محمد واحدی

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.

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.

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.

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.

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.

Phase inversion is a common method for preparation of polymeric membranes. It is noticeable that most of the membranes prepared by this method have an asymmetrical structure. In this type of membranes, separation of particles occurs only by top dense layer in a high operating pressure. On the other hand, the separation process using symmetric membranes containing surface pores occurs on the top surface and in the depth of the membrane at lower operating pressure. In this research, preparation of polyethersulfone-based membranes was performed through the phase inversion method by dimethylacetamide as a solvent and water as the nonsolvent. Changing the coagulation conditions by applying one pause stage in an environment with the precise control of temperature and humidity, along with using polyvinylpyrrolidone as a hydrophilic additive, were attempted in order to control the porosity and structural changes of the membrane. Scanning electron microscopy (SEM) images, bubble point test, porosity, and mean pore radius measurements were used to study the structure of the prepared membranes. The performance of the membranes was evaluated by pure water permeation test and elimination of bacteria from cell culture medium. The results obtained illustrate that the implemented method is capable of preparation of membranes with symmetrical structure and pore diameter less than 0.4 μm featuring acceptable pure water flux and bacteria removalability. It was also observed that increase in the concentration of polyvinylpyrrolidone additive leads to an increase in porosity, permeation and pore size of the membrane samples. On the other hand, the tensile strength and elongation-at-break of the membrane samples were reduced upon increasing in polyvinylpyrrolidone concentration.

Probiotics have been associated to various benefits on oral health, partially through regulation of local immunity. The purpose of this study was to evaluate the effect of probiotics on salivary IgA. This randomized, triple-blind trial was conducted on 40 healthy non-smoker volunteers. The subjects were assigned to two age- and sex-matched groups ingesting 200 g of a regular yoghurt (control) or a yoghurt containing probiotic bacteria (treatment group) once daily for 8 weeks. Unstimulated salivary samples were collected from the subjects at weeks 0, 4 and 8 of trial and total salivary IgA concentration was determined using ELISA. Saliva volume was measured and salivary IgA secretion rate was calculated. The differences in IgA means were statistically analyzed by repeated measurments (α=0.05). Over the trial period, no significant changes were found among the salivary IgA concentrations of control group; however, treatment group presented a non-significant increase (P>0.05). There were not significant differences in concentration and secretion rate between two groups at each time point of study (P>0.05). Within the limitations of this study, an 8-week period daily consumption of probiotic yoghurt could not alter the salivary IgA concentrations, although it persuades an increase trend in salivary IgA secretion rate.

Multiple choice exams are one of the most common objective exams used in medical education. So, it is important to find ways to improve the quality of these exams, especially in residency programs. Thus the aim of this study was to investigate the effect of education on quality improvement of Multiple Choice Questions (MSQ) designed in Annual Residency Exams of Dental Faculty. In this experimental study, the structure and taxonomy in all MCQs designed by dental faculty for annual residency exams in 2008 were analyzed through valid and reliable checklist. Checklist items were based on Millman’s principles and several other resources. The same process was repeated for MCQs after running a workshop for question designers. The pre- and post- workshop data were compared using Z test. From 1239 questions, 63.1% and 76.3% of the questions developed in 2008 and 2009 had no structural flaw, which revealed a significant difference between the two years (P<0.001). Regarding high taxonomy questions, a significant increase was observed in the year 2009 (P=0.039). Considering the results of this study, designing and running training workshop for question designers improved quality of MCQs and these workshops can lead to improvement of MCQ exams in other universities.

Oral health problems of chronic renal failure patients can compromise systemic health. The purpose of this study was to investigate the dental and periodontal status of patients on regular hemodialysis (HD) maintenance therapy and the effect of duration of HD on oral health. Methods & Materials: In this historical cohort study 65 HD patients and 65 healthy people were collected as case and control groups. Decayed (D), Missed (M) and Filled (F) teeth, DMFT Index, Plaque Index (PI), Gingival Index (GI), and Probing depth (PD) were examined and compared between case and control groups. Also, HD patients were divided into two subgroups based on duration of hemodialysis: 1: three and less than three years and 2: more than three years). In this study all variables were examined and compared between these subgroups. T-test and chi-square and SPSS software were used for statistical analysis.

Except M and DMFT index, significant differences were found in other indices between case and control groups (P<0.05). D, M, F, DMFT values showed no significant differences between the two HD subgroups, whereas, PD, GI and PD values had significant increase in two groups based on the duration of hemodialysis.

The dental and periodontal health is poor in HD patients and periodontal status becomes worse specially during the time of dialysis.

Background and The core of the health information system in the hospitals lies within medical records. Ït is a means of communication between the care providers. Good medical record documentation is essential for effective clinical care. This study is designed to evaluate the condition of documentation of the data for diabetic patients and its effect on treatment in educational hospitals of Mazandaran Üniversity of Medical Sciences through the years 2006 and 2007. This is a descriptive study and the subjects recruited were medical records of diabetic patients from Ïmam Khomeini and Bou Âli educational hospitals in Sari Çity، Ïran 2006-2007. The collected data were analyzed using SPSS software version 17. Ôf total 270 diabetic records، 16 records (5. 92%) belonged to Ïnsulin-dependent diabetes mellitus (ÏDDM)، 14 records (5. 19%) to non-insulin-dependent diabetes mellitus (NÏDDM)، 50 records (18. 52%) to gestational diabetes and 190 records (70. 37%) to unidentified type of diabetes. 201 patients (74. 44%) were women and 69 (25. 56%) were men and of 227 patients 84. 7% were married. Çonclusion: Despite of efforts made in recent years in context of improving the documents of admitted patients and contrary to all practical training that physicians received on the basis of basic requirements for international classification of diseases (ÏÇD)، still، there are major problems in record of main data. We conclude that more attention must be paid by medical administrators، physicians and medical record staffs to this matter. We suggest health authorities must reform the system of recording and more training courses must be funded to improve involving staffs’ awareness.

Regarding the importance of orofacial complications in thalassemic patients and lack of enough information about this disease in Iran, it seemed necessary to perform a research to help better diagnosis and reducing the orofacial complications of thalassemia. in a descriptive study all patients of Qazvin thalassemia center were examined (110 patients). Orofacial examination (shape of face and nose, maxillary protrusion, oral paleness, delayed eruption of teeth, caries rate and type of occlusion) was done and their relation with medical treatment was evaluated. Statistical analysis was conducted using SPSS software and x2test. The prevalence of orofacial complications are as fallow: saddle nose (71.08%), maxillary protrusion (55.5%), paleness of oral mucosa (48.2%), rodent face (30%), deep bite (28.2%), spaces between maxillary anterior teeth (22.7%), open bite (13.6%) and delayed eruption of primary (10%) and permanent (8.2%) teeth. Prevalence of occlusion types decreased as fallow: class I, II and III. Caries index (DMFT) was significantly more among thalassemic patients than healthy cases (P<0.05). The prevalence of orofacial complications of thalassemia was very considerable. This study also showed the importance of early diagnosis and intensive medical treatment in reducing these complications.

Diabetes mellitus is a complex disease that results in severe metabolic disorders. Recently; great advances about diagnostic criteria of diabetes have occurred. The aim of the present study was cytomorphometric and microscopic analysis of buccal epithelium in diabetic patients in order to find a new procedure for diagnosis. In this cohort study, buccal epithelial smear of 12 patients with type I diabetes, 12 patients with type II diabetes, and 24 normal subjects as a control were taken. Papaniculao technique was used for staining the samples and the nuclear and Cytoplasmic area were measured by counting point method. Cytoplasmic / nuclear ratio was calculated. t-test was used for statistical analysis through SPSS13. The epithelial cells of diabetic patients showed binucleation and karyorrhexis. The nuclear and cytoplasmic area as well as cytoplasmic/ nuclear ratio were significantly lower in diabetic patients compared to healthy controls (P<0.05). Diabetes mellitus can produce some alterations in oral epithelial cells. Although these changes are not specific in diabetes, they can be used in diagnosis of this disease.

Statement of problem:

 Recurrent aphthous ulcers (RAU) are one of the most common ulcers in the oral cavity. Several studies have shown conflicting variations for inflammatory cytokines and other biologic markers in recurrent aphthous ulcers.

The aim of the present study was to determine the level of IL-8 and IL-6 in the serum of patients with recurrent aphthous ulcers.

In this case- control study, the serum levels of IL-8 and IL-6 were measured in patients with recurrent aphthous ulcers (n=40) and in healthy control subjects (n=40). The cytokines levels were measured in the serum by ELISA. The data were analyzed with SPSS software using T- test.

The mean value of the IL-8 and IL-6 in the patient group was 52.24 pg/ml and 9.39 pg/ml which was 10 and 4 times higher than that of the control group, respectively. The differences were statistically significant (p <0.01).

The results of the present study showed that the serum levels of IL-8 and IL-6 were elevated in the patient group, IL-8 level being more considerable.

Contaminated dental handpieces have the potential to transfer infection to patients. New generation of autoclavable turbines have to some extent overcome the problem however, in clinic sometimes it is necessary to use chemical to disinfect handpieces. The aim of this study was to determine the antimicrobial effect of some routinely used disinfectant solutions on dental contaminated handpieces. In this experimental study 35 turbines were sterilized. The turbine's heads were inserted into microbial suspension containing staphylococcus, pseudomonas and candida and then exposed to the disinfectant solutions. Inoculations into culture medium were made at different intervals. All medium was incubated for 24 hours at 37oC followed by spectrophotometer inspection for detection of microbial growth. Serial dilutions of disinfectant agents were used to determine the highest dilution in which there was no microbial growth. Kruskal wallis test was used for statistical analysis and p<0.05 was considered as the level significance. Ethanol had antimicrobial effect on all of the tested microorganisms at dilution of 1:4. Betadine at dilution of 1:64 caused inhibition of all of the microbes except pseudomonas. Micro 10 had antimicrobial effect up to dilution of 1:256 but could not inhibit microbial growth at higher dilution. Sodium hypochlorite inhibited growth of the three microoganisms up to dilution of 1:1024. Based of on the results of this study sodium hypochlorite was found to be the most effective antimicrobial agent among those used in this study, inhibiting microbial growth at the highest dilution