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The trade-offs of using thermo-optical phase shifter in different standard CMOS silicon-on-insulator (SOI) structures (strip and rib waveguides) are studied. Twelve different thermo-optic phase shifters, considering metal and highly doped silicon (both n- and p-type), are studied using numerical simulations and measurements. The performance of heater type, size, and distance to the strip waveguide in terms of energy efficiency, crosstalk, and response time is investigated. The required power to reach π phase shift is measured and compared with the numerical simulation. The time response and the corresponding figure of merit of the interferometer affected by each heater is analyzed and the design strategies for optimizing the designs are discussed. A new compact design for the phase shifter is suggested with low thermal crosstalk (ΔT < 0.1 °C at a distance of 10 μm) and low electrical power consumption (Pπ = 13.2 mW). [ABSTRACT FROM AUTHOR]

Multiple sclerosis (MS) is a progressive neurological autoimmune disease that usually starts in the late third and early forth decades of life. Demyelination of neurons in the central nervous system (CNS) and, subsequently, loss of nerve cells is the known disease pathogenesis. The disease is controlled by a class of medicines which are mainly immunomodulators. Fingolimod (FIN) is the first approved oral medication for controlling relapsing-remitting type of MS. It is chemically modified form of a fungus metabolite with long history of use in traditional Chinese medicine. Its mechanism of action is through functional antagonism of sphingosine-1 phosphate receptors which leads to lymphocyte entrapment in lymphoid tissues and reduction of their circulating number in the CNS. FIN efficacy comparing with placebo and first line therapies for MS (e.g. Interferon) has been proved through several clinical trials. Common side effects of FIN are usually mild and are well tolerated. FIN can pass through placenta and has been assigned to pregnancy category C according to the observed effects in animal studies. Since the drug molecule is secreted into milk, lactation during consumption is not recommended. Considering oral administration and mild side effects of FIN, it can be useful in management of MS. However, due to the incidence of some rare but serious adverse effects such as systemic viral infections, macular edema, and cardiovascular complications, physicians should investigate patient's clinical status and underlying comorbidities carefully. [ABSTRACT FROM AUTHOR]

Selenium nanoparticles (Se NPs) have predominant characteristics compared to that in their bulk usage due to their high surface-to-volume ratio. The walnut (Juglans regia L.) leaf extract containing different bioactive compounds that act as reductant and stabilizing agents has been used for the green synthesis of the Se NPs. Influences of two synthetic variables, namely, the amount of selenium salt solution ranging from 15 to 25 mL and the amount of walnut leaf extract ranging from 1 to 5 mL, on broad emission peak (λmax) and absorbance of colloidal solutions having Se NPs were evaluated via the response surface methodology. Obtained results indicated that using microwave radiation (800 W for 4 min) and 5 mL of walnut leaf extract and 15 mL of selenium salt solution, Se NPs with λmax, absorbance, particle size, polydispersity index, and zeta potential values of 375 nm, 3.65% absorbance unit (a.u.), 208 nm, 0.206, and −24.7 mV were synthesized, which had high bactericidal activity toward Escherichia coli and Staphylococcus aureus. The transmission electron microscopy analysis also indicated that spherical and monodispersed Se NPs with a mean particle size of 150 nm were formed using the walnut leaf extract.

A novel compact fiber-coupled NIR system based on a DFB diode laser source is employed as a portable and sensitive gas sensor for trace detection of combustion pollutant molecules. We demonstrate the performance of such an NIR gas sensor by tracing the absorption lines of CO and CH4 using 2f-WMS technique at moderate temperature of T ∼ 600°C in the recuperator channel of an industrial furnace provided by Mobarakeh steel company. This measurement shows the excellent sensitivity of the applied NIR gas sensor to the on-line and in-situ monitoring of such molecular species. [ABSTRACT FROM AUTHOR]

Background/Objective: Multislice computed tomographic (MSCT) angiography is a rapid and minimally invasive method for the detection of intracranial aneurysms. The purpose of this study was to compare MSCT angiography with digital subtraction angiography (DSA) in the diagnosis of cerebral aneurysms. Patients and Methods: In this cross sectional study we evaluated 111 consecutive patients [42(37.8%) male and 69(62.2%) female], who were admitted under clinical symptoms and signs, suggestive of harboring an intracranial aneurysm by using a four detector MSCT angiography. Then we compared results of MSCT angiography with DSA results as a gold standard method. DSA was performed by bilateral selective common carotid artery injections and either unilateral or bilateral vertebral artery injections, as necessary. MSCT angiography images were interpreted by one radiologist and DSA was performed by another radiologist who was blinded to the interpretation of the MSCT angiograms. Results: The mean±SD age of the patients was 49.1±13.6 years (range: 12-84 years). We performed MSCT in 111 and DSA in 85 patients. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive and negative likelihood ratio (LR) of MSCT angiography, when compared with DSA as the gold standard, were 100%, 90%, 87.5%, 100%, 10 and 0, respectively. Conclusion: MSCT angiography seems to be an accurate and non-invasive imaging modality in the diagnosis of intracranial aneurysms. [ABSTRACT FROM AUTHOR]

Background/Objective: Pulmonary tuberculosis (TB) is a common worldwide lung infection. It remains an important cause of morbidity and mortality. Radiographic manifestations of pulmonary tuberculosis are diverse and varied. This study was performed to define the various radiographic manifestations of this infection in the pediatric age group in children who were referred to Mofid Children's Hospital. Patients and Methods: We reviewed chest x-rays of 30 pulmonary TB patients admitted to our hospital to ascertain the extent of parenchymal and mediastinal involvements on chest xray. Results: Male to female ratio was 1.7:1. The patients' age ranged from 2-163 months with a mean age of 36.9 months. Mediastinal lymphadenopathy was detected in 90% of the cases and pulmonary involvement, especially alveolar shadowing was seen in 83.3% of the cases (of which 43.3% had an air-space pattern and 40% had an interstitial pattern). 19 of the 30 patients (66.3%) were under 36 months, in which 17 of the 19 patients (89.5%) revealed lymphadenopathy. Therefore 63% of all detected lymphadenopathies were seen in this age group. Mediastinal lymphadenopathy was more common on the right side (73.3%). Furthermore, 60% of all alveolar infiltrations were seen on the right side. Conclusion: Pulmonary tuberculosis most commonly represents as a mediastinal and thereafter as a parenchymal involvement. Hilo-mediastinal lymphadenopathy is the most common presentation in infants and young children. [ABSTRACT FROM AUTHOR]

Presents an active image-rejection filter which applies actively coupled passive resonators. Description of the filter; Elimination of using a low-noise amplifier in front-end applications; Diameter of the GaAs monolithic-microwave integrated-circuit; Insertion gain, image rejection and noise figure of the filter; Power dissipation.