Sharif Digital Repository

Lung cancer (LC) is the leading cause of cancer mortality so, the analysis of exhaled human breath has great significance for early non-invasive diagnosis. Poor selectivity and strong humidity are two bottlenecks for the application of gas sensors to exhaled breath analysis. The development of novel extractive phases for the analysis of exhaled breath by chromatography is therefore a lucrative object. Polyhedral oligomeric silsesquioxanes (POSS) are among the 3D porous materials whose unique properties make them promising coatings for solid-phase microextraction (SPME). Selective enrichment of polar or nonpolar targets depends on the pore size and functional groups on the POSSs. Herein, we... 

Cancer is a deadly disease that has long plagued humans and has become more prevalent in recent years. The common treatment modalities for this disease have always faced many problems and complications, and this has led to the discovery of strategies for cancer diagnosis and treatment. The use of magnetic nanoparticles in the past two decades has had a significant impact on this. One of the objectives of the present study is to introduce the special properties of these nanoparticles and how they are structured to load and transport drugs to tumors. In this study, iron oxide (Fe3O4) nanoparticles with 6 nm sizes were coated with hyperbranched polyglycerol (HPG) and folic acid (FA). The... 

In the present study, first, Fe3O4nanoparticles were functionalized using glutaric acid and then composited with CQDs. Doxorubicin (DOX) drug was loaded to evaluate the performance of the nanocomposite for targeted drug delivery applications. The XRD pattern confirmed the presence of characteristic peaks of CQDs and Fe3O4. In the FTIR spectrum, the presence of carboxyl functional groups on Fe3O4/CQDs was observed; DOX (positive charge) is loaded onto Fe3O4/CQDs (negative charge) by electrostatic absorption. FESEM and AFM images showed that the particle sizes of Fe3O4and CQDs were 23-75 and 1-3 nm, respectively. The hysteresis curves showed superparamagnetic properties for Fe3O4and Fe3O4/CQDs... 

In this research, a green solid catalyst of phosphomolybdic acid (HPA) prated on Chitosan was synthesized to produce biodiesel. The prepared catalyst was characterized using Fourier Transform Infrared spectroscopy (FTIR), Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-Ray (EDX), X-ray diffraction (XRD), and XRF analyses. The catalyst was applied in microwave-assisted trans-esterification of Pomegranate oil, and the biodiesel production process was optimized by response surface methodology based on central composite design (RSM-CCD). The effect of influential reaction parameters, including time (33–142 min), catalyst weight (0.15–5.6 wt%), and methanol to oil molar... 

A comprehensive study was carried out for the first time on the acidity of eleven different leaves. After functionalization of the leaves with –SO3H groups, the most acidic one was magnetized using nickel ferrite nanoparticles. This novel, inexpensive, green and biodegradable catalyst showed high activity in the synthesis of pyrazoline and 2-amino nicotinonitriles. Some compounds are new and have never been synthesized before and confirmed by FT-IR, 1H NMR and 13C NMR analysis. All of these compounds possess multiple biological activities. The heterogeneous magnetic catalyst (NiFe2O4-Alnus-SO3H) was characterized by various physicochemical techniques such as FT-IR spectroscopy, field... 

Abstract: Commercially pure titanium and titanium alloys have been among the most commonly used materials for biomedical applications since the 1950s. Due to the excellent mechanical tribological properties, corrosion resistance, biocompatibility, and antibacterial properties of titanium, it is getting much attention as a biomaterial for implants. Furthermore, titanium promotes osseointegration without any additional adhesives by physically bonding with the living bone at the implant site. These properties are crucial for producing high-strength metallic alloys for biomedical applications. Titanium alloys are manufactured into the three types of α, β, and α + β. The scientific and clinical... 

In this study, multivariate classification techniques combined with proton nuclear magnetic resonance (1HNMR) spectroscopy is proposed to identify breast cancer biomarkers that can precisely distinguish between healthy control and breast cancer (BC) patients. In this regard, first optimizing the metabolite extraction procedure was performed using Box-Behnken design (BBD). Then, data-driven soft independent modeling of class analogy (DD-SIMCA) model and partial least squares-discriminant analysis (PLS-DA) were successfully utilized for separating healthy from BC patient's classes. On this matter, both DD-SIMCA and PLS-DA models could successfully distinguish the healthy class from the BC... 

A search for new heavy resonances decaying to a pair of Higgs bosons (HH) in proton-proton collisions at a center-of-mass energy of 13 TeV is presented. Data were collected with the CMS detector at the LHC in 2016–2018, corresponding to an integrated luminosity of 138 fb−1. Resonances with a mass between 0.8 and 4.5 TeV are considered using events in which one Higgs boson decays into a bottom quark pair and the other into final states with either one or two charged leptons. Specifically, the single-lepton decay channel HH→ b b ¯ WW∗→ b b ¯ ℓvq q ¯ ′ and the dilepton decay channels HH→ b b ¯ WW∗→ b b ¯ ℓvℓv and HH→ b b ¯ ττ→ b b ¯ ℓvvℓvv are examined, where ℓ in the final state corresponds to... 

Food choice is one of the most fundamental and most frequent value-based decisions for all animals including humans. However, the neural circuitry involved in food-based decisions is only recently being addressed. Given the relatively fast dynamics of decision formation, electroencephalography (EEG)-informed fMRI analysis is highly beneficial for localizing this circuitry in humans. Here, by using the EEG correlates of evidence accumulation in a simultaneously recorded EEG-fMRI dataset, we found a significant role for the right temporal-parietal operculum (PO) and medial insula including gustatory cortex (GC) in binary choice between food items. These activations were uncovered by using the... 

Systemic chemotherapy has lost its position to treat cancer over the past years mainly due to drug resistance, side effects, and limited survival ratio. Among a plethora of local drug delivery systems to solve this issue, the combinatorial strategy of chemo-hyperthermia has recently received attention. Herein we developed a magneto-thermal nanocarrier consisted of superparamagnetic iron oxide nanoparticles (SPIONs) coated by a blend formulation of a three-block copolymer Pluronic F127 and F68 on the oleic acid (OA) in which Curcumin as a natural and chemical anti-cancer agent was loaded. The subsequent nanocarrier SPION@OA-F127/F68-Cur was designed with a controlled gelation temperature of... 

The CLLC resonant converter is a promising candidate for high efficient, bidirectional power transfer applications, such as vehicle-to-grid on-board charger and hybrid vehicle dc-dc converter. Nevertheless, the analysis of CLLC still remains challenging because of its complex multiresonant nature and several storage elements. In this article, a circuit analysis method based on change of variables is presented that maps the state-space equations into two decoupled sets of equations. The analyses are carried out in two state-plane coordinate systems, then the results are mapped onto the original region. The proposed method is then used to thoroughly analyze the CLLC resonant converter... 

Tunable metamaterials functionalities change in response to external stimuli. Mechanical deformation is known to be an efficient approach to tune the electromagnetic response of a deformable metamaterial. However, in the case of large mechanical deformations, which are usually required to fully exploit the potential of the tunable metamaterials, the linear elastic mechanical analysis is no longer suitable. Nevertheless, nonlinear mechanical analysis is missing in the studies of mechanically tunable metamaterials. In this paper, we study the importance of considering nonlinearity in mechanical behavior when analyzing the response of a deformable metamaterial and its effects on electromagnetic... 

A cavity resonator containing graphene nanopores (GNPs), along with a metallic layer (Ag, as a reflector) and a dielectric layer (SiO2, as a spacer), has been proposed for broadband wide-angle absorption of light. The GNP/SiO2/Ag multilayers showed high significant increase in the absorption efficiency (with respect to the G/SiO2/Ag multilayer) in a broad spectral range (from ultra-violet (UV) and visible range to near-infrared (NIR)), due to the cavity resonance and absorptions induced by the oxygen-containing functional groups formed around the nanopores of graphene. The dependences of the cavity resonance absorption on the quality of the GNP layer, dimension of the cavity and the incident... 

Molecular imaging (MI) can provide not only structural images utilizing temporal imaging techniques, but also functional and molecular data using a variety of newly developed imaging techniques. Nanotechnology’s application in MI has commanded a lot of attention in recent decades, and it has provided tremendous potential for imaging living subjects. In this study, D-glucosamine conjugated functionalized magnetic iron oxide nanoparticles (Fe3O4-PEG-DG NPs) were prepared and studied as magnetic resonance imaging (MRI) contrast agents. To evaluate their distribution, single-photon emission computed tomography (SPECT) is performed. Fe3O4 NPs are made using a well-known co-precipitation process... 

Asthma is a chronic inflammatory disease associated with a high prevalence of psychiatric disorders. There are specific brain networks responsible for emotional processes, including two important networks associated with psychiatric problems: the default mode network (DMN), which is more active in the resting state, and the salience network (SN), which is structurally connected to DMN. Although previous studies suggested that neuro-phenotypes of asthma may be recognizable by the neural activity of brain circuits, an association between the brain's functional alterations and psychiatric impairments induced by asthma remains unknown. We aimed to assess DMN and SN activity and its association... 

In this study, a numerical investigation was done on the optical properties of silver nanostructures using the boundary element method (BEM) and finite element method (FEM). The BEM simulation was done using a freely available code called MNBEM in MATLAB with minor modifications. The FEM simulation was done by Comsol Multiphysics, a commercial software package. Silver nanostructures in the sphere, rod, and triangle geometries and the presence of different polarization angles were compared between these two methods. According to the obtained results, the absorption cross-sections for both BEM and FEM were consistent with their actual optical properties. For instance, both longitudinal and... 

This article proposes the theory and implementation of an even-harmonic class-E CMOS oscillator that displays an excellent phase noise performance. Starting from zero voltage switching (ZVS) and zero derivative switching (ZDS) conditions, expressions for drain voltage and current waveforms are derived. Based on a 1:1 transformer, a custom-designed tank is proposed, which satisfies ZVS and ZDS conditions for the core transistors, provides high-Q resonances at both fundamental and second harmonics of the oscillation frequency, and yields a passive voltage gain from the drain to the gate of the core transistors. Satisfying ZVS and ZDS conditions reduces the overlap between the voltage and... 

Darrieus type vertical axis wind turbines have several advantages over other wind turbines for local electricity generation in urban environments. However, the main aerodynamic challenge is the negative impacts of the dynamic stall phenomenon on the turbine performance. This study numerically scrutinizes the effects of plasma actuators on the dynamic stall control and performance improvement of a Darrieus turbine. For this sake, unsteady Reynolds-averaged Navier-Stokes equations are solved using a pressure-based finite volume method. The Suzen-Hoang plasma actuator model is employed to calculate the body forces attributed to the plasma actuator. First, the dynamic stall characteristics of... 

Parametric resonance is a phenomenon caused by time-varying changes in the parameters of a system which may result in undesirable motion responses and instability. Floating bodies like ships and spar-buoys are prone to Mathieu instability mainly due to the instantaneous change of the metacentric height. With the fast-growing developments in Ocean Renewable Energy systems, spar-buoys are commonly used for wave energy convertors and floating wind turbines. Undesirable, unstable motions as a result of the parametric resonance can be problematic as it may cause inefficiency in operations and structural risk integrity. In this research, a new approach has been developed to investigate these... 

In recent years, the regression dynamic causal modelling (rDCM) method was introduced as a new version of dynamic causal modelling (DCM) to derive effective connectivity in whole-brain networks for functional magnetic resonance imaging (fMRI) data. In this research, we used data obtained while applying the stimulation of audio movie comprised different emotional states. We applied this method to two networks consisting of ten auditory and forty-four regions, respectively. This method was used to study effective connections between emotional states and represent the distinction between emotions. Finally, significant effective connections were found in emotional processing and auditory...