Nanohydroxyapatite Silicate-Based Cement Improves the Primary Stability of Dental Implants: An In Vitro Study

Objectives. Insufficient cortical bone volume when placing implants can lead to lack of primary stability. The use of cement as a bone fill material in bone defects around dental implant could result in better clinical outcome. HA has shown excellent biological properties in implant dentistry. The purpose of this study was to evaluate the effect of nanohydroxyapatite powder (Nano-HA) in combination with accelerated Portland cement (APC) on implant primary stability in surgically created circumferential bone defects in a bovine rib in vitro model. Materials and Methods. Sixteen bovine rib bones and thirty-six implants of same type and size (4 mm × 10 mm) were used. Implants were divided into six groups: no circumferential bone defect, defect and no grafting, bone chips grafting, Nano-HA grafting, APC grafting, and Nano-HA mixed to APC grafting (Nano-HA-APC). Circumferential defects around the implants were prepared. The implant stability quotient (ISQ) values were measured before and after the grafting. Results. APC exhibited the highest ISQ values. A significant increase of ISQ values following the grafting of Nano-HA-APC (18.08±5.82) and APC alone (9.50±4.12) was achieved. Increase of ISQ values after 72 hours was 24.16±5.01 and 17.58±4.89, respectively. Nano-HA grafting alone exhibited the least rise in ISQ values. Conclusions. Nanohydroxyapatite silicate-based cement could improve the primary stability of dental implants in circumferential bone defect around implants

Identifying the optimal model of educational leadership in education (Case study: school principals of the first elementary school in Tehran)

The aim of this study was to present the model of educational-oriented leadership in cultural organizations with emphasis on school principals in the first elementary school in Tehran. The research was an exploratory mixed method (qualitative and quantitative) that required the required data in the qualitative section (based on grounded theory) and quantitative (based on cross-sectional survey method). In the qualitative section, the statistical population included experts and specialists in the field of educational leadership who were selected by targeted sampling method and snowballs. Data were collected using a semi-structured interview. Then it was completed with the help of Delphi technique and brainstorming. The results of coding based on Grounded theory led to the identification of 248 indicators, 39 components and 5 dimensions including belief dimension, dimension of work and environment, dimension of leadership style, dimension of organizational and work ability of leader and dimension of personal, intellectual and emotional characteristics of leadership. The study population in a quantitative section included all school principals in the first elementary school in Tehran (415 people). The Cochran's formula was used to determine the sample size, and 199 individuals were identified and randomly selected from the sample class. Data analysis using the confirmatory factor analysis test showed that the findings of the quantitative section are exactly the same as the qualitative section. According to the obtained results, it can be said that the obtained pattern is more comprehensive than other patterns, and on the other hand, this pattern is only suitable for the characteristics and implications of the first elementary period. Therefore, applying and implementing this model can be of great help to effective educational leadership in the first elementary period school

Existence of Solutions for a System of Integral Equations Using a Generalization of Darbo’s Fixed Point Theorem

In this paper, an extension of Darbo’s fixed point theorem via θ -F-contractions in a Banach space has been presented. Measure of noncompactness approach is the main tool in the presentation of our proofs. As an application, we study the existence of solutions for a system of integral equations. Finally, we present a concrete example to support the effectiveness of our results.The authors are grateful to the Basque Government by the support of this work through Grant IT1207-19

Mathematically and experimentally defined porous bone scaffold produced for bone substitute application

Objective (s): Artificial bone implants have been studied as a possible bone replacement for fractured and destroyed facial tissue; the techniques employed to determine the success of the dental implants. The stability, porosity and resistance of the bone implant which is subjected to varying forces and stresses within the surrounding bone is a subject of interest among the dentists. Materials and Methods: An experimental analysis was conducted on bio-nanocomposite scaffold using space holder methods. The reaction of the bio-nanocomposites deformation under load was determined using Abaqus software. Thereafter, an analytical solution was presented to express explicitly the deformation responses of the artificial bone implant. Results: It was seen that the vibrational behavior and mechanical performance of the sample containing 15 wt% additives have shown better mechanical characteristic compared to the pure specimen. On the other hand, the additive weight fraction has a significant effect on the compression test and porosity value. Also, the elastic modulus of the samples increases more than two times with the addition of additive (from 60 MPa to 145 MPa). From the results, it can be concluded that the highest vibration variation is seen in the sample with lower MNPs percentages.Conclusion: By observing the results of the stresses, it was seen that the stresses were in a small value in the bio-nanocomposites with highest amount of reinforcement

Degradation of Rhodamine 6G in aqueous solution by using Au/Fe3O4 core\shell nanoparticles

In this study, magnetic Fe3O4 nanoparticles were synthesized by co-precipitation method and then Au shell was extended over these nanoparticles via chemical reduction of chloroauric acid with sodiumborohydride under ultrasound irradiation. The obtained Au/Fe3O4 nanoparticles were characterized by using X-ray diffraction technique and Fourier transform infrared spectroscopy and their physical properties was studied by scanning electron microscopy and transmission electron microscopy. The characterized nanoparticles were used as efficient catalyst in the degradation of Rhodamine 6G dye in aqueous solution. UV-Vis spectroscopy was used to determine the dye concentration during optimization of the reaction conditions, and effect of various parameters such as pH, catalyst loading, temperature, and amount of the oxidant was investigated. It was found that Au/Fe3O4 catalyst at 80 oC in the pH of 12 can effectively degrade Rhodamine 6G dye molecules in the presence of hydrogen peroxide as an inexpensive and available oxidant. The catalyst after recycling was also, able to perform its role in successive runs

Fractional derivative generalization of Noether’s theorem

The symmetry of the Bagley–Torvik equation is investigated by using the Lie group analysis method. The Bagley–Torvik equation in the sense of the Riemann–Liouville derivatives is considered. Then we prove a Noetherlike theorem for fractional Lagrangian densities with the Riemann-Liouville fractional derivative and few examples are presented as an application of the theory

Determination of Serum D-Dimer Levels in Breast Cancer Patients Referred to Imam Sajjad Hospital in Ramsarin 2016

Introduction Breast cancer is one of the most common cancers among women and is spreading with the highest rate in developing countries. The aim of this study was to evaluate serum levels of D-dimer in patients with breast cancer.  Materials and Methods : In this cross-sectional study, 100 the patients with the diagnosis of breast cancer who have been admitted at Imam Sajjad Hospital for further treatment were enrolled. Results The average serum D-dimer in stage IV was 628±304, in stage III was 229±101 and in stage II was 180±29. In addition, the frequency of abnormal D-dimer was higher in patients at stage IV. The D-dimer level and the frequency of abnormal D-dimer level were higher in patients with lymph node involvement. Moreover, patients who had abnormal CEA and CA15-3 tumor markers had higher D-dimer level. We have also found serum D-dimer levels in patients 41-50 years old group was higher than other groups. Conclusion In general, increase in serum D-dimer levels are associated with advanced disease stage, lymph node involvement, and worse prognosis and since the D-dimer is a safe, inexpensive, and available marker can be used to assess prognosis of disease and survival of the patient

Oral findings in chronic kidney disease. A cross-sectional study in Shiraz, Iran.

Background: In hemodialysis patients, there are some oral hard and soft tissue changes. Objectives: The aim of this single-center, cross-sectional study was to evaluate oral findings in hemodialysis patients. Patients and Methods: A total of 144 patients participated. Of them, 28 patients (19%) had diabetes mellitus (DM), 17 patients (12%) had systemic lupus erythematosus (SLE), and 15 patients (10%) had severe hypertension. The oral cavity was inspected by an oral medicine specialist using proper light, mirror and explorer. The lips, cheek, tongue, palatal mucosa, floor of the mouth, gingiva, pharyngeal fauces, dentures, teeth and occlusion were checked. The significance level was P<0.05. Results: Around 78% of the studied population had oral manifestations. The most diagnosed finding in hemodialysis patients was dryness of the mouth followed by tooth loss due to mobility and poor oral hygiene. Diabetic cases showed numerous oral symptoms than nondiabetic subjects. Conclusions: Oral lesions in hemodialysis patients is a prominent finding and untreated lesions may cause severe side effects

On New Extensions of Darbo's Fixed Point Theorem with Applications

Isik, Huseyin/0000-0001-7558-4088; Parvaneh, Vahid/0000-0002-3820-3351; banaei, shahram/0000-0003-0552-1836; Park, Choonkil/0000-0001-6329-8228WOS:000525824300099In this paper, we extend Darbo's fixed point theorem via weak JS-contractions in a Banach space. Our results generalize and extend several well-known comparable results in the literature. The technique of measure of non-compactness is the main tool in carrying out our proof. As an application, we study the existence of solutions for a system of integral equations. Finally, we present a concrete example to support the effectiveness of our results