Sharif Digital Repository

Water-soluble peptidocalix[4]arenes were synthesized by the introduction of arginine-rich narrow groove-binding residues at lower rims through solid-phase synthesis. The study of binding of these water-soluble bidentate ligands to well-matched and mismatched DNA duplexes by fluorescent titrations, ethidium bromide (EB) displacement assays, DNA-melting experiments, and circular dichroism (CD) analysis revealed a sequence-dependent groove-binding mechanism  

The aim of this paper is the design and development of a novel user interface to interact with a meta system. Our focus is rather on interacting with Ambient Intelligence as a whole, which would for example enable users to influence the overall behaviors and attributes of dynamic device compositions. We call such interfaces Meta User Interfaces. The design details of a proposed user interface as well as a cognitive walkthrough evaluation are presented in this paper  

Fabrication of scaffolds with enhanced mechanical properties and desirable cellular compatibility is critical for numerous tissue engineering applications. This study was aimed at fabrication and characterization of a nanofiber skin substitute composed of collagen (Col)/sodium alginate (SA)/ polyethylene oxide (PEO)/Rhodotorula mucilaginosa sp. GUMS16 produced exopolysaccharides (EPS) were prepared using the biaxial electrospinning technique. This study used collagen extracted from the bovine tendon as a natural scaffold, sodium alginate as an absorber of excess wound fluids, and GUMS16 produced exopolysaccharides as an antioxidant. Collagen was characterized using FTIR and EDS analyses. The... 

Optical tweezers (OT) are widely used for pico (and femto)-Newton range force measurements. The appropriate choice of the bead size is not well understood for biopolymer stretching applications of OT. We have shown, both by theory and experiment, that wrong choice of the bead size could cause errors as large as 295% in the measured force. We provide a simple map for correct choice of the bead size and the direction of pulling for such applications. There is a good agreement between our theoretical and experimental results  

In this paper, the degradation of C5H4O2 "Furfural" in aqueous solution by photooxidation technology using UV, UV/H2O2, UV/H2O2/O2, UV/H2O2/Fe2+, UV/O2/Fe2+, O3, UV/O3 process and also oxidation by sodium hypochlorite was investigated in a lab-scale batch photo-reactor. To evaluate the performance of different processes, the efficiency of furfural degradation was studied by measuring the total organic carbon (TOC) throughout the experimentation. Results show that compare to other reactions studied in this research, the UV/H2O2 is a simple and effective process for furfural degradation and presence of Fe2+ ions (UV/H2O2/Fe2+) enhanced removal of furfural in solution. The influence of... 

In this paper, we are planning to introduce a new method for relay selection and resource allocation in OFDM-based cooperative networks. Up to now, there have been relatively few works clearly concentrating on the combination of relay selection and resource allocation in such networks. In our work, a network with a single transmitter, a single receiver and a group of relays is considered. Relays work on Amplify and Forward (AF) method and there is no direct link between the transmitter and the receiver. The optimization problem is to maximize the throughput of the receiver with constraints on the amounts of the power of the transmitter and relays, and subcarriers. We will introduce an... 

We propose a cosmological model, üΛCDM, based on "über gravity," which is a canonical ensemble average of many theories of gravity. In this model, we have a sharp transition from (a purely) ΛCDM era to a phase in which the Ricci scalar is a constant. This transition occurs when the Ricci scalar reaches a critical scale or alternatively a transition redshift, z. We use the observations of baryonic acoustic oscillations and supernovae Ia, as well as the cosmic microwave background data to constrain üΛCDM. This yields H0=70.6-1.3+1.1 km/s/Mpc, ωm=0.2861±0.0092, and z=0.537-0.375+0.277, providing a marginally better fit with a Akaike information criterion of 0.8. Therefore, üΛCDM can ease the H0... 

Design technology is expected to rise to electronic system-level (ESL). This necessitates new techniques and tools for synthesizing ESL designs and for verifying them before and after ESL synthesis. A promising verification strategy for future very complex designs is to initially verify the design at the highest level of abstraction, and then check the equivalence of the lower level automatically generated models against that initial golden model. We present one such approach to simulation-based functional verification implemented in our ESL design methodology called ODYSSEY. Our ESL synthesis tool generates a transaction-level model (TLM) at TLM level 2 (i.e., design with partial timing)... 

Soluble N-functionalized basic and cationic polysaccharides have been synthesized using polysaccharide phenyl carbonate as a precursor. The products and intermediates were thoroughly characterized by conventional methods. The quaternization of amino intermediates in various conditions was studied. Moreover, the potential of basic polymers as green and selective catalysts in Knoevenagel reaction was investigated. In all cases, only one isomer was obtained  

In the contemporary sustainable urban set up, one of the critical issues adversely affecting the quality of life in urban areas and inflicting immense costs on cities is traffic congestion. Traffic congestion is an outgrowth of increased traffic flow in certain locations of large cities. Recently, urban decision-makers and transportation planners resort to one-way traffic system as an effective traffic management strategy, which has a profound effect on reducing traffic congestion and improving traffic flow, leading to urban sustainability. In the present paper, the authors endeavored to develop a novel methodological framework based on optimization techniques in order to mitigate traffic... 

In the contemporary sustainable urban set up, one of the critical issues adversely affecting the quality of life in urban areas and inflicting immense costs on cities is traffic congestion. Traffic congestion is an outgrowth of increased traffic flow in certain locations of large cities. Recently, urban decision-makers and transportation planners resort to one-way traffic system as an effective traffic management strategy, which has a profound effect on reducing traffic congestion and improving traffic flow, leading to urban sustainability. In the present paper, the authors endeavored to develop a novel methodological framework based on optimization techniques in order to mitigate traffic... 

The aim of this research is the study of hexyltriphenylphosphonium bromide (HTPB) ionic liquid as a bifunctional promoter (solvent and catalyst) in the presence of cerium(IV) ammonium nitrate as a single electron oxidant for the Michael reaction at room temperature and solvent-free conditions. A novel, one-pot and environmentally benign the process to achieve the chemoselective of 2-(3-oxo-1,3-diarylpropyl)malononitrile derivatives instead of 2-(1,3-diarylallylidene)malononitriles using a three-component reaction involving acetophenone derivatives, various aromatic aldehydes and malononitrile was developed. This protocol is simple and provides biologically interesting products in good... 

We study active galactic nucleus (AGN) activity in the fossil galaxy cluster RX J1416.4+2315. Radio observations were carried out using the Giant Metrewave Radio Telescope at two frequencies, 1420 and 610 MHz. A weak radio lobe that extends from the central nucleus is detected in the 610 MHz map. Assuming the radio lobe originated from the central AGN, we show that the energy injection into the intergalactic medium is only sufficient to heat up the central 50 kpc within the cluster core, while the cooling radius is larger (∼130 kpc). In the hardness ratio map, three low energy cavities have been identified. No radio emission is detected for these regions. We evaluated the power required to... 

Progressive conversion/shrinking core (PC-SC) models of constant-size cylinders were exploited to interpret the decarburization reactions of MgO-C-Si bricks heated up under blown air. Chemical adsorption/solid (or pore) diffusion mechanisms governed the reaction rate. With 5% silicon, chemical adsorption vanished at 1000 and 1100°C. The oxidation rate lowered then with temperature. This was due apparently to the blocking of the pore-end gorges by the voluminous compounds (like Forstrite). Arrhenius plots of the specific rates yielded the activation energies of the prevailing steps. Without Si antioxidant, three steps were appreciated having activation energies of 51.65 (for chemical... 

Improvement of microcantilever-based sensors and actuators chiefly depends on how comprehensively they are modeled and precisely formulated. Atomic Force Microscopy (AFM) is the most widespread application of microcantilever beam as a sensor, which is usually influenced by the tip-sample interaction force. For this, vibration of AFM microcantilever probe is analyzed in this paper, along with analytical, numerical and experimental investigation of the influence of the sample interaction force on the microcantilever vibration. Nonlinear integro-partial equation of microcantilever vibration subject to the tip-sample interaction is then derived and numerically simulated. Moreover, multiple time... 

Distributed-parameters vibration model of microcantilevers in tapping-mode Atomic Force Microscopy (AFM) is developed and is shown to be highly nonlinear. The question of why these nonlinearities are important and how they influence the predicted frequency response behavior of the cantilevers is addressed by comparing the results of developed model with a simple lumpedparameters model that has been extensively studied in the literature so far. The interaction forces between the microcantilever tip and the sample is supposed to be the same in both models and consist of attractive and repulsive interaction force regimes. In addition, experimental measurements are provided for a typical... 

Despite their simple structure and design, microcantilevers are receiving increased attention due to their unique sensing and actuation features in many MEMS and NEMS. Along this line, a non-linear distributed-parameters modeling of a microcantilever beam under the influence of a nanoparticle sample is studied in this paper. A long-range Van der Waals force model is utilized to describe the microcantilever-particle interaction along with an inextensibility condition for the microcantilever in order to derive the equations of motion in terms of only one generalized coordinate. Both of these considerations impose strong nonlinearities on the resultant integro-partial equations of motion. In... 

Frequency response behavior of microcantilever is analytically and experimentally investigated in amplitude modulation Atomic Force Microscopy (AFM). AFM microcantilever probe is modeled as a continuous beam, and tip-sample interaction force is considered to include both attractive and repulsive force regimes. The developed model is compared with the linear lumped-parameters model that has been extensively used in the literature so far. Experimental measurements are also provided for the frequency response of a typical microcantilever-sample system to demonstrate the advantages of the developed model over the linear formulation. The results indicate that the nonlinear continuous model is... 

Improvement of microcantilever-based sensors and actuators chiefly depends on how comprehensively they are modeled and precisely formulated. Atomic Force Microscopy (AFM) is the most widespread application of microcantilever beam as a sensor, which is usually influenced by the tip-sample interaction force. For this, vibration of AFM microcantilever probe is analyzed in this paper, along with analytical, numerical and experimental investigation of the influence of the sample interaction force on the microcantilever vibration. Nonlinear integro-partial equation of microcantilever vibration subject to the tip-sample interaction is then derived and numerically simulated. Moreover, multiple time...