bashis De

Biogenic synthesis of silver nanoparticles from Cassia fistula (Linn.): In vitro assessment of their antioxidant, antimicrobial and cytotoxic activities

The present study reports on biogenic-synthesised silver nanoparticles (AgNPs) derived by treating Ag ions with an extract of Cassia fistula leaf, a popular Indian medicinal plant found in natural habitation. The progress of biogenic synthesis was monitored time to time using a ultraviolet-visible spectroscopy. The effect of phytochemicals present in C. fistula including flavonoids, tannins, phenolic compounds and alkaloids on the homogeneous growth of AgNPs was investigated by Fourier-transform infrared spectroscopy. The dynamic light scattering studies have revealed an average size and surface Zeta potential of the NPs as, -39.5 nm and -21.6 mV, respectively. The potential antibacterial and antifungal activities of the AgNPs were evaluated against Bacillus subtilis, Staphylococcus aureus, Candida kruseii and Trichophyton mentagrophytes. Moreover, their strong antioxidant capability was determined by radical scavenging methods (1,1-diphenyl-2-picryl-hydrazil assay). Furthermore, the AgNPs displayed an effective cytotoxicity against A-431 skin cancer cell line by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, with the inhibitory concentration (IC50) predicted as, 92.2 ± 1.2 μg/ml. The biogenically derived AgNPs could find immense scope as antimicrobial, antioxidant and anticancer agents apart from their potential use in chemical sensors and translational medicine.

C2OF2N: a low power cooperative code offloading method for femtolet-based fog network

Power and delay aware cloud service provisioning to mobile devices has become a promising domain today. This paper proposes and implements a cooperative offloading approach for indoor mobile cloud network. In the proposed work mobile devices register under femtolet which is a home base station with computation and data storage facilities. The resources of the mobile devices are collaborated in such a way that different mobile devices can execute different types of computations based on cooperative federation. The proposed offloading scheme is referred as cooperative code offloading in femtolet-based fog network. If none of the mobile device can execute the requested computation, then femtolet executes the computation. Use of femtolet provides the mobile devices voice call service as well as cloud service access. Femtolet is used as the fog device in our approach. The proposed model is simulated using Qualnet version 7. The simulation results demonstrate that the proposed scheme minimizes the energy by 15% and average delay up to 12% approximately than the existing scheme. Hence, the proposed model is referred as a low power offloading approach.

Atomic scale modeling of electrically doped p-i-n FET from adenine based single wall nanotube

The Field Effect Transistor (FET) characteristics has been observed from a single-walled Adenine nanotube device using Density Functional Theory associated with Non Equilibrium Greens Function based First Principle approach. This device is electrically doped which shows both n and p channel characteristics of a p-i-n FET. This device is designed and originated from a single-walled biomolecular nanotube structure. The p and n regions have been induced at the two ends of the device using electrical doping process. Thus both n and p channel current-voltage response can be obtained within a single nano-scale device at room temperature operation. The device is 3.35nm long and 1.4nm wide. The quasi-ballistic quantum transmission property reveals impressive and almost ideal current-voltage characteristics of the FET. Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) gap reveals the possibility of quasi-ballistic coherent transmission of the device. The electronic properties based on Molecular Projected Self-consistent Hamiltonian are analyzed using Hilbert space spanned basis functions. The maximum tunneling current observed for the bio-molecular FET is 15.9μA for n-channel and 13.8μA for p-channel. The device is operated in atomic scale regime with 1000THz frequency. The present results reveal the role of quantum-ballistic tunneling phenomenon in the current-voltage characteristics and channel conductance properties of the bio nanotube structure, which is useful in future generation nano-electronics.

An Automated Malicious Host Recognition Model in Cloud Forensics

Cloud forensics is the new emerging science where traditional digital forensics methodology and cloud computational intelligence have been blended in such a way that all the malicious cloud criminals can be identified and punished in a justified manner. The distributed and black-box architecture of the cloud has faded the concept of examining each and every local host to identify proper malicious actors. Here, an obvious demand of an automated criminal recognition model has come into play. This paper mainly focuses on this legitimate demand of cloud forensic investigators by proposing a Cloud Malicious Actor Identifier model. This model identifies the malicious actors related to a particular crime scene and ranks them according to their probability of being malicious using a very well-known machine learning technique, Boosting. The main purpose of this model is to mitigate the overhead of probing each and every IP address while investigation. The performance evaluation of the proposed model has also been explained with logical explanation and achieved output.

An efficient design of left shifter in quantum cellular automata

Quantum-dot Cellular Automata (QCA) is one of the rapidly growing nano-electronic computing technology. QCA is based on electron presents in quantum dots. QCA technology have features on high density, low power and smallest design compare to the other technologies. This paper proposed the basic paradigm of an efficient design of a 4-bit binary Logical Left Shifter circuit for single shift as well as multiple shifts. Due to inherent nature, QCA has been utilized in this paper to achieve low power faster circuit for proposed design. These shifter circuits are useful in floating point processing systems, particularly very useful for mantissa multiplication technique. All the designs are implemented with QCADesigner tool. The accuracy is verified comparing theoretical values and corresponding simulation results.

Nano-Router Design for Nano-Communication in Single Layer Quantum Cellular Automata

Quantum dot Cellular Automata(QCA) is a new electronics paradigm for information technology and communication. It has been recognized as one of the revolutionary nano-scale computing devices. In this work, we have selected few basic gates using QCA to develop a 4: 4 router. The main function of this design is to transfer information from four input ports through a DEMUX and receive this information at the four different receiver port. The information that has been provided is being routed via crossbar in the present study. We use a parallel to serial converter to receive the information at the receiver port. This router has been implemented with less clock delay and less QCA, which results into an efficient router comparing to any other router. This Nano-router can be used for distributed computing. The QCA Designer Software is used for designing and simulating the circuits.

Design and Electronic Characterization of Bio-Molecular QCA: A First Principle Approach

Molecular Quantum-dot Cellular Automata is the most promising and challenging technology nowadays for its high operating frequency, extremely high device density and non-cryogenic working temperature. In this paper, we report a First Principle approach based on analytical model of 3-dot Bio Molecular Quantum-dot Cellular Automata. The device is 19.62Å long and this bio molecular Quantum dot Cell has been made with two Adenine Nucleotide bio-molecules along with one Carbazole and one Thiol group. This whole molecular structure is supported onto Gold substrate. In this paper, two Adenine Nucleotides act as two quantum dots and Carbazole acts as another dot. These 3-Quantum-dots are mounted in a tree like structure supported with Thiol group. This model has been demonstrated with Extended Hückel Theory based semi-empirical method. The quantum ballistic transmission and HOMO-LUMO plot support the polarization state change. This state changing ability has been observed for this molecular device. Therefore, this property has been investigated and reported in this paper. HOMO-LUMO plot shows the two logic states along with null state for this 3-dots system. This phenomenon illustrates how the charge transfers take place. Two polarization states along with one additional null state have been obtained for this bio molecular nano device. This molecular device has been operated with 1000THz frequency. This nanoscale design approach will initiate one step towards the modeling of high frequency bio molecular Quantum dot Cell at room temperature.

First principle study of structural and electronic transport properties of zigzag GaAs SWNT

The structural and electronic transport properties of the zigzag single walled GaAs nanotube has been investigated using the combination of Density Functional Theory conjugated with Non Equilibrium Greens Function based First Principle approach. The quantum mechanical transmission and tunneling current have been investigated for two different chiralities nanotubes. These results prove that these parameters depend on the diameter of the nanotube. The analysis shows that the quantum mechanical energy and current increases with the increasing diameter of the tube. Though the bond length increases with the increasing diameter of the nanotube, but still the amount of total energy received for (4, 0) confirms the stability of the GaAs nanotubes with high chiralities.

Design of resistor string digital to analog converter using nano dimensional MOS transistor for low power and high speed circuit application

In this work the design of resistor string based digital to analog converter (DAC) using nano dimensional metal oxide semiconductor field effect transistor (MOSFET) has been demonstrated. Two bit binary word is taken as input digital data. Analog values corresponding to digital data are passes through transmission gate (TG) to output terminal. In order to clarify the functionality of the DAC, power supply voltage VDD varied from 0.5 volt to 1.2 volt. The satisfactory analog output corresponds to binary data indicates the correctness in design of the DAC. Average power consumption, conversion delay and power delay product(PDP) of the DAC is also presented in this work. The results are satisfactory context to low power and high speed very large scale integrated (VLSI) circuit application. The circuit of the DAC has been designed at 150nm channel length of MOS transistor using Tanner SPICE (T-SPICE) software.

Observation of the unconventional optoelectronic properties of silicon conjugated graphene nanosheets

Graphene has been realized for its significant physico-chemical properties. The extraordinary surface area and high electronical conductivity of graphene makes it a potential candidate in the field of nanoelectronics and sensors. In this study, graphene has been conjugated with silicon and its different physical and chemical properties were evaluated. The total energy of the composite system came out to be −6111.62 eV. Chemical potential of the composite system exhibits ∼ 5.64 eV. DOS calculations for composite of silicon and graphene came out to be ∼ 17 eV−1 for the applied bias voltage of 40 eV, as when compared to higher values of DOS for monolayer silicon and graphene nanosheets. Silicon is widely known to exhibit semiconducting behavior and has already been used in fabricating various CMOS devices. In this present work, we try to study the outcome of the conjugation of graphene nanosheets with silicon nanosheets in different combinations. Understanding the interactions between two semiconducting materials could shed some light in the underlying physical and chemical interaction which would help in devising novel optoelectronic systems.