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A Telescoping Numerical Scheme for the Solution of Retarded Delay Differential Systems
S. Jahangiri,S. Karimi,J. Sedighi
Journal of Applied Sciences , 2012,
Abstract: In this study, approximate and/or exact analytical solutions of the Retarded Delay Differential Systems (RDDSs) are obtained by Telescoping Decomposition Method (TDM). TDM is a modified form of the well-known Adomian Decomposition Method (ADM). The main features of the TDM are that it deforms a difficult problem into a set of problems which are easier to solve and avoids calculating the Adomian polynomials. The analytical approximations with high accuracy are obtained using the TDM which agree well with the numerical results. Some illustrative linear and nonlinear experiments are given to indicate the validity and great potential of the proposed method for solving RDDSs.
Prevalence and Risk Factors of Osteoporosis in Postmenopausal Women with Rheumatoid Arthritis: A Brief Report
M Aghaei,S Sedighi,N Behnam Pour,SH Hezar Khani
Tehran University Medical Journal , 2012,
Abstract: Background: Low bone mass is a serious health problem mostly seen in postmeno-pausal women with rheumatoid arthritis. The purpose of this study was to determine the prevalence of osteoporosis and some related risk factors in postmenopausal women with rheumatoid arthritis.Methods: The data for this descriptive analytical study was extracted from the medical records of 98 postmenopausal women with rheumatoid arthritis who had attended the 5th of Azar Teaching Hospital affiliated to Gorgan University of Medical Sciences, in Iran, in 2009.Results: The mean durations of menopause and rheumatoid arthritis were 9.39 and 5.13 years, respectively. The overall prevalence of osteoporosis was 13.3%. We found a significant correlation between age, disease duration, and duration of menopause with bone mineral density (P<0.05).Conclusion: Our results indicate a high prevalence of osteoporosis at the lumbar spine of postmenopausal women with rheumatoid arthritis.
Evaluation of two preoparative chemotherapy regimens for complete operability of advanced gastric adenocarcinoma: a clinical trial
S. Sedighi,M. Mohagheghi,F. Memari,R. Jahangir
Tehran University Medical Journal , 2006,
Abstract: Background: This prospective phase III study was designed to compare the activity of two combinations chemotherapy drugs in advanced gastric adenocarcinoma Methods: In a double blinded clinical trial, From Jan. 2002 to Jan. 2005, ninety patients with advanced gastric adenocarcinoma were randomly assigned to 1) Cisplatin and continuous infusion of 5FU and Epirubicin (ECF), and 2) Cisplatin and continuous infusion of 5FU with Docetaxel (TCF). Reduction in tumor mass, overall survival (OS), time to progression (TTP), and safety were measured outcome. Results: About 90% of patients had stage III or IV disease and the most common sites of tumor spread were peritoneal surfaces, liver and Paraaortic lymph nodes in either group. The objective clinical response rate (more than 50% decreases in tumor mass) was 38% and 43% in ECF and TCF group respectively. Global quality of life increased (p=0 002) and symptoms of pain and insomnia decreased after chemotherapy. Patients in TCF had more grade one or two skin reactions, neuropathy and diarrhea. Fourteen patients underwent surgery. Complete microscopic (R0) resection had done in two of ECF and six of TCF tumors (p=0.015). Two cases in TCF group showed complete pathologic response. Median TTP was nine months and 10 months in ECF and TCF group respectively. Median OS was 12 months in both groups. Conclusion: Although there wasn’t statistically significant difference regarded to clinical response or survival between two groups, TCF showed more complete pathologic response.
Gravity Field Implied Density Modeling of Topography, for Precise Determination of the Geoid
M. Sedighi,M. Najafi-alamdari,S.H. Tabatabaie
Journal of Applied Sciences , 2008,
Abstract: The aim of this research is to built up a three dimensional density model of topography in the region of interest from the observed gravity field then computing the geoid model for the region. The range of mass density variation within the topography is between 1000 and 3100 kg m-3. Assigning the global average value of ? = 2670 kg m-3 at a point, instead of its real point value, may cause errors of decimeter magnitude in the geoid determination. A regional-local gravity anomaly separation technique using Bouguer gravity anomaly (BA) along with the Free air gravity Anomaly (FA) in the region of Iran are used to estimate the local topographical effect on gravity from the observed anomalies after eliminating the non-density origin long wavelength including isostatic features into the observed BA. A Global Geopotential Model (GGM) is also used to eliminate the deep sited density-origin long wavelength features from the observed anomalies as well. Then, the power spectral analysis, apparent density mapping and forward modeling techniques are used to convert the local topographical effect on gravity into the corresponding 3-D density (GRADEN) model in the region. The model showed thorough correlation with the superficial geological density (GEODEN) model at the surface level, provided that the reliable digitization of the model is in order. The GRADEN model minus the constant density demonstrates contributions up to a meter in mountainous areas and 7 cm in RMS scale to the geoid in the region.
Operational Tau Approximation for Neutral Delay Differential Systems
J. Sedighi Hafshejani,S. Karimi Vanani,J. Esmaily
Journal of Applied Sciences , 2011,
Abstract: Neutral Delay Differential Systems (NDDSs) arise in many areas of various mathematical modeling. Infectious diseases, population dynamics, physiological and pharmaceutical kinetics and chemical kinetics, the navigational control of ships and mechanical systems, chemical process simulation and optimal control are the main field concerning with NDDSs. The purpose of this study was to present an extension of the algebraic formulation of the Operational Tau Method (OTM) for the numerical solution of NDDSs. The proposed method converts the delay parts of the desired NDDS to some operational matrices. Then the NDDS reduces to a set of algebraic equations. Some orthogonal bases including shift Chebyshev and shifted Legendre polynomials are used to decrease the volume of computations. Two illustrative linear and nonlinear experiments are included to show the high accuracy and efficiency of the proposed method.
Breast Imaging in Evaluation of Breast Cancer: Radiologist’s Point of View
Nahid Sedighi
Iranian Journal of Radiology , 2010,
Abstract: In every breast imaging, the radiologist confronts these questions:"n1. Finding the lesion"n2. Is the lesion real?"n3. Where the pathology lies"n4. What the lesion is "n5. What should be done about it?"nThe major objective in breast imaging is the detection of breast cancers at a small size and early stage in an effort to reduce mortality."nSome conditions limit evaluation of breast cancer imaging."nWhen additional mammographic views or ultrasound are unable to triangulate the location of a lesion, computed tomography can be very helpful for locating lesions three dimensionally. MRI with and without contrast is the other modality for evaluation of problematic cases or ambiguous findings in other modalities."nImplants present a problem for breast imaging in that they may prevent optimal visualization of the tissues."nA focal asymmetric density may merely represent an island of breast tissue. DCIS, with or without calcification, and metastatic axillary lymph nodes in a normal mammogram are some of the problematic cases of breast cancer."nThis presentation is expected to include real cases of breast cancer with the above-mentioned problems or unusual manifestations, which are resolved by a combination of different imaging modalities.
Imaging of CNS Vasculitis
Nahid Sedighi
Iranian Journal of Radiology , 2010,
Abstract: The vasculitides are the most interesting assorted group of diseases. Most have an imunologic basis resulting in vascular injury."nInflammatory changes within and surrounding the vessel wall result in narrowing and obliteration of the vascular lumen with subsequent thrombotic occlusion or necrosis and rupture of the vessel. The pathologic features in this lesion include spasm, edema, cellular infiltration, and proliferation. "nThese inflammatory changes result in the classic angiographic picture of segmental narrowing and dilataion. Long segments of vessels are involved, circumferentially."nWhen seen in the cerebral arteries, these features strongly favor vasculitis, although other disease processes can produce this picture."nMR scan is quite sensitive detecting abnormalities in patients with vasculitis, but falls short in specificity. MRA is very limited in this diagnosis, both because of technique and its limited ability to visualize distal vessels. "nThe aim of this lecture is to try to categorize and narrow the differential diagnosis, presenting some of our cases in the department of radiology in Shariati hospital and the private practice.
Imaging in Tumors of he Mandible: Case Series, Pathologic Correlation & Literature Review
N. Sedighi
Iranian Journal of Radiology , 2008,
Abstract: Most of the radiologists do not have opportunity to be exposing to the radiologic investigation of patients suspicious for mandibular neoplasms in Iran."nWe had the opportunity to study interesting cases of mandibular bone tumors with proved pathologic diagnosis. In the present study, we describe clinical history and physical examination of these patients, moreover, the results of radiologic and pathologic findings will be assessed. The results of the current study could be helpful to increase the knowledge of radiologists in challenging with these tumors. It also will provide useful information about their characteristics in imaging.
Video Frame’s Background Modeling: Reviewing the Techniques  [PDF]
Hamid Hassanpour, Mehdi Sedighi, Ali Reza Manashty
Journal of Signal and Information Processing (JSIP) , 2011, DOI: 10.4236/jsip.2011.22010
Abstract: Background modeling is a technique for extracting moving objects in video frames. This technique can be used in ma-chine vision applications, such as video frame compression and monitoring. To model the background in video frames, initially, a model of scene background is constructed, then the current frame is subtracted from the background. Even-tually, the difference determines the moving objects. This paper evaluates a number of existing background modeling techniques in term of accuracy, speed and memory requirement.
Comparison between E. coli O157:H7 and Bifidobacterium spp. Activity in Almond Pudding Infant Supplemental Food  [PDF]
Rashin Sedighi, Mehrdad Tajkarimi, Salam A. Ibrahim
Food and Nutrition Sciences (FNS) , 2011, DOI: 10.4236/fns.2011.29124
Abstract: Almond pudding is a common traditional Iranian complementary food for infants after starting solid foods. Escherichia coli O157:H7 is one of the leading pathogenic microorganisms that cause serious foodborne disease in different populations including infants. The large intestine of breast-fed infants is colonized predominantly by bifidobacteria, which have a protective effect against acute diarrhea. The study objective of this research was to screen the survival characteristics of E. coli O157:H7 as well as four strains of Bifidobacterium subspecies (spp.) in almond pudding. The bacterial strains were studied after three and six hours of incubation at 37℃ in-vitro. Luria-Bertani (LB) broth was used as a basic medium for both Bifidobacterium spp. and E. coli experiments in anaerobic and aerobic conditions, respectively. The viability of Bifidobacterium spp. increased from 2.46 ± 0.2 to 6.57 ±1.3 log10 CFU/ml in low inoculum and from 4.53 ± 0.7 to 7.2 ± 0.4 in high inoculum experiments in 6 hours. However, the growth of E. coli O157:H7 from 3.12 ± 0.2 to 4.99 ± 0.1 log10 CFU/ml was significantly (P < 0.05) lower compared to Bifidobacterium spp. The results illus- trate impaired growth of E. coli O157:H7 and enhanced growth of Bifidobacterium spp. in almond pudding. The finding demonstrated that almond pudding in infant’s diet may indirectly enhance the protection against survival and growth of E. coli O157:H7 by increasing the Bifidobacterium spp. populations in infant’s gastrointestinal system.
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