Carbon nanotubes field effect transistors : A review

899-904Carbon nanotubes field effect transistors (CNTFETs) are one of the most promising candidates for future nanoelectronics. In this paper, the review of CNTFETs is presented. The structure, operation and the characteristics of carbon nanotubes metal-insulator-semiconductor capacitors have been discussed. The operation and dc characteristics of CNTFETs have been presented. In future, we expect the performance of CNTFETs will be better by improving CNT quality and on optimizing device structures

Toxic Potential of Synthesized Graphene Zinc Oxide Nanocomposite in the Third Instar Larvae of Transgenic Drosophila melanogaster (hsp70-lacZ)Bg9

In the present study the graphene zinc oxide nanocomposite (GZNC) was synthesized, characterized, and evaluated for its toxic potential on third instar larvae of transgenic Drosophila melanogaster (hsp70-lacZ)Bg9. The synthesized GZNC was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The GZNC in 0.1% dimethyl sulphoxide (DMSO) was sonicated for 10 minutes and the final concentrations 0.033, 0.099, 0.199, and 3.996 μg/μL of diet were established. The third instar larvae were allowed to feed on it separately for 24 and 48 hr. The hsp70 expression was measured by o-nitrophenyl-β-D-galactopyranoside assay, tissue damage was measured by trypan blue exclusion test, and β-galactosidase activity was monitored by in situ histochemical β-galactosidase staining. Oxidative stress was monitored by performing lipid peroxidation assay and total protein estimation. Ethidium bromide/acridine orange staining was performed on midgut cells for apoptotic index and the comet assay was performed for the DNA damage. The results of the present study showed that the exposure of 0.199 and 3.996 μg/μL of GZNC was toxic for both 24 hr and 48 hr of exposure. The doses of 0.033 μg/μL and 0.099 of GZNC showed no toxic effects on its exposure to the third instar larvae for 24 hr as well as 48 hr of duration

Biofabricated Silver Nanoparticles Act as a Strong Fungicide against <i>Bipolaris sorokiniana</i> Causing Spot Blotch Disease in Wheat

<div><p>The present study is focused on the extracellular synthesis of silver nanoparticles (AgNPs) using culture supernatant of an agriculturally important bacterium, <i>Serratia</i> sp. BHU-S4 and demonstrates its effective application for the management of spot blotch disease in wheat. The biosynthesis of AgNPs by <i>Serratia</i> sp. BHU-S4 (denoted as bsAgNPs) was monitored by UV–visible spectrum that showed the surface plasmon resonance (SPR) peak at 410 nm, an important characteristic of AgNPs. Furthermore, the structural, morphological, elemental, functional and thermal characterization of bsAgNPs was carried out using the X-ray diffraction (XRD), electron and atomic microscopies, energy dispersive X-ray (EDAX) spectrometer, FTIR spectroscopy and thermogravimetric analyzer (TGA), respectively. The bsAgNPs were spherical in shape with size range of ∼10 to 20 nm. The XRD and EDAX analysis confirmed successful biosynthesis and crystalline nature of AgNPs. The bsAgNPs exhibited strong antifungal activity against <i>Bipolaris sorokiniana</i>, the spot blotch pathogen of wheat. Interestingly, 2, 4 and 10 µg/ml concentrations of bsAgNPs accounted for complete inhibition of conidial germination, whereas in the absence of bsAgNPs, conidial germination was 100%. A detached leaf bioassay revealed prominent conidial germination on wheat leaves infected with <i>B. sorokiniana</i> conidial suspension alone, while the germination of conidia was totally inhibited when the leaves were treated with bsAgNPs. The results were further authenticated under green house conditions, where application of bsAgNPs significantly reduced <i>B. sorokiniana</i> infection in wheat plants. Histochemical staining revealed a significant role of bsAgNPs treatment in inducing lignin deposition in vascular bundles. In summary, our findings represent the efficient application of bsAgNPs in plant disease management, indicating the exciting possibilities of nanofungicide employing agriculturally important bacteria.</p></div

Anthelmintic Effect of Biocompatible Zinc Oxide Nanoparticles (ZnO NPs) on Gigantocotyle explanatum, a Neglected Parasite of Indian Water Buffalo.

Helminth parasites of veterinary importance cause huge revenue losses to agrarian economy worldwide. With the emergence of drug resistance against the current formulations, there is a need to focus on the alternative approaches in order to control this menace. In the present study, biocompatible zinc oxide nanoparticles (ZnO NPs) were used to see their in vitro effect on the biliary amphistomes, Gigantocotyle explanatum, infecting Bubalus bubalis because these nanoparticles are involved in generation of free radicals that induce oxidative stress, resulting in disruption of cellular machinery. The ZnO NPs were synthesized by using egg albumin as a biotemplate and subsequently characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Diffraction and Spectrophotometrical, which showed that ZnO NPs were highly purified wurtzite type polycrystals, with a mean size of 16.7 nm. When the parasites were treated with lower concentrations (0.004% and 0.008%) of the ZnO NPs, the worms mounted a protective response by stimulating the antioxidant system but the treatment of G. explanatum with 0.012% ZnO NPs produced significant inhibition of the antioxidant enzymes like superoxide dismutase (SOD) (p< 0.05) and glutathione S- transferase (GST) (p<0.01), while the level of malondialdehyde (MDA), a lipid peroxidation marker, was significantly (p< 0.01) elevated. SEM and histopathology revealed pronounced tegumental damage showing the disruption of surface papillae and the annulations, particularly in the posterior region near acetabulum. The under expression of a number of polypeptides, loss of worm motility in a time dependent manner, further reflect strong anthelmintic potential of ZnO NPs. It can be concluded that the anthelmintic effect might be due to the production of reactive oxygen species that target a variety of macromolecules such as nucleic acid, protein and lipids which are involved in different cellular processes

Kinetic Study on Mutagenic Chemical Degradation through Three Pot Synthesiszed Graphene@ZnO Nanocomposite

<div><p>The study was taken up with the objective to synthesize graphene-zinc oxide nano particles (NPs) nanocomposite (Gr@ZnO-Nc) via <i>In-situ</i> synthesis method. The structural, optical, thermal, electrical and photocatalytic properties of the synthesized Gr@ZnO-Nc were studied. The characterization data confirmed that the ZnO NPs were successfully incorporated into the graphene sheets. Further, TGA/DTA results exhibited an enhanced thermal stability of the Gr@ZnO-Nc compared with the graphene. The Gr@ZnO-Nc, graphene sheets were uniformly wrapped by ZnO NPs, which can protect graphene and delay their oxidation in air. The synthesized Gr@ZnO-Nc was used for the efficient photodegradation of a carcinogenic methyl orange (MO) dye. The results exhibited promising photodegradation of the MO dye under UV light irradiation through the production of reactive oxygen species (ROS). The promising effect of Gr@ZnO-Nc on the photodegradation properties was conferred by the large surface area which increased adsorption capacity, and the strong electron transfer ability. Thus, it is encouraging to conclude that the synthesized Gr@ZnO-Nc has environmental significance with its utility in remediation in the hazardous MO dye.</p></div

Biosynthesis of Stable Antioxidant ZnO Nanoparticles by <i>Pseudomonas aeruginosa</i> Rhamnolipids

<div><p>During the last several years, various chemical methods have been used for synthesis of a variety of metal nanoparticles. Most of these methods pose severe environmental problems and biological risks; therefore the present study reports a biological route for synthesis of zinc oxide nanoparticles using <i>Pseudomonas aeruginosa</i> rhamnolipids (RLs) (denoted as <a href="mailto:RL@ZnO" target="_blank">RL@ZnO</a>) and their antioxidant property. Formation of stable <a href="mailto:RL@ZnO" target="_blank">RL@ZnO</a> nanoparticles gave mostly spherical particles with a particle size ranging from 35 to 80 nm. The <a href="mailto:RL@ZnO" target="_blank">RL@ZnO</a> nanoparticles were characterized by UV-visible (UV–vis) spectroscopy, scanning electron microscopy, transmission electron microscopy, dynamic light scattering, Fourier transform infrared spectroscopy, X-ray diffraction (XRD), and thermal gravimetric analysis. The UV–vis spectra presented a characteristic absorbance peak at ∼360 nm for synthesized <a href="mailto:RL@ZnO" target="_blank">RL@ZnO</a> nanoparticles. The XRD spectrum showed that <a href="mailto:RL@ZnO" target="_blank">RL@ZnO</a> nanoparticles are crystalline in nature and have typical wurtzite type polycrystals. Antioxidant potential of <a href="mailto:RL@ZnO" target="_blank">RL@ZnO</a> nanoparticles was assessed through 2,2–diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, and superoxide anion free radicals with varying concentration and time of the storage up to 15 months, while it was found to decline in bare ZnO nanoparticles. Similarly, the inhibitory effects on β-carotene oxidation and lipid peroxidation were also observed. These results elucidate the significance of <i>P</i>. <i>aeruginosa</i> RL as effective stabilizing agents to develop surface protective ZnO nanoparticles, which can be used as promising antioxidants in biological system.</p></div

Inhibitory effects of bsAgNPs by <i>Serratia</i> sp. BHU-S4 on conidial germination of <i>B. sorokiniana</i> after 24 h as determined by cavity slide experiment.

<p>Conidial germination in control set (without bsAgNPs) was prominent as indicated by arrow (A). Detached leaf assay showing conidial germination over leaf surface in pathogen treated leaf (BC), while in presence of bsAgNPs (B4) conidial germination was totally inhibited (B).</p

Effect of different treatments on lignification in wheat stem by histochemical staining.

<p>Control (C), <i>Bipolaris</i> control (BC); <i>Bipolaris</i> + bsAgNPs by <i>Serratia</i> sp. BHU-S4 (B4).</p