Sharif Digital Repository

A set of small battery-operated sensors with low-power transceivers that can automatically form a network and collect some desired physical characteristics of the environment is called a wireless sensor network. The communications must be designed to conserve the limited energy resources of the sensors [14].By clustering sensors we can save energy. In this paper, we introduce a new concept called "Center of Energy Mass" which is a combination of both energy level and location of the nodes which is used to form the new factor of "distance of the nodes to the CEM ".Distance of the nodes to the CEM is used together with Probability Density Function of the normal distribution in optimizing... 

Fragile data hiding has been extensively used for secure transmission of the sensitive data using cover images, audios and videos. In the past decade, increasingly the remote sensing applications require transmission and archiving of large number of aerial images and videos. Storage and processing of remote sensing data in the public cloud computing and storage platforms, with servers outside the control of the data owners, requires sufficient attention to persevering the privacy of the data. Furthermore, in the past few years the applications of drones and unmanned aerial vehicles demand algorithms designed especially for low altitude remote sensing data. In this paper, a novel fragile data... 

Fragile data hiding has been extensively used for secure transmission of the sensitive data using cover images, audios and videos. In the past decade, increasingly the remote sensing applications require transmission and archiving of large number of aerial images and videos. Storage and processing of remote sensing data in the public cloud computing and storage platforms, with servers outside the control of the data owners, requires sufficient attention to persevering the privacy of the data. Furthermore, in the past few years the applications of drones and unmanned aerial vehicles demand algorithms designed especially for low altitude remote sensing data. In this paper, a novel fragile data... 

In this paper, a fast phoneme recognition system is introduced based on sparse representation. In this approach, the phoneme recognition is fulfilled by Viterbi decoding on support vector machines (SVM) output probability estimates. The candidate classes for classification are adaptively pruned by a k-dimensional (KD) tree search followed by a sparse representation (SR) based class selector with adaptive number of classes. We applied the proposed approach to introduce a phoneme recognition system and compared it with some well-known phoneme recognition systems according to accuracy and complexity issues. By this approach, we obtain competitive phoneme error rate with promising computational... 

Although exemplar based approaches have shown good accuracy in classification problems, some limitations are observed in the accuracy of exemplar based automatic speech recognition (ASR) applications. The main limitation of these algorithms is their high computational complexity which makes them difficult to extend to ASR applications. In this paper, an N-best class selector is introduced based on sparse representation (SR) and a tree search strategy. In this approach, the classification is fulfilled in three steps. At first, the set of similar training samples for the specific test sample is selected by k-dimensional (KD) tree search algorithm. Then, an SR based N-best class selector is... 

Printing technologies have opened larger windows of innovation and creativity to biomaterials engineers by providing them with the ability to fabricate complex shapes in a reasonable time, cost, and weight. However, there has always been a trouble with function adjusting in printing technologies in view of the multiplicity of materials and apparatus parameters. 3D printing, also known as additive manufacturing, revolutionized biomaterials engineering by the conversion of a digital subject into a printed object (implants, scaffolds, or diagnostics and drug delivery devices/systems). Inspired by the lessons learned from 3D printing, the concept of 4D printing (better called shape-morphing... 

The composition and topology of metal-organic frameworks (MOFs) are exceptionally tailorable; moreover, they are extremely porous and represent an excellent Brunauer–Emmett–Teller (BET) surface area (≈3000–6000 m2·g−1). Nanoscale MOFs (NMOFs), as cargo nanocarriers, have increasingly attracted the attention of scientists and biotechnologists during the past decade, in parallel with the evolution in the use of porous nanomaterials in biomedicine. Compared to other nanoparticle-based delivery systems, such as porous nanosilica, nanomicelles, and dendrimer-encapsulated nanoparticles, NMOFs are more flexible, have a higher biodegradability potential, and can be more easily functionalized to meet... 

Progress in tissue engineering and regenerative medicine necessitates the use of novel materials with promising bio-surface for biomedical applications. In this work, TixNy thin films are applied on biological TC4 substrates in a mixed atmosphere of Ar and N2 via magnetron sputtering system for the protection of TC4 alloy. The effects of N/Ti ratio on the phase structure, growth orientation, contact angle, and the mechanical and corrosion performances of thin films are discussed by implementation of composition-microstructure-property interrelationships. The phase structure of TixNy thin films is changed from amorphous-like to single phase Ti2N structure with increasing N/Ti ratio. In the... 

Natural and biodegradable polymers are of particular interest as green sources with low-cost and environmentally friendly features, and have been widely used for polymer composite development. The term “Green Composites” refers to polymer/filler systems in which polymer, filler, or sometimes both components are green in view of sources from which they are yielded or their biodegradability. Natural fibers obtained from plants, animals, and/or geological processes are a big class of green sources widely applied in green composite development. There has also been continued research on recycling of green composite as well as developing hybrid systems for advanced applications. In view of their... 

Natural and biodegradable polymers are of particular interest as green sources with low-cost and environmentally friendly features, and have been widely used for polymer composite development. The term “Green Composites” refers to polymer/filler systems in which polymer, filler, or sometimes both components are green in view of sources from which they are yielded or their biodegradability. Natural fibers obtained from plants, animals, and/or geological processes are a big class of green sources widely applied in green composite development. There has also been continued research on recycling of green composite as well as developing hybrid systems for advanced applications. In view of their... 

MOFs exhibit inherent extraordinary features for diverse applications ranging from cataly-sis, storage, and optics to chemosensory and biomedical science and technology. Several procedures including solvothermal, hydrothermal, mechanochemical, electrochemical, and ultrasound techniques have been used to synthesize MOFs with tailored features. A continued attempt has also been directed towards functionalizing MOFs via “post-synthetic modification” mainly by changing linkers (by altering the type, length, functionality, and charge of the linkers) or node components within the MOF framework. Additionally, efforts are aimed towards manipulating the size and morphology of crystallite domains in... 

In this work, a green synthesis method was designed and practiced to develop bioactive and biocompatible carbon-based nanocomposites biomaterials. ZnO nanoparticles were synthesized in assistance of leaf extracts and added to a composite nanostructure composed of the reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNT). The resulting green nanocomposite revealed ability to make π-π interactions, hydrogen bonding, and van der Waals interactions with the doxorubicin (DOX). Then, the surface morphology of the synthesized nanocomposite was investigated, and the interrelationship between the surface morphology, relative cell viability, and drug uptake and release behavior were... 

In this work, a green synthesis method was designed and practiced to develop bioactive and biocompatible carbon-based nanocomposites biomaterials. ZnO nanoparticles were synthesized in assistance of leaf extracts and added to a composite nanostructure composed of the reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNT). The resulting green nanocomposite revealed ability to make π-π interactions, hydrogen bonding, and van der Waals interactions with the doxorubicin (DOX). Then, the surface morphology of the synthesized nanocomposite was investigated, and the interrelationship between the surface morphology, relative cell viability, and drug uptake and release behavior were... 

A one-pot synthesis method was conceptualized and implemented to develop green carbon-based nanocomposites working as biosensors. Porphyrin was synthesized to adorn the surface of nanocomposites making them highly sensitive for giving rise to π-π interactions between the genetic materials, proteins and porphyrin rings. The hydrogen bond formed between the proteins (analytes) and the nitrogen in the porphyrin structure as well as the surface hydroxyl groups was equally probable. In this context, different forms of porphyrins were incorporated to explore the interrelationship between the surface morphology and the ability of detection of genetic material and/or proteins by the aid of the... 

The advent of computer-aided concepts and cognitive algorithms, along with fuzzy sets and fuzzy logic thoughts, supported the idea of ‘making computers think like people’ (Lotfi A. Zadeh, IEEE Spectrum, 21 (26–32), 1984). Such a school of thought enabled the sophistication of mission-oriented development of biomaterials and biosystems with the aid of ‘Artificial Intelligence’ (AI). Since polysaccharides (PSA) are medically safe and rely on stimuli-responsiveness, we herein highlight the importance of using AI-based algorithms in PSA-based biomedical engineering. Since manufacturing PSA-based biomaterials by AI experiences a very early stage of maturity, pattern recognition and behavior... 

A one-pot and facile method with assistance of high gravity was applied for the synthesis of inorganic two-dimensional MOF-5 embedded MXene nanostructures. The innovative inorganic MXene/MOF-5 nanostructure was applied in co-delivery of drug and gene, and to increase its bioavailability and interaction with the pCRISPR, the nanomaterial was coated with alginate and chitosan. The polymer-coated nanosystems were fully characterized, and the sustained DOX delivery and comprehensive cytotoxicity studies were conducted on the HEK-293, PC12, HepG2, and HeLa cell lines, demonstrating acceptable and excellent cell viability at both very low (0.1 μg.mL-1) and high (10 μg·mL-1) concentrations. The... 

Tissue adhesives have been widely used for preventing wound leaks, sever bleeding, as well as for enhancing drug delivery and biosensing. However, only a few among suggested platforms cover the circumstances required for high-adhesion strength and biocompatibility, without toxicity. Antibacterial properties, controllable degradation, encapsulation capacity, detectability by image-guided procedures and affordable price are also centered to on-demand tissue adhesives. Herein we overview the history of tissue adhesives, different types of polysaccharide-based tissue adhesives, their mechanism of gluing, and different applications of polysaccharide-based tissue adhesives. We also highlight the... 

3D printing is a state-of-the-art technology for the fabrication of biomaterials with myriad applications in translational medicine. After stimuli-responsive properties were introduced to 3D printing (known as 4D printing), intelligent biomaterials with shape configuration time-dependent character have been developed. Polysaccharides are biodegradable polymers sensitive to several physical, chemical, and biological stimuli, suited for 3D and 4D printing. On the other hand, engineering of mechanical strength and printability of polysaccharide-based scaffolds along with their aneural, avascular, and poor metabolic characteristics need to be optimized varying printing parameters. Multiple... 

Performances of small- and large-pore, porous graphene nanomembranes (PGNMs) (pristine and functionalized by amide, sulfonic acid, thiourea, and carbamate functional groups) for purification of heavy metal ions and nitrate-contaminated wastewater were determined using molecular dynamics (MD) simulation. At the operational conditions of the simulated membrane (150 and 0.1 MPa pressure on the left and right piston sides at 300 K), higher water flow rates were obtained in the functionalized PGNMs possessing large pores, as opposed to the non-functionalized and small-pore ones. Amide-functionalized PGNM provided the highest flow rate (380 and 330 molecules/ns for large and small pores,...