Fracture resistance of upper central incisors restored with different posts and cores

Saeid Tavanafar,,Kamran Amirian Chaijan,Saeid Tavanafar 대한치과보존학회 2015 Restorative Dentistry & Endodontics Vol.40 No.3

Objectives: To determine and compare the fracture resistance of endodontically treated maxillary central incisors restored with different posts and cores. Materials and Methods: Forty-eight upper central incisors were randomly divided into four groups: cast post and core (group 1), fiber-reinforced composite (FRC) post and composite core (group 2), composite post and core (group 3), and controls (group 4). Mesio-distal and bucco-lingual dimensions at 7 and 14 mm from the apex were compared to ensure standardization among the groups. Twelve teeth were prepared for crown restoration (group 4). Teeth in other groups were endodontically treated, decoronated at 14 mm from the apex, and prepared for posts and cores. Resin-based materials were used for cementation in groups 1 and 2. In group 3, composite was used directly to fill the post space and for core build-up. All samples were restored by standard metal crowns using glass ionomer cement, mounted at 135° vertical angle, subjected to thermomechanical aging, and then fractured using a universal testing machine. Kruskal-Wallis and Mann-Whitney U tests were used to analyze the data. Results: Fracture resistance of the groups was as follows: Control (group 4) > cast post and core (group 1) > fiber post and composite core (group 2) > composite post and core (group 3). All samples in groups 2 and 3 fractured in restorable patterns, whereas most (58%) in group 1 were non-restorable. Conclusions: Within the limitations of this study, FRC posts showed acceptable fracture resistance with favorable fracture patterns for reconstruction of upper central incisors.

UNIFORM TOPOLOGY ON DIFFERENCE ALGEBRAS

SAEID, ARSHAM BORUMAND Korean Mathematical Society 2005 대한수학회보 Vol.42 No.2

In this paper, we consider a collection of ideals of a difference algebra X. We use the concept of congruence relation with respect to ideals to construct a uniformity that induces a topology on X which makes this to a topological difference algebras. We study the properties of this topology regarding different ideals.

(WEAK) IMPLICATIVE HYPER K-IDEALS

Saeid, A.Borumand,Borzooei, R.A.,Zahedi, M.M. Korean Mathematical Society 2003 대한수학회보 Vol.40 No.1

In this note first we define the notions of weak implicative and implicative hyper K-ideals of a hyper K-algebra H. Then we state and prove some theorems which determine the relationship between these notions and (weak) hyper K-ideals. Also we give some relations between these notions and all types of positive implicative hyper K-ideals. Finally we classify the implicative hyper K-ideals of a hyper K-algebra of order 3.

Effects of Methylprednisolone on Neuroprotective Effects of Delay Hypothermia on Spinal Cord Injury in Rat

Saeid Karamouzian,Sadegh Akhtarshomar,Alireza Saied,Ahmad Gholamhoseinian 대한척추외과학회 2015 Asian Spine Journal Vol.9 No.1

Study Design: A retrospective study. Purpose: The aim of this study was to evaluate the effects of delayed hypothermia on spinal cord injuries in rats. In addition, the effect of methylprednisolone on therapeutic window of hypothermia was evaluated. Overview of Literature: Several studies have demonstrated that early hypothermia is the most effective neuroprotective modality. However, delayed hypothermia seems to be more practical for patients with traumatic spinal cord injuries. A combination of hypothermia and other neuroprotective methods, such as using methylprednisolone, may help extend the therapeutic window of hypothermia. Methods: One hundred and twenty male rats were categorized into six groups. The rats in five groups were subjected to spinal cord injury using the weight drop method, followed by treatment, consisting of early hypothermia, late hypothermia, late hypothermia plus methylprednisolone, or methylprednisolone only. Biochemical tests including catalase, malondialdehyde, and superoxide level were evaluated in the injured spinal cord. Behavioral functions of the hind limb were evaluated by Basso-Battle-Bresnaham locomotor rating scale and tail-flick tests. Results: Functional and biochemical evaluation showed both early and late hypothermia had significant neuroprotective effects. The treated groups did not differ significantly from one another in the behavioral tests. Hypothermia had better biochemical results compared to methylprednisolone. Also, methylprednisolone was shown to extend the therapeutic window of delayed hypothermia. Conclusions: Hypothermia showed a significant neuroprotective effect, which can be improved with further studies optimizing the duration of hypothermia and the rewarming period. Moreover, the therapeutic effect of the delayed hypothermia can be extended by methylprednisolone.

Isotherm, kinetic and thermodynamic studies for Th(IV) sorption by amino group-functionalized titanosilicate from aqueous solutions

Saeid Alamdar Milani,Mohammad Karimi 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.4

The 3-aminopropyltriethoxysilane-modified titanosilicate was prepared as an alternative for developing efficient adsorbents of heavy metals. The obtained material was characterized by X-ray diffraction analysis, infrared spectroscopy, textural analysis, and scanning electron microscopy. Adsorption of thorium from aqueous solutions was investigated by adsorption isotherms, kinetic and thermodynamic studies. The isothermal data were found to be correlated with the Langmuir model. The maximum sorption capacity of Th(IV) was 83.4mg g−1. The experimental data show that the external diffusion and intra-particular diffusion are significant in the sorption of thorium. The thermodynamic parameters indicated that the sorption process was physisorption, endothermic and spontaneous.

Adsorption of 2,4-dichlorophenoxyacetic acid pesticide by graphitic carbon nanostructures prepared from biomasses

Saeid Azizian,Maryam Khoshnood 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.5

Removal of a pesticide (2,4-dichlorophenoxyacetic acid) from aqueous solution by magnetic and graphitic carbon nanostructures was studied from both equilibrium and kinetic point of view. The magnetic and graphitic carbon nanostructures as adsorbents were prepared from two different biomasses, cotton and filter paper. The resultant adsorbents were characterized with TEM and N2adsorption–desorption methods. The kinetic and equilibrium data were modeled with different models. The adsorption capacities for the prepared adsorbents from filter paper and cotton are about 77 and 33 mg/g, respectively. The effect of initial pH of solution on the pesticide removal efficiency was studied too. 2012 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Uniform Topology on Hilbert Algebras

Saeid, A. Borumand,Babaei, H.,Haveshki, M. Department of Mathematics 2005 Kyungpook mathematical journal Vol.45 No.3

We use a congruence relation on deductive systems of a Hilbert algebra H, to define a uniform structure on H and investigate the corresponding topology.

SMARANDACHE WEAK BE-ALGEBRAS

Saeid, Arsham Borumand Korean Mathematical Society 2012 대한수학회논문집 Vol.27 No.3

In this paper, we introduce the notions of Smarandache weak BE-algebra, Q-Smarandache filters and Q-Smarandache ideals. We show that a nonempty subset F of a BE-algebra X is a Q-Smarandache filter if and only if $A(x,y){\subseteq}F$, which A($x,y$) is a Q-Smarandache upper set The relationship between these notions are stated and proved.

Implementation of soft computing approaches for prediction of physicochemical properties of ionic liquid mixtures

Saeid Atashrouz,Hamed Mirshekar,Abdolhossein Hemmati-Sarapardeh,Mostafa Keshavarz Moraveji,Bahram Nasernejad 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.2

The main objective of this study was to develop soft computing approaches for prediction of physicochemical properties of IL mixtures including: density, heat capacity, thermal conductivity, and surface tension. The proposed models in this study are based on support vector machine (SVM), least square support vector machines (LSSVM), and group method of data handling type polynomial neural network (GMDH-PNN) systems. To find the LSSVM and SVM adjustable parameters, genetic algorithm (GA) as a meta-heuristic algorithm was utilized. The results showed that LSSVM is more robust and reliable for prediction of physicochemical properties of IL mixtures. The proposed GALSSVM model provides average absolute relative deviations of 0.38%, 0.18%, 0.77% and 1.18% for density, heat capacity, thermal conductivity, and surface tension, respectively, which demonstrates high accuracy of the model for prediction of physicochemical properties of IL mixtures.

Application of experimental design for removal of sunset yellow by copper sulfide nanoparticles loaded on activated carbon

Saeid Khodadoust,Mehrorang Ghaedi,Reza Sahraei,Ali Daneshfar 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

In this study, copper sulfide nanoparticles loaded on activated carbon (CuS-NP-AC) was synthesized by novel, low cost and green approach and characterized using different techniques such as SEM, and BET. This material was used for the removal of sunset yellow (SY) from aqueous solutions was investigated. The dependency of removal percentages to variables such as pH, initial SY concentration, adsorbent dosage and sonication time were studied by central composite design (CCD) coupled with response surface methodology (RSM) by considering the desirability function (DF). The accuracy and ability of method at optimum values predicted by this model was studied by conduction of similar experiments at the same previously optimized conditions. A good agreement between experimental and predicted data was achieved that efficiency of this model for prediction of real optimum point. Among the well known previously isotherm models, the experimental equilibrium data efficiently can be represented by the Langmuir model, while the rate of adsorption. Kinetic data efficiently can be interpreted by combination of pseudo-second order as well as intraparticle diffusion models. The small amount of this adsorbent (0.016 g) is applicable for removal of high amount of SY (>90%) in reasonable time (17 min).