Comparative study of 2mol%Li-and Mn-substituted lead-free potassium sodium niobate ceramics

The effect of Li and Mn substitution on the dielectric, ferroelectric and piezoelectric properties of lead free K0.5Na0.5NbO3 （KNN） was investigated. Samples were prepared using a conventional solid state reaction method. The sintefing temperature for all the samples was 1050℃. The optimum doping concentration for the enhancement of different properties without the introduction of any other co-dopants such as Ti, Sb, and La was investigated. X-ray diffraction analysis confirmed that all the samples crystallize in a single phase perovskite structure. The dielectric properties were investigated as a function of temperature and applied electric field frequency. Compared with Li-substituted KNN （KLNN）, Mn-substituted KNN （KMNN） exhibited a higher dielectric constant εmax （i.e., 4840） at its critical transition temperature Tc （i.e., 421℃） along with a lower value of tangent loss at 10 kHz and greater values of saturation polarisation Ps （i.e., 20.14 μC/cm^2） and remnant polarisation Pr （i.e., 15.48 μC/cm^2）. The piezoelectric constant （d33） of KMNN was 178 pC/N, which is comparable to that of lead-based hard ceramics. The results presented herein suggest that B-site or Mn substitution at the optimum concentration results in good enhancement of different properties required for materials used in memory devices and other applications.     

Low standby leakage 12T SRAM cell characterisation

In this work, a low power and variability-aware static random access memory (SRAM) architecture based on a twelve-transistor (12T) cell is proposed. This cell obtains low static power dissipation due to a parallel global latch (G-latch) and storage latch (S-latch), along with a global wordline (GWL), which offer a high cell ratio and pull-up ratio for reliable read and write operations and a low cell ratio and pull-up ratio during idle mode to reduce the standby power dissipation. In the idle state, only the S-latch stores bits, while the G-latch is isolated from the S-latch and the GWL is deactivated. The leakage power consumption of the proposed SRAM cell is thereby reduced by 38.7% compared to that of the conventional six-transistor (6T) SRAM cell. This paper evaluates the impact of the chip supply voltage and surrounding temperature variations on the standby leakage power and observes considerable improvement in the power dissipation. The read/write access delay, read static noise margin (SNM) and write SNM were evaluated, and the results were compared with those of the standard 6T SRAM cell. The proposed cell, when compared with the existing cell using the Monte Carlo method, shows an appreciable improvement in the standby power dissipation and layout area.     

Ex Vivo Human Colon Tissue Exposure to Pristine Graphene Activates Genes Involved in the Binding,Adhesion and Proliferation of Epithelial Cells

Toxicology studies on pristine graphene are limited and lack significant correlations with actual human response. The goal of the current study was to determine the response of total colonic human tissue to pristine graphene exposure. Biopsy punches of colon tissues from healthy human were used to assess the biological response after ex vivo exposure to graphene at three different concentrations (1, 10, and 100 µg/mL). mRNA expression of specific genes or intestinal cytokine abundance was assessed using real-time PCR or multiplex immunoassays, respectively. Pristine graphene-activated genes that are related to binding and adhesion (GTPase and KRAS) within 2 h of exposure. Furthermore, the PCNA (proliferating cell nuclear antigen) gene was upregulated after exposure to graphene at all concentrations. Ingenuity pathway analysis revealed that STAT3 and VEGF signaling pathways (known to be involved in cell proliferation and growth) were upregulated. Graphene exposure (10 µg/mL) for 24 h significantly increased levels of pro-inflammatory cytokines IFNγ, IL-8, IL-17, IL-6, IL-9, MIP-1α, and Eotaxin. Collectively, these results indicated that graphene may activate the STAT3–IL23–IL17 response axis. The findings in this study provide information on toxicity evaluation using a human-relevant ex vivo colon model and serve as a basis for further exploration of its bio-applications.     

Systematic Surface Engineering of Magnetic Nanoworms for In vivo Tumor Targeting

In the design of nanoparticles that can target disease tissue in vivo, parameters such as targeting ligand density, type of target receptor, and nanoparticle shape can play an important role in determining the extent of accumulation. Herein, a systematic study of these parameters for the targeting of mouse xenograft tumors is performed using superparamagnetic iron oxide as a model nanoparticle system. The type of targeting peptide (recognizing cell surface versus extracellular matrix), the surface coverage of the peptide, its attachment chemistry, and the shape of the nanomaterial [elongated (nanoworm, NW) versus spherical (nanosphere, NS)] are varied. Nanoparticle circulation times and in vivo tumor‐targeting efficiencies are quantified in two xenograft models of human tumors (MDA‐MB‐435 human carcinoma and HT1080 human fibrosarcoma). It is found that the in vivo tumor‐targeting ability of the NW is superior to that of the NS, that the smaller, neutral CREKA targeting group is more effective than the larger, positively charged F3 molecule, that a maximum in tumor‐targeting efficiency and blood half‐life is observed with ≈60 CREKA peptides per NW for either the HT1080 or the MDA‐MB‐435 tumor types, and that incorporation of a 5‐kDa polyethylene glycol linker improves targeting to both tumor types relative to a short linker. It is concluded that the blood half‐life of a targeting molecule–nanomaterial ensemble is a key consideration when selecting the appropriate ligand and nanoparticle chemistry for tumor targeting.     

Optimized area efficient quantum dot cellular automata based reversible code converter circuits: design and energy performance estimation

The Journal of Supercomputing - Quantum-dot cellular automata (QCA) based circuit designs are creating a surge in transistorless computational technologies. Due to its quasi-adiabatic switching...     

Silicon-On-Nothing Electrostatically Doped Junctionless Tunnel Field Effect Transistor (SON-ED-JLTFET): A Short Channel Effect Resilient Design

Silicon - This work investigates the novel device structure, silicon-on-nothing electrostatically doped junctionless tunnel field effect transistor (SON-ED-JLTFET) with high-K stacked hetero-gate...     

Tertiary recycling of waste plastic using catalytic cracking into crude oil

Disposal of waste plastic and excessive use of fossil fuels have caused environmental problems in the world. According to an estimate, more than 100 million tonnes plastics are produced every year and after their usage these plastics are discarded to become waste. Both plastic- and petroleum-derived fuels are hydrocarbons that contain the elements of carbon and hydrogen. The main difference between these hydrocarbons is that plastic molecules have longer carbon chains than those of LPG, petrol and diesel fuels. Therefore, it is possible to convert waste plastic into fuels. Pyrolysis is a prospective method to handle waste plastics. The purpose of this study is to explore the ability of different types of catalysts in conversion of plastic waste to low-emissive hydrocarbon fuel. Pyrolysis experiments were conducted using three different catalysts to check their ability in increasing the production. Catalytic degradation with potato peels yielded 74.52 wt% liquid fuel product. So far, the use of potato peels as a biocatalyst in pyrolysis process has not been reported. The pyrolysis oil was analyzed by GC/MS to determine its elemental composition. The liquid products obtained were compatible with international standards. Therefore, two main global problems such as problem of waste plastic management and problem of shortage of fuel are being tackled together.     

Role-Based Channel Hopping Algorithm for a Cognitive Radio Network in Asynchronous Environment

Wireless Personal Communications - Cognitive radio network (CRN) has been recognized by researchers to solve the spectrum shortage problem, where the unlicensed users opportunistically exploit the...     

Rapid casting of patterned vascular networks for perfusable engineered three-dimensional tissues

In the absence of perfusable vascular networks, three-dimensional (3D) engineered tissues densely populated with cells quickly develop a necrotic core. Yet the lack of a general approach to rapidly construct such networks remains a major challenge for 3D tissue culture. Here, we printed rigid 3D filament networks of carbohydrate glass, and used them as a cytocompatible sacrificial template in engineered tissues containing living cells to generate cylindrical networks that could be lined with endothelial cells and perfused with blood under high-pressure pulsatile flow. Because this simple vascular casting approach allows independent control of network geometry, endothelialization and extravascular tissue, it is compatible with a wide variety of cell types, synthetic and natural extracellular matrices, and crosslinking strategies. We also demonstrated that the perfused vascular channels sustained the metabolic function of primary rat hepatocytes in engineered tissue constructs that otherwise exhibited suppressed function in their core.