Perturbative Analysis of Spectral Singularities and Their Optical Realizations

We develop a perturbative method of computing spectral singularities of a Schreodinger operator defined by a general complex potential that vanishes outside a closed interval. These can be realized as zero-width resonances in optical gain media and correspond to a lasing effect that occurs at the threshold gain. Their time-reversed copies yield coherent perfect absorption of light that is also known as an antilaser. We use our general results to establish the exactness of the n-th order perturbation theory for an arbitrary complex potential consisting of n delta-functions, obtain an exact expression for the transfer matrix of these potentials, and examine spectral singularities of complex barrier potentials of arbitrary shape. In the context of optical spectral singularities, these correspond to inhomogeneous gain media.Comment: 13 pages, 2 figures, one table, a reference added, typos correcte

Evaluation of the Level of Protection in Radiology Departments of Kermanshah, Iran

Introduction Radiation protection is an important safety issue for radiographers and patients. The aim of this study was to assess the observance of radiation protection regulations in radiology departments of Kermanshah University of Medical Sciences, Kermanshah, Iran. Materials and Methods In total, 48 radiographers and 8 radiography rooms were evaluated in three hospitals of Kermanshah, Iran. Additionally, 120 patients were randomly selected in the present study. For data collection, a questionnaire on radiation protection devices, radiographers, and patients was completed. Data were analyzed, using Microsoft Excel. Results Based on the analysis, 56.8% of radiation protection devices were accessible to radiographers. Overall, 81.3% of radiographers stated that they utilized film badges for radiographic procedures, while only 71.7% had used these badges in practice. Additionally, 54.2% of radiographers claimed that they regularly performed medical check-ups; however, based on the documents available at personnel offices, only 43.8% had taken this measure into account. Also, 60.4% of radiographers claimed that they had participated in annual training courses, while based on the records, only 41.7% had participated in such courses. Conclusion The majority of radiographers had no regard for radiation protection principles for either themselves or the patients. Apparently, not only hospital authorities, but also heads of departments ignore radiation protection principles for the patients and radiographers

Role of CT scan in theranostic and management of traumatic spinal cord injury

Traumatic spinal cord injury (TSCI) is a condition with suffering of neural structures from acute trauma with short-term or permanent sensory and motor problems. This study was conducted with the aim of determining the prevalence of TSCI in Tehran with emphasis on demographic characteristics of patients and to evaluate the effect of computed tomography (CT) in determining fracture type and severity grade of injury among TSCI patients. In a cross-sectional study, all TSCI and spinal fracture patients (N = 520) who referred to the main trauma center in Tehran, Iran, in 2013 and 2014 were selected. Radiography and CT scan were prepared and reported blindedly by two radiologists. Majority of the patients was 21-30. years male, married and their most common occupation was car driver. A significant difference was observed between gender and etiology (P = 0.001). The main etiology was traffic accident followed by falling from height. While the most common location of injury for males was thoracic vertebrae followed by lumbar vertebrae; for females it was lumbar followed by thoracic. Majority of patients had ASIA (American Spinal Injury Association) impairment scale of E (normal), followed by B (sensory incomplete). Most of the cases were hospitalized less than one week. Age of the patient and duration of hospitalization had a significant association (P = 0.015). The results showed that in traumatic spinal cord events, traffic accident and falling from height are the main etiologies; hence, authorities in Iranian health system could consider preventive policies to decline the load and TSCI effects in hospitals and population

Effects of cell phone waves on granular cells migration of cerebellum in neonatal rat

زمینه و هدف: استفاده روز افزون از تلفن های همراه باعث افزایش نگرانی ها در مورد آثار بیولوژیک امواج این دستگاه بر بافت های بدن، بخصوص سیستم عصبی مرکزی شده است. این مطالعه با هدف بررسی اثر امواج تلفن همراه بر مهاجرت سلول‌های گرانولار مخچه در رت انجام شده است. روش بررسی: در این مطالعه تجربی 40 سر نوزاد رت به طور تصادفی به 4 گروه ده تایی تقسیم شدند. یک گروه شاهد و سه گروه آزمایشی I، II و III که در روزهای 7 تا 13 بعد از تولدشان روزانه بترتیب 5/0، 2 و 8 ساعت از فاصله cm10 مورد تابش امواج تلفن همراه قرار ‌گرفتند. در روز چهاردهم، پس از کشتن رت ها و تهیه مقاطع بافتی، با استفاده از نرم‌افزار موتیک سلول های گرانولار مخچه شمارش شدند؛ همچنین ضخامت لایه گرانولار با نرم‌افزار Nikon اندازه‌گیری شد. یافته‌ها: جمعیت سلولی ناحیه گرانولار داخلی مخچه در گروه آزمایشی III نسبت به گروه شاهد، به طور معنی ‌داری کاهش یافت (05/0

Molecular imaging using by diffusion-weighted imaging of brain tumor through signal intensity: Progress in molecular cancer imaging

Introduction: Characterizing the variations of the brain tumors has the significant effect in the treatment process of affected patients. Brain metastatic tumors are usually diagnosed following by the neurological symptoms in patients. The purpose of this thesis is the role of diffusion-weighted-magnetic resonance imaging (DW-MRI) and apparent diffusion coefficient (ADC) values in the evaluation of different benign and malignant brain mass lesions before surgery with histopathological correlation. Materials and Methods: In this study MR examination of 54 patients who with brain metastatic tumor referring to 7th-Tir Hospital were randomly selected and imaged with T2W Multi-echo sequences and GRE-EPI (DWI) in addition to taking the routine sequence of the brain. Results: In analyzing the data for ADCmin values were measured within the tumors and mean values were evaluated regarding statistical differences between groups.9 The ADCmin values of low-grade gliomas(1.09 ± 0.20 × 10−3 mm2/s) were signi=icantly higher (p < .001) than those of other tumors. Generally, ADC value of 0.5613 ± 0.02580 indicates brain metastatic tumors with lung origin, ADC value of 1.009 ± 0.03820 tumors with liver and breast origin, and ADC value of 1.556 ± 0.03500 tumors with colon and prostate origin. Conclusion: According to our results, Diffusion parameters during treatment were evaluated for early noninvasive biomarkers. The ADC changes from mid- to post-treatment suggest such a possible early non-invasive biomarker

Diagnostic efficacy of sonography for diagnosis of ovarian torsion

Objectives: Misdiagnosing ovarian torsion is now suggested as an important issue in clinical setting. The aim of this study was to determine the diagnostic accuracy of sonography for ovarian torsion. Methods: In this study 323 women with acute pelvic pain with highly suspected ovarian torsion signs and symptoms attending Imam Reza Medical Center in Kermanshah between 2011 through 2012 were included and underwent a transabdominal sonography (2-5 MHz probes). Then findings of sonography were compared with laparatomy. Results: The ultrasound correctly diagnosed 72.1% of ovarian torsion and missed 27.9% of them (false negatives). However, one free subject (0.4%) was misclassified as ovarian torsion (false positive). There was a strong correlation between sonography and laparatomy with a kappa value of 84.0%. The sensitivity and specificity of sonography were 72.1% and 99.6%, respectively. Sonography had a positive predictive value of 96.9%, a negative predictive value of 95.9%, and a total accuracy of 96.0% for detection of ovarian torsion. Conclusion: Sonography appears to be an excellent method to evaluate patients with suspected ovarian torsion. Abnormal blood flow detected by sonography is highly predictive of ovarian torsion and is therefore useful in the diagnosis of this phenomenon

Fahr’s syndrome with seizure presentation

Fahr's disease (FD) or Fahr’s syndrome is characterized by basal ganglia calcification with clinical manifestations in the form of neuropsychiatric disorders, neurological symptoms, and cognitive symptoms. FD commonly affects young to middle aged adults. The etiology of this syndrome does not identify a specific agent. Clinical manifestations of this disease incorporate a wide variety of symptoms. The diagnostic criteria of Fahr’s Syndrome consist of bilateral calcification of basal ganglia, progressive neurologic dysfunction, absence of biochemical abnormalities, infectious, traumatic, and a significant family history. Medical imaging techniques for the diagnosis consist of computed tomography (CT), magnetic resonance imaging (MRI), and plain radiography of the skull. This paper presents a case of Fahr’s syndrome in a 60-year-old married prisoner with antisocial personality and seizures. Furthermore, CT and MRI scans showed bilateral symmetric calcifications in the basal ganglia calcification (BGC) and dentate nuclei, cerebellum, and centrum semiovale

Noninvasive Stem Cell Labeling Using USPIO Technique and their Detection with MRI

Background: To date, several imaging techniques to track stem cells are used such as positron emission tomography (PET), single photon emission computed tomography (SPECT), Bioluminescence imaging (BLI), fluorescence imaging, CT scan and magnetic resonance imaging (MRI). Although, overall sensitivity of MRI compared to SPECT and Bioluminescence techniques are lower, but due to high spatial resolution (~100 mm), long term three-dimensional imaging capability, in vivo quick access to images in three different sections, and noninvasiveness it is being used as the method of choice. Methods: The present study is the search results for authors and sources of information in the field of molecular and cellular imaging to examine the problems and perspectives about stem cells labeling with Ultrasmall Super Paramagnetic Iron Oxide (USPIO) and their tracking by MRI. Results: With the advancement of technology, including quantum physics, chemistry, and computer software, MRI with an excellent spatial resolution and contrast, is surpasses other imaging modalities in the analysis of anatomical and pathological features and images of all body tissues. From the other side, advances in the astronomical science, chemistry and nanotechnology, high biocompatibility and cytotoxicity of nanoparticles, and due to analysis in the metabolic pathways of iron made the procedure easier; however, there are still several fundamental questions in understanding the mechanism of biological molecules in the living cells including: 1- How to detect not only the location but also the performance of the labeled cells? Probably combination of USPIO nanoparticles with other reporter genes as contrast agents for MRI and PET can simultaneously be used to overcome these limitations 2) How to trace stem cells from pre-clinical models to translate to humans? Up to now, due to issues of bioethics, little studies have been done in this area. 3) Whether the transplanted stem cells that have reached the target tissue, will remain or migrate? Despite the fact that cell proliferation and exocytosis are two main factors for long term protection of USPIO nanoparticles inside cells, their signals cannot be received for a long time. 4) What mechanisms cause stem cells reaching the target tissue to react with their environment? And 5) what is the number of transplanted cells in live tissue, and what is their half-life? Conclusion: This study showed that USPIO nanoparticles can enter the cell with a clear dose without any adverse biological effects and could be detected by SWI and T2* techniques under MRI (1.5 Tesla) scanner for almost one month. MRI as a secure mean can illustrate with optimal resolution the spatial-resolution and three-dimensional positions of the stem cells. Keywords: Ultrasmall Super Paramagnetic Iron Oxide (USPIO), labeled stem cell, in vivo tracking, MRI

The effect of Melatonin on histological changes of ovary in induced polycystic ovary syndrome model in mice

Antioxidants can be used as adjuvant treatment of polycystic ovary syndrome (PCOS). Melatonin (MT) is one of the antioxidant that is used nowadays. Objective: In this study, the effect of MT on the histological changes of ovary in the experimental model of polycystic ovary syndrome is investigated. Methods: In this study 30 immature female NMRI mice were divided into 5 groups including: (1) control group received distilled water, (2) received a dose of 10. mg/kg MT for 5. days, (3) received Dehydroepiandrostenedione (DHEA) at a dose of 6. mg/kg for 20. days to induce PCOS, (4) after induction of PCOS received MT at a dose of 10. mg/kg for 5. days, and (5) received 6. mg/kg DHEA and 10. mg/kg MT for 20. days simultaneously. Results: The evaluation of ovarian tissue characteristics such as the granulosa layer, theca, number and diameter of cysts and follicles was performed. PCOS caused a significant reduction in the number of antral follicles and corpus luteum and an increase in the number of primordial, primary, pre-antral and cystic follicles in comparison with the control group (P. <. 0.05). Moreover, MT resulted in a significant increase in the granulosa layer thickness in group 4 (P. <. 0.001), and group 5 (P = 0.001) and a significant reduction in the thickness of theca layer between groups 4 and 5 compared with group 3 (P. <. 0.001). Conclusion: These findings indicate that MT have a protective effects on polycystic ovary damages induced by DHEA, although the mechanism is unclear. It is likely that this is happening by reducing oxidative damage. © 2017

A review on role of medicinal plants in polycystic ovarian syndrome: Pathophysiology, neuroendocrine signaling, therapeutic status and future prospects

Polycystic ovary syndrome (PCOS) is one of the most important gynecological disorders among reproductive-age women. In patients with PCOS, the secretion rate and metabolism of androgens and estrogens are disrupted. With regards to the increasing prevalence of PCOS and associated physical and mental problems as well as the effects of changes in sex hormones in development of this disease, our aim is to investigate the effects of different herbal extracts on changes in the serum levels of sex hormones and ovarian tissue. To conduct this review, an extensive literature search was conducted using, relevant publications published between 1990 and 2017, and indexed in Google Scholar, PubMed, Elsevier, Scientific Information Database, and Science Direct were studied. The search terms used to retrieve the publications were as follows: Herbal medical extract، Names of medicinal plants ، polycystic ovary syndrome, PCOS, the mechanism of hormone. According to the evidence, herbal extracts containing phytoestrogens cause decrease in hyperandrogenism, insulin resistance, and ovary weight as well as increase in ovulation. Therefore, these plants can be partly effective in this syndrome via affecting the serum levels of different hormones and ovarian weight and morphology, representing an opportunity to investigate and discovery new bioactive products. © 2018 Middle East Fertility Societ