Ultrasonographic findings of mesenchymal chondrosarcoma of the mandible: report of a case

Shahidi, Shoaleh,Shakibafard, Alireza,Zamiri, Barbod,Mokhtare, Mohammad Reza,Houshyar, Maneli,Houshyar, Maral,Amanpour, Sara Korean Academy of Oral and Maxillofacial Radiology 2012 Imaging Science in Dentistry Vol.42 No.2

Today, ultrasound imaging is being widely used to assess soft tissue lesions in the maxillofacial region. However, ultrasound investigations of intra-osseous lesions are rare, especially for tumors of the jaws. This report emphasized the capability of this useful imaging modality in identification of the characteristics of malignant conditions involving the bone. Mesenchymal chondrosarcoama, one of the unusual malignant conditions of the jaw, was presented in a young male with significant facial swelling. Different imaging modalities parallel with the histopathologic investigation confirmed the diagnosis. Interestingly, destruction of the bony cortex and new bone formation with a characteristic "sun ray appearance", highly suggestive of sarcomas, was manifested on the ultrasonograph. Thus, this report presented the ultrasonographic features of chondrosarcoma of mandible and considered the ultrasonography to be a useful imaging modality to evaluate intra-osseous jaw lesions.

Ultrasonographic findings of mesenchymal chondrosarcoma of the mandible: report of a case

Shoaleh Shahidi,Alireza Shakibafard,Barbod Zamiri,Mohammad Reza Mokhtare,Maneli Houshyar,Maral Houshyar,Sara Amanpour 대한구강악안면방사선학회 2012 Imaging Science in Dentistry Vol.42 No.2

Today, ultrasound imaging is being widely used to assess soft tissue lesions in the maxillofacial region. However, ultrasound investigations of intra-osseous lesions are rare, especially for tumors of the jaws. This report emphasized the capability of this useful imaging modality in identification of the characteristics of malignant conditions involving the bone. Mesenchymal chondrosarcoama, one of the unusual malignant conditions of the jaw, was presented in a young male with significant facial swelling. Different imaging modalities parallel with the histopathologic investigation confirmed the diagnosis. Interestingly, destruction of the bony cortex and new bone formation with a characteristic “sun ray appearance”, highly suggestive of sarcomas, was manifested on the ultrasonograph. Thus, this report presented the ultrasonographic features of chondrosarcoma of mandible and considered the ultrasonography to be a useful imaging modality to evaluate intra-osseous jaw lesions.

ON KIRCHHOFF TYPE EQUATIONS WITH SINGULAR NONLINEARITIES, SUB-CRITICAL AND CRITICAL EXPONENT

M. El Mokhtar Ould El Mokhtar,Saleh Fahad Aljurbua 경남대학교 수학교육과 2024 Nonlinear Functional Analysis and Applications Vol.29 No.2

This paper is devoted to the existence of solutions for Kirchhoff type equations with singular nonlinearities, sub-critical and critical exponent. By using the Nehari manifold and Maximum principle theorem, the existence of at least two distinct positive solutions is obtained.

Film Formation in CO2 Corrosion with the Presence of Acetic: An Initial Study

( Mokhtar Che Ismail ),( Muhammad Azmi Mohd ),( Stephen Turgoose ) 한국부식방식학회 2008 Corrosion Science and Technology Vol.7 No.1

Vibration response and wave propagation in FG plates resting on elastic foundations using HSDT

Mokhtar Nebab,Hassen Ait Atmane,Riadh Bennai,Abdelouahed Tounsi,E.A. Adda Bedia 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.69 No.5

This paper presents an analytical study of wave propagation in simply supported graduated functional plates resting on a two-parameter elastic foundation (Pasternak model) using a new theory of high order shear strain. Unlike other higher order theories, the number of unknowns and governing equations of the present theory is only four unknown displacement functions, which is even lower than the theory of first order shear deformation (FSDT). Unlike other elements, the present work includes a new field of motion, which introduces indeterminate integral variables. The properties of the materials are assumed to be ordered in the thickness direction according to the two power law distributions in terms of volume fractions of the constituents. The wave propagation equations in FG plates are derived using the principle of virtual displacements. The analytical dispersion relation of the FG plate is obtained by solving an eigenvalue problem. Numerical examples selected from the literature are illustrated. A good agreement is obtained between the numerical results of the current theory and those of reference. A parametric study is presented to examine the effect of material gradation, thickness ratio and elastic foundation on the free vibration and phase velocity of the FG plate.

Fragility based performance evaluation of mid rise reinforced concrete frames in near field and far field earthquakes

Mokhtar Ansari,Amir Safiey,Mehdi Abbasi 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.76 No.6

Available records of recent earthquakes show that near-field earthquakes have different characteristics than far-field earthquakes. In general, most of these unique characteristics of near-fault records can be attributed to their forward directivity. This phenomenon causes the records of ground motion normal to the fault to entail pulses with long periods in the velocity time history. The energy of the earthquake is almost accumulated in these pulses causing large displacements and, accordingly, severe damages in the building. Damage to structures caused by past earthquakes raises the need to assess the chance of future earthquake damage. There are a variety of methods to evaluate building seismic vulnerabilities with different computational cost and accuracy. In the meantime, fragility curves, which defines the possibility of structural damage as a function of ground motion characteristics and design parameters, are more common. These curves express the percentage of probability that the structural response will exceed the allowable performance limit at different seismic intensities. This study aims to obtain the fragility curve for low- and mid-rise structures of reinforced concrete moment frames by incremental dynamic analysis (IDA). These frames were exposed to an ensemble of 18 ground motions (nine records near-faults and nine records far-faults). Finally, after the analysis, their fragility curves are obtained using the limit states provided by HAZUS-MH 2.1. The result shows the near-fault earthquakes can drastically influence the fragility curves of the 6-story building while it has a minimal impact on those of the 3-story building.

Efficacy of Corrective Surgery for Gait and Energy Expenditure in Patients with Scoliosis: A Literature Review

Mokhtar Arazpour,Aliyeh Daryabor,Navid Golchin 대한척추외과학회 2018 Asian Spine Journal Vol.12 No.5

The aim of this literature review was to evaluate selected original papers that measured gait parameters and energy expenditure in idiopathic scoliosis (IS) treated with surgical intervention. IS is a progressive growth disease that affects spinal anatomy, mobility, and left–right trunk symmetry. Consequently, IS can modify human gait. Spinal fusions remain the primary approach to correcting scoliosis deformities, thereby halting progression. Using the population intervention comparison outcome measure framework and selected keywords, 15 studies that met the inclusion criteria were selected. Alteration of spatial and temporal variables in patients with IS was contradictory among the selected studies. Ankle and foot kinematics did not change after surgery; however, pelvic and hip frontal motions increased and pelvic rotation decreased following surgery. Patients with IS continued to show excessive energy expenditure following surgery in the absence of a physical rehabilitation protocol. Spinal surgery may be considered for gait improvement and IS treatment. There were inadequate data regarding the effect of corrective surgery on the kinetics, energy expenditure, and muscle activity parameters.

Corrosion effects on mechanical behavior of steel fiber reinforced concrete, including fibers from recycled tires

Mokhtar Ansari,Amir Safiey 사단법인 한국계산역학회 2020 Computers and Concrete, An International Journal Vol.26 No.4

Today, the use of special technologies in the admixture of concrete has made tremendous progress, but the problem that has always existed in the construction of concrete members is the brittleness and lack of loading bearing after cracking, which leads to reduced strength and energy absorption. One of the best ways to fix this is to reinforce the concrete with steel fibers. Steel fibers also control cracks due to dry shrinkage, reduce structural crack width, and improve impact resistance. In this study, recycled steel fibers from worn tires have been used in the manufacture of concrete samples, the secondary benefits of which are the reduction of environmental pollution. One of the disadvantages of steel fiber reinforced concrete is the corrosion of steel fibers and their deterioration in harsh environments such as coastal areas. Corrosion caused by chlorine ions in metal fibers causes deterioration and early decommissioning of structures in corrosive environments. In this study, the effect of the dosage of steel fibers (dosages of 15, 30, and 45 kg of fibers per cubic meter of concrete) and aspect ratio of fibers (aspect ratio of 25 and 50) on compressive and flexural strength of concrete samples are investigated. In the following, the effect of fiber corrosion on the results of the mechanical properties of concrete samples is examined. The results show that the increase in fiber causes a relative increase in compressive strength, and a significant increase in flexural strength, and corrosion of steel fibers without reducing workability reduces compressive strength and flexural strength by up to 6 to 11%, respectively.

Financial Capability and Differences in Age and Ethnicity

MOKHTAR, Nuradibah,SABRI, Mohamad Fazli,HO, Catherine Soke Fun Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.10

The objective of this study is to disclose the effect of socio-demographic characteristics such as, age and ethnicity which is comprised of Malay, Chinese, Indian and Others on four financial capability domains namely planning ahead, managing money, choosing products and staying informed. A closed ended self-administered questionnaire was disseminated to a total of 2000 respondents among four types of groups which consist of FELDA or rural area residents, private sector employees, government sector employees and youth in institutions of higher learning in Malaysia. Those four groups were selected to cover a wide range of Malaysian population. 500 respondents were involved in this study for each types of groups through purposive sampling technique. Analysis of Variance (ANOVA) and analysis via Statistical Package for Social Science (SPSS) was utilized in this study. The results revealed that age has significant effect on planning ahead, managing money, choosing products and staying informed. Whereas, ethnicities were found to have no effect on financial capability except planning ahead domain. It is suggested that more devotion should be placed on research and professional training in building respondents' financial capability. Furthermore, government and non-government organizations should develop a comprehensive approach to intensify their financial capability and upgrade their standards of living especially of financially vulnerable households.

Interaction of magnetic water and polypropylene fiber on fresh and hardened properties of concrete

Mokhtar Ansari,Amir Safiey 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.39 No.3

Utilizing fibers is an effective way to avoid the brittle behavior of the conventional concrete and can enhance its ductility. In particular, propylene fibers can improve concrete properties, including energy absorption, physical and mechanical properties, controlling shrinkage cracks. The increase of fiber density leads to an increase of the overlapping surface of the fiber of concrete and, in turn, a decrease of cracks developed in the concrete. However, the workability of fiber reinforced concrete tends to be lower than the conventional concrete owing mainly to the hairline thickness and excessive concentration of fibers. The low slump of concrete impedes the construction of reinforced concrete members. In this research, we study if the utilization of magnetic water can alleviate the workability issue of young fiber reinforced concrete. To this end, the compressive and flexural strength of four types of concrete (conventional concrete, fiber reinforced concrete, magnetic concrete, magnetic fiber-reinforced concrete) is studied and compared at three different ages of 7, 14, and 28 days. In order to study the influence of the fiber density and length, a study on specimens with three different fiber density (1, 2, 5 kg of fiber in each cubic meter of concrete) and fiber length (6, 12, 18 mm) is undertaken. The result shows the magnetic fiber concrete can result in an increase of the flexural and compressive strength of concrete at higher ages.