Sharif Digital Repository

The initial step in radiotherapy treatment planning involves delineating the clinical target volumes (CTVs) and organs at risk (OARs). However, manual contouring is a time-consuming, labor-intensive, and subjective process. This study explores the potential of utilizing convolutional neural networks (CNNs) as an automated segmentation tool and an alternative to manual delineation. 218 Computed Tomography (CT) scans were gathered from two local hospitals in Tehran and the Whole Abdominal Organ Dataset (WORD). We employed ResUNet, a variant of UNet, as well as the original UNet from the Medical Open Network for AI (MONAI), an open-source framework for Deep Learning (DL) in healthcare imaging,... 

Increasing demand for digital systems has led to developing signal processing in the digital domain. For this purpose, Analog to Digital Converters is used to convert analog signals to digital ones. Apart from that, by decreasing the size of transistors, it has been possible to implement the system on a chip that needs communication between analog and digital signals. The designed converter in this project is suitable for instrumentation purposes and especially for use in the control loop of a DC­DC digitally voltage converter. ADC architectures are mainly classified into two groups attributed with high bandwidth or with high resolution. Nature of on­chip measurement requires high... 

In this work, wool keratin/polyethylene oxide (PEO) nanofibrous scaffolds were fabricated by electrospinning method. Bacterial cellulose nanofibrils (BCNFs) were embedded in the electrospun keratin/PEO nanofibers. Incorporation of BCNFs into the nanofibers enhances their hydrophilicity, mechanical properties and cell viability, adhesion and proliferation. Water contact angle of the nanofibers decreased from 126˚ to 83˚by addition of 1 wt % BCNFs. A thermogelling hydrogel based on carboxylated pluronic (Pl-COOH) and gum tragacanth (GT) was fabricated and polymer conjugation was confirmed by FTIR and H-NMR spectroscopy. Morphological and viscoelastic properties of GT-grafted Pl-COOH hydrogels... 

The X-ray attosecond pulses have many useful applications for studying atomic and sub-atomic scales phenomena in attosecond scale duration. Generation and optimization of high-order harmonics is an efficient way to produce such attosecond pulses which are studied in this thesis. There are several limitations in the attosecond pulse generation such as low efficiency of high-order harmonics, long duration of output pulses and the impossibility of producing an attosecond pulse with any desired wavelength in the x-ray region. Therefore, more investigations into high harmonic generation and fully control and optimization of this process is significant. In this thesis, high harmonic generation... 

Nitrite (〖NO〗_2^-) anions are ubiquitous within the physiological, industrial, environmental, and food industries. The potential toxicity risk of these inorganic compounds has well been recognized; thus, the precise detection of these ions by developing reliable and high-throughput analytical methods is crucial for health and environment security. In this study, we present a reagentless electrochemical biosensor using cobalt-based metal-organic frameworks (ZIF-67) and gold nanoparticles (Au NPs) for determination of nitrite ions. The developed biosensor provides the advantages of MOF properties including high surface area, hierarchical porosity, and tunable functionalities along with high... 

Today, the use of carbon nanostructures hybridized with noble metals has attracted considerable attention for the fabrication of bio-electrochemical sensors. Since the specific surface area has an immense effect on the sensing response, three-dimensional structures of graphene have a great capability to utilize in these sensors. In this research, three-dimensional graphene was provided on the porous nickel foam by chemical vapor deposition technique. By evaluation of raman spectroscopy, the time period of 20 minutes for solving of the carbon atoms into the nickel foam was selected as the main parameter of optimized conditions for the synthesis of graphene. Afterward, production of few-layer... 

A Brain-Computer Interface (BCI) is a communication system that does not need any peripheral muscular activity. The huge goal of BCI is to translate brain activity into a command for a computer. One of the most important topics in the brain-computer interface is motor imagery (MI), which shows the reconstruction of subjects. The electrical activities of the brain are measured as electroencephalogram (EEG). EEG signals behave as low to noise ratio also show the dynamic behaviors.In the present work, a novel approach has been employed which is based on feature extraction with discretion wavelet transform (DWT), support vector machine (SVM), Artificial Neural Network (ANN) and Convolutional...