| 1. |
- Mukai, M., et al.
(author)
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In-gas-cell laser resonance ionization spectroscopy of Ir-196,Ir-197,Ir-198
- 2020
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In: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 102:5
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Journal article (peer-reviewed)abstract
- Hyperfine structure (HFS) measurements of neutron-rich iridium isotopes Ir-196,Ir-197,Ir-198 (Z = 77, N = 119-121) were performed via in-gas-cell laser resonance ionization spectroscopy at the KEK Isotope Separation System. Magnetic dipole moments mu and isotope shifts were determined from the HFS spectra. The variation of mean-square charge radii and quadrupole deformation parameters of these isotopes were evaluated from the isotope shifts. The mu value of (197)h, agreed with a theoretical value based on the strong coupling model, and the Ir nucleus was interpreted as prolately deformed by the theoretical calculations. The mu values of Ir-196,Ir-198 were also compared with semiempirical values calculated based on the strong coupling model. From the comparison, we can suggest the possible spin values of I-pi = 1,2(-) for Ir-196 and I-pi = 1(-) for Ir-198.
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| 2. |
- Rayyan, Mohammad M., et al.
(author)
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Comparison of interim restorations fabricated by CAD/CAM with those fabricated manually
- 2015
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In: The Journal of prosthetic dentistry (Print). - : Mosby. - 0022-3913 .- 1097-6841. ; 114:3, s. 414-419
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Journal article (peer-reviewed)abstract
- Statement of problem. Interim restorations represent an essential treatment step; however, the optimal resin material for long-term interim restorations requires investigation. Purpose. The purpose of this in vitro study was to compare the color stability, water sorption, wear resistance, surface hardness, fracture resistance, and microleakage of computer-aided design/computer-aided manufacturing-(CAD/CAM) fabricated interim restorations with those of manually fabricated interim restorations. Material and methods. Epoxy replicas were made from a prepared maxillary first premolar. On the replicas, interim crowns were fabricated and divided into the following groups: CAD/CAM poly(methyl methacrylate) (PMMA) blocks (CC), autopolymerizing temporary resin (AP), automix temporary resin (AM), and thermoplastic resin (TP). After cementation, all specimens were subjected to thermocycling and dynamic fatigue. The CIE Laboratory color coordinates were then recorded before and after immersion in coffee, tea, carbonated cola, and red wine. Water sorption was evaluated by using an immersion technique. Wear resistance was measured in a surface abrasion device. Vickers microhardness was measured on polished specimens. Fracture resistance was evaluated by axial loading with a universal testing machine. Marginal dye penetration was evaluated by sectioning the interim restorations after immersion in methylene blue (alpha=.05). Results. Colorimetric analysis revealed a large degree of color alteration (SE) in the manually fabricated interim restorations: AP = Delta E of 6.7 +/- 2); AM = Delta E of 7.1 +/- 1.5), and TP = Delta E of =5.4 +/- 3.1. The CC group demonstrated color stability (Delta E=2.1 +/- 0.2). CAD/CAM interim restorations demonstrated significantly lower water sorption, higher wear resistance, higher surface hardness, and significantly higher fracture resistance (1 289 +/- 56N) compared with manually fabricated interim restorations (AP=996 +/- 45, AM=899 +/- 37, and TP=1179 +/- 41). The stereomicroscopic examination of sectioned specimens demonstrated the absence of dye penetration in all tested specimens. Conclusions. CAD/CAM interim crowns presented stable physical and mechanical properties and may be used for long-term interim restorations.
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| 3. |
- Elmisery, Ahmed M., et al.
(author)
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Privacy-enhanced middleware for location-based sub-community discovery in implicit social groups
- 2016
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In: Journal of Supercomputing. - : Springer Science+Business Media B.V.. - 0920-8542 .- 1573-0484. ; 72:1, s. 247-274
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Journal article (peer-reviewed)abstract
- In our connected world, recommender services have become widely known for their ability to provide expert and personalize information to participants of diverse applications. The excessive growth of social networks, a new kind of services are being embraced which are termed as "group based recommendation services", where recommender services can be utilized to discover sub-communities within implicit social groups and provide referrals to new participants in order to join various sub-communities of other participants who share similar preferences or interests. Nevertheless, protecting participants' privacy in recommendation services is a quite crucial aspect which might prevent participants from exchanging their own data with these services, which in turn detain the accuracy of the generated referrals. So in order to gain accurate referrals, recommendation services should have the ability to discover previously unknown sub-communities from different social groups in a way to preserve privacy of participants in each group. In this paper, we present a middleware that runs on end-users' mobile phones to sanitize their profiles' data when released for generating referrals, such that computation of referrals continues over the sanitized version of their profiles' data. The proposed middleware is equipped with cryptography protocols to facilitate private discovery of sub-communities from the sanitized version of participants' profiles in a university scenario. Location data are added to participants' profiles to improve the awareness of surrounding sub-communities, so the offered referrals can be filtered based on adjacent locations for participant's location. We performed a number of different experiments to test the efficiency and accuracy of our protocols. We also developed a formal model for the tradeoff between privacy level and accuracy of referrals. As supported by the experiments, the sub-communities were correctly identified with good accuracy and an acceptable privacy level.
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| 4. |
- Partiyan, Arthur, et al.
(author)
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Fracture resistance of three-unit zirconia fixed partial denture with modified framework
- 2017
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In: Odontology. - : Springer. - 1618-1247 .- 1618-1255. ; 105:1, s. 62-67
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Journal article (peer-reviewed)abstract
- Obtaining ideal prosthetic framework design is at times hindered by anatomical limitations in the posterior region that might increase the risk for zirconia restoration fracture. Modification such as increasing the bulk thickness especially in the connector region could result in strengthening the zirconia framework. Three-unit zirconia fixed partial dentures replacing mandibular molars were fabricated using the following two techniques: CAD/CAM technology and manual copy milling. Modified framework with unveneered full thickness connectors were designed and fabricated with the aforementioned methods. Conventional frameworks (0.5 mm thick with rounded 3 mm connectors) served as control (N = 20). After cementation on epoxy dies, the frameworks were loaded to fracture in a universal testing machine. Fractured surfaces were prepared for examination using scanning electron microscopy. Statistical analysis revealed significant differences in fracture resistance between conventional and modified framework design for both fabrication techniques tested. SEM examination indicated that critical crack originated at the tensile surface of the connectors for conventional frameworks. The critical crack for modified frameworks occurred on the axial wall of the abutments. The modification of the zirconia framework design presented significant improvement of the fracture resistance compared to the conventional design.
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| 5. |
- Shanbhag, S., et al.
(author)
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Ectopic Bone Tissue Engineering in Mice Using Human Gingiva or Bone Marrow-Derived Stromal/Progenitor Cells in Scaffold-Hydrogel Constructs
- 2021
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In: Frontiers in Bioengineering and Biotechnology. - : Frontiers Media S.A.. - 2296-4185. ; 9
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Journal article (peer-reviewed)abstract
- Three-dimensional (3D) spheroid culture can promote the osteogenic differentiation and bone regeneration capacity of mesenchymal stromal cells (MSC). Gingiva-derived progenitor cells (GPC) represent a less invasive alternative to bone marrow MSC (BMSC) for clinical applications. The aim of this study was to test the in vivo bone forming potential of human GPC and BMSC cultured as 3D spheroids or dissociated cells (2D). 2D and 3D cells encapsulated in constructs of human platelet lysate hydrogels (HPLG) and 3D-printed poly (L-lactide-co-trimethylene carbonate) scaffolds (HPLG-PLATMC) were implanted subcutaneously in nude mice; cell-free HPLG-PLATMC constructs served as a control. Mineralization was assessed using micro-computed tomography (µCT), histology, scanning electron microscopy (SEM) and in situ hybridization (ISH). After 4–8 weeks, µCT revealed greater mineralization in 3D-BMSC vs. 2D-BMSC and 3D-GPC (p < 0.05), and a similar trend in 2D-GPC vs. 2D-BMSC (p > 0.05). After 8 weeks, greater mineralization was observed in cell-free constructs vs. all 2D- and 3D-cell groups (p < 0.05). Histology and SEM revealed an irregular but similar mineralization pattern in all groups. ISH revealed similar numbers of 2D and 3D BMSC/GPC within and/or surrounding the mineralized areas. In summary, spheroid culture promoted ectopic mineralization in constructs of BMSC, while constructs of dissociated GPC and BMSC performed similarly. The combination of HPLG and PLATMC represents a promising scaffold for bone tissue engineering applications.
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