Wound healing is important for survival of organism. Many local and systemic factors effect on speed of wound healing. In the oral cavity, mucosal wounds healed faster than skin wound because of presence of saliva which contain different proteins, enzymes and elements with different regenerative functions. The aim of this study is to investigate the role of salivary histatin-1 in enhancing oral wound healing in-vitro. Human periodontal ligament fibroblast cell lines were grown in 24 well plates till confluence, then subjected to scratch assay that resemble oral wound. Complete medium added to control wells and complete medium with histatin-1 (10 ng) added in study wells. Cell migration assay was observed using an inverted microscope at 6, 12 and 24 hr. and gene expression for MMP-8 was quantified. Results showed that salivary histatin-1 enhances cell proliferation, migration and increase MMP-8 gene expression, enhancing the in-vitro wound healing process.
Objective: This study aimed to assess the fatigue resistance after thermo-mechanical cycling in a chewing simulator machine, and the fracture resistance by recording the load to failure in a universal testing machine, of two thicknesses of ultra-thin porcelain laminate veneers (UTLV) (0.2 and 0.4 mm), using two different cementation techniques (light cure resin cement and preheated resin composite).
Objective. The aim of the study was to assess the prevalence and characteristics of the referred pain associated with TMD diagnosed according to the DC/TMD. Study design: A total of 50 patients were enrolled in this study and they were examined according to DC/TMD criteria (Axis I and Axis II). MRI and CBCT were used for diagnosis of specific TMD classes. Results: The highest incidence of referred pain was recorded in patients diagnosed with anterior disc displacement with reduction (16%). A positive Pearson product-moment correlation was found between the Axis I DC/TMD diagnosis, pain level, mouth opening, duration of symptom and referred pain. A negative Pearson product-moment correlation was found between referred pain and the disability score. Conclusion: The results of this study facilitate the diagnosis process of TMD by evaluating the prevalence and characteristics of referred pain which is the main factor that complicates the diagnosis of TMD.
A high resolution (~30m) 2D Hydrodynamic model was run to investigate the impact of a 0.5m sea level rise on the Abu Dhabi coastline. The model incorporates the combined effects of sea level rise tidal forcing and storm surge (using the DELFT3D model), wind and wave forcings encountered during a typical Shamal wind event (using the SWAN model) in addition to wave run-up calculations. The model results showed that several islands and coastal areas containing important highway links would be inundated during such an event. While the northern coastlines of Saadiyat Island, Lulu Island are mainly affected by storm run-up and waves, some inland inlets such as the head of the South Mussafah Channel may also be affected by the tidal elevations experienced by sea level rise.
This research is focusing on the behavior of a tapered concrete filled steel tube column (CFST) connected to encased composite column (SRC) under axial compression and uni-axial bending. The purpose of having two different sections along the column height is to enhance flexure resistance of the column at the top edge by introducing CFST element, while the lower part is modeled as SRC element which is subjected mainly to axial compression with significant reduction in bending moments. The behavior of the composite column has been studied using different cylinder concrete strength ranging from C40MPa to C70MPa. Two steel grades of S275MPa and S355MPa has been adopted in this research. The research illustrates Load Path and Stress / Strain distribution under Axial compression and Uni-axial bending. Furthermore, it displays the composite column capacity along its height by adopting 3D-finite element fiber model and simplified approach by Eurocode and American Standards.
The efficiency of carbon fiber reinforced polymer (CFRP) strips to enhance reinforced concrete (RC) columns were investigated. Concentric and eccentric loads were imposed on the columns, leading to uniaxial and biaxial bending. 27 RC column specimens that had varying strengthening ratios have been utilized. The samples were categorized into 3 groups: axial, uniaxial and biaxial. In every category it was divided into several sub-groups accompanied with a control specimen that was not strengthened. The strengthened specimens showed a significant increase in the load-carrying capacity and ductility over the control specimens. The increase in the load-carrying capacity for confined columns strengthened with strips in axial, uniaxial and biaxial bending ranged from 36 to 49%, 48 to 95% and 76 to 128%, respectively.
Dynamic properties of soil are important for the design of structures under seismic loadings. The United Arab Emirates (UAE) is experiencing significant construction development; however, there is no systematic study to characterize the regional soils for dynamic properties. Also, correlations developed for other regions may not be suitable for the UAE. This research presents the findings of a laboratory testing program involving cyclic (CT) tests along with bender element (BE) testing on representative samples of regional soils. The BE tests are used to evaluate the low strain shear wave velocity (Vs), whereas the CT test is used to evaluate the shear modulus (G) and the damping ratio (?) at different strain levels and confinement pressures. The research presents degradation of the dynamic properties of regional soils. The results of the experimental program indicate that the degradation of dynamic properties generally agrees with previous studies however the model parameters are different.
3D concrete printing, 3DCP, is considered the latest digital technology in the construction industry, it has shown its potential in a wide range of disciplines. 3DCP on a large scale will have several Environmental, economic and societal advantages such as time, cost and waste savings. The lack of advanced research in this technology doesn't allow it to confidently prove itself in the construction industry. This study will assess the compressive and flexural performance of 3DCP reinforced with polypropylene fibers. Cube samples are tested for 3DCP with and without polypropylene fibers. In addition, 4 different concrete mixes are tested to assess its flexural strengths. Traditional concrete beams with and without reinforcement; in addition to fiber reinforced beams with and without reinforcement. Results from the beams were analyzed and compared through deflection-force curves to evaluate the flexural behavior of 3DPC.
In this study bond performance of GFRP bar in normal weight concrete was investigated using the numerical modeling technique. A 3D finite element model (FEM) was developed for direct pullout test in ABAQUS?. The model was calibrated by comparing the numerical findings with the experimental results from the available literature. The validated model was used to conduct a parametric study; compressive strength (f_c^'), size of glass fiber reinforced polymer (GFRP) bars (d_b) and embedded length of GFRP bar (l_d) were chosen as the variables to do this study. Bond strength (?_b) increased when higher compressive strength, lower size of GFRP bar and lesser embedded length were used. The direct pullout test FEM model was compared with beam type pullout test experimental results. Finally, analytical models were proposed to predict the bond-slip performance and bond strength of GFRP-concrete interference and the proposed model was compared with current international standards.
Among different classes of 2D materials, the new interest is focusing on MXene which is extracted from the MAX phase of ceramics. Our study aims to elucidate the potentials for applying MXene as a biosensor system. To achieve the goal, this study analyzes the in vitro cytotoxicity of the material, in other words, the impact of MXene on the viability of macrophage immune cells (RAW 264.7). The viability of macrophages which are classical immune cells within MXene colloidal solution were tested by MTT assay. The cytotoxicity testing results have shown that the MXene is toxic at a certain concentration. The results hypothetically promise that the MXene will perform a high rate of biocompatibility compared to other available 2D materials owing to its high hydrophilicity and large surface area.
