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Maxillofacial surgeons face great challenges in the reconstruction of extensive mandibular defects, especially cancer patients. The function of the mandibular reconstruction system and aesthetics are the most important factors that have a significant effect on the quality of life of patients after recovery. In this study, a customized implant was designed and implemented using additive manufacturing method to treat a patient with a lateral mandibular tumor using the CAD/CAM technique. The anatomy of the patient's mandible and the geometry of the defect site were taken into account while designing the customized implant. The reconstruction system performance was evaluated using COMSOL V5.4, a finite element method. Inclusion criteria include maximum von-Mises stress and deformation implant as well as maximum von-Mises stress and strain in cortical bone around screws. Finite element results showed that the maximum von-Mises stress of the plate was 106 MPa and plate deformation was 54.42 μm. Also, the maximum von-Mises strain and stress of cortical bone around screws were 1940 μm/m and 44 MPa, respectively. After evaluating the biomechanical behavior of the customized implant, it can be concluded that this system has sufficient flexibility and stability and the facial aesthetics will be maintained after recovery. Therefore, the success rate of surgery can be increased by using customized implants in the reconstruction of large mandibular defects while maintaining the aesthetic appearance of the patient.

Background and objectives The left atrial appendage (LAA) is the most common region for thrombus formation in atrial fibrillation (AF). Morphological parameters such as shape, size, and LAA volume can cause insufficient effectiveness of available therapeutic options. This study aimed to examine blood flow inside LAA and its removal effects. Computational fluid dynamic (CFD) simulations were carried out on two patients with different morphologies. Methods Two patients' CT was used to reconstruct the 3D geometries of the left atrium (LA) and left atrial appendage (LAA). Then, the geometries were refined in the mentioned software, and the LAA in some models was removed. Next, in generated 3D volume mesh, sinus rhythm (SR) and atrial fibrillation (AF) outflow velocity were imposed at the mitral valve as boundary conditions. Finally, CFD simulation was conducted to analyzing blood flow within LA with/without LA. Results The results confirmed that velocity and vorticity decreased under AF conditions inside the LA domain for both patients. However, removing LAA may cause unpredictable consequences, due to different shape and volume of LAA. LAA removal had insignificant effects on velocity and vorticity within LA in SR-mitral outflow. However, removing LAA increased the blood flow rate by 9.15% and vorticity by 7.27% for patient one under AF rhythm (SR)-outflow. In contrast, for patient two, LAA removal in both AF and SR decreased velocity and vorticity within the LA domain. In SR-mitral outflow, velocity dropped by 18.8 %, and vorticity by 13.2%. Also, under AF velocity and vorticity decreased by 23.33% and 18.6% respectively. Meanwhile, the results indicated that the vorticity magnitude increased inside the LAA under AF associated with the risk of thrombus formation, particularly for patient one under AF. The distal part of LAA in both patients was the most common region for blood stasis because of the lowest velocity magnitude. Conclusion Overall, the morphology of LAA could be the critical parameter to determine the possibility of thrombosis formation, particularly under AF conditions. High volume, low blood flow velocity and two-lobe-appendage are more likely to have blood stasis. Furthermore, the morphology difference can affect the LAA removal result and make it more complicated. So, it could be challenging to generalize LAA removal as a therapeutic option for different patients. The implication of this CFD observation needs more investigation.

Sheep was among the first domesticated animals, but its demographic history is little understood. Here we present combined analyses of mitochondrial and nuclear polymorphism data from ancient central and west Anatolian sheep dating to the Late Glacial and early Holocene. We observe loss of mitochondrial haplotype diversity around 7500 BCE during the early Neolithic, consistent with a domestication-related bottleneck. Post-7000 BCE, mitochondrial haplogroup diversity increases, compatible with admixture from other domestication centres and/or from wild populations. Analysing archaeogenomic data, we further find that Anatolian Neolithic sheep (ANS) are genetically closest to present-day European breeds, and especially those from central and north Europe. Our results indicate that Asian contribution to south European breeds in the post-Neolithic era, possibly during the Bronze Age, may explain this pattern.

Background: C-Pulse is a new, nonblood contacting device based on the concept of counter-pulsation that is designed for long-term implantation. However, there is a lack of comprehensive investigation of the pressure and velocity fields under the action of C-Pulse. Aim: In this paper, we aim to conduct a numerical simulation of the underlying mechanism of the device in order to analyze its performance and related undesirable issues. Materials & methods: A 3D finite element model is utilized to simulate the mechanism of the blood pumping. Results & conclusion: The simulation well reproduced the essential characteristics of the C-Pulse. Preliminary results were in a reasonable range while a couple of irregular flow patterns were identified.

Background: Poor sleep quality in medical students may negatively affect their professional training and deteriorate neurocognitive and academic performance. Objectives: In this study, we aim to determine the prevalence and determinants of poor sleep quality and its scales in a group of medical students in Tehran, Iran in 2017. Methods: In this cross-sectional study, Pittsburgh Sleep Quality Index (PSQI) was completed by 154 medical students in Tehran, Iran. Demographic characteristics were also gathered. Global PSQI and scales scores were calculated. Results: Median Global PSQI score was 5. Poor sleep quality was observed in 65 (42%) students. Participants scored worst in sleep duration and daytime dysfunction scales, and 84.4% of the total participants reported some degree of daytime dysfunction. More than 90% of the participants reported no use of sleep medication. Neither of the variables sex, age, place of residence, being a freshman or having a history of sleep problems showed any significant association with sleep quality. When evaluating the scales, sleep duration problem was mostly observed in freshmen (P = 0.02), while medication use and daytime dysfunction were more common in second-year students (P = 0.04 and P = 0.01, respectively). Conclusions: The prevalence of poor sleep quality was high in this group of medical students in Tehran. The problem was largely observed in sleep duration and daytime dysfunction subscales of sleep quality.

Introduction: Maternal mental health during pregnancy has a major impact on fetal growth and consequently, child health. The objective of this study was to assess the effect of "Cooperative-Supportive" Intervention Program on Pregnancy. Methods: The present before and after interventional research was conducted on 114 pregnant women referring to Khoy health centers in 2014. Pregnant women were randomly divided into intervention (n=57) and control groups (n=57). The data collection tool in this research was the researcher-made questionnaire based on the Predisposing, Reinforcing and Enabling Constructs in Educational Diagnosis and Evaluation (PRECEDE) model which assessed the participants’ predisposing, enabling, and reinforcing factors. The educational interventions for enhancing pregnant women’s stress controlling skills were conducted and also practical pacifying lessons were held for the intervention group during five weeks with relaxation exercises. In order to assess health status among pregnant women, knowledge, attitude, depression, anxiety and self-efficacy were investigated by applying different scales and questioners. The questionnaires were completed before and after the interventional program. The data were analyzed, using suitable statistical tests. Results: After the intervention, the mean score of PRECEDE major components significantly increased and the total anxiety and depression scores decreased in the intervention group in comparison to those of the control group. Conclusion: The present study showed the positive impact of educational intervention programs based on PRECEED model and major components on reducing anxiety and depression, and finally mental health promotion in the studied population.

Background Circle of Willis (COW) is a network of cerebral artery which continually supplies the brain with blood. Any disturbance in this supply will result in trauma or even death. One of these damages is known as brain Aneurysm. Clinical methods for diagnosing aneurysm can only measure blood velocity; while, in order to understand the causes of these occurrences it is necessary to have information about the amount of pressure and wall shear stress, which is possible through computational models. Objective In this study purpose is achieving exact information of hemodynamic blood flow in COW with an aneurysm and investigation of effective factors on growth and rupture of aneurysm. Methods Here, realistic three-dimensional models have been produced from angiography images. Considering fluid-structure interaction have been simulated by the ANSYS.CFX software. Results Hemodynamic Studying of the COW and intra-aneurysm showed that the WSS and wall tension in the neck of aneurysms for case A are 129.5 Pa, and 12.2 kPa and for case B they are 53.3 Pa and 56.2 kPa, and more than their fundus, thus neck of aneurysm is prone to rupture. Conclusion This study showed that the distribution of parameters was dependent on the geometry of the COW, and maximum values are seen in areas prone to aneurysm formation.

Accumulation of cholesterol and other atherogenic lipids such as low-density lipoprotein (LDL) in artery wall causes reduction of vessel diameter and artery stenosis. The study of the mass transfer of these large molecules in the wall with considering effective factors on lumen flow and different physiological factors is the subject considered nowadays. In this paper, results of two dimensional and axi-symmetric simulations of three different models of the artery with 60% stenosis under pulsatile blood flow are presented. Filtration velocity of LDL mass transport in the permeable artery wall and shear stress of blood flow are investigated using ADINA software Three different flow models are considered. In the first and second models, the filtration velocity considered as a given parameter and constant in arterial wall boundary, while in third model arterial wall considered as porous wall, the filtration velocity is calculated from pressure difference as an input parameter of the model. The results show that filtration velocity is strongly depend on geometry and it is not constant along the wall, contrary to simplified models. The results of concentration variations in lumen and wall illustrate the increase in near wall LDL concentration or concentration polarization.

In this study, the performance of magneto-acousto-electrical tomography (MAET) is investigated quantitatively by considering interrelations between its sensitivity, resolution and conductivity contrast. An analytical solution for the forward problem of MAET is derived for two-dimensional (2D) concentric bodies by the separation of variables method. The electric potential and the acoustic pressure are separated into their angular and radial components. The series coefficients for these solutions are obtained from their respective boundary conditions. The electric potential on the boundary is related to the acoustic boundary acceleration analytically. From this relation, a sensitivity expression is derived relating fractional change in conductivity contrast to fractional change in the measured electric potential. This expression is a function of the resolution and conductivity contrast of the imaging system. It also depends on the acoustic wave number and the dimensions of the body. The pair-wise relations between these parameters are presented. The sensitivity behavior of MAET is compared with applied current electrical impedance tomography and the improvements for small inhomogeneities are presented. For eccentric bodies, a modified expression for the sensitivity is obtained by conformal mapping. For arbitrary periodic boundary excitations, the sensitivity expressions for harmonic cases are combined to obtain a unified sensitivity expression.

Occupational Health Surveillance System (OHSS) provides a critical opportunity to monitor and evaluate occupational disorders and injuries over the time. Among more than 21 million employees in Iran, 62.08% and 38.03% had been worked in the industrial and private sections respectively. Present qualitative study was designed for collection of expert opinion of staffs in this field and determined proper characters of suitable Iranian OHSS. Present qualitative study was performed on an interview based on data from occupational medicine staffs. Some questions about OHSS definition, temporary accompaniment of occupational diseases and injuries surveillance system, OHSS promoters and consumers, type of requested data for OHSS and rewarding and controlling systems to prepare qualitative and valid OHSS data. Interview answers were read, summarized and presented. Most of study participants’ staff believed that OHSS in the scientific base must cover all of essentially its parts including disorders, hazards and accidents together. They believed that this combination was made by a team working with occupational medicine staffs and other specialties such as occupational hygienist and information technologists. They emphasized that the Iranian ministry of health had the capacity to promote OHSS and organizing executive committee with all of OHSS involved as team working in this field. Occupational staff had been focused on this fact that OHSS data must cover all of needed data of Iranian working population and their relatives. Iranian occupational registry system must be change and develop as Occupational Health Surveillance system according the main parameters which were found in occupational staff interview.

Brain tumors are one of the main worldwide causes of mortality and morbidity and a critical issue in health risk. Tumor growth prediction is a proper method for better understanding the phenomena and choosing the appropriate therapy for patients. Since tumors’ physiological and morphological properties vary significantly in different individuals, using patient specific data is valuable for modelling tumor growth in staging and personalized-therapy planning. However, the validity of the models should be evaluated for their precision assessment based on the decision criteria. There are different sources of uncertainties affecting model prediction accuracy and decision making for the therapy. In this paper, an image-based tumor growth model is evaluated by taking into account uncertainties in the model parameters. The proposed reaction–diffusion model integrates cancerous cell proliferation and invasion through reaction and diffusion terms, respectively. Uncertainties in diffusion and proliferation coefficients were analyzed through Monte Carlo simulation. The time needed for tumor to grow to its fatal size was estimated through numerical solution of the model. Comparison of the predicted time distribution with and without considering uncertainties in model parameters shows a decrease in dispersity of predicted data that highlights the importance of uncertainty. Also, the wide range for survival time shows the importance of choosing proper parameters in order to enhance model accuracy. The recommendations were made for increasing the validity of the tumor growth models.

Ultrasound contrast agents have been recently utilized in therapeutical implementations for targeted delivery of pharmaceutical substances. Radial pulsations of the encapsulated microbubbles under the action of an ultrasound field are complex and high nonlinear, particularly for drug and gene delivery applications with high acoustic pressure amplitudes. The dynamics of a polymer-shelled agent are studied through applying the method of chaos physics whereas the effects of the outer medium compressibility and the shell were considered. The stability of the ultrasound contrast agent is examined by plotting the bifurcation diagrams, Lyapunov exponent, and time series over a wide range of variations of influential parameters. The findings of the study indicate that by tuning the shear modulus of surrounding medium and shell viscosity, the radial oscillations of microbubble cluster undergoes a chaotic unstable region as the amplitude and frequency of ultrasonic pulse are increased mainly due to the period doubling phenomenon. Furthermore, influences of various parameters which present a comprehensive view of the radial oscillations of the microbubble are quantitatively discussed with clear descriptions of the stable and unstable regions of the microbubble oscillations for typical therapeutic ultrasound pulses.

Background: Iranian Registry of Clinical Trials (IRCT) started as a primary registry in 2008. We examined the characteristics and scientometric measures of prospectively registered clinical trials in IRCT over time and compared them with that of ClinicalTrials.gov. Methods: We selected eligible trial records between 2008 and 2016 from the IRCT database. We assessed their characteristics and the journal metrics of ensuing outputs over the study period and compared our findings with the corresponding information from ClinicalTrials.gov reported by Magdalena Zwierzyna et al. and a random sample of trials registered with this registry. We used the chi-square test for comparison of proportions and Mann-Whitney U test for comparison of medians. P-value

Orthodontic tooth movement in the alveolar bone is due to the mechanical response of periodontal ligament to applied forces. Definition of a proper constitutive model of the periodontal ligament to investigate its response to orthodontic loading is required. For this purpose, a three-dimensional finite element model of incisor tooth, periodontal ligament, and bone was built utilizing the hydro-mechanical coupling theory. Tooth displacement in response to orthodontic loading was then investigated, and the effect of different mechanical behaviors assigned to the solid phase of the periodontal ligament was compared. Results showed that where the periodontal ligament was placed in tension, pore volume was filled with fluid intake from the bone, but fluid flow direction was from the periodontal ligament toward the bone where the periodontal ligament was placed in compression. Because of the existence of interaction between solid and fluid phases of the periodontal ligament, considering biphasic material formulation was capable to address its microscopic behavior as well as time-dependent and large deformation behaviors. This article provides beneficial biomechanical data for future dental studies in determination of optimal orthodontic force.

Despite the high success rate achieved in current dental implantation, there are still important problems to solve like incomplete early osteointegration, bone damage, and long-term implant loosening. Highly compliant stress absorbers are a possible solution to these problems. Although several works examined the stress-strain distribution in bone without and with absorbers to show their favorable results, none of them analyzed their impact on long-term remodeling. Here, we analyze this effect by comparing the evolution of stress and bone mass density without and with different designs of absorbers with those of the healthy tooth. Several finite element models with ABAQUS, corresponding to each design considered, were built to obtain the mechanical conditions in bone and implant. Then a mechanobiological bone remodeling model that considers damage accumulation and its repair during the remodeling process was used to compute the bone density redistribution. This approach allows assessing both the short-term density loss and the relative micromovement between bone and implant. We analyze the stress distributions in both bone and implant as well as the relative micromovement of the implant. We also present the evolution of damage and bone volume fraction. These results show that the addition of absorbers can reduce the stress in the bone around the implant. The obtained results also show that using stress absorbers reduces damage in bone, while increasing the number of absorbers does not necessarily improves damage reduction. We conclude that using implants with a correct design of absorbers prevents damage and stress shielding, reducing implant loosening.

Magneto-acousto-electrical tomography (MAET) is an imaging modality to image the electrical conductivity of biological tissues. It is based on electrical current induction by using ultrasound under a static magnetic field. The aim of this study is to develop a data acquisition system for MAET based on magnetic field measurements. The static magnetic field is generated by six permanent neodymium magnets. A 16-element linear phased array (LPA) transducer is utilized to generate acoustic pressure waves inside the phantom. To measure the magnetic field intensity generated by the induced currents, contactless receiver sensors are developed using two similar disk multiple layer coils, which are Helmholtz coil sensor. Physical properties and electrical characteristics of the sensors are assessed. A two-stage cascaded amplifier is designed and utilized in the receiving system. The gain of the cascaded amplifier at 1 MHz is adjusted to be 96 dB. Experimental studies are conducted with two different phantoms, having 3 S m-1 and 58 S m-1 electrical conductivity, respectively. A-scan and B-scan images of phantoms are obtained with the LPA transducer. Comparison of the ultrasound (A-scan) and MAET signals reveals that 3 S m-1 conductive inhomogeneity can be detected with this data acquisition system. Furthermore, the front and rear interfaces of an inhomogeneity ([Formula: see text]) of 58 S m-1 conductivity are detectable.

The purpose of this study was to develop a new method for the sampling and analysis of naphthalene (Nap) and phenanthrene (Phe) in air. XAD-2 sorbent was prepared with polyaniline (PANI) to increase its adsorption area. Thus, 22-gauge needles were packed with XAD-2/PANI sorbent for the extraction of Nap and Phe, and sampling of the analytes of interest. The compounds were dynamically sampled from the headspace of the flask in laboratory and then analyzed using a gas chromatography (GC) device equipped with flame ionization detector (FID). The needle trap device (NTD) with the proposed sorbent was more sensitive and accurate than the NIOSH 5515 method. The results showed that the optimal temperature and time for the desorption of the analytes were 350 °C and 8 min, respectively. The analytical parameters such as carryover effect, breakthrough volume, and storage time were examined. The repeatability of the method was determined to be 9.4–13.5% for Nap and 7.1–15.7% for Phe. The limits of detection (LOD) for the analytes were in the range 0.002 - 0.09 ng L−1, and the limits of quantitation (LOQ) were in the range 0.01- 0.23 ng L−1. It was also found that the NTD packed with XAD-2/PANI sorbent was a sensitive and cost-effective method, and offered a high accuracy for the sampling and analysis of PAHs in air.

Minimally invasive steerable catheters, commonly implemented in cardiac ablation, are currently operated by interventionalists exposing them to X-ray radiation and requiring the dexterity for accurate steering. To conduct robot-assisted cardiac ablation, highly accurate stable control platform for precise force/position control on the moving tissue is required. This paper introduces hybrid force/position control strategy to apply a constant force to the cardiac tissue while tracking the desired trajectory. The position controller is based on a nonlinear model predictive tracking control satisfying the input constraints. Cosserat rod theory is incorporated for the distal shaft modeling of tendon-driven catheters, and the model is reformulated for controller design and stability proof. Lyapunov-based stability analysis is conducted. To apply the controller, the force-displacement mapping of the cardiac tissue is obtained through ex vivo experimental tests. The performance of the controller is evaluated, and the catheter is capable of regulating the force with the RMSE of 4.9 mN and tracking the position with the RMSE of 0.89 mm. The promising results verify the potential of the application of the introduced approach in real applications including in vitro and clinical cardiac ablation.

Introduction: One of the most popular methods for evaluating old people’s health condition is to assess their functional practice. The aim of this study was to assess the status of daily living activities among the older people of Maku, Iran. Methods: The present cross-sectional study was accomplished among 216 older people in Maku via simple random sampling. Participant’s subjective and demographic information were gathered and their daily living activities status was measured by the KATZ index. Results: The participants' mean age was 70.09±7.98. Most of the elderlies were men (59.3%) and illiterate (38.4%). Of them, 10.6% were dependent, 6% needed help or were partially dependent, and 82.9% were independent in their daily living activities. Significant associations were observed between daily living activities and age, education level, marital status and living condition (p

Introduction: The rejuvenation characteristics of fat tissue grafting has been established for many years. Recently it has been shown that stromal vascular fraction (SVF) of fat tissue contributes to its rejuvenation properties. As the SVF is a minimal processed cell population (based on FDA guidance), therefore it is a suitable cell therapy for skin rejuvenation. This clinical trial was aimed to evaluate the ultrastructural improvement of aging skin in the facial nasolabial region after transplantation of autologous SVF. Methods: Our study was conducted in 16 patients aged between 38 and 56 years old that were interested in face lifting at first. All of the cases underwent the lipoaspiration procedure from the abdomen for sampling of fat tissue. Quickly, the SVF was harvested from 100 mL of harvested fat tissue and then transplanted at dose of 2.0×107 nucleated cells in each nasolabial fold. The changes in the skin were evaluated using Visioface scanner, skin-scanner DUB, Visioline, and Cutometer with multi probe adopter. Results: By administration of autologous SVF, the elasticity and density of skin were improved significantly. There were no changes in the epidermis density in scanner results, but we noticed a significant increase in the dermis density and also its thickness with enrichment in the vascular bed of the hypodermis. The score of Visioface scanner showed slight changes in wrinkle scores. The endothelial cells and mesenchymal progenitors from the SVF were found to chang the architecture of the skin slightly, but there was not obvious phenotypic changes in the nasolabial grooves. Conclusion: The current clinical trial showed the modification of dermis region and its microvascular bed, but no changes in the density of the epidermis. Our data represent the rejuvenation process of facial skin by improving the dermal architecture.

Purpose The bonding strength of bracket–adhesive tooth system should be high enough to withstand different loads applied either for treatment purpose or by patient. Different parameters affect the bond strength of bracket–adhesive-tooth system; however, only a few studies have reviewed the effect of orthodontic bracket base on bond strength of bracket–adhesive-tooth system. In this study, optimization of the bracket base geometry for teeth with planar enamel surface was investigated in order to increase the shear, tensile and torsional bond strength of bracket–adhesive-tooth system. Materials and methods Rectangular bracket was primarily bonded on maxilla central tooth to measure stress distribution of bracket–adhesive-tooth system with applying shear and tensile forces and torsional moment. Trapezoidal, hexagonal and elliptical brackets were then modeled for this planar enamel surface tooth. All of these brackets were bonded to tooth separately and similar loading conditions were applied on the bracket of each system. Stress distributions of bracket–adhesive-tooth systems were calculated and compared to each other. Results It was observed that for hexagonal bracket–adhesive-tooth system, adhesive layer and enamel, and for elliptical bracket the bracket and enamel layer were of more symmetric and appropriate pattern of stress distribution and lower maximum stress. Therefore, these shapes of bracket are more proper than the other two shapes for a planar enamel surface tooth. Conclusion Bracket base geometry was confirmed to crucially affect the bond strength of bracket–adhesive-tooth system through finite element analysis approach.

Laminar, turbulent, transitional, or combine areas of all three types of viscous flow can occur downstream of a stenosis depending upon the Reynolds number and constriction shape parameter. Neither laminar flow solver nor turbulent models for instance the k-ω (k-omega), k-ε (k-epsilon), RANS or LES are opportune for this type of flow. In the present study attention has been focused vigorously on the effect of the constriction in the flow field with a unique way. It means that the laminar solver was employed from entry up to the beginning of the turbulent shear flow. The turbulent model (k-ω SST Transitional Flows) was utilized from starting of turbulence to relaminarization zone while the laminar model was applied again with onset of the relaminarization district. Stenotic flows, with 50 and 75% cross-sectional area, were simulated at Reynolds numbers range from 500 to 2000 employing FLUENT (v6.3.17). The flow was considered to be steady, axisymmetric, and incompressible. Achieving results were reported as axial velocity, disturbance velocity, wall shear stress and the outcomes were compared with previously experimental and CFD computations. The analogy of axial velocity profiles shows that they are in acceptable compliance with the empirical data. As well as disturbance velocity and wall shear stresses anticipated by this new approach, part by part simulation, are reasonably valid with the acceptable experimental studies.