3,549 research outputs found

    Healing Following Periodontal Reconstructive Surgery : Surgical Implantation of a Collagen Matrix or Demineralized Freeze-dried Bone Allograft

    Get PDF
    Healing following periodontal reconstructive surgery including surgical implantation of a collagen matrix or demineralized freeze-dried bone allograft (DFDBA) was evaluated in a preclinical (collagen) and a clinical (DFDB A) study. Contralateral periodontal fenestration defects in 7 beagle dogs were used to evaluate the effect of a collagen matrix on periodontal healing. The defects (6x4 mm) were created through the buccal cortical plates of the maxillary canine teeth following elevation of mucoperiosteal flaps. The collagen was fitted to the defects on one side, while contralateral defects served as controls. Raps were repositioned and sutured. Dogs were sacrificed 4 weeks after surgery and block sections including teeth and surrounding structures were prepared for histometric analysis. No meaningful differences in cementum and bone regeneration were observed between treatments. There was seemingly more bone regeneration and significantly more cementum regeneration in the apical than in the coronal aspect of the defects. Root resorption was observed in one collagen and one control defect. Ankylosis was not observed. The results suggest that the maxillary canine periodontal fenestration defect can be used as a model to evaluate factors that may enhance cementum and bone regeneration. The collagen matrix neither enhanced nor inhibited periodontal healing in this model. Clinical healing following periodontal reconstructive surgery including wound closure supported by an expanded polytetrafluoroethylene (ePTFE) membrane with or without DFDBA was evaluated in 20 intrabony defects. Ten intrabony defects, one in each of 10 patients, were treated with reconstructive surgery including the ePTFE membrane with DFDBA. Another 10 defects, one in each of 10 other patients, received the ePTFE membrane alone. A postsurgical protocol emphasizing wound stabilization and infection control was used. Healing was evaluated 6 months post surgery. Both groups exhibited similar pre-surgical probing and defect depths. For the ePTFE with DFDBA group, pre-surgical probing and defect depths averaged 7.9±1.8 and 8.3±1.6 mm, respectively. Probing depth reduction following therapy approximated 2.8±2.5 mm, clinical attachment gain 2.1±2.8 mm, defect bone fill 1.5+1.9 mm, and gingival recession increase 0.7±1.5 mm. For the ePTFE group, pre-surgical probing and defect depths averaged 7.2±1.1 and 6.3±1.9 mm, respectively. Probing depth reduction following therapy approximated 3.7+1.2 mm, clinical attachment gain 1.8±2.1 mm, defect bone fill 1.7±2.1 mm, and gingival recession increase 1.9±1.4 mm. Probing depth reduction, clinical attachment gain, and defect bone fill were statistically significant compared to baseline for both treatment groups. No significant differences were found between groups for the clinical parameters except for a significant difference in probing depth reduction at defect adjacent sites. The addition of DFDBA to the membrane procedure did not appear to enhance periodontal healing beyond that achieved by the membrane alone in the treatment of intrabony defects. It may be concluded that, within the limitations of this studies, neither the collagen matrix nor the DFDBA-implant significantly influenced periodontal healing

    Do Financial Analysts Facilitate Investors’ Assessment Of Earnings?: Evidence From The Korean Stock Market

    Get PDF
    This paper seeks to enhance our understanding of financial analysts in assisting market investors’ use of accounting earnings in the Korean stock market. We examine whether stock returns differentially reflect earnings information for firms with analyst coverage. We propose that the role of analysts as external monitors as well as information intermediaries enhances the market investors’ valuation of earnings. We find that market valuation of earnings is higher for firms with analyst following. Furthermore, market investors’ valuation of earnings increases (or decreases) with the number of analysts (or with the dispersion of analysts’ forecasts). This suggests that the beneficial effect of analysts arises through the quantity and quality of analysts’ information. This study contributes to the literature by investigating the important role of analysts in emerging market

    FE implementation of HAH model using FDM-based stress update algorithm for springback prediction of AHSS sheets

    Get PDF
    The homogeneous anisotropic hardening (HAH) model was implemented into a finite element (FE) code in order to predict springback for an advanced high strength steel (AHSS) sheet sample after double-stage U-draw bending. The finite difference method (FDM) was utilized as an alternative way to calculate the derivatives of this advanced distortional plasticity model allowing the update of the equivalent plastic strain and stress tensor at each time step in the user-material subroutines (UMAT and VUMAT). The FDM makes it easier to derive the stress gradient of complex yield surfaces. The proposed FDM-based stress update algorithm was verified by comparing the springback profiles after the single- and double-stage U-draw bending tests for a DP980 sheet sample predicted with analytical and numerical approaches. In addition, the springback measurement parameters and computational efficiencies depending on both approaches were also compared. The results indicate that the computational efficiency and accuracy of the FE simulations with the FDM-based stress update algorithm were similar to those of the analytical method. © 2018 Institute of Physics Publishing. All rights reserved.11Ysciescopu

    Fabrication of Gd containing duplex stainless steel sheet for neutron absorbing structural materials

    Get PDF
    A duplex stainless steel sheet with 1 wt.% gadolinium was fabricated for a neutron absorbing material with high strength, excellent corrosion resistance, and low cost as well as high neutron absorption capability. The microstructure of the as-cast specimen has typical duplex phases including 31% ferrite and 69% austenite. Main alloy elements like chromium (Cr), nickel (Ni), and gadolinium (Gd) are relatively uniformly distributed in the matrix. Gadolinium rich precipitates were present in the grains and at the grain boundaries. The solution treatment at 1070 ??C for 50 minutes followed by the hot-rolling above 950 ??C after keeping the sheet at 1200 ??C for 1.5 hours are important points of the optimum condition to produce a 6 mm-thick plate without cracking.close0

    The Fruit Hull of Gleditsia sinensis

    Get PDF
    Lung cancer has substantial mortality worldwide, and chemotherapy is a routine regimen for the treatment of patients with lung cancer, despite undesirable effects such as drug resistance and chemotoxicity. Here, given a possible antitumor effect of the fruit hull of Gleditsia sinensis (FGS), we tested whether FGS enhances the effectiveness of cis-diammine dichloridoplatinum (II) (CDDP), a chemotherapeutic drug. We found that CDDP, when administered with FGS, significantly decreased the viability and increased the apoptosis and cell cycle arrest of Lewis lung carcinoma (LLC) cells, which were associated with the increase of p21 and decreases of cyclin D1 and CDK4. Concordantly, when combined with FGS, CDDP significantly reduced the volume and weight of tumors derived from LLC subcutaneously injected into C57BL/6 mice, with concomitant increases of phosphor-p53 and p21 in tumor tissue. Together, these results show that FGS could enhance the antitumor activity of CDDP, suggesting that FGS can be used as a complementary measure to enhance the efficacy of a chemotherapeutic agent such as CDDP

    Gelatin-layered and multi-sized porous β-tricalcium phosphate for tissue engineering scaffold

    Get PDF
    The multi-sized porous β-tricalcium phosphate scaffolds were fabricated by freeze drying followed by slurry coating using a multi-sized porous sponge as a template. Then, gelatin was dip coated on the multi-sized porous β-tricalcium phosphate scaffolds under vacuum. The mechanical and biological properties of the fabricated scaffolds were evaluated and compared to the uniformly sized porous scaffolds and scaffolds that were not coated by gelatin. The compressive strength was tested by a universal testing machine, and the cell viability and differentiation behavior were measured using a cell counting kit and alkaline phosphatase activity using the MC3T3-E1 cells. In comparison, the gelatin-coated multi-sized porous β-tricalcium phosphate scaffold showed enhanced compressive strength. After 14 days, the multi-sized pores were shown to affect cell differentiation, and gelatin coatings were shown to affect the cell viability and differentiation. The results of this study demonstrated that the multi-sized porous β-tricalcium phosphate scaffold coated by gelatin enhanced the mechanical and biological strengths

    Trichosanthes kirilowii

    Get PDF
    Trichosanthes kirilowii tuber is a traditional medicine which exhibits various medicinal effects including antidiabetic and anticancer activities in several cancer cells. Recently, it was reported that Cucurbitacin D (CuD) isolated from Trichosanthes kirilowii also induces apoptosis in several cancer cells. Constitutive signal transducer and activator of transcription 3 (STAT3), which is an oncogenic transcription factor, is often observed in many human malignant tumor, including breast cancer. In the present study, we tested whether Trichosanthes kirilowii ethanol extract (TKE) or CuD suppresses cell growth and induces apoptosis through inhibition of STAT3 activity in breast cancer cells. We found that both TKE and CuD suppressed proliferation and induced apoptosis and G2/M cell cycle arrest in MDA-MB-231 breast cancer cells by inhibiting STAT3 phosphorylation. In addition, both TKE and CuD inhibited nuclear translocation and transcriptional activity of STAT3. Taken together, our results indicate that TKE and its derived compound, CuD, could be potent therapeutic agents for breast cancer, blocking tumor cell proliferation and inducing apoptosis through suppression of STAT3 activity

    Lumbopelvic Sagittal Alignment and Foraminal Height from Single Interbody Cage in L5-S1 Segment: Comparison between Anterior Cage for OLIF (Oblique Lumbar Interbody Fusion) and Curvilinear Cage for TLIF (Transforaminal Interbody Fusion)

    Get PDF
    Objective To evaluate a radiological difference between the oblique lumbar interbody fusion (OLIF) L5-S1 and transforaminal lumbar interbody fusion (TLIF) L5-S1 procedure. Methods 16 patients who underwent single-level OLIF L5-S1 and 32 patients of TLIF L5-S1 were retrospectively reviewed. Assessment of the lumbopelvic parameters and the height of disc space and L5-S1 neural foramen was performed before surgery as well as a month after surgery. Results Preoperatively, OLIF L5-S1 group and TLIF group showed similar lumbar lordosis (LL), segmental lordosis (SL), pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS); (p=0.08, 0.48, 0.67, 0.19 and 0.12, respectively). Postoperatively those parameters did not show statistically significant differences between two groups (p=0.17, 0.32, 0.53, 0.16 and 0.19, respectively). In terms of disc and foraminal height, the OLIF L5-S1 group showed significant greater increase of posterior disc height and foraminal height (p=0.01 and 0.00). There was no significant differences between the two groups in mean VAS and ODI score over the follow-up period. Conclusion This study demonstrates that both OLIF L5-S1 group and TLIF L5-S1 group had similar ability of achieving lumbopelvic alignment however, increase of foraminal height was greater in patients with OLIF L5-S1 group

    Role of Amphipathic Helix of a Herpesviral Protein in Membrane Deformation and T Cell Receptor Downregulation

    Get PDF
    Lipid rafts are membrane microdomains that function as platforms for signal transduction and membrane trafficking. Tyrosine kinase interacting protein (Tip) of T lymphotropic Herpesvirus saimiri (HVS) is targeted to lipid rafts in T cells and downregulates TCR and CD4 surface expression. Here, we report that the membrane-proximal amphipathic helix preceding Tip's transmembrane (TM) domain mediates lipid raft localization and membrane deformation. In turn, this motif directs Tip's lysosomal trafficking and selective TCR downregulation. The amphipathic helix binds to the negatively charged lipids and induces liposome tubulation, the TM domain mediates oligomerization, and cooperation of the membrane-proximal helix with the TM domain is sufficient for localization to lipid rafts and lysosomal compartments, especially the mutivesicular bodies. These findings suggest that the membrane-proximal amphipathic helix and TM domain provide HVS Tip with the unique ability to deform the cellular membranes in lipid rafts and to downregulate TCRs potentially through MVB formation
    corecore