mohammad vahedi

Statement of the Problem:

 The creation of a proper seal of the root canal with canal-filling materials, such as gutta-percha and sealer, is one of the essential factors in the success of root canal treatment. In addition, the penetration depth of the sealer is one of the influential factors in creating a proper seal, which improves the sealing ability of the canal and the burial of microorganisms.

This study aimed to investigate the effect of cold atmospheric plasma on the depth of tubular penetration of two types of resin sealer: AH26 and Beta RCS sealers.

In this experimental study, thirty-two premolar teeth with single root and single canal were selected as samples and after cutting their crowns from the apex distance of 15mm, the canals were prepared with rotary files. Samples were divided into four groups of eight, according to the type of sealer and plasma application: AH26 sealer (AH), plasma+AH26 sealer (PAH), Beta RCS sealer (Beta), and plasma+Beta RCS sealer (PBeta). The cold lateral condensation technique was used for the obturation of canals. The maximum penetration depth and the percentage of sealer penetration were obtained from microscopic images at three coronal, middle, and apical sections. Due to the non-normal distribution of data, the Mann-Whitney U test was used for statistical analysis (p< 0.05).

No significant difference was observed between the study groups in the penetration percentage and maximum penetration depth of AH and Beta in the presence and absence of plasma. However, in the coronal section, the depth of maximum sealer penetration was significantly higher in the AH group than in the Beta group (p< 0.05).

The use of plasma did not affect the maximum penetration depth and penetration percentage of AH26 sealer and Beta RCS sealer.

The present study was an attempt to investigate the possible effect of using WordUp Software on Iranian EFL learners’ vocabulary learning. The participants were 60 upper-intermediate EFL learners who were selected out of 72 based on the Oxford Proficiency Test. Then, the participants were randomly divided into two groups of study namely experimental and control. The participants in the experimental group underwent an eight-session treatment including learning vocabulary based on using WordUp Software. In the control group, however, the participants gained new vocabulary by conventional methods. The quantitative approach employed a quasi-experimental method to obtain pre-test and post-test results from learners in both the experimental and control groups. The results of the study revealed that using WordUp Software caused a considerable improvement in learning the vocabulary among the learners in the experimental group. The findings of this study could benefit language learners, language teachers, and curriculum developers by providing valuable insights into vocabulary acquisition through WordUp for EFL learners.

The studied area is located in N-Sonqor and in the Sanandaj-Sirjan zone. Field relationships and petrographic evidence show that volcanic rocks of the north of Bashirabad comprise of trachydacite to trachyandesite (and altered basaltic trachyandesite) and in the south of this area, it consists of andesite to trachyte. Their texture is mainly porphyry. Geochemical data {total abundance of (Na2O+K2O), enrichment of large lithophile ion elements and rare light earth elements) indicate that these rocks belong to the alkaline series. Spider diagrams show enrichment in LREE and depletion HREE, and parallel patterns in all volcanic samples confirm their common origin. According to modeling magmatic processes, fractional crystallization, assimilation and crustal contamination have played an important role in the magma forming the studied rocks. The discriminating diagrams the tectonic setting the Bashirabad volcanic rocks indicate their subduction-related volcanic arc that was formed in an active continental margin environment with local tensions.

In this paper, a comprehensive study was performed to investigate the effect of the absorbent layer thickness on the tapered fiber sensor sensitivity, which leads to the highest sensitivity for the sensor. For this purpose, a staircase method was introduced to investigate the effect of layer thickness on the sensitivity of fiber optic sensors. According to the results obtained from the simulations performed using this method, it was found that the type of variation in the sensitivity of the tapered fiber optic sensor depends on the refractive index of the layer. To investigate the dependence of sensitivity on the layer thickness and refractive index of the layer, two different general cases have been considered. If the refractive index of the layer is smaller than the refractive index of the fiber, it can be seen that the sensitivity increases with increasing the layer thickness. On the other hand, when the refractive index of the layer is greater than the refractive index of the fiber, there are optimal points in the sensitivity plot versus the layer thickness, which demonstrate the highest sensitivities.

This paper presents the fabrication process and operation of a bio-sensor based on tapered optical fiber by using optical spectrum shift in the presence of PBS buffer and dissolved streptavidin. The taper-fiber sensors are 18 and 24 μm in diameter and are fabricated by use of an oxy-butane torch. The optical spectrum is obtained using a broadband light source and an optical spectrum analyzer (OSA) in a 40 nm wavelength range. The existence of streptavidin on the tapered fiber surface is confirmed. The experiments on PBS buffer have shown that, the output spectrum demonstrates a red-shift by adding the streptavidin. The maximum sensitivity obtained is 29000 nm/RIU.

We study the interaction of a microwave cavity with a magnetic sphere. We show that achieving the strong coupling regime in this hybrid system is feasible. The simulation results demonstrate that the coupling rate is proportional to the square root of the volume of the magnet and also is mode dependent and decreases with increasing the mode index. Since the dielectric constant of the magnetic sphere differs from that of the medium, it can act as a spherical cavity, and coupling between its eigenmodes and the electric field of the microwave cavity also occurs. The reflection spectrum includes more than one anti-crossing for relatively larger magnetic spheres

In this research, the effect of adsorbent layer on the hydrogen gas sensing of tapered optical fiber sensors has been investigated. First, the taperd optical fiber is prepared by heating and pulling a single mode optical fiber. Then, by using magnetic sputtering method, two samples of palladium and palladium-copper layers were deposited on one-side of the surface of the fiber as an adsorbent layer. The results of X-ray energy dispersion spectroscopy analysis (EDX) showed that the ratio of palladium to copper in the sample area is 97. 53 to 2. 47%. Sensor operation tests for different percentages of hydrogen gas showed that the palladium-copper composite layer (Pd97. 53Cu2. 47) demonstrates lower sensitivity in comparison to the palladium layer Typically, the percentage change in output power in the presence of 3% hydrogen gas was 3. 38% for sensors with palladium-copper adsorbent layer and 16. 77% for sensors with palladium adsorbent layer. But anyway the response of the composite layer to different hydrogen precentages exposure is linear, in contrast to the palladium layer which shows a nonlinear behavior.

Standard PID controllers are one of the most desirable controllers for industrial automation and the most widely used control in feedback systems. However, linear controllers have limitations that represent tation controllers can be used to overcome these limitations. In this paper, a robust reset control based on optimal output feedback to control a robot with two degrees of freedom. In general, the behavior of reset controllers is similar to that of linear controllers, in other words, they are easy to implement. In this regard, in this paper, by introducing a special combination control called robust reset output feedback control, the disadvantages of the linear controller are eliminated and its main purpose is to reduce overexposure and increase the response speed and better stability of the controlled system. Therefore, this paper introduces a systematic method for reset optimal output feedback controller. To do this, an optimal output feedback controller is first designed without the reset action, so that the poles of the closed-loop system are located in a predefined area. This area is selected to ensure the stability of the exponential and the arrival time of the closed loop in a finite time. Then, the reset value at reset times is designed to minimize a cost-effective function for better performance. In this paper, for the first time, the reset value is specified only with the system output information and then the stability of the system will be guaranteed. The robot used in this article is a practical and industrial example that has two arms and two joints with separate control capability. The position and behavior of the arms based on the governing equations and mathematical relations indicate its direct effect on each other. Finally, to prove the proposed design, numerical simulation will be performed using Matlab software and a comparison between the proposed controller and a similar controller will be performed.

Benign migratory glossitis, or geographic tongue, is usually an asymptomatic inflammatory disorder of unknown etiology that affects the epithelium of the tongue. Among the etiologic factors proposed, emotional causes were suspected by several investigators. The objective of this study was to evaluate the anxiety and cortisol level in patients with geographic tongue compared with healthy controls.

In this case-control study, 21 patients with geographic tongue referred to several educational and medical centers in Hamedan city were se-lected. The patients had no systemic disease or history of cigarette smoking. A control group of 21 healthy individuals without geographic tongue, systemic diseases and cigarette smoking was also selected. The participants were asked to complete the Beck Anxiety Inventory. Also, unstimulated saliva samples were collected to measure the salivary cortisol level in both groups. The two groups were compared after adjusting for age and gender. The Mann-Whitney test was used to com-pare the salivary level of cortisol in the two groups with and without geographic tongue.

The anxiety score of the geographic tongue group was higher but not significantly (P=0.745). The concentration of salivary cortisol was significantly higher in the control group (P=0.01). No strong correlation was found between the salivary cortisol level and the Beck Anxiety Inventory score.

It seems that among various factors associated with geographic tongue, psychological conditions are less related.

This paper constructs a new 6–D hyper–chaotic system with complex dynamic behaviors for se-cure communication scheme. We analyze the chaotic attractor, bifurcation diagram, equilibrium points, Poincare map, Lyapunov exponent behaviors, and Control parameter. The more nonlinear the autonomous system is and the higher the parametric sensitivity it is, the more performative it will be and the more difficult it will be to decode. We will show that the designed system will have attractive and different behaviors due to very small changes in control parameters, which is a sign of the high sensitivity of the system. Then, with the construction of master-slave systems and the design of a new terminal sliding mode controller, the application of the hyper-chaotic system in synchronization and transmission of secure communications is shown. Finally, using the MATLAB simulation, the results are confirmed for the new hyper–chaotic system.

In this paper, a plasmonic refractive index sensor is designed based on a Metal-Insulator-Metal waveguide coupled to a bragg reflector side-coupled to a rectangular cavity. A 2D-FDTD method is used to simulate the results. Results show that a maximum of 1320 nm/RIU for sensitivity and 45.5 RIU-1 for figure-of-merit could be obtained which shows the applicability of the sensor for accurate and compact sensing applications.

This paper constructs a new complex hyper-chaotic system with attractive coexisting dynamic behaviors. We analyze the hyper-chaotic attractors, equilibrium points, Poincaré maps, Kaplan-York dimension, and Lyapunov exponent behaviors. The characteristics of hyper-chaotic systems include higher complexity, higher parametric resistance and sensitivity to very small changes in initial conditions. We prove that the introduced hyper–chaotic system is much more complex than the similar hyper-chaotic systems, that can suitable for use in encryption and secure communication. Next, the work describes a fast terminal sliding mode controller scheme for the fast synchronization and stability of the new complex hyper–chaotic system. It is shown that by applying uncertainty to the system, both steps of the sliding mode control have finite-time convergence properties. Next, a comparison will be made between a newly designed controller and a similar. Finally, using the MATLAB simulation, the results are confirmed for the new system. The results shown that the new hyper-chaotic system with many adsorbents is much more complex than similar systems, and the proposed controller has a faster convergence response than the similar controller.

The main aim of the present article is to produce a smaller and cheaper heat exchanger with similar performance. The second goal of this investigation is to study the effects of using oil-based nano-fluids in a refinery heat exchanger. The third objective of this paper is to compare the results which are obtained from the singe- and multi-phase approaches. To fulfill this demand, ANSYS-Fluent and Aspen-HYSYS softwares are employed. Also, MgO-SAE10 nanofluid is studied in this paper using two-phase approaches. The THPEC, Thermal-Hydraulic Performance Evaluation Criteria, and specific heat flux, q", have major roles in this paper. In the second step, the authors try to achieve an efficient model which has not only the THPEC > 1 but also the maximum value of q". According to obtained results, the usage of nanofluid and turbulators can enhance thermal-hydraulic performances of the heat exchanger significantly. Furthermore, it is concluded that by employing nanofluid and turbulators, the cost of manufacturing refinery heat exchangers are sharply reduced. A heat exchanger filled with MgO-SAE10 nanofluid and equipped with SOL-shaped turbulators with =0.5mm, =5.8mm and =5.8mm is suggested as the best configuration, which can improve the thermal characteristics of heat exchanger about 62% in this work.

Control of the force exerted on an object is important for boosting system performance in robotics manipulators. Any undesired applied force may leave remarkable effects on the system, with the potential to damage the object. In addition, measuring external force is another challenge associated with such cases. Proposing an appropriate force estimation algorithm is a solution to overcome this deficiency. In this research, a control strategy is proposed to control the external force applied on the n-dof robotics. To eliminate force measurement in the controller, a force estimation strategy based on a disturbance observer is employed. Subsequently, a sliding-mode based control is implemented to cope with the force estimation error. The closed-loop stability of the system in the presence of estimated force is analytically considered. The proposed algorithm was implemented on piezoelectric actuators as the experimental setup. The experimental results confirm that by employing the proposed control scheme, precise force control is achievable. The force estimation algorithm can also suitably estimate external force.

We proposea newimpedance control algorithmfordelayed linear bilateral teleoperation systems. In thepresented control strategy, with regard to a preferredimpedance model for the master and slave robots, aspecialdynamic featureat the human and the masterrobotalong withthe slaverobotand environment interface isproposed. In addition, external forces signalsincluding operator and remote environmental forcesare used in the controllerto attain desired impedance model.A force estimationschemeispresentedto removemeasurement of external forces. Then, thedesiredimpedance model is locatedintoanappropriatesliding-mode control schemeto compensatetheparametersuncertainties emerged by external force estimation errors. Then, the absolute stability criterionis usedto investigatethe stability of theclosed-loopteleoperationsystemalong withtransparency. Consequently, the control strategyis implemented on 1-DOF robotic systemas the master and slave robots. Simulation results verifythe effectivenessof the presentedimpedance controller by usingestimated external forces.

The tension-type headache (TTH) is the most common type of headache across the world with the greatest socioeconomic impact on patient’s life in comparison with other primary headaches. Salivary α-amylase could reflect changes associated with stress in the body. The present study investigated the relationship between stress and frequent episodic tension-type headache by measuring the salivary α-amylase levels.

In this case- control study, 90 females in two groups, a case group with 45 females with frequent episodic TTH and a control group with 45 healthy females were enrolled. The Hamilton stress questionnaire was completed in the two groups to examine the level of stress. Then, salivary α-amylase levels were measured. The data were analyzed with SPSS 18 using t-test and Mann-Whitney test (α = 0.05).

The mean salivary α-amylase activity levels and mean Hamilton questionnaire scores in the case group were significantly higher than those in the control group (p value = 0.001). In addition, there was a significant correlation between the salivary α-amylase activity and Hamilton questionnaire scores in the case (p value = 0.002) and control (p value= 0.001) groups.

According to the result of the present study, salivary α-amylase levels can be an appropriate marker for assessing anxiety in patients with frequent episodic tensiontype headache.

The integrated health system (IHS) entitled “SIB” was launched in 2016 aimed to electronic health record (EHR) in the field of health. Given that, in addition to deploying the system, its acceptance criteria by users has a significant effect on its effectiveness and benefits: therefore, the present study was carried out aimed to determine the acceptance rate of IHS technology in health centers.

This study as a cross-sectional survey and applied research was conducted in Zahedan University of Medical Sciences (ZAUMS) in 2017. The population in the present study consisted of all users of SIB system affiliated ZAUMS. Of these, 285 users were selected (physician, health care provider, Behvarz) in five counties affiliated with ZAUMS using multistage cluster sampling. In this study, standard technology acceptance questionnaire was used for data collection. The data were analyzed by SPSS22 software and analyzed using descriptive statistics, one-way Anova, T test and other related tests.

About 77.9 % of users used the system for several times a day. The SIB system acceptance rate by 49.5 % of users was moderate and 38.9 % of the users had excellent acceptance of this system. There was a significant relationship between the acceptance rate of SIB system among the users with age, gender, city, level of education, type of employment, place of work and organizational position (P < 0.05).

The results of this study show that, most users have accepted and confirmed the SIB system. Modification of the system with regional approach with the opinion and participation of specialists in comprehensive health service centers is suggested. .

 One of the most important united nation Millennium Development Goals is to control Tuberculosis (TB). This study aimed to identify the high-risk areas of TB and other related factors of it in an epidemiological study.

 In this retrospective study, the records of 1566 TB infected patients in healthcare centers of 17 cities of Mazandaran University of Medical Sciences were investigated during 2009-2013 years. Information of patients was gathered using a check list. The collected data was then analyzed using chi-square.

The mean age of the patients was 46.17± 20.6 years. The 5-year incidence rate was 12.14 in 100,000 populations. Cities in the east of Province (Sari, Behshahr, and Neka) had highest incidence rate (about 16 cases in 100,000 population). The incidence rate was different based on gender as, 15.3 % of the men and 10.2 % of the women were infected. The median delay time in the diagnosis was 34 days.

The incidence rate of TB in Mazandaran was found to be almost similar to the previous reported rate in Iran. High incidence rate in east of province may be due to bordering to the Golestan Province as the immigrant province. The short delay time of TB diagnosis during this period indicated the well health services practices in this province. More attention should be paid to high risk areas for identification and giving education to those patients.

In this research via CT scan, the relationship between physical properties of pears and storage times with bruise due to loading force was investigated. Before dynamic loading force and storing, 45 pears were examined using Scan CT and 27 pears with zero bruise percentage were selected  and dimensions of pears (length, width, thickness) were measured, then properties such as the equivalent diameter, geometric mean diameter, spherical coefficient, surface area and aspect ratio of calculus were calculated, next selected pears were subjected to dynamic loading with three  mass of weights 300, 350 and 400 g and  5, 10 and 15 days storage was used to investigate the effect of impact on pears. Then, after dynamic loading and storing, using the CT scan in each period of storage, the rate of pear bruise was calculated. The results of the experiments showed that there is an inverse relation between geometric diameter, arithmetic diameter, equivalent diameter and surface area with the bruise percentage. Also a direct and unreasonable relationship between the spherical coefficient and aspect ratio and the percentage of bruising was absorbed. Also, according to the results obtained for mass weighing 300 g or less in 5-day storage period, the amount of geometric diameter, arithmetic and equivalent diameter, spherical and aspect ratio on percentage of bruising were not significantly affected and percentage of bruising can be almost zero and with increasing amount mass weighing and storage, the above parameter's will affect the percentage of bruising.

Pear damage is one of the main causes of the loss of fruit quality. Bruises occur during dynamic and quasi-static loading, which causes damage to the healthy tissue of the fruit. In this research, pears were placed under quasi-static loading (thin edge and wide edge) and dynamic loading. Then they were stored in 5, 10 and 15 days and after each storage period, using the CT-Scan non-destructive technique the bruise percentage was estimated. In this study, multi-layer perceptron artificial neural network (MLP) by 2 hidden layers and 3, 5, 7 and 9 neurons hidden layers was selected for modeling of loading force and storage period to predict bruise rate. The highest R2 values for training and testing for quasi-static loading of thin edge and wide edge in a 9-neural network were training Thin-edge=0.91, test Thin-edge =0.99 and training Wide-edge=0.95, test Wide-edge =0.99. For the dynamic loading of a network with 3 neurons in the hidden layer has the highest value (training Wide-edge=0.98, test Wide-edge =0.99). For learning (9 neurons) quasi-static loading thin edge (7 neurons) quasi-static loading wide edge and dynamic loading (7 neurons) have been the best network. According to the results obtained for R2, RMSE and learning cycle, it can be said that the neural network has the ability to predict the bruise percentage to an acceptable level for pears.

We design and simulate an efficient wavelength division demultiplexer (WDDM) based on photonic crystal without using either specific materials or complexities in the fabrication process. The photonic crystal consists of a square lattice of Chalcogenide glass with  embedded in air in two dimensions. The structure involves three cavities around the boundary of the waveguide with specified distance from each other for wavelength selection. For obtaining resonant frequencies of the cavities, two dimensional Finite-Difference-Time-Domain (FDTD) simulation is used. Through simulations, characteristic resonant wavelengths of the cavities are obtained in terms of the size of the coupling rods and the inner rod of the cavity. To show the design flexibility of the proposed structure, a WDDM is designed to divide a common input containing wavelengths  and into three distinct ports with a high efficiency..

In this paper, we report simulation and fabrication of a gas sensor based on tapered fiber by measuring the output power in the presence of different hydrogen concentrations. The fibers were tapered to 15.5 μm and 26.6 μm by using oxy-butane torch and the output spectrum is obtained using a 1550nm laser source and an optical spectrum analyzer (OSA) and the sensitivities of the tapered fiber sensors were determined. It is shown that by increasing the percentage of the hydrogen in the surrounding environment, the output power is changed by 7% and 2.3% in the presence of 4% hydrogen for tapered fibers of diameter 15.5μm and 26.6 μm respectively. The response time of the aforementioned sensors were 13 and 17.6 seconds respectively. In addition, the repeatability tests of the fabricated sensors demonstrates acceptable results. Simulation of the tapered fiber sensors demonstrates good agreement with experimental results. The obtained sensitivity makes hydrogen detection below 4% easy and accurate.

Tension-type headache is the most common type of headache across the world. Saliva as a non-invasive medium is used to detect a wide range of diseases. Salivary Alpha-Amylase (SAA) levels has been suggested as a potential indirect marker for detecting Sympathoadrenal Medullary (SAM) activity, which is activated by pain. Significant correlation was found between SAA levels and pain scale in patients with chronic pain. The purpose of the present study was to measure SAA activity in Frequent Episodic Tension-Type Headache (FETTH). In addition to the Visual Analogue Scale (VAS), we intend to assess intensity and various aspects of pain by McGill Pain Questionnaire (MPQ).
A total of 45 females with FETTH (case group) and 45 healthy voluntary females (control group) were enrolled in our case-control study. Unstimulated saliva by spitting method was taken from each participant.
SAA levels were significantly higher in patients with FETTH (P This is the first study using MPQ as a subjective means of assessing quality and quantity of pain alongside the VAS as an objective tool for evaluating pain in patients with FETTH. SAA may be an appropriate marker for assessing of pain levels in patients with FETTH. MPQ versus the VAS may be a more accurate measurement tools along VAS.

Burning mouth syndrome (BMS) is pain or burning sensation on the tongue or other mucosal membranes with at least 4 - 6 months duration and without clinical or laboratory findings. Its etiology is unknown and the prevalence varies across studies.
The current study aimed at evaluating the prevalence of BMS in female patients referred to Al-Zahra Hospital of Rasht, Iran, and investigating its related factors.
A descriptive cross sectional study was conducted from March to December 2015. A total of 2400 females referred to the gynecological clinic of Al-Zahra hospital were examined and a researcher-made check list was completed. The diagnosis of BMS was based on patients’ self-report about burning sensation in the oral mucosa with no clinical symptoms in the oral cavity. After the check list was completed, the SPSS software version 16 was used for statistical analysis using chi-square and the Cramer test.
According to the results of the current study, 3% of patients had burning mouth syndrome. The age range of most patients was 40 to 49 (54.2%) years and 38.9% of them were menopause. The most common sites of involvement were the tip of the tongue (33.3%), and lower lip (19.4%), respectively. The most common type of BMS was type 1 (51.4%). About 63.9% of participants had xerostomia; 9.7% of patients had para functional habits. No significant relationship was observed between oral hygiene, systemic disease, using denture, and BMS. There was a weak relationship between seasonal allergies and BMS.
To the authors best knowledge, BMS prevalence in the current study was consistent with that of international statistics. BMS more commonly affected females younger than 50 years old. About 65% of patients had xerostomia. Several factors may impact on BMS, but the effect is not yet definite.

Length of hospitalization is an important indicator for optimal management and to reduce and save the costs.
Considering the limited hospital capacity as a referral center for psychiatric patients, the high prevalence of the disease, and the high expense of the treatment, this study aimed to identify the factors associated with psychiatric patients’ length of hospitalization.
The data were obtained from the records of all patients hospitalized for the first time since the April 2007 to the March 2012. The data collection tool was a checklist comprising of demographic variables, variables related to the socioeconomic status, psychiatric disorders, and the related variables such as length of hospitalization and a previous history.
In the present study, 2397 (72.8% males and 27.2% females) medical documentations were investigated. Median length of stay was 25 days. Using the Cox model, the variables including age, educational level, material status, employment, the insurance status, the history of hospitalization at psychiatric center, type of treatment and disorder, duration of disorder, the referral source , and hospitalization during religious months (Ramadan and Muharram) and agricultural seasons had a significant relationship with the length of hospitalization (P value