoea (OSA) who underwent endoscope-guided tongue base coblation resection or transoral robotic surgery (TORS) in combination with lateral pharyngoplasty at a single institution in South Korea between April 2013 and December 2016 were investigated. Forty-five patients who had moderate-to-severe OSA with tongue base collapse and a minimum follow-up period of 6 months with postoperative polysomnography (PSG) were enrolled in this study.All patients underwent pre- and postoperative (at least 4 months after surgery) overnight PSG. Available information on results of the PSG, Epworth sleepiness scale and complications of the TORS and coblation groups were compared.Postoperative PSG studies showed improved sleep quality for most patients. The mean postoperative apnoea-hypopnea index (AHI) was reduced significantly from 45.0 to 17.0 events/h (P .0001) in the TORS group and from 45.6 to 16.2 events/h (P .0001) in the coblation group. The mean rates of improvement (AHI reduction 50%) were 75.0% in TORS patients and 62.1% in coblation patients and the difference was not significant. Less frequent postoperative morbidity, including bleeding, taste dysfunction and foreign body sensation, was recorded in TORS patients.Both the coblation and TORS groups showed similar surgical outcomes, TORS achieved PSG results non-inferior to and complication rates comparable to coblation.

In this pilot study, a 3D printed Grade V titanium dental implant with a novel dual-stemmed design was investigated for its biocompatibility in vivo. Both dual-stemmed (n = 12) and conventional stainless steel conical (n = 4) implants were inserted into the tibial metaphysis of New Zealand white rabbits for 3 and 12 weeks and then retrieved with the surrounding bone, fixed, dehydrated, and embedded into epoxy resin. The implants were analyzed using correlative histology, microcomputed tomography, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The histological presence of multinucleated osteoclasts and cuboidal osteoblasts revealed active bone remodeling in the stemmed implant starting at 3 weeks and by 12 weeks in the conventional implant. Bone-implant contact values indicated that the stemmed implants supported bone growth along the implant from the coronal crest at both 3- and 12-week time periods and showed bone growth into microporosities of the 3D printed surface after 12 weeks. In some cases, new bone formation was noted in between the stems of the device. Conventional implants showed mechanical interlocking but did have indications of stress cracking and bone debris. This study demonstrates the comparable biocompatibility of these 3D printed stemmed implants in rabbits up to 12 weeks.

Implanted devices are prone to bacterial infections, which can result in implant loosening and device failure. Mitigating these infections is important to both implant stability and patient health. The development of antibacterial implant coatings can decrease the presence of bacterial colonies, reducing the risk for bacterial-dependent implant failure. Here, we show that electrospun polycaprolactone (PCL) fibers doped with silver nanoparticles (NPs) from a silver nitrate precursor have the potential to decrease the prevalence of Streptococcus pneumoniae while supporting osteoblast attachment and proliferation. An air plasma reduction method of PCL electrospun fibers was used to prepare fibers doped with silver NPs. Fibers were characterized using scanning electron microscopy and transmission electron microscopy for qualitative evaluation of NP distribution and quantitative analysis of fiber diameters. Antibacterial testing against S. pneumoniae was performed with successful inhibition observed after 24 h of exposure. In vitro testing was completed using Saos-2 cells and suggests that the negative surface charge has the potential to increase mammalian cell viability even in the presence of fibers containing NPs. In conclusion, this study describes a novel method to produce bioresorbable implant coatings with the ability to reduce bacterial infections surrounding the implant surface while remaining biocompatible to the host.

Surface modifications of titanium are widespread in an effort to improve the osseointegration capabilities of the metal for orthopaedic and dental applications. Here, electrical discharge machining (EDM) was used to create modified, notably, dual-topography surfaces on titanium. By swapping conventional copper electrodes for a titanium electrode and water dielectric, modified surfaces free of trace element contaminants were produced. Three surfaces were produced by varying the peak currents at 10 A, 29 A and a uniquely hierarchical multi-current combination of 29 A followed by 2.4 A. The physicochemical properties of these surfaces were analyzed by scanning electron microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDX), and Auger Spectroscopy. These revealed the topography of the modified surfaces and a titanium oxide layer that was markedly thicker on the EDM samples compared to controls. In vitro cell testing was carried out with osteoblast-like MC3T3-E1 cells. Cell differentiation was increased in all EDM modified surfaces compared to controls and early differentiation was promoted on the dual-topography surface. The present study suggests the promise of dual-topography surfaces created using EDM for implant applications.

Modifications to the compositional, topographical and morphological aspects of bone implants can lead to improved osseointegration, thus increasing the success of bone implant procedures. This study investigates the creation of dual-scale topography on Ti-5Al-5Mo-5V-3Cr (Ti5553), an alloy not presently used in the biomedical field, and compares it to Ti-6Al-4V (Ti64), the most used Ti alloy for bone implants. Dual-scale surface topography was obtained by combining selective laser melting (SLM) and electrochemical anodization, which resulted in micro- and nanoscale surface features, respectively. Ti5553 and Ti64 samples were manufactured by SLM and showed comparable surface topography. Subsequent electrochemical anodization succeeded in forming titania nanotubes (TNTs) on both alloys, with larger nanotubes obtained with Ti5553 at all investigated anodization voltages. At an anodization voltage of 40 V, a minimum time of 20 min was necessary to have nanotube formation on the surface of either alloy, while only nanopores were evident for shorter times. Seeded Saos-2 cells showed ideal interactions with surface-modified structures, with filopodia extending to both surface microparticles characteristic of SLM and to the interior of TNTs. Attractiveness of Ti5553 lies in its lower elastic modulus (E = 72 GPa) compared to Ti64, which should mitigate stress-shielding phenomena in vivo. This, combined with the analogous results obtained in terms of dual-scale surface topography and cell-substrate interaction, could indicate Ti5553 as a promising alternative to the widely-employed Ti64 for bone implant device manufacturing.

Chemically cross-linked cellulose nanocrystal (CNC) aerogels possess many properties beneficial for bone tissue scaffolding applications. CNCs were extracted using sulfuric acid or phosphoric acid, to produce CNCs with sulfate and phosphate half-ester surface groups, respectively. Hydrazone cross-linked aerogels fabricated from the two types of CNCs were investigated using scanning electron microscopy, X-ray micro-computed tomography, X-ray photoelectron spectroscopy, nitrogen sorption isotherms, and compression testing. CNC aerogels were evaluated in vitro with osteoblast-like Saos-2 cells and showed an increase in cell metabolism up to 7 days while alkaline phosphatase assays revealed that cells maintained their phenotype. All aerogels demonstrated hydroxyapatite growth over 14 days while submerged in simulated body fluid solution with a 0.1 M CaCl2 pre-treatment. Sulfated CNC aerogels slightly outperformed phosphated CNC aerogels in terms of compressive strength and long-term stability in liquid environments, and were implanted into the calvarian bone of adult male Long Evans rats. Compared to controls at 3 and 12 week time points, sulfated CNC aerogels showed increased bone volume fraction of 33% and 50%, respectively, compared to controls, and evidence of osteoconductivity. These results demonstrate that cross-linked CNC aerogels are flexible, porous and effectively facilitate bone growth after they are implanted in bone defects. Statement of Significance Due to the potential complications associated with autografts, there is a need for synthetic bone tissue scaffolds. Here, we report a new naturally-based aerogel material for bone regeneration made solely from chemically cross-linked cellulose nanocrystals (CNC). These highly porous CNC aerogels were shown to promote the proliferation of bone-like cells and support the growth of hydroxyapatite on their surface in vitro. The first in vivo study on these materials was conducted in rats and showed their osteconductive properties and an increase in bone volume up to 50% compared to sham sites. This study demonstrates the potential of using functionalized cellulose nanocrystals as the basis for aerogel scaffolds for bone tissue engineering.

For the first time, a biomimetic method has been developed for the chemical modification of poly-l-lysine (PLL) with catechol in order to improve polymer adhesion to inorganic particles and surfaces. The method is based on the Schiff base reaction of amino groups of PLL monomers and aldehyde groups of 3,4-dihydroxybenzylaldehyde (DHBA) molecules. It was found that adherent PLL-DHBA films can be prepared by cathodic electrophoretic deposition (EPD). Nanocomposite coating with dual micro-nano topography has been developed for orthopaedic and dental coating applications. The catechol groups of PLL-DHBA facilitated its adsorption on hydroxyapatite (HA) and rutile (TiO2) and allowed the fabrication of stable suspensions for EPD. PLL-DHBA was used as both a charging and film-forming agent for EPD of HA and TiO2. Moreover, the methods allowed co-deposition of HA and TiO2 and fabrication of composite films, which allows the benefits of both bioceramics to be combined. In addition to having dual scale topography, the films exhibited both sub-micron surface roughness and hydrophilic behaviour, which both have been found to promote osteoblast adhesion and proliferation. in vitro studies revealed that the fabricated coatings showed increased cell metabolism and alkaline phosphatase activity over the period studied, with PLL-DHBA-TiO2 showing the greatest increase. This work paves the way for both the development of the next generation of biomedical implant coatings, with improved osseointegration and lifespan, as well as one-step low-temperature processing.

Osteocytes are contained within spaces called lacunae and play a central role in bone remodelling. Administered frequently to prevent osteoporotic fractures, anti-resorptive agents such as bisphosphonates suppress osteocyte apoptosis and may be localised within osteocyte lacunae. Bisphosphonates also reduce osteoclast viability, and thereby hinder the repair of damaged tissue. Osteocyte lacunae contribute to toughening mechanisms. Following osteocyte apoptosis, the lacunar space undergoes mineralisation, termed ‘micropetrosis’. Hypermineralised lacunae are believed to increase bone fragility. Using nano-analytical electron microscopy with complementary spectroscopic and crystallographic experiments, post-apoptotic mineralisation of osteocyte lacunae in bisphosphonate-exposed human bone was investigated. We report an unprecedented presence of ~80 nm to ~3 µm wide, distinctly facetted, magnesium whitlockite [Ca18Mg2(HPO4)2(PO4)12] crystals and consequently altered local nanomechanical properties. These find...

The mid-latitude zone can be broadly defined as part of the hemisphere between 30°–60° latitude. This zone is home to over 50 % of the world population and encompasses about 36 countries throughout the principal region, which host most of the world’s development and poverty related problems. In reviewing some of the past and current major environmental challenges that parts of mid-latitudes are facing, this study sets the context by limiting the scope of mid-latitude region to that of Northern hemisphere, specifically between 30°–45° latitudes which is related to the warm temperate zone comprising the Mid-Latitude ecotone – a transition belt between the forest zone and southern dry land territories. The ongoing climate change reveals a substantial increase of temperature and simultaneous decrease in the amount of precipitation across vast continental regions in the mid-latitudes. According to climatic predictions, these tendencies will continue during the 21st century, which will likely increase the frequency and severity of droughts and water stress of vegetation. Along with climate change, ongoing land degradation and deforestation are observed in many regions of the mid-latitude region. For example, the Korean peninsula, which is divided into South and North Korea, is characterized by drastically different forest conditions. Deforestation in North Korea has been exacerbating at a noticeable pace due to excessive logging and human intervention. Such problems are not confined to Korean peninsula but are witnessed across vast regions of the mid-latitude region. Within this context – acquiring better understanding in the role of terrestrial ecosystems located at different latitudes is critical – for building resilience against the negative impact of climate change and for maintaining the stability of the environment and landscapes.

Effective methods of accelerating the bone regeneration healing process are in demand for a number of bone-related diseases and trauma. This work developed scaffolds with improved properties for bone tissue engineering by electrospinning composite polycaprolactone-gelatin-hydroxyapatite-niobium pentoxide (PGHANb) membranes. Composite membranes, with average fiber diameters ranging from 123 to 156 nm, were produced by adding hydroxyapatite (HA) and varying concentrations of niobium pentoxide (Nb2O5) particles (0, 3, 7, and 10 wt%) to a polycaprolactone (PCL) and gelatin (GL) matrix prior to electrospinning. The morphology, mechanical, chemical and biological properties of resultant membranes were evaluated. Bioactivity was assessed using simulated body fluid (SBF) and it confirmed that the presence of particles induced the formation of hydroxyapatite crystals on the surface of the membranes. Samples were hydrophilic and cell metabolism results showed that the niobium-containing membranes were non-toxic while improving cell proliferation and differentiation compared to controls. This study demonstrated that electrospun membranes containing HA and Nb2O5 particles have potential to promote cell adhesion and proliferation while exhibiting bioactive properties. PGHANb membranes are promising candidates for bone tissue engineering applications.

Transmission electron microscopic (TEM) images of ion-milled bovid cortical bone cut approximately normal to the axes of fibrils show that mineral occurs in the form of plates surrounding and laying between circular or elliptical features about 50 nm in diameter. The classification of these features as either pores or collagen fibrils is highly debated. Electron energy loss spectroscopy (EELS) mapping of these features in ion milled sections shows that they are lacking significant amounts of mineral or collagen, although their appearance suggests that they are cross sections of collagen fibrils. However, analogous sections prepared using an ultramicrotome show that, while these circular features show reduced concentrations of calcium and phosphorus, some of them contain quantities of carbon and nitrogen in bonding states comparable to the composition of collagen. This work demonstrates that the observed circular features are sections of collagen fibrils, but that bombardment by argon ions during broad beam ion milling destroys the collagen and associated gap-zone mineral.

Osteocytes are key contributors to bone remodeling. During the remodeling process, trapped osteoblasts undergo a phenotypic change to become osteocytes. The specific mechanisms by which osteocytes work are still debatable and models that exist to study them are sparse. This work presents an in vitro, bioprinted model based on the previously developed technique, ExCeL, in which a cell-embedded hydrogel is printed and immediately crosslinked using paper as a crosslinker-storing substrate. This process mimics the phenotypical change of osteoblast to osteocyte by altering the mechanical properties of the hydrogel. By printing Saos-2, osteosarcoma cells, embedded in the alginate hydrogel with differing mechanical properties, their morphology, protein, and gene expression can be changed from osteoblast-like to osteocyte-like. The stiffer gel is 30 times stiffer and results in significantly smaller cells with reduced alkaline phosphatase activity and expression of osteoblast-marker genes such as MMP9 and TIMP2. There is no change in viability between cells despite encapsulation in gels with different mechanical properties. The results show that the phenomenon of osteoblasts becoming encapsulated during the bone remodeling process can be replicated using the ExCeL bioprinting technique. This model has potential for studying how osteocytes can interact with external mechanical stimuli or drugs.

This study investigates the performance of hybrid renewable microgeneration systems in load sharing application between a detached residential house and a small office building. Two renewable energy systems are investigated: a ground source heat pump (GSHP) system and a hybrid GSHP/fuel cell (FC) system. The renewable systems performance is compared to a conventional system that utilizes boiler and chiller to meet the thermal loads of the two buildings. Models are developed for the three selected systems and then simulated in TRNSYS-17 environment over one full year under Ottawa, Canada weather conditions. The simulation results showed that, by implementing a single GSHP system able to meet both heating and cooling loads of the buildings, an overall energy saving of 39% can be achieved mainly due to the introduction of a significant renewable component. The integrated hybrid GSHP–FC system results an overall energy saving of 24%. However, the hybrid GSHP–FC system generates additional electricity and based on the energy pricing structure can lead to more significant cost savings. Additionally, the GSHP–FC microgeneration system's capability to generate both heat and power at the point of use is considered more attractive for new and remote community applications and for inclusion in the “smart” grid applications.

An experimental field study was performed during the growing season to assess water and nutrient balances in a paddy field over a 3-year period. The plots were separated according to irrigation water: groundwater (TR#1), wastewater (TR#2), and filtered wastewater with ultraviolet (UV) treatment (TR#3). The hydrology and water quality of rainfall, irrigation, surface water, and infiltration were monitored throughout the crop stages. More than half of the total water inflow of about 1840 mm in each treatment was contributed by precipitation and the remainder by irrigation. The water balance analysis indicated that approximately 13% of the total outflow was lost by surface drainage, 30% was consumed by plant uptake, and 57% was lost by evapotranspiration and infiltration. The nitrogen (N) levels in the irrigation water in the mass inputs for TR#1 and TR#3 were 22% and 49%, respectively, while the output balances in the drainage water for TR#1 and TR#3 averaged 2% and 6%, respectively. The N in the crop harvest for TR#1 and TR#3 occupied 59.62 and 121.35 kg ha −1 , respectively. The N in the fertilizer comprised a large proportion of the N in TR#1 while the N in the irrigation water and fertilizer were the major inputs in TR#3. The major P input was fertilizer in TR#3, and crop harvest was a main output in the P balance. In contrast, surface drainage and infiltration were relatively small components, due to the high drainage outlet height. The difference between inputs and crop harvest shows that it is possible to improve water quality by reducing the fertilization rates in paddy fields irrigated with reclaimed wastewater.