Sharif Digital Repository

The simple, effective and highly sensitive detection of hydrogen peroxide (H2O2), which belongs to the reactive oxygen species (ROS), at low concentrations plays an indispensable role in the field of environmental protection, biological research and safety. In this study, a dual-mode optical biosensor, UiO-66@OPD, was developed based on the inherent peroxidase mimicking activity of UiO-66 (Zr) and the optical reaction of ortho-phenylenediamine (OPD) by extending the π-system through oxidative coupling, prototropism and elimination to form OPDox, thereby exhibiting strong orangish absorbance and greenish fluorescence. The catalase-mimicking activity of UiO-66 (Zr) was demonstrated by the... 

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... 

On the afternoon of October 14, 2020, we serendipitously discovered a novel “valley-hill” structure on the surface of a Metal-Organic Framework (MOF) after mixing it with a solution of tangerine peel extract (L) in the laboratory. This unexpected observation led to the formation of channels within the MOF surface and significantly improved release performance, particularly with doxorubicin (DOX). The unique valley-hill morphology and the resultant channels facilitated exceptional DOX diffusion into the MOF's porosity. Building on this structure, we systematically engineered the A520 (aluminum fumarate) MOF using green chemistry methodologies in a dual-stage process, incorporating L as a... 

In order to simulate the performance of pure methane in chemical looping using iron-based oxygen carrier, simultaneously production of three pure streams of hydrogen, nitrogen and carbon dioxide has been investigated. For this purpose, proper operating conditions have been discussed for maximum production of hydrogen, complete consumption of oxygen of inlet air and complete combustion of methane. Professional software is used to simulate the chemical looping reactors and optimize their output streams. Results show that in this process each mole of methane fuel can produce 2.533, 2.65 and 0.99 mol of pure N 2, H2 and CO2, respectively which contributes 80.2% energy conversion of CH4 to H2.... 

Background: Current development of sequencing technologies is towards generating longer and noisier reads. Evidently, accurate alignment of these reads play an important role in any downstream analysis. Similarly, reducing the overall cost of sequencing is related to the time consumption of the aligner. The tradeoff between accuracy and speed is the main challenge in designing long read aligners. Results: We propose Meta-aligner which aligns long and very long reads to the reference genome very efficiently and accurately. Meta-aligner incorporates available short/long aligners as subcomponents and uses statistics from the reference genome to increase the performance. Meta-aligner estimates... 

Cancer is one of the most serious and challenging issues in the life sciences, with complicated and multifactorial mechanisms making it difficult to manage. With this complexity comes various strategies for attacking tumors, including using nanomaterials to target tumor cells, bioavailability and deliver anticancer drugs directly. Doxorubicin (DOX) is a well-known and powerful anticancer drug, but its high toxicity limits its application. Intending to reduce the cytotoxic effects of DOX on normal cell line and deliver it to cancerous cell line, the present study attempts to design and synthesize a modified metal–organic framework (MOF) named A520 and a composite containing DOX (A520@DOX).... 

Using multiple antennas at the transmit and receive sides of a passive radar brings both the benefits of MIMO radar and passive radar. However one of the obstacles arisen in such configuration is the receive antennas placement in proper positions so that the radar performance is improved. Here we just consider the case of positioning one receiver among multiple illuminators of opportunity. Indeed it is a start for the solution of optimizing the geometry of the multiple receivers in a passive radar  

SbCl3 supported on montmorillonite K-10 is an efficient catalyst for the ring opening of epoxides with aromatic amines under solvent-free conditions and microwave irradiation to give the corresponding b-amino alcohols in high yields with high regioselectivity  

In this paper, we consider an integrated sensing and communication (ISAC) system with wireless power transfer (WPT) where an unmanned aerial vehicle (UAV)-based radar serves a group of energy-limited communication users in addition to its sensing functionality. In this architecture, the radar senses the environment in phase 1 (namely sensing phase) and mean-while, the communications users (nodes) harvest and store the energy from the radar transmit signal. The stored energy is then used for information transmission from the nodes to UAV in phase 2, i.e., uplink phase. Performance of the radar system depends on the transmit signal as well as the receive filter; the energy of the transmit... 

One of the important obstacles in MIMO (Multiple Input Multiple Output) radars is the issue of designing proper transmit signals. Indeed, the capability of signal design is a significant advantage in MIMO radars, through which, the system can achieve much better performance. Many different aspects of this performance improvement have been considered yet, and the transmit signals have been designed to attain such goal, e.g., getting higher SNR or better detector's performance at the receiver. However, an important tool for evaluating the radar's performance is its ambiguity function. In this paper, we consider the problem of transmit signal design, in order to optimize the ambiguity function... 

Two gains play key roles in recently developed MIMO wireless communication systems: "spatial diversity" gain and "spatial multiplexing" gain. The diversity gain refers to the capability to decrease the error rate of the MIMO channel, while the multiplexing gain implicitly refers to the amount of increase in the capacity of the MIMO channel. It has been shown that there is a fundamental tradeoff between these two types of gains, meaning interplay between increasing reliability (via an increase in the diversity gain) and increasing data rate (via an increase in the multiplexing gain). On the other hand, recently, MIMO radars have attracted much attention for their superior ability to enhance... 

It is a well known fact that using multiple antennas at transmit and receive sides improves the detection performance. However, in such multiple-input multiple-output (MIMO) configuration, proper positioning of transmitters and receivers is a big challenge that can have significant influence on the performance of the overall system. In addition, determining the power of each transmitter under a total power constraint is a problem that should be solved in order to enhance the performance and coverage of such a system. In this paper, we design the Neyman-Pearson detector under the Rayleigh scatter model and use it to introduce a criterion for the antenna placement at both transmit and receive... 

There has been much interest, recently, towards exploiting the Multiple-Input Multiple-Output (MIMO) technique in radar. It is shown that using multiple antennas at transmit and receive sides can improve the performance of the system. However, in order to analyze the system's performance, its ambiguity function, i.e. the ambiguity function of a MIMO radar, is needed to be defined. In this paper, beginning from the information theoretic definitions, we derive such function, specifically for a MIMO radar with widely separated antennas  

By combining the two ideas of MIMO (Multiple Input Multiple Output) and PCL (Passive Coherent Location) in radar, one can achieve the advantages of both recently developed techniques simultaneously. While using multiple antennas at the receive side provides a spatial diversity of the object to be detected, using multiple illuminators of opportunity, most importantly, makes the radar covert to the interceptors. One obstacle in such MIMO configuration is choosing the positions of the receive antennas. In this paper, after analyzing the Neyman-Pearson detector for the DVB-T based PCL, we introduce the probability of missed detection as a criterion to place the receive antenna. Here, we only... 

One of the most important obstacles in passive radar applications is removing the direct signal from the target channel. Otherwise, week echoes from the targets in the target channel would be ignored due to the limited dynamic range of the system. One of the most effective techniques in this field is using adaptive filters. In this paper various adaptive filters are introduced and their performances are shown and compared  

It has been shown that using multiple antennas in a radar system improves the performance considerably, since multiple target echoes are received from different aspect angles of the target. In this way, the target detection is improved. However, when using multiple antennas, some problems, such as designing the transmit signals, synchronization, etc. emerge that should be solved. One of such problems is the receiver placement. Receiver placement deals with choosing a proper position for the receive antenna in order to optimize the whole system's performance. In this paper, a receiver placement procedure based on improving the radar ambiguity function is proposed for the case of a multisite... 

By employing the MIMO (multiple-input-multiple-output) technology in radar, some new problems emerged, that, in order to benefit the MIMO gains in radar, it was necessary to solve them suitably. One of such obstacles is determining the positions of receive antennas in a MIMO radar system with widely separated antennas (WS MIMO radar), since it is shown that the antennas' positions affect the whole system's performance considerably. In this study, a proper receivers' positioning procedure is proposed. To do this end, four criteria are developed based on the proposed MIMO detector and the MIMO ambiguity function. The simulations verify that the proposed positioning procedure improves the... 

Phenols and alcohols are silylated with hexamethyldisilazane (HMDS) under microwave irradiation in solvent-free condition in good to excellent yields  

Carbon capture is crucial for mitigating climate change and achieving global emissions reduction targets. Among various technologies, absorption-based methods using aqueous solvents are among the most common and efficient, offering high capture rates and retrofit capabilities for existing industrial facilities. However, selecting the optimal solvent is challenging due to its direct impact on the performance, efficiency, and cost-effectiveness of the carbon capture process. This research introduces a novel multi-class classification methodology for solvent selection in carbon capture. Leveraging a dataset of 656 data points, including features such as temperature, pressure, molar ratio, and... 

Purpose: Intensive actions implemented to alleviate poverty created many challenges. Millions of people face acute food insecurity; hence, food production needs to be increased to feed the existing and increasing population through sustainable agricultural practices. Sustainable agricultural development is the only way forward to assist humanity. Research Method: TExisting literature on sustainable agriculture was reviewed, explored, understood, described, evaluated, and synthesized and their relationships to sustain smallholder farmers were analyzed. Findings: Technological innovations in increasing resource use efficiency, modern breeding techniques, and renewable energy sources aid in...