3 research outputs found

    An analytical approach to calculate effective channel length in graphene nanoribbon field effect transistors

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    A compact analytical approach for calculation of effective channel length in graphene nanoribbon field effect transistor (GNRFET) is presented in this paper. The modelling is begun by applying Gauss's law and solving Poisson's equation. We include the effect of quantum capacitance and GNR's intrinsic carrier concentration in our model. Based on the model the effects of several parameters such as drain-source voltage, channel length, and oxide thickness are studied on the length of effective channel in GNRFETs

    A data mining approach for diagnosis of coronary artery disease

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    Cardiovascular diseases are very common and are one of the main reasons of death. Being among the major types of these diseases, correct and in-time diagnosis of coronary artery disease (CAD) is very important. Angiography is the most accurate CAD diagnosis method; however, it has many side effects and is costly. Existing studies have used several features in collecting data from patients, while applying different data mining algorithms to achieve methods with high accuracy and less side effects and costs. In this paper, a dataset called Z-Alizadeh Sani with 303 patients and 54 features, is introduced which utilizes several effective features. Also, a feature creation method is proposed to enrich the dataset. Then Information Gain and confidence were used to determine the effectiveness of features on CAD. Typical Chest Pain, Region RWMA2, and age were the most effective ones besides the created features by means of Information Gain. Moreover Q Wave and ST Elevation had the highest confidence. Using data mining methods and the feature creation algorithm, 94.08 accuracy is achieved, which is higher than the known approaches in the literature. © 2013 Elsevier Ireland Ltd

    Evaluation of combination therapy with vitamin C and pentoxifylline on preventing kidney failure secondary to intravenous contrast material in coronary angioplasty

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    Background- Contrast nephropathy is the third leading cause of new-onset renal failure in hospitalized patients. Contrast nephropathy has been associated with increased in-hospital and long-term morbidity and mortality. Several interventions for the prevention of contrast nephropathy have been tested in clinical trials. Recent studies have produced conflicting results regarding the efficacy of the antioxidant agents. Objectives- The aim of this study was to evaluate the preventive effect of Pentoxifylline and Ascorbic Acid on contrast-induced nephropathy. Methods and Materials- This clinical trial study was done in 2012 in Rajaie Cardiovascular, Medical and Research Center. Totally, 328 patients who were candidated for coronary artery angioplasty were entered in the study. Pentoxifylline and Ascorbic Acid 24 hours before the procedure and 24 hours after the procedure were administered orally in 164 patients (case group), and the 164 patients did not receive the medication (control group), randomly. Contrast nephropathy was defined by an absolute increase of serum creatinine >0.5 mg/dL or a relative increase of >25 measured after the procedure. Contrast nephropathy was compared between the two groups. Results- Totally, 121 (73.8) patients in the case group and 113 (68.9) in the control group were male (p value=0.329). Mean of age was 58.8±10 and 58.5±10.5 years in the case and control groups, respectively (p value=0.756). Contrast nephropathy was detected in 14 (8.5) patients in the case group and 23 (14) in the control group (p value=0.116; odds ratio=0.572, CI 95: 0.243-1.150). Conclusions- Prophylactic oral administration of Pentoxifylline and Ascorbic Acid could not protect against contrast nephropathy in the patients undergoing a coronary procedure. More future studies are necessary for final judgment